]> git.sesse.net Git - movit/blobdiff - effect_chain.cpp
Microoptimization in calculate_scaling_weights.
[movit] / effect_chain.cpp
index d56a24806771a0a1e8d444078a28935731305720..30849306db298a31a0bf5661f35f6618956faace 100644 (file)
@@ -34,12 +34,15 @@ namespace movit {
 
 namespace {
 
-// An effect that does nothing.
-class IdentityEffect : public Effect {
+// An effect whose only purpose is to sit in a phase on its own and take the
+// texture output from a compute shader and display it to the normal backbuffer
+// (or any FBO). That phase can be skipped when rendering using render_to_textures().
+class ComputeShaderOutputDisplayEffect : public Effect {
 public:
-       IdentityEffect() {}
-       virtual string effect_type_id() const { return "IdentityEffect"; }
-       string output_fragment_shader() { return read_file("identity.frag"); }
+       ComputeShaderOutputDisplayEffect() {}
+       string effect_type_id() const override { return "ComputeShaderOutputDisplayEffect"; }
+       string output_fragment_shader() override { return read_file("identity.frag"); }
+       bool needs_texture_bounce() const override { return true; }
 };
 
 }  // namespace
@@ -162,6 +165,7 @@ Node *EffectChain::add_node(Effect *effect)
        node->output_alpha_type = ALPHA_INVALID;
        node->needs_mipmaps = false;
        node->one_to_one_sampling = false;
+       node->strong_one_to_one_sampling = false;
 
        nodes.push_back(node);
        node_map[effect] = node;
@@ -408,9 +412,17 @@ void EffectChain::compile_glsl_program(Phase *phase)
                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";
+                       Node *input = node->incoming_links[0];
+                       if (i != 0 && input->effect->is_compute_shader()) {
+                               // First effect after the compute shader reads the value
+                               // that cs_output() wrote to a global variable.
+                               frag_shader += string("#define INPUT(tc) CS_OUTPUT_VAL\n");
+                       } else {
+                               frag_shader += string("#define INPUT ") + phase->effect_ids[input] + "\n";
+                       }
                } else {
                        for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
+                               assert(!node->incoming_links[j]->effect->is_compute_shader());
                                char buf[256];
                                sprintf(buf, "#define INPUT%d %s\n", j + 1, phase->effect_ids[node->incoming_links[j]].c_str());
                                frag_shader += buf;
@@ -435,7 +447,17 @@ void EffectChain::compile_glsl_program(Phase *phase)
                }
                frag_shader += "\n";
        }
-       frag_shader += string("#define INPUT ") + phase->effect_ids[phase->effects.back()] + "\n";
+       if (phase->is_compute_shader) {
+               frag_shader += string("#define INPUT ") + phase->effect_ids[phase->compute_shader_node] + "\n";
+               if (phase->compute_shader_node == phase->effects.back()) {
+                       // No postprocessing.
+                       frag_shader += "#define CS_POSTPROC(tc) CS_OUTPUT_VAL\n";
+               } else {
+                       frag_shader += string("#define CS_POSTPROC ") + phase->effect_ids[phase->effects.back()] + "\n";
+               }
+       } else {
+               frag_shader += string("#define INPUT ") + phase->effect_ids[phase->effects.back()] + "\n";
+       }
 
        // If we're the last phase, add the right #defines for Y'CbCr multi-output as needed.
        vector<string> frag_shader_outputs;  // In order.
@@ -500,9 +522,10 @@ void EffectChain::compile_glsl_program(Phase *phase)
        }
 
        if (phase->is_compute_shader) {
-               frag_shader.append(read_file("footer.compute"));
-               phase->output_node->effect->register_uniform_vec2("inv_output_size", (float *)&phase->inv_output_size);
-               phase->output_node->effect->register_uniform_vec2("output_texcoord_adjust", (float *)&phase->output_texcoord_adjust);
+               frag_shader.append(read_file("footer.comp"));
+               phase->compute_shader_node->effect->register_uniform_ivec2("output_size", phase->uniform_output_size);
+               phase->compute_shader_node->effect->register_uniform_vec2("inv_output_size", (float *)&phase->inv_output_size);
+               phase->compute_shader_node->effect->register_uniform_vec2("output_texcoord_adjust", (float *)&phase->output_texcoord_adjust);
        } else {
                frag_shader.append(read_file("footer.frag"));
        }
@@ -522,6 +545,7 @@ void EffectChain::compile_glsl_program(Phase *phase)
                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_ivec2, "ivec2", effect_id, &phase->uniforms_ivec2, &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);
@@ -533,20 +557,31 @@ void EffectChain::compile_glsl_program(Phase *phase)
                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);
+       // the origin, tell the vertex or compute shader so.
+       bool is_last_phase;
+       if (has_dummy_effect) {
+               is_last_phase = (phase->output_node->outgoing_links.size() == 1 &&
+                       phase->output_node->outgoing_links[0]->effect->effect_type_id() == "ComputeShaderOutputDisplayEffect");
+       } else {
+               is_last_phase = phase->output_node->outgoing_links.empty();
+       }
+       if (is_last_phase && output_origin == OUTPUT_ORIGIN_TOP_LEFT) {
+               if (phase->is_compute_shader) {
+                       frag_shader_header += "#define FLIP_ORIGIN 1\n";
+               } else {
+                       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';
+                       vert_shader[pos + needle.size() - 1] = '1';
+               }
        }
 
+       frag_shader = frag_shader_header + frag_shader_uniforms + frag_shader;
+
        if (phase->is_compute_shader) {
                phase->glsl_program_num = resource_pool->compile_glsl_compute_program(frag_shader);
 
@@ -574,6 +609,7 @@ void EffectChain::compile_glsl_program(Phase *phase)
        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_ivec2);
        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);
@@ -597,7 +633,8 @@ Phase *EffectChain::construct_phase(Node *output, map<Node *, Phase *> *complete
 
        Phase *phase = new Phase;
        phase->output_node = output;
-       phase->is_compute_shader = output->effect->is_compute_shader();
+       phase->is_compute_shader = false;
+       phase->compute_shader_node = nullptr;
 
        // 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
@@ -605,6 +642,7 @@ Phase *EffectChain::construct_phase(Node *output, map<Node *, Phase *> *complete
        // 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();
+       output->strong_one_to_one_sampling = output->effect->strong_one_to_one_sampling();
 
        // Effects that we have yet to calculate, but that we know should
        // be in the current phase.
@@ -615,6 +653,8 @@ Phase *EffectChain::construct_phase(Node *output, map<Node *, Phase *> *complete
                Node *node = effects_todo_this_phase.top();
                effects_todo_this_phase.pop();
 
+               assert(node->effect->one_to_one_sampling() >= node->effect->strong_one_to_one_sampling());
+
                if (node->effect->needs_mipmaps()) {
                        node->needs_mipmaps = true;
                }
@@ -631,6 +671,10 @@ Phase *EffectChain::construct_phase(Node *output, map<Node *, Phase *> *complete
                }
 
                phase->effects.push_back(node);
+               if (node->effect->is_compute_shader()) {
+                       phase->is_compute_shader = true;
+                       phase->compute_shader_node = node;
+               }
 
                // Find all the dependencies of this effect, and add them to the stack.
                vector<Node *> deps = node->incoming_links;
@@ -644,12 +688,6 @@ Phase *EffectChain::construct_phase(Node *output, map<Node *, Phase *> *complete
                                start_new_phase = true;
                        }
 
-                       // Compute shaders currently always end phases.
-                       // (We might loosen this up in some cases in the future.)
-                       if (deps[i]->effect->is_compute_shader()) {
-                               start_new_phase = true;
-                       }
-
                        // Propagate information about needing mipmaps down the chain,
                        // breaking the phase if we notice an incompatibility.
                        //
@@ -690,7 +728,15 @@ Phase *EffectChain::construct_phase(Node *output, map<Node *, Phase *> *complete
                                }
                        }
 
-                       if (deps[i]->effect->sets_virtual_output_size()) {
+                       if (deps[i]->effect->is_compute_shader()) {
+                               // Only one compute shader per phase; we should have been stopped
+                               // already due to the fact that compute shaders are not one-to-one.
+                               assert(!phase->is_compute_shader);
+
+                               // If all nodes so far are strong one-to-one, we can put them after
+                               // the compute shader (ie., process them on the output).
+                               start_new_phase = !node->strong_one_to_one_sampling;
+                       } else 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.
@@ -709,6 +755,8 @@ Phase *EffectChain::construct_phase(Node *output, map<Node *, Phase *> *complete
                                // 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();
+                               deps[i]->strong_one_to_one_sampling = node->strong_one_to_one_sampling &&
+                                       deps[i]->effect->strong_one_to_one_sampling();
                        }
                }
        }
@@ -1005,7 +1053,7 @@ void EffectChain::inform_input_sizes(Phase *phase)
 // desired output size might change based on the inputs.
 void EffectChain::find_output_size(Phase *phase)
 {
-       Node *output_node = phase->effects.back();
+       Node *output_node = phase->is_compute_shader ? phase->compute_shader_node : phase->effects.back();
 
        // If the last effect explicitly sets an output size, use that.
        if (output_node->effect->changes_output_size()) {
@@ -1722,8 +1770,15 @@ void EffectChain::add_dither_if_needed()
 void EffectChain::add_dummy_effect_if_needed()
 {
        Node *output = find_output_node();
-       if (output->effect->is_compute_shader()) {
-               Node *dummy = add_node(new IdentityEffect());
+
+       // See if the last effect that's not strong one-to-one is a compute shader.
+       Node *last_effect = output;
+       while (last_effect->effect->num_inputs() == 1 &&
+              last_effect->effect->strong_one_to_one_sampling()) {
+               last_effect = last_effect->incoming_links[0];
+       }
+       if (last_effect->effect->is_compute_shader()) {
+               Node *dummy = add_node(new ComputeShaderOutputDisplayEffect());
                connect_nodes(output, dummy);
                has_dummy_effect = true;
        }
@@ -1882,9 +1937,18 @@ void EffectChain::render(GLuint dest_fbo, const vector<DestinationTexture> &dest
 
        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.
+       // We keep one texture per output, but only for as long as we actually have any
+       // phases that need it as an input. (We don't make any effort to reorder phases
+       // to minimize the number of textures in play, as register allocation can be
+       // complicated and we rarely have much to gain, since our graphs are typically
+       // pretty linear.)
        map<Phase *, GLuint> output_textures;
+       map<Phase *, int> ref_counts;
+       for (Phase *phase : phases) {
+               for (Phase *input : phase->inputs) {
+                       ++ref_counts[input];
+               }
+       }
 
        size_t num_phases = phases.size();
        if (destinations.empty()) {
@@ -1896,7 +1960,7 @@ void EffectChain::render(GLuint dest_fbo, const vector<DestinationTexture> &dest
                assert(num_phases >= 2);
                assert(!phases.back()->is_compute_shader);
                assert(phases.back()->effects.size() == 1);
-               assert(phases.back()->effects[0]->effect->effect_type_id() == "IdentityEffect");
+               assert(phases.back()->effects[0]->effect->effect_type_id() == "ComputeShaderOutputDisplayEffect");
 
                // We are rendering to a set of textures, so we can run the compute shader
                // directly and skip the dummy phase.
@@ -1972,6 +2036,15 @@ void EffectChain::render(GLuint dest_fbo, const vector<DestinationTexture> &dest
                if (do_phase_timing) {
                        glEndQuery(GL_TIME_ELAPSED);
                }
+
+               // Drop any input textures we don't need anymore.
+               for (Phase *input : phase->inputs) {
+                       assert(ref_counts[input] > 0);
+                       if (--ref_counts[input] == 0) {
+                               resource_pool->release_2d_texture(output_textures[input]);
+                               output_textures.erase(input);
+                       }
+               }
        }
 
        for (const auto &phase_and_texnum : output_textures) {
@@ -2084,6 +2157,8 @@ void EffectChain::execute_phase(Phase *phase,
                phase->outbuf_image_unit = 0;
                glBindImageTexture(phase->outbuf_image_unit, destinations[0].texnum, 0, GL_FALSE, 0, GL_WRITE_ONLY, destinations[0].format);
                check_error();
+               phase->uniform_output_size[0] = phase->output_width;
+               phase->uniform_output_size[1] = phase->output_height;
                phase->inv_output_size.x = 1.0f / phase->output_width;
                phase->inv_output_size.y = 1.0f / phase->output_height;
                phase->output_texcoord_adjust.x = 0.5f / phase->output_width;
@@ -2113,7 +2188,7 @@ void EffectChain::execute_phase(Phase *phase,
 
        if (phase->is_compute_shader) {
                unsigned x, y, z;
-               phase->output_node->effect->get_compute_dimensions(phase->output_width, phase->output_height, &x, &y, &z);
+               phase->compute_shader_node->effect->get_compute_dimensions(phase->output_width, phase->output_height, &x, &y, &z);
 
                // Uniforms need to come after set_gl_state() _and_ get_compute_dimensions(),
                // since they can be updated from there.
@@ -2177,6 +2252,12 @@ void EffectChain::setup_uniforms(Phase *phase)
                        glUniform1iv(uniform.location, uniform.num_values, uniform.value);
                }
        }
+       for (size_t i = 0; i < phase->uniforms_ivec2.size(); ++i) {
+               const Uniform<int> &uniform = phase->uniforms_ivec2[i];
+               if (uniform.location != -1) {
+                       glUniform2iv(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) {