Implement gamma expansion from sRGB.

[movit] / effect_chain.cpp

diff --git a/effect_chain.cpp b/effect_chain.cpp
index 05adfd835a5b2189e3e5da319c12dd47ac5ff45a..a8381505109affe8ade2becd09009c58b15b1233 100644 (file)
--- a/effect_chain.cpp
+++ b/effect_chain.cpp
@@ -1,12 +1,21 @@
+#define GL_GLEXT_PROTOTYPES 1
+
+#include <stdio.h>
+#include <string.h>
 #include <assert.h>
 
+#include <GL/gl.h>
+#include <GL/glext.h>
+
+#include "util.h"
 #include "effect_chain.h"
 #include "gamma_expansion_effect.h"
 #include "lift_gamma_gain_effect.h"
 #include "colorspace_conversion_effect.h"
+#include "texture_enum.h"
 
 EffectChain::EffectChain(unsigned width, unsigned height)
-       : width(width), height(height) {}
+       : width(width), height(height), finalized(false) {}
 
 void EffectChain::add_input(const ImageFormat &format)
 {
@@ -53,7 +62,143 @@ Effect *EffectChain::add_effect(EffectId effect_id)
                current_color_space = COLORSPACE_sRGB;
        }
 
+       // not handled yet
+       assert(!effect->needs_many_samples());
+       assert(!effect->needs_mipmaps());
+
        effects.push_back(effect);
        return effect;
 }
 
+// GLSL pre-1.30 doesn't support token pasting. Replace PREFIX(x) with <effect_id>_x.
+std::string replace_prefix(const std::string &text, const std::string &prefix)
+{
+       std::string output;
+       size_t start = 0;
+
+       while (start < text.size()) {
+               size_t pos = text.find("PREFIX(", start);
+               if (pos == std::string::npos) {
+                       output.append(text.substr(start, std::string::npos));
+                       break;
+               }
+
+               output.append(text.substr(start, pos - start));
+               output.append(prefix);
+               output.append("_");
+
+               pos += strlen("PREFIX(");
+       
+               // Output stuff until we find the matching ), which we then eat.
+               int depth = 1;
+               size_t end_arg_pos = pos;
+               while (end_arg_pos < text.size()) {
+                       if (text[end_arg_pos] == '(') {
+                               ++depth;
+                       } else if (text[end_arg_pos] == ')') {
+                               --depth;
+                               if (depth == 0) {
+                                       break;
+                               }
+                       }
+                       ++end_arg_pos;
+               }
+               output.append(text.substr(pos, end_arg_pos - pos));
+               ++end_arg_pos;
+               assert(depth == 0);
+               start = end_arg_pos;
+       }
+       return output;
+}
+
+void EffectChain::finalize()
+{
+       std::string frag_shader = read_file("header.glsl");
+
+       for (unsigned i = 0; i < effects.size(); ++i) {
+               char effect_id[256];
+               sprintf(effect_id, "eff%d", i);
+       
+               frag_shader += "\n";
+               frag_shader += std::string("#define FUNCNAME ") + effect_id + "\n";
+               frag_shader += replace_prefix(effects[i]->output_convenience_uniforms(), effect_id);
+               frag_shader += replace_prefix(effects[i]->output_glsl(), effect_id);
+               frag_shader += "#undef PREFIX\n";
+               frag_shader += "#undef FUNCNAME\n";
+               frag_shader += "#undef LAST_INPUT\n";
+               frag_shader += std::string("#define LAST_INPUT ") + effect_id + "\n";
+               frag_shader += "\n";
+       }
+       frag_shader.append(read_file("footer.glsl"));
+       printf("%s\n", frag_shader.c_str());
+       
+       glsl_program_num = glCreateProgram();
+       GLhandleARB vs_obj = compile_shader(read_file("vs.glsl"), GL_VERTEX_SHADER);
+       GLhandleARB fs_obj = compile_shader(frag_shader, GL_FRAGMENT_SHADER);
+       glAttachShader(glsl_program_num, vs_obj);
+       check_error();
+       glAttachShader(glsl_program_num, fs_obj);
+       check_error();
+       glLinkProgram(glsl_program_num);
+       check_error();
+
+       finalized = true;
+}
+
+void EffectChain::render_to_screen(unsigned char *src)
+{
+       assert(finalized);
+
+       check_error();
+       glUseProgram(glsl_program_num);
+       check_error();
+
+       glActiveTexture(GL_TEXTURE0);
+       glBindTexture(GL_TEXTURE_2D, SOURCE_IMAGE);
+
+       // TODO: use sRGB textures if applicable
+       if (input_format.pixel_format == FORMAT_RGB) {
+               glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, src);
+       } else if (input_format.pixel_format == FORMAT_RGBA) {
+               glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, src);
+       } else {
+               assert(false);
+       }
+       check_error();
+       glUniform1i(glGetUniformLocation(glsl_program_num, "input_tex"), 0);
+
+       //for (unsigned i = 0; i < effects.size(); ++i) {
+       //      effects[i]->set_uniforms();
+       //}
+
+       glDisable(GL_BLEND);
+       check_error();
+       glDisable(GL_DEPTH_TEST);
+       check_error();
+       glDepthMask(GL_FALSE);
+       check_error();
+
+       glMatrixMode(GL_PROJECTION);
+       glLoadIdentity();
+       glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
+
+       glMatrixMode(GL_MODELVIEW);
+       glLoadIdentity();
+
+       glBegin(GL_QUADS);
+
+       glTexCoord2f(0.0f, 1.0f);
+       glVertex2f(0.0f, 0.0f);
+
+       glTexCoord2f(1.0f, 1.0f);
+       glVertex2f(1.0f, 0.0f);
+
+       glTexCoord2f(1.0f, 0.0f);
+       glVertex2f(1.0f, 1.0f);
+
+       glTexCoord2f(0.0f, 0.0f);
+       glVertex2f(0.0f, 1.0f);
+
+       glEnd();
+       check_error();
+}