Allow storing values in intermediate framebuffers as sqrt(x).

[movit] / effect_chain.cpp

diff --git a/effect_chain.cpp b/effect_chain.cpp
index fa7340d7a456839f7ef2563d76c5a872182491ff..b0a14777287733fe5c1210ca0d0e6b38e77cfa32 100644 (file)
--- a/effect_chain.cpp
+++ b/effect_chain.cpp
@@ -32,13 +32,14 @@ using namespace std;
 
 namespace movit {
 
-EffectChain::EffectChain(float aspect_nom, float aspect_denom, ResourcePool *resource_pool, GLenum intermediate_format)
+EffectChain::EffectChain(float aspect_nom, float aspect_denom, ResourcePool *resource_pool)
        : aspect_nom(aspect_nom),
          aspect_denom(aspect_denom),
          output_color_rgba(false),
          output_color_ycbcr(false),
          dither_effect(NULL),
-         intermediate_format(intermediate_format),
+         intermediate_format(GL_RGBA16F),
+         intermediate_transformation(NO_FRAMEBUFFER_TRANSFORMATION),
          num_dither_bits(0),
          output_origin(OUTPUT_ORIGIN_BOTTOM_LEFT),
          finalized(false),
@@ -332,7 +333,14 @@ void EffectChain::compile_glsl_program(Phase *phase)
        
                frag_shader += string("uniform sampler2D tex_") + effect_id + ";\n";
                frag_shader += string("vec4 ") + effect_id + "(vec2 tc) {\n";
-               frag_shader += "\treturn tex2D(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";
 
@@ -415,6 +423,15 @@ void EffectChain::compile_glsl_program(Phase *phase)
                        frag_shader_outputs.push_back("RGBA");
                }
        }
+
+       // 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.append(read_file("footer.frag"));
 
        // Collect uniforms from all effects and output them. Note that this needs
@@ -1176,6 +1193,12 @@ 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;