gl_rasterizer: Add documentation to ShaderCacheKey.

This commit is contained in:
bunnei 2015-10-06 18:34:50 -04:00
parent 4b5141954e
commit f2e7f7e101
1 changed files with 16 additions and 0 deletions

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@ -17,6 +17,14 @@
#include "video_core/renderer_opengl/gl_state.h"
#include "video_core/shader/shader_interpreter.h"
/**
* This struct contains all state used to generate the GLSL shader program that emulates the current
* Pica register configuration. This struct is used as a cache key for generated GLSL shader
* programs. The functions in gl_shader_gen.cpp should retrieve state from this struct only, not by
* directly accessing Pica registers. This should reduce the risk of bugs in shader generation where
* Pica state is not being captured in the shader cache key, thereby resulting in (what should be)
* two separate shaders sharing the same key.
*/
struct ShaderCacheKey {
using Regs = Pica::Regs;
@ -36,6 +44,11 @@ struct ShaderCacheKey {
return (stage_index < 4) && ((combiner_buffer_input >> 4) & (1 << stage_index));
}
/**
* This function is used to construct a ShaderCacheKey with the current Pica register
* configuration. Don't construct a ShaderCacheKey manually, instead call this function (and
* extend it as additional state needs to be captured to generate shaders).
*/
static ShaderCacheKey CurrentConfig() {
const auto& regs = Pica::g_state.regs;
ShaderCacheKey config;
@ -43,6 +56,9 @@ struct ShaderCacheKey {
config.alpha_test_func = regs.output_merger.alpha_test.enable ?
regs.output_merger.alpha_test.func.Value() : Pica::Regs::CompareFunc::Always;
// Copy relevant TevStageConfig fields only. We're doing this manually (instead of calling
// the GetTevStages() function) because BitField explicitly disables copies.
config.tev_stages[0].source_raw = regs.tev_stage0.source_raw;
config.tev_stages[1].source_raw = regs.tev_stage1.source_raw;
config.tev_stages[2].source_raw = regs.tev_stage2.source_raw;