]> git.sesse.net Git - movit/blobdiff - effect_chain.cpp
Remove some unneeded conversions from ResampleEffect. Speeds up texture generation...
[movit] / effect_chain.cpp
index 22ba189013d0961dcd00f10212a3abca6309875e..efd4abc49a611c233164089858d586a0538d075b 100644 (file)
@@ -1,8 +1,5 @@
-#define GL_GLEXT_PROTOTYPES 1
-
-#include <GL/glew.h>
+#include <epoxy/gl.h>
 #include <assert.h>
-#include <locale.h>
 #include <math.h>
 #include <stddef.h>
 #include <stdio.h>
@@ -13,6 +10,7 @@
 #include <stack>
 #include <utility>
 #include <vector>
+#include <Eigen/Core>
 
 #include "alpha_division_effect.h"
 #include "alpha_multiplication_effect.h"
 #include "dither_effect.h"
 #include "effect.h"
 #include "effect_chain.h"
+#include "effect_util.h"
 #include "gamma_compression_effect.h"
 #include "gamma_expansion_effect.h"
 #include "init.h"
 #include "input.h"
 #include "resource_pool.h"
 #include "util.h"
+#include "ycbcr_conversion_effect.h"
 
+using namespace Eigen;
 using namespace std;
 
 namespace movit {
@@ -34,16 +35,31 @@ namespace movit {
 EffectChain::EffectChain(float aspect_nom, float aspect_denom, ResourcePool *resource_pool)
        : aspect_nom(aspect_nom),
          aspect_denom(aspect_denom),
+         output_color_rgba(false),
+         num_output_color_ycbcr(0),
          dither_effect(NULL),
+         ycbcr_conversion_effect_node(NULL),
+         intermediate_format(GL_RGBA16F),
+         intermediate_transformation(NO_FRAMEBUFFER_TRANSFORMATION),
          num_dither_bits(0),
+         output_origin(OUTPUT_ORIGIN_BOTTOM_LEFT),
          finalized(false),
-         resource_pool(resource_pool) {
+         resource_pool(resource_pool),
+         do_phase_timing(false) {
        if (resource_pool == NULL) {
                this->resource_pool = new ResourcePool();
                owns_resource_pool = true;
        } else {
                owns_resource_pool = false;
        }
+
+       // Generate a VBO with some data in (shared position and texture coordinate data).
+       float vertices[] = {
+               0.0f, 2.0f,
+               0.0f, 0.0f,
+               2.0f, 0.0f
+       };
+       vbo = generate_vbo(2, GL_FLOAT, sizeof(vertices), vertices);
 }
 
 EffectChain::~EffectChain()
@@ -59,6 +75,8 @@ EffectChain::~EffectChain()
        if (owns_resource_pool) {
                delete resource_pool;
        }
+       glDeleteBuffers(1, &vbo);
+       check_error();
 }
 
 Input *EffectChain::add_input(Input *input)
@@ -72,8 +90,50 @@ Input *EffectChain::add_input(Input *input)
 void EffectChain::add_output(const ImageFormat &format, OutputAlphaFormat alpha_format)
 {
        assert(!finalized);
+       assert(!output_color_rgba);
+       output_format = format;
+       output_alpha_format = alpha_format;
+       output_color_rgba = true;
+}
+
+void EffectChain::add_ycbcr_output(const ImageFormat &format, OutputAlphaFormat alpha_format,
+                                   const YCbCrFormat &ycbcr_format, YCbCrOutputSplitting output_splitting,
+                                   GLenum output_type)
+{
+       assert(!finalized);
+       assert(num_output_color_ycbcr < 2);
        output_format = format;
        output_alpha_format = alpha_format;
+
+       if (num_output_color_ycbcr == 1) {
+               // Check that the format is the same.
+               assert(output_ycbcr_format.luma_coefficients == ycbcr_format.luma_coefficients);
+               assert(output_ycbcr_format.full_range == ycbcr_format.full_range);
+               assert(output_ycbcr_format.num_levels == ycbcr_format.num_levels);
+               assert(output_ycbcr_format.chroma_subsampling_x == 1);
+               assert(output_ycbcr_format.chroma_subsampling_y == 1);
+               assert(output_ycbcr_type == output_type);
+       } else {
+               output_ycbcr_format = ycbcr_format;
+               output_ycbcr_type = output_type;
+       }
+       output_ycbcr_splitting[num_output_color_ycbcr++] = output_splitting;
+
+       assert(ycbcr_format.chroma_subsampling_x == 1);
+       assert(ycbcr_format.chroma_subsampling_y == 1);
+}
+
+void EffectChain::change_ycbcr_output_format(const YCbCrFormat &ycbcr_format)
+{
+       assert(num_output_color_ycbcr > 0);
+       assert(output_ycbcr_format.chroma_subsampling_x == 1);
+       assert(output_ycbcr_format.chroma_subsampling_y == 1);
+
+       output_ycbcr_format = ycbcr_format;
+       if (finalized) {
+               YCbCrConversionEffect *effect = (YCbCrConversionEffect *)(ycbcr_conversion_effect_node->effect);
+               effect->change_output_format(ycbcr_format);
+       }
 }
 
 Node *EffectChain::add_node(Effect *effect)
@@ -88,6 +148,8 @@ Node *EffectChain::add_node(Effect *effect)
        node->output_color_space = COLORSPACE_INVALID;
        node->output_gamma_curve = GAMMA_INVALID;
        node->output_alpha_type = ALPHA_INVALID;
+       node->needs_mipmaps = false;
+       node->one_to_one_sampling = false;
 
        nodes.push_back(node);
        node_map[effect] = node;
@@ -149,6 +211,22 @@ void EffectChain::insert_node_between(Node *sender, Node *middle, Node *receiver
        assert(middle->incoming_links.size() == middle->effect->num_inputs());
 }
 
+GLenum EffectChain::get_input_sampler(Node *node, unsigned input_num) const
+{
+       assert(node->effect->needs_texture_bounce());
+       assert(input_num < node->incoming_links.size());
+       assert(node->incoming_links[input_num]->bound_sampler_num >= 0);
+       assert(node->incoming_links[input_num]->bound_sampler_num < 8);
+       return GL_TEXTURE0 + node->incoming_links[input_num]->bound_sampler_num;
+}
+
+GLenum EffectChain::has_input_sampler(Node *node, unsigned input_num) const
+{
+       assert(input_num < node->incoming_links.size());
+       return node->incoming_links[input_num]->bound_sampler_num >= 0 &&
+               node->incoming_links[input_num]->bound_sampler_num < 8;
+}
+
 void EffectChain::find_all_nonlinear_inputs(Node *node, vector<Node *> *nonlinear_inputs)
 {
        if (node->output_gamma_curve == GAMMA_LINEAR &&
@@ -177,7 +255,7 @@ Effect *EffectChain::add_effect(Effect *effect, const vector<Effect *> &inputs)
        return effect;
 }
 
-// GLSL pre-1.30 doesn't support token pasting. Replace PREFIX(x) with <effect_id>_x.
+// ESSL doesn't support token pasting. Replace PREFIX(x) with <effect_id>_x.
 string replace_prefix(const string &text, const string &prefix)
 {
        string output;
@@ -218,43 +296,100 @@ string replace_prefix(const string &text, const string &prefix)
        return output;
 }
 
-Phase *EffectChain::compile_glsl_program(
-       const vector<Node *> &inputs,
-       const vector<Node *> &effects)
+namespace {
+
+template<class T>
+void extract_uniform_declarations(const vector<Uniform<T> > &effect_uniforms,
+                                  const string &type_specifier,
+                                  const string &effect_id,
+                                  vector<Uniform<T> > *phase_uniforms,
+                                  string *glsl_string)
 {
-       Phase *phase = new Phase;
-       assert(!effects.empty());
+       for (unsigned i = 0; i < effect_uniforms.size(); ++i) {
+               phase_uniforms->push_back(effect_uniforms[i]);
+               phase_uniforms->back().prefix = effect_id;
+
+               *glsl_string += string("uniform ") + type_specifier + " " + effect_id
+                       + "_" + effect_uniforms[i].name + ";\n";
+       }
+}
+
+template<class T>
+void extract_uniform_array_declarations(const vector<Uniform<T> > &effect_uniforms,
+                                        const string &type_specifier,
+                                        const string &effect_id,
+                                        vector<Uniform<T> > *phase_uniforms,
+                                        string *glsl_string)
+{
+       for (unsigned i = 0; i < effect_uniforms.size(); ++i) {
+               phase_uniforms->push_back(effect_uniforms[i]);
+               phase_uniforms->back().prefix = effect_id;
+
+               char buf[256];
+               snprintf(buf, sizeof(buf), "uniform %s %s_%s[%d];\n",
+                       type_specifier.c_str(), effect_id.c_str(),
+                       effect_uniforms[i].name.c_str(),
+                       int(effect_uniforms[i].num_values));
+               *glsl_string += buf;
+       }
+}
 
-       // Deduplicate the inputs.
-       vector<Node *> true_inputs = inputs;
-       sort(true_inputs.begin(), true_inputs.end());
-       true_inputs.erase(unique(true_inputs.begin(), true_inputs.end()), true_inputs.end());
+template<class T>
+void collect_uniform_locations(GLuint glsl_program_num, vector<Uniform<T> > *phase_uniforms)
+{
+       for (unsigned i = 0; i < phase_uniforms->size(); ++i) {
+               Uniform<T> &uniform = (*phase_uniforms)[i];
+               uniform.location = get_uniform_location(glsl_program_num, uniform.prefix, uniform.name);
+       }
+}
 
-       bool input_needs_mipmaps = false;
-       string frag_shader = read_file("header.frag");
+}  // namespace
+
+void EffectChain::compile_glsl_program(Phase *phase)
+{
+       string frag_shader_header = read_version_dependent_file("header", "frag");
+       string frag_shader = "";
 
-       // Create functions for all the texture inputs that we need.
-       for (unsigned i = 0; i < true_inputs.size(); ++i) {
-               Node *input = true_inputs[i];
+       // Create functions and uniforms for all the texture inputs that we need.
+       for (unsigned i = 0; i < phase->inputs.size(); ++i) {
+               Node *input = phase->inputs[i]->output_node;
                char effect_id[256];
                sprintf(effect_id, "in%u", i);
                phase->effect_ids.insert(make_pair(input, effect_id));
        
                frag_shader += string("uniform sampler2D tex_") + effect_id + ";\n";
                frag_shader += string("vec4 ") + effect_id + "(vec2 tc) {\n";
-               frag_shader += "\treturn texture2D(tex_" + string(effect_id) + ", tc);\n";
+               frag_shader += "\tvec4 tmp = tex2D(tex_" + string(effect_id) + ", tc);\n";
+
+               if (intermediate_transformation == SQUARE_ROOT_FRAMEBUFFER_TRANSFORMATION &&
+                   phase->inputs[i]->output_node->output_gamma_curve == GAMMA_LINEAR) {
+                       frag_shader += "\ttmp.rgb *= tmp.rgb;\n";
+               }
+
+               frag_shader += "\treturn tmp;\n";
                frag_shader += "}\n";
                frag_shader += "\n";
-       }
 
-       vector<Node *> sorted_effects = topological_sort(effects);
+               Uniform<int> uniform;
+               uniform.name = effect_id;
+               uniform.value = &phase->input_samplers[i];
+               uniform.prefix = "tex";
+               uniform.num_values = 1;
+               uniform.location = -1;
+               phase->uniforms_sampler2d.push_back(uniform);
+       }
 
-       for (unsigned i = 0; i < sorted_effects.size(); ++i) {
-               Node *node = sorted_effects[i];
+       // Give each effect in the phase its own ID.
+       for (unsigned i = 0; i < phase->effects.size(); ++i) {
+               Node *node = phase->effects[i];
                char effect_id[256];
                sprintf(effect_id, "eff%u", i);
                phase->effect_ids.insert(make_pair(node, effect_id));
+       }
 
+       for (unsigned i = 0; i < phase->effects.size(); ++i) {
+               Node *node = phase->effects[i];
+               const string effect_id = phase->effect_ids[node];
                if (node->incoming_links.size() == 1) {
                        frag_shader += string("#define INPUT ") + phase->effect_ids[node->incoming_links[0]] + "\n";
                } else {
@@ -267,7 +402,6 @@ Phase *EffectChain::compile_glsl_program(
        
                frag_shader += "\n";
                frag_shader += string("#define FUNCNAME ") + effect_id + "\n";
-               frag_shader += replace_prefix(node->effect->output_convenience_uniforms(), effect_id);
                frag_shader += replace_prefix(node->effect->output_fragment_shader(), effect_id);
                frag_shader += "#undef PREFIX\n";
                frag_shader += "#undef FUNCNAME\n";
@@ -281,157 +415,317 @@ Phase *EffectChain::compile_glsl_program(
                        }
                }
                frag_shader += "\n";
+       }
+       frag_shader += string("#define INPUT ") + phase->effect_ids[phase->effects.back()] + "\n";
 
-               input_needs_mipmaps |= node->effect->needs_mipmaps();
+       // If we're the last phase, add the right #defines for Y'CbCr multi-output as needed.
+       vector<string> frag_shader_outputs;  // In order.
+       if (phase->output_node->outgoing_links.empty() && num_output_color_ycbcr > 0) {
+               switch (output_ycbcr_splitting[0]) {
+               case YCBCR_OUTPUT_INTERLEAVED:
+                       // No #defines set.
+                       frag_shader_outputs.push_back("FragColor");
+                       break;
+               case YCBCR_OUTPUT_SPLIT_Y_AND_CBCR:
+                       frag_shader += "#define YCBCR_OUTPUT_SPLIT_Y_AND_CBCR 1\n";
+                       frag_shader_outputs.push_back("Y");
+                       frag_shader_outputs.push_back("Chroma");
+                       break;
+               case YCBCR_OUTPUT_PLANAR:
+                       frag_shader += "#define YCBCR_OUTPUT_PLANAR 1\n";
+                       frag_shader_outputs.push_back("Y");
+                       frag_shader_outputs.push_back("Cb");
+                       frag_shader_outputs.push_back("Cr");
+                       break;
+               default:
+                       assert(false);
+               }
+
+               if (num_output_color_ycbcr > 1) {
+                       switch (output_ycbcr_splitting[1]) {
+                       case YCBCR_OUTPUT_INTERLEAVED:
+                               frag_shader += "#define SECOND_YCBCR_OUTPUT_INTERLEAVED 1\n";
+                               frag_shader_outputs.push_back("YCbCr2");
+                               break;
+                       case YCBCR_OUTPUT_SPLIT_Y_AND_CBCR:
+                               frag_shader += "#define SECOND_YCBCR_OUTPUT_SPLIT_Y_AND_CBCR 1\n";
+                               frag_shader_outputs.push_back("Y2");
+                               frag_shader_outputs.push_back("Chroma2");
+                               break;
+                       case YCBCR_OUTPUT_PLANAR:
+                               frag_shader += "#define SECOND_YCBCR_OUTPUT_PLANAR 1\n";
+                               frag_shader_outputs.push_back("Y2");
+                               frag_shader_outputs.push_back("Cb2");
+                               frag_shader_outputs.push_back("Cr2");
+                               break;
+                       default:
+                               assert(false);
+                       }
+               }
+
+               if (output_color_rgba) {
+                       // Note: Needs to come in the header, because not only the
+                       // output needs to see it (YCbCrConversionEffect and DitherEffect
+                       // do, too).
+                       frag_shader_header += "#define YCBCR_ALSO_OUTPUT_RGBA 1\n";
+                       frag_shader_outputs.push_back("RGBA");
+               }
        }
-       for (unsigned i = 0; i < sorted_effects.size(); ++i) {
-               Node *node = sorted_effects[i];
-               if (node->effect->num_inputs() == 0) {
-                       CHECK(node->effect->set_int("needs_mipmaps", input_needs_mipmaps));
+
+       // If we're bouncing to a temporary texture, signal transformation if desired.
+       if (!phase->output_node->outgoing_links.empty()) {
+               if (intermediate_transformation == SQUARE_ROOT_FRAMEBUFFER_TRANSFORMATION &&
+                   phase->output_node->output_gamma_curve == GAMMA_LINEAR) {
+                       frag_shader += "#define SQUARE_ROOT_TRANSFORMATION 1\n";
                }
        }
-       frag_shader += string("#define INPUT ") + phase->effect_ids[sorted_effects.back()] + "\n";
-       frag_shader.append(read_file("footer.frag"));
 
-       phase->glsl_program_num = resource_pool->compile_glsl_program(read_file("vs.vert"), frag_shader);
-       phase->input_needs_mipmaps = input_needs_mipmaps;
-       phase->inputs = true_inputs;
-       phase->effects = sorted_effects;
+       frag_shader.append(read_file("footer.frag"));
 
-       return phase;
+       // Collect uniforms from all effects and output them. Note that this needs
+       // to happen after output_fragment_shader(), even though the uniforms come
+       // before in the output source, since output_fragment_shader() is allowed
+       // to register new uniforms (e.g. arrays that are of unknown length until
+       // finalization time).
+       // TODO: Make a uniform block for platforms that support it.
+       string frag_shader_uniforms = "";
+       for (unsigned i = 0; i < phase->effects.size(); ++i) {
+               Node *node = phase->effects[i];
+               Effect *effect = node->effect;
+               const string effect_id = phase->effect_ids[node];
+               extract_uniform_declarations(effect->uniforms_sampler2d, "sampler2D", effect_id, &phase->uniforms_sampler2d, &frag_shader_uniforms);
+               extract_uniform_declarations(effect->uniforms_bool, "bool", effect_id, &phase->uniforms_bool, &frag_shader_uniforms);
+               extract_uniform_declarations(effect->uniforms_int, "int", effect_id, &phase->uniforms_int, &frag_shader_uniforms);
+               extract_uniform_declarations(effect->uniforms_float, "float", effect_id, &phase->uniforms_float, &frag_shader_uniforms);
+               extract_uniform_declarations(effect->uniforms_vec2, "vec2", effect_id, &phase->uniforms_vec2, &frag_shader_uniforms);
+               extract_uniform_declarations(effect->uniforms_vec3, "vec3", effect_id, &phase->uniforms_vec3, &frag_shader_uniforms);
+               extract_uniform_declarations(effect->uniforms_vec4, "vec4", effect_id, &phase->uniforms_vec4, &frag_shader_uniforms);
+               extract_uniform_array_declarations(effect->uniforms_float_array, "float", effect_id, &phase->uniforms_float, &frag_shader_uniforms);
+               extract_uniform_array_declarations(effect->uniforms_vec2_array, "vec2", effect_id, &phase->uniforms_vec2, &frag_shader_uniforms);
+               extract_uniform_array_declarations(effect->uniforms_vec3_array, "vec3", effect_id, &phase->uniforms_vec3, &frag_shader_uniforms);
+               extract_uniform_array_declarations(effect->uniforms_vec4_array, "vec4", effect_id, &phase->uniforms_vec4, &frag_shader_uniforms);
+               extract_uniform_declarations(effect->uniforms_mat3, "mat3", effect_id, &phase->uniforms_mat3, &frag_shader_uniforms);
+       }
+
+       frag_shader = frag_shader_header + frag_shader_uniforms + frag_shader;
+
+       string vert_shader = read_version_dependent_file("vs", "vert");
+
+       // If we're the last phase and need to flip the picture to compensate for
+       // the origin, tell the vertex shader so.
+       if (phase->output_node->outgoing_links.empty() && output_origin == OUTPUT_ORIGIN_TOP_LEFT) {
+               const string needle = "#define FLIP_ORIGIN 0";
+               size_t pos = vert_shader.find(needle);
+               assert(pos != string::npos);
+
+               vert_shader[pos + needle.size() - 1] = '1';
+       }
+
+       phase->glsl_program_num = resource_pool->compile_glsl_program(vert_shader, frag_shader, frag_shader_outputs);
+       GLint position_attribute_index = glGetAttribLocation(phase->glsl_program_num, "position");
+       GLint texcoord_attribute_index = glGetAttribLocation(phase->glsl_program_num, "texcoord");
+       if (position_attribute_index != -1) {
+               phase->attribute_indexes.insert(position_attribute_index);
+       }
+       if (texcoord_attribute_index != -1) {
+               phase->attribute_indexes.insert(texcoord_attribute_index);
+       }
+
+       // Collect the resulting location numbers for each uniform.
+       collect_uniform_locations(phase->glsl_program_num, &phase->uniforms_sampler2d);
+       collect_uniform_locations(phase->glsl_program_num, &phase->uniforms_bool);
+       collect_uniform_locations(phase->glsl_program_num, &phase->uniforms_int);
+       collect_uniform_locations(phase->glsl_program_num, &phase->uniforms_float);
+       collect_uniform_locations(phase->glsl_program_num, &phase->uniforms_vec2);
+       collect_uniform_locations(phase->glsl_program_num, &phase->uniforms_vec3);
+       collect_uniform_locations(phase->glsl_program_num, &phase->uniforms_vec4);
+       collect_uniform_locations(phase->glsl_program_num, &phase->uniforms_mat3);
 }
 
 // Construct GLSL programs, starting at the given effect and following
 // the chain from there. We end a program every time we come to an effect
 // marked as "needs texture bounce", one that is used by multiple other
-// effects, every time an effect wants to change the output size,
-// and of course at the end.
+// effects, every time we need to bounce due to output size change
+// (not all size changes require ending), and of course at the end.
 //
 // We follow a quite simple depth-first search from the output, although
-// without any explicit recursion.
-void EffectChain::construct_glsl_programs(Node *output)
+// without recursing explicitly within each phase.
+Phase *EffectChain::construct_phase(Node *output, map<Node *, Phase *> *completed_effects)
 {
-       // Which effects have already been completed?
-       // We need to keep track of it, as an effect with multiple outputs
-       // could otherwise be calculated multiple times.
-       set<Node *> completed_effects;
+       if (completed_effects->count(output)) {
+               return (*completed_effects)[output];
+       }
 
-       // Effects in the current phase, as well as inputs (outputs from other phases
-       // that we depend on). Note that since we start iterating from the end,
-       // the effect list will be in the reverse order.
-       vector<Node *> this_phase_inputs;
-       vector<Node *> this_phase_effects;
+       Phase *phase = new Phase;
+       phase->output_node = output;
+
+       // If the output effect has one-to-one sampling, we try to trace this
+       // status down through the dependency chain. This is important in case
+       // we hit an effect that changes output size (and not sets a virtual
+       // output size); if we have one-to-one sampling, we don't have to break
+       // the phase.
+       output->one_to_one_sampling = output->effect->one_to_one_sampling();
 
        // Effects that we have yet to calculate, but that we know should
        // be in the current phase.
        stack<Node *> effects_todo_this_phase;
+       effects_todo_this_phase.push(output);
 
-       // Effects that we have yet to calculate, but that come from other phases.
-       // We delay these until we have this phase done in its entirety,
-       // at which point we pick any of them and start a new phase from that.
-       stack<Node *> effects_todo_other_phases;
+       while (!effects_todo_this_phase.empty()) {
+               Node *node = effects_todo_this_phase.top();
+               effects_todo_this_phase.pop();
 
-       effects_todo_this_phase.push(output);
+               if (node->effect->needs_mipmaps()) {
+                       node->needs_mipmaps = true;
+               }
 
-       for ( ;; ) {  // Termination condition within loop.
-               if (!effects_todo_this_phase.empty()) {
-                       // OK, we have more to do this phase.
-                       Node *node = effects_todo_this_phase.top();
-                       effects_todo_this_phase.pop();
-
-                       // This should currently only happen for effects that are inputs
-                       // (either true inputs or phase outputs). We special-case inputs,
-                       // and then deduplicate phase outputs in compile_glsl_program().
-                       if (node->effect->num_inputs() == 0) {
-                               if (find(this_phase_effects.begin(), this_phase_effects.end(), node) != this_phase_effects.end()) {
-                                       continue;
-                               }
-                       } else {
-                               assert(completed_effects.count(node) == 0);
+               // This should currently only happen for effects that are inputs
+               // (either true inputs or phase outputs). We special-case inputs,
+               // and then deduplicate phase outputs below.
+               if (node->effect->num_inputs() == 0) {
+                       if (find(phase->effects.begin(), phase->effects.end(), node) != phase->effects.end()) {
+                               continue;
                        }
+               } else {
+                       assert(completed_effects->count(node) == 0);
+               }
 
-                       this_phase_effects.push_back(node);
-                       completed_effects.insert(node);
+               phase->effects.push_back(node);
 
-                       // Find all the dependencies of this effect, and add them to the stack.
-                       vector<Node *> deps = node->incoming_links;
-                       assert(node->effect->num_inputs() == deps.size());
-                       for (unsigned i = 0; i < deps.size(); ++i) {
-                               bool start_new_phase = false;
+               // Find all the dependencies of this effect, and add them to the stack.
+               vector<Node *> deps = node->incoming_links;
+               assert(node->effect->num_inputs() == deps.size());
+               for (unsigned i = 0; i < deps.size(); ++i) {
+                       bool start_new_phase = false;
 
-                               if (node->effect->needs_texture_bounce() &&
-                                   !deps[i]->effect->is_single_texture()) {
-                                       start_new_phase = true;
-                               }
+                       if (node->effect->needs_texture_bounce() &&
+                           !deps[i]->effect->is_single_texture() &&
+                           !deps[i]->effect->override_disable_bounce()) {
+                               start_new_phase = true;
+                       }
 
-                               if (deps[i]->outgoing_links.size() > 1) {
-                                       if (!deps[i]->effect->is_single_texture()) {
-                                               // More than one effect uses this as the input,
-                                               // and it is not a texture itself.
-                                               // The easiest thing to do (and probably also the safest
-                                               // performance-wise in most cases) is to bounce it to a texture
-                                               // and then let the next passes read from that.
-                                               start_new_phase = true;
-                                       } else {
-                                               assert(deps[i]->effect->num_inputs() == 0);
-
-                                               // For textures, we try to be slightly more clever;
-                                               // if none of our outputs need a bounce, we don't bounce
-                                               // but instead simply use the effect many times.
-                                               //
-                                               // Strictly speaking, we could bounce it for some outputs
-                                               // and use it directly for others, but the processing becomes
-                                               // somewhat simpler if the effect is only used in one such way.
-                                               for (unsigned j = 0; j < deps[i]->outgoing_links.size(); ++j) {
-                                                       Node *rdep = deps[i]->outgoing_links[j];
-                                                       start_new_phase |= rdep->effect->needs_texture_bounce();
-                                               }
-                                       }
+                       // Propagate information about needing mipmaps down the chain,
+                       // breaking the phase if we notice an incompatibility.
+                       //
+                       // Note that we cannot do this propagation as a normal pass,
+                       // because it needs information about where the phases end
+                       // (we should not propagate the flag across phases).
+                       if (node->needs_mipmaps) {
+                               if (deps[i]->effect->num_inputs() == 0) {
+                                       Input *input = static_cast<Input *>(deps[i]->effect);
+                                       start_new_phase |= !input->can_supply_mipmaps();
+                               } else {
+                                       deps[i]->needs_mipmaps = true;
                                }
+                       }
 
-                               if (deps[i]->effect->changes_output_size()) {
+                       if (deps[i]->outgoing_links.size() > 1) {
+                               if (!deps[i]->effect->is_single_texture()) {
+                                       // More than one effect uses this as the input,
+                                       // and it is not a texture itself.
+                                       // The easiest thing to do (and probably also the safest
+                                       // performance-wise in most cases) is to bounce it to a texture
+                                       // and then let the next passes read from that.
                                        start_new_phase = true;
-                               }
-
-                               if (start_new_phase) {
-                                       effects_todo_other_phases.push(deps[i]);
-                                       this_phase_inputs.push_back(deps[i]);
                                } else {
-                                       effects_todo_this_phase.push(deps[i]);
+                                       assert(deps[i]->effect->num_inputs() == 0);
+
+                                       // For textures, we try to be slightly more clever;
+                                       // if none of our outputs need a bounce, we don't bounce
+                                       // but instead simply use the effect many times.
+                                       //
+                                       // Strictly speaking, we could bounce it for some outputs
+                                       // and use it directly for others, but the processing becomes
+                                       // somewhat simpler if the effect is only used in one such way.
+                                       for (unsigned j = 0; j < deps[i]->outgoing_links.size(); ++j) {
+                                               Node *rdep = deps[i]->outgoing_links[j];
+                                               start_new_phase |= rdep->effect->needs_texture_bounce();
+                                       }
                                }
                        }
-                       continue;
-               }
 
-               // No more effects to do this phase. Take all the ones we have,
-               // and create a GLSL program for it.
-               if (!this_phase_effects.empty()) {
-                       reverse(this_phase_effects.begin(), this_phase_effects.end());
-                       phases.push_back(compile_glsl_program(this_phase_inputs, this_phase_effects));
-                       this_phase_effects.back()->phase = phases.back();
-                       this_phase_inputs.clear();
-                       this_phase_effects.clear();
+                       if (deps[i]->effect->sets_virtual_output_size()) {
+                               assert(deps[i]->effect->changes_output_size());
+                               // If the next effect sets a virtual size to rely on OpenGL's
+                               // bilinear sampling, we'll really need to break the phase here.
+                               start_new_phase = true;
+                       } else if (deps[i]->effect->changes_output_size() && !node->one_to_one_sampling) {
+                               // If the next effect changes size and we don't have one-to-one sampling,
+                               // we also need to break here.
+                               start_new_phase = true;
+                       }
+
+                       if (start_new_phase) {
+                               phase->inputs.push_back(construct_phase(deps[i], completed_effects));
+                       } else {
+                               effects_todo_this_phase.push(deps[i]);
+
+                               // Propagate the one-to-one status down through the dependency.
+                               deps[i]->one_to_one_sampling = node->one_to_one_sampling &&
+                                       deps[i]->effect->one_to_one_sampling();
+                       }
                }
-               assert(this_phase_inputs.empty());
-               assert(this_phase_effects.empty());
+       }
 
-               // If we have no effects left, exit.
-               if (effects_todo_other_phases.empty()) {
-                       break;
+       // No more effects to do this phase. Take all the ones we have,
+       // and create a GLSL program for it.
+       assert(!phase->effects.empty());
+
+       // Deduplicate the inputs, but don't change the ordering e.g. by sorting;
+       // that would be nondeterministic and thus reduce cacheability.
+       // TODO: Make this even more deterministic.
+       vector<Phase *> dedup_inputs;
+       set<Phase *> seen_inputs;
+       for (size_t i = 0; i < phase->inputs.size(); ++i) {
+               if (seen_inputs.insert(phase->inputs[i]).second) {
+                       dedup_inputs.push_back(phase->inputs[i]);
                }
+       }
+       swap(phase->inputs, dedup_inputs);
 
-               Node *node = effects_todo_other_phases.top();
-               effects_todo_other_phases.pop();
+       // Allocate samplers for each input.
+       phase->input_samplers.resize(phase->inputs.size());
 
-               if (completed_effects.count(node) == 0) {
-                       // Start a new phase, calculating from this effect.
-                       effects_todo_this_phase.push(node);
+       // We added the effects from the output and back, but we need to output
+       // them in topological sort order in the shader.
+       phase->effects = topological_sort(phase->effects);
+
+       // Figure out if we need mipmaps or not, and if so, tell the inputs that.
+       phase->input_needs_mipmaps = false;
+       for (unsigned i = 0; i < phase->effects.size(); ++i) {
+               Node *node = phase->effects[i];
+               phase->input_needs_mipmaps |= node->effect->needs_mipmaps();
+       }
+       for (unsigned i = 0; i < phase->effects.size(); ++i) {
+               Node *node = phase->effects[i];
+               if (node->effect->num_inputs() == 0) {
+                       Input *input = static_cast<Input *>(node->effect);
+                       assert(!phase->input_needs_mipmaps || input->can_supply_mipmaps());
+                       CHECK(input->set_int("needs_mipmaps", phase->input_needs_mipmaps));
                }
        }
 
-       // Finally, since the phases are found from the output but must be executed
-       // from the input(s), reverse them, too.
-       reverse(phases.begin(), phases.end());
+       // Tell each node which phase it ended up in, so that the unit test
+       // can check that the phases were split in the right place.
+       // Note that this ignores that effects may be part of multiple phases;
+       // if the unit tests need to test such cases, we'll reconsider.
+       for (unsigned i = 0; i < phase->effects.size(); ++i) {
+               phase->effects[i]->containing_phase = phase;
+       }
+
+       // Actually make the shader for this phase.
+       compile_glsl_program(phase);
+
+       // Initialize timers.
+       if (movit_timer_queries_supported) {
+               phase->time_elapsed_ns = 0;
+               phase->num_measured_iterations = 0;
+       }
+
+       assert(completed_effects->count(output) == 0);
+       completed_effects->insert(make_pair(output, phase));
+       phases.push_back(phase);
+       return phase;
 }
 
 void EffectChain::output_dot(const char *filename)
@@ -612,17 +906,18 @@ void EffectChain::inform_input_sizes(Phase *phase)
                }
        }
        for (unsigned i = 0; i < phase->inputs.size(); ++i) {
-               Node *input = phase->inputs[i];
-               input->output_width = input->phase->virtual_output_width;
-               input->output_height = input->phase->virtual_output_height;
-               assert(input->output_width != 0);
-               assert(input->output_height != 0);
+               Phase *input = phase->inputs[i];
+               input->output_node->output_width = input->virtual_output_width;
+               input->output_node->output_height = input->virtual_output_height;
+               assert(input->output_node->output_width != 0);
+               assert(input->output_node->output_height != 0);
        }
 
        // Now propagate from the inputs towards the end, and inform as we go.
        // The rules are simple:
        //
-       //   1. Don't touch effects that already have given sizes (ie., inputs).
+       //   1. Don't touch effects that already have given sizes (ie., inputs
+       //      or effects that change the output size).
        //   2. If all of your inputs have the same size, that will be your output size.
        //   3. Otherwise, your output size is 0x0.
        for (unsigned i = 0; i < phase->effects.size(); ++i) {
@@ -644,8 +939,19 @@ void EffectChain::inform_input_sizes(Phase *phase)
                                this_output_height = 0;
                        }
                }
-               node->output_width = this_output_width;
-               node->output_height = this_output_height;
+               if (node->effect->changes_output_size()) {
+                       // We cannot call get_output_size() before we've done inform_input_size()
+                       // on all inputs.
+                       unsigned real_width, real_height;
+                       node->effect->get_output_size(&real_width, &real_height,
+                                                     &node->output_width, &node->output_height);
+                       assert(node->effect->sets_virtual_output_size() ||
+                              (real_width == node->output_width &&
+                               real_height == node->output_height));
+               } else {
+                       node->output_width = this_output_width;
+                       node->output_height = this_output_height;
+               }
        }
 }
 
@@ -659,6 +965,9 @@ void EffectChain::find_output_size(Phase *phase)
        if (output_node->effect->changes_output_size()) {
                output_node->effect->get_output_size(&phase->output_width, &phase->output_height,
                                                     &phase->virtual_output_width, &phase->virtual_output_height);
+               assert(output_node->effect->sets_virtual_output_size() ||
+                      (phase->output_width == phase->virtual_output_width &&
+                       phase->output_height == phase->virtual_output_height));
                return;
        }
 
@@ -667,14 +976,14 @@ void EffectChain::find_output_size(Phase *phase)
        bool all_inputs_same_size = true;
 
        for (unsigned i = 0; i < phase->inputs.size(); ++i) {
-               Node *input = phase->inputs[i];
-               assert(input->phase->output_width != 0);
-               assert(input->phase->output_height != 0);
+               Phase *input = phase->inputs[i];
+               assert(input->output_width != 0);
+               assert(input->output_height != 0);
                if (output_width == 0 && output_height == 0) {
-                       output_width = input->phase->virtual_output_width;
-                       output_height = input->phase->virtual_output_height;
-               } else if (output_width != input->phase->virtual_output_width ||
-                          output_height != input->phase->virtual_output_height) {
+                       output_width = input->virtual_output_width;
+                       output_height = input->virtual_output_height;
+               } else if (output_width != input->virtual_output_width ||
+                          output_height != input->virtual_output_height) {
                        all_inputs_same_size = false;
                }
        }
@@ -706,10 +1015,10 @@ void EffectChain::find_output_size(Phase *phase)
        output_width = 0;
        output_height = 0;
        for (unsigned i = 0; i < phase->inputs.size(); ++i) {
-               Node *input = phase->inputs[i];
-               assert(input->phase->output_width != 0);
-               assert(input->phase->output_height != 0);
-               size_rectangle_to_fit(input->phase->output_width, input->phase->output_height, &output_width, &output_height);
+               Phase *input = phase->inputs[i];
+               assert(input->output_width != 0);
+               assert(input->output_height != 0);
+               size_rectangle_to_fit(input->output_width, input->output_height, &output_width, &output_height);
        }
        for (unsigned i = 0; i < phase->effects.size(); ++i) {
                Effect *effect = phase->effects[i]->effect;
@@ -932,6 +1241,11 @@ void EffectChain::propagate_alpha()
 
                if (alpha_handling == Effect::INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA ||
                    alpha_handling == Effect::INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK) {
+                       // This combination (requiring premultiplied alpha, but _not_ requiring
+                       // linear light) is illegal, since the combination of premultiplied alpha
+                       // and nonlinear inputs is meaningless.
+                       assert(node->effect->needs_linear_light());
+
                        // If the effect has asked for premultiplied alpha, check that it has got it.
                        if (any_postmultiplied) {
                                node->output_alpha_type = ALPHA_INVALID;
@@ -1320,6 +1634,22 @@ void EffectChain::fix_output_gamma()
                connect_nodes(output, conversion);
        }
 }
+
+// If the user has requested Y'CbCr output, we need to do this conversion
+// _after_ GammaCompressionEffect etc., but before dither (see below).
+// This is because Y'CbCr, with the exception of a special optional mode
+// in Rec. 2020 (which we currently don't support), is defined to work on
+// gamma-encoded data.
+void EffectChain::add_ycbcr_conversion_if_needed()
+{
+       assert(output_color_rgba || num_output_color_ycbcr > 0);
+       if (num_output_color_ycbcr == 0) {
+               return;
+       }
+       Node *output = find_output_node();
+       ycbcr_conversion_effect_node = add_node(new YCbCrConversionEffect(output_ycbcr_format, output_ycbcr_type));
+       connect_nodes(output, ycbcr_conversion_effect_node);
+}
        
 // If the user has requested dither, add a DitherEffect right at the end
 // (after GammaCompressionEffect etc.). This needs to be done after everything else,
@@ -1358,10 +1688,6 @@ Node *EffectChain::find_output_node()
 
 void EffectChain::finalize()
 {
-       // Save the current locale, and set it to C, so that we can output decimal
-       // numbers with printf and be sure to get them in the format mandated by GLSL.
-       char *saved_locale = setlocale(LC_NUMERIC, "C");
-
        // Output the graph as it is before we do any conversions on it.
        output_dot("step0-start.dot");
 
@@ -1406,30 +1732,44 @@ void EffectChain::finalize()
        fix_internal_gamma_by_asking_inputs(15);
        fix_internal_gamma_by_inserting_nodes(16);
 
-       output_dot("step17-before-dither.dot");
+       output_dot("step17-before-ycbcr.dot");
+       add_ycbcr_conversion_if_needed();
 
+       output_dot("step18-before-dither.dot");
        add_dither_if_needed();
 
-       output_dot("step18-final.dot");
+       output_dot("step19-final.dot");
        
        // Construct all needed GLSL programs, starting at the output.
-       construct_glsl_programs(find_output_node());
+       // We need to keep track of which effects have already been computed,
+       // as an effect with multiple users could otherwise be calculated
+       // multiple times.
+       map<Node *, Phase *> completed_effects;
+       construct_phase(find_output_node(), &completed_effects);
 
-       output_dot("step19-split-to-phases.dot");
+       output_dot("step20-split-to-phases.dot");
 
        assert(phases[0]->inputs.empty());
        
        finalized = true;
-       setlocale(LC_NUMERIC, saved_locale);
 }
 
 void EffectChain::render_to_fbo(GLuint dest_fbo, unsigned width, unsigned height)
 {
        assert(finalized);
 
+       // This needs to be set anew, in case we are coming from a different context
+       // from when we initialized.
+       check_error();
+       glDisable(GL_DITHER);
+       check_error();
+
+       const bool final_srgb = glIsEnabled(GL_FRAMEBUFFER_SRGB);
+       check_error();
+       bool current_srgb = final_srgb;
+
        // Save original viewport.
        GLuint x = 0, y = 0;
-       GLuint fbo = 0;
 
        if (width == 0 && height == 0) {
                GLint viewport[4];
@@ -1441,6 +1781,7 @@ void EffectChain::render_to_fbo(GLuint dest_fbo, unsigned width, unsigned height
        }
 
        // Basic state.
+       check_error();
        glDisable(GL_BLEND);
        check_error();
        glDisable(GL_DEPTH_TEST);
@@ -1448,64 +1789,38 @@ void EffectChain::render_to_fbo(GLuint dest_fbo, unsigned width, unsigned height
        glDepthMask(GL_FALSE);
        check_error();
 
-       if (phases.size() > 1) {
-               glGenFramebuffers(1, &fbo);
-               check_error();
-               glBindFramebuffer(GL_FRAMEBUFFER, fbo);
-               check_error();
-       }
+       // Generate a VAO that will be used during the entire execution,
+       // and bind the VBO, since it contains all the data.
+       GLuint vao;
+       glGenVertexArrays(1, &vao);
+       check_error();
+       glBindVertexArray(vao);
+       check_error();
+       glBindBuffer(GL_ARRAY_BUFFER, vbo);
+       check_error();
+       set<GLint> bound_attribute_indices;
 
-       set<Node *> generated_mipmaps;
+       set<Phase *> generated_mipmaps;
 
        // We choose the simplest option of having one texture per output,
        // since otherwise this turns into an (albeit simple) register allocation problem.
        map<Phase *, GLuint> output_textures;
 
-       for (unsigned phase = 0; phase < phases.size(); ++phase) {
-               // Find a texture for this phase.
-               inform_input_sizes(phases[phase]);
-               if (phase != phases.size() - 1) {
-                       find_output_size(phases[phase]);
-
-                       GLuint tex_num = resource_pool->create_2d_texture(GL_RGBA16F_ARB, phases[phase]->output_width, phases[phase]->output_height);
-                       output_textures.insert(make_pair(phases[phase], tex_num));
-               }
-
-               const GLuint glsl_program_num = phases[phase]->glsl_program_num;
-               check_error();
-               glUseProgram(glsl_program_num);
-               check_error();
+       for (unsigned phase_num = 0; phase_num < phases.size(); ++phase_num) {
+               Phase *phase = phases[phase_num];
 
-               // Set up RTT inputs for this phase.
-               for (unsigned sampler = 0; sampler < phases[phase]->inputs.size(); ++sampler) {
-                       glActiveTexture(GL_TEXTURE0 + sampler);
-                       Node *input = phases[phase]->inputs[sampler];
-                       glBindTexture(GL_TEXTURE_2D, output_textures[input->phase]);
-                       check_error();
-                       if (phases[phase]->input_needs_mipmaps) {
-                               if (generated_mipmaps.count(input) == 0) {
-                                       glGenerateMipmap(GL_TEXTURE_2D);
-                                       check_error();
-                                       generated_mipmaps.insert(input);
-                               }
-                               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
-                               check_error();
+               if (do_phase_timing) {
+                       GLuint timer_query_object;
+                       if (phase->timer_query_objects_free.empty()) {
+                               glGenQueries(1, &timer_query_object);
                        } else {
-                               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-                               check_error();
+                               timer_query_object = phase->timer_query_objects_free.front();
+                               phase->timer_query_objects_free.pop_front();
                        }
-                       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
-                       check_error();
-                       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-                       check_error();
-
-                       string texture_name = string("tex_") + phases[phase]->effect_ids[input];
-                       glUniform1i(glGetUniformLocation(glsl_program_num, texture_name.c_str()), sampler);
-                       check_error();
+                       glBeginQuery(GL_TIME_ELAPSED, timer_query_object);
+                       phase->timer_query_objects_running.push_back(timer_query_object);
                }
-
-               // And now the output.
-               if (phase == phases.size() - 1) {
+               if (phase_num == phases.size() - 1) {
                        // Last phase goes to the output the user specified.
                        glBindFramebuffer(GL_FRAMEBUFFER, dest_fbo);
                        check_error();
@@ -1516,75 +1831,285 @@ void EffectChain::render_to_fbo(GLuint dest_fbo, unsigned width, unsigned height
                                CHECK(dither_effect->set_int("output_width", width));
                                CHECK(dither_effect->set_int("output_height", height));
                        }
-               } else {
-                       glFramebufferTexture2D(
-                               GL_FRAMEBUFFER,
-                               GL_COLOR_ATTACHMENT0,
-                               GL_TEXTURE_2D,
-                               output_textures[phases[phase]],
-                               0);
-                       check_error();
-                       GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
-                       assert(status == GL_FRAMEBUFFER_COMPLETE);
-                       glViewport(0, 0, phases[phase]->output_width, phases[phase]->output_height);
                }
+               bool last_phase = (phase_num == phases.size() - 1);
 
-               // Give the required parameters to all the effects.
-               unsigned sampler_num = phases[phase]->inputs.size();
-               for (unsigned i = 0; i < phases[phase]->effects.size(); ++i) {
-                       Node *node = phases[phase]->effects[i];
-                       node->effect->set_gl_state(glsl_program_num, phases[phase]->effect_ids[node], &sampler_num);
+               // Enable sRGB rendering for intermediates in case we are
+               // rendering to an sRGB format.
+               bool needs_srgb = last_phase ? final_srgb : true;
+               if (needs_srgb && !current_srgb) {
+                       glEnable(GL_FRAMEBUFFER_SRGB);
+                       check_error();
+                       current_srgb = true;
+               } else if (!needs_srgb && current_srgb) {
+                       glDisable(GL_FRAMEBUFFER_SRGB);
                        check_error();
+                       current_srgb = true;
                }
 
-               // Now draw!
-               float vertices[] = {
-                       0.0f, 1.0f,
-                       0.0f, 0.0f,
-                       1.0f, 1.0f,
-                       1.0f, 0.0f
-               };
+               execute_phase(phase, last_phase, &bound_attribute_indices, &output_textures, &generated_mipmaps);
+               if (do_phase_timing) {
+                       glEndQuery(GL_TIME_ELAPSED);
+               }
+       }
 
-               GLuint vao;
-               glGenVertexArrays(1, &vao);
-               check_error();
-               glBindVertexArray(vao);
-               check_error();
+       for (map<Phase *, GLuint>::const_iterator texture_it = output_textures.begin();
+            texture_it != output_textures.end();
+            ++texture_it) {
+               resource_pool->release_2d_texture(texture_it->second);
+       }
+
+       glBindFramebuffer(GL_FRAMEBUFFER, 0);
+       check_error();
+       glUseProgram(0);
+       check_error();
+
+       glBindBuffer(GL_ARRAY_BUFFER, 0);
+       check_error();
+       glBindVertexArray(0);
+       check_error();
+       glDeleteVertexArrays(1, &vao);
+       check_error();
+
+       if (do_phase_timing) {
+               // Get back the timer queries.
+               for (unsigned phase_num = 0; phase_num < phases.size(); ++phase_num) {
+                       Phase *phase = phases[phase_num];
+                       for (std::list<GLuint>::iterator timer_it = phase->timer_query_objects_running.begin();
+                            timer_it != phase->timer_query_objects_running.end(); ) {
+                               GLint timer_query_object = *timer_it;
+                               GLint available;
+                               glGetQueryObjectiv(timer_query_object, GL_QUERY_RESULT_AVAILABLE, &available);
+                               if (available) {
+                                       GLuint64 time_elapsed;
+                                       glGetQueryObjectui64v(timer_query_object, GL_QUERY_RESULT, &time_elapsed);
+                                       phase->time_elapsed_ns += time_elapsed;
+                                       ++phase->num_measured_iterations;
+                                       phase->timer_query_objects_free.push_back(timer_query_object);
+                                       phase->timer_query_objects_running.erase(timer_it++);
+                               } else {
+                                       ++timer_it;
+                               }
+                       }
+               }
+       }
+}
+
+void EffectChain::enable_phase_timing(bool enable)
+{
+       if (enable) {
+               assert(movit_timer_queries_supported);
+       }
+       this->do_phase_timing = enable;
+}
+
+void EffectChain::reset_phase_timing()
+{
+       for (unsigned phase_num = 0; phase_num < phases.size(); ++phase_num) {
+               Phase *phase = phases[phase_num];
+               phase->time_elapsed_ns = 0;
+               phase->num_measured_iterations = 0;
+       }
+}
+
+void EffectChain::print_phase_timing()
+{
+       double total_time_ms = 0.0;
+       for (unsigned phase_num = 0; phase_num < phases.size(); ++phase_num) {
+               Phase *phase = phases[phase_num];
+               double avg_time_ms = phase->time_elapsed_ns * 1e-6 / phase->num_measured_iterations;
+               printf("Phase %d: %5.1f ms  [", phase_num, avg_time_ms);
+               for (unsigned effect_num = 0; effect_num < phase->effects.size(); ++effect_num) {
+                       if (effect_num != 0) {
+                               printf(", ");
+                       }
+                       printf("%s", phase->effects[effect_num]->effect->effect_type_id().c_str());
+               }
+               printf("]\n");
+               total_time_ms += avg_time_ms;
+       }
+       printf("Total:   %5.1f ms\n", total_time_ms);
+}
 
-               GLuint position_vbo = fill_vertex_attribute(glsl_program_num, "position", 2, GL_FLOAT, sizeof(vertices), vertices);
-               GLuint texcoord_vbo = fill_vertex_attribute(glsl_program_num, "texcoord", 2, GL_FLOAT, sizeof(vertices), vertices);  // Same as vertices.
+void EffectChain::execute_phase(Phase *phase, bool last_phase,
+                                set<GLint> *bound_attribute_indices,
+                                map<Phase *, GLuint> *output_textures,
+                                set<Phase *> *generated_mipmaps)
+{
+       GLuint fbo = 0;
 
-               glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+       // Find a texture for this phase.
+       inform_input_sizes(phase);
+       if (!last_phase) {
+               find_output_size(phase);
+
+               GLuint tex_num = resource_pool->create_2d_texture(intermediate_format, phase->output_width, phase->output_height);
+               output_textures->insert(make_pair(phase, tex_num));
+       }
+
+       // Set up RTT inputs for this phase.
+       for (unsigned sampler = 0; sampler < phase->inputs.size(); ++sampler) {
+               glActiveTexture(GL_TEXTURE0 + sampler);
+               Phase *input = phase->inputs[sampler];
+               input->output_node->bound_sampler_num = sampler;
+               glBindTexture(GL_TEXTURE_2D, (*output_textures)[input]);
                check_error();
+               if (phase->input_needs_mipmaps && generated_mipmaps->count(input) == 0) {
+                       glGenerateMipmap(GL_TEXTURE_2D);
+                       check_error();
+                       generated_mipmaps->insert(input);
+               }
+               setup_rtt_sampler(sampler, phase->input_needs_mipmaps);
+               phase->input_samplers[sampler] = sampler;  // Bind the sampler to the right uniform.
+       }
+
+       // And now the output. (Already set up for us if it is the last phase.)
+       if (!last_phase) {
+               fbo = resource_pool->create_fbo((*output_textures)[phase]);
+               glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+               glViewport(0, 0, phase->output_width, phase->output_height);
+       }
 
-               cleanup_vertex_attribute(glsl_program_num, "position", position_vbo);
-               cleanup_vertex_attribute(glsl_program_num, "texcoord", texcoord_vbo);
+       GLuint instance_program_num = resource_pool->use_glsl_program(phase->glsl_program_num);
+       check_error();
 
-               glUseProgram(0);
+       // Give the required parameters to all the effects.
+       unsigned sampler_num = phase->inputs.size();
+       for (unsigned i = 0; i < phase->effects.size(); ++i) {
+               Node *node = phase->effects[i];
+               unsigned old_sampler_num = sampler_num;
+               node->effect->set_gl_state(instance_program_num, phase->effect_ids[node], &sampler_num);
                check_error();
 
-               for (unsigned i = 0; i < phases[phase]->effects.size(); ++i) {
-                       Node *node = phases[phase]->effects[i];
-                       node->effect->clear_gl_state();
+               if (node->effect->is_single_texture()) {
+                       assert(sampler_num - old_sampler_num == 1);
+                       node->bound_sampler_num = old_sampler_num;
+               } else {
+                       node->bound_sampler_num = -1;
                }
+       }
 
-               glDeleteVertexArrays(1, &vao);
-               check_error();
+       // Uniforms need to come after set_gl_state(), since they can be updated
+       // from there.
+       setup_uniforms(phase);
+
+       // Clean up old attributes if they are no longer needed.
+       for (set<GLint>::iterator attr_it = bound_attribute_indices->begin();
+            attr_it != bound_attribute_indices->end(); ) {
+               if (phase->attribute_indexes.count(*attr_it) == 0) {
+                       glDisableVertexAttribArray(*attr_it);
+                       check_error();
+                       bound_attribute_indices->erase(attr_it++);
+               } else {
+                       ++attr_it;
+               }
        }
 
-       for (map<Phase *, GLuint>::const_iterator texture_it = output_textures.begin();
-            texture_it != output_textures.end();
-            ++texture_it) {
-               resource_pool->release_2d_texture(texture_it->second);
+       // Set up the new attributes, if needed.
+       for (set<GLint>::iterator attr_it = phase->attribute_indexes.begin();
+            attr_it != phase->attribute_indexes.end();
+            ++attr_it) {
+               if (bound_attribute_indices->count(*attr_it) == 0) {
+                       glEnableVertexAttribArray(*attr_it);
+                       check_error();
+                       glVertexAttribPointer(*attr_it, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
+                       check_error();
+                       bound_attribute_indices->insert(*attr_it);
+               }
        }
 
-       glBindFramebuffer(GL_FRAMEBUFFER, 0);
+       glDrawArrays(GL_TRIANGLES, 0, 3);
        check_error();
+       
+       for (unsigned i = 0; i < phase->effects.size(); ++i) {
+               Node *node = phase->effects[i];
+               node->effect->clear_gl_state();
+       }
+
+       resource_pool->unuse_glsl_program(instance_program_num);
 
-       if (fbo != 0) {
-               glDeleteFramebuffers(1, &fbo);
+       if (!last_phase) {
+               resource_pool->release_fbo(fbo);
+       }
+}
+
+void EffectChain::setup_uniforms(Phase *phase)
+{
+       // TODO: Use UBO blocks.
+       for (size_t i = 0; i < phase->uniforms_sampler2d.size(); ++i) {
+               const Uniform<int> &uniform = phase->uniforms_sampler2d[i];
+               if (uniform.location != -1) {
+                       glUniform1iv(uniform.location, uniform.num_values, uniform.value);
+               }
+       }
+       for (size_t i = 0; i < phase->uniforms_bool.size(); ++i) {
+               const Uniform<bool> &uniform = phase->uniforms_bool[i];
+               assert(uniform.num_values == 1);
+               if (uniform.location != -1) {
+                       glUniform1i(uniform.location, *uniform.value);
+               }
+       }
+       for (size_t i = 0; i < phase->uniforms_int.size(); ++i) {
+               const Uniform<int> &uniform = phase->uniforms_int[i];
+               if (uniform.location != -1) {
+                       glUniform1iv(uniform.location, uniform.num_values, uniform.value);
+               }
+       }
+       for (size_t i = 0; i < phase->uniforms_float.size(); ++i) {
+               const Uniform<float> &uniform = phase->uniforms_float[i];
+               if (uniform.location != -1) {
+                       glUniform1fv(uniform.location, uniform.num_values, uniform.value);
+               }
+       }
+       for (size_t i = 0; i < phase->uniforms_vec2.size(); ++i) {
+               const Uniform<float> &uniform = phase->uniforms_vec2[i];
+               if (uniform.location != -1) {
+                       glUniform2fv(uniform.location, uniform.num_values, uniform.value);
+               }
+       }
+       for (size_t i = 0; i < phase->uniforms_vec3.size(); ++i) {
+               const Uniform<float> &uniform = phase->uniforms_vec3[i];
+               if (uniform.location != -1) {
+                       glUniform3fv(uniform.location, uniform.num_values, uniform.value);
+               }
+       }
+       for (size_t i = 0; i < phase->uniforms_vec4.size(); ++i) {
+               const Uniform<float> &uniform = phase->uniforms_vec4[i];
+               if (uniform.location != -1) {
+                       glUniform4fv(uniform.location, uniform.num_values, uniform.value);
+               }
+       }
+       for (size_t i = 0; i < phase->uniforms_mat3.size(); ++i) {
+               const Uniform<Matrix3d> &uniform = phase->uniforms_mat3[i];
+               assert(uniform.num_values == 1);
+               if (uniform.location != -1) {
+                       // Convert to float (GLSL has no double matrices).
+                       float matrixf[9];
+                       for (unsigned y = 0; y < 3; ++y) {
+                               for (unsigned x = 0; x < 3; ++x) {
+                                       matrixf[y + x * 3] = (*uniform.value)(y, x);
+                               }
+                       }
+                       glUniformMatrix3fv(uniform.location, 1, GL_FALSE, matrixf);
+               }
+       }
+}
+
+void EffectChain::setup_rtt_sampler(int sampler_num, bool use_mipmaps)
+{
+       glActiveTexture(GL_TEXTURE0 + sampler_num);
+       check_error();
+       if (use_mipmaps) {
+               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
+               check_error();
+       } else {
+               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
                check_error();
        }
+       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+       check_error();
+       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+       check_error();
 }
 
 }  // namespace movit