Make shader generation more deterministic by removing a sort of pointers.

[movit] / effect_chain.cpp

diff --git a/effect_chain.cpp b/effect_chain.cpp
index 8a72e1756dd90a98502de0944ffc00225a676227..30dc3e499a7c334f4d0a8e867e9ebbf2d97dd901 100644 (file)
--- a/effect_chain.cpp
+++ b/effect_chain.cpp
@@ -376,16 +376,23 @@ void EffectChain::compile_glsl_program(Phase *phase)
        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.
        if (phase->output_node->outgoing_links.empty() && output_color_ycbcr) {
                switch (output_ycbcr_splitting) {
                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);
@@ -396,6 +403,7 @@ void EffectChain::compile_glsl_program(Phase *phase)
                        // 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");
                }
        }
        frag_shader.append(read_file("footer.frag"));
@@ -439,7 +447,7 @@ void EffectChain::compile_glsl_program(Phase *phase)
                vert_shader[pos + needle.size() - 1] = '1';
        }
 
-       phase->glsl_program_num = resource_pool->compile_glsl_program(vert_shader, frag_shader);
+       phase->glsl_program_num = resource_pool->compile_glsl_program(vert_shader, frag_shader, frag_shader_outputs);
 
        // Collect the resulting location numbers for each uniform.
        collect_uniform_locations(phase->glsl_program_num, &phase->uniforms_sampler2d);
@@ -581,9 +589,17 @@ Phase *EffectChain::construct_phase(Node *output, map<Node *, Phase *> *complete
        // and create a GLSL program for it.
        assert(!phase->effects.empty());
 
-       // Deduplicate the inputs.
-       sort(phase->inputs.begin(), phase->inputs.end());
-       phase->inputs.erase(unique(phase->inputs.begin(), phase->inputs.end()), phase->inputs.end());
+       // 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);
 
        // Allocate samplers for each input.
        phase->input_samplers.resize(phase->inputs.size());