1 files changed, 109 insertions, 2 deletions

diff --git a/src/video_core/renderer_opengl/gl_shader_gen.h b/src/video_core/renderer_opengl/gl_shader_gen.h
index 7ec3bb53f..e01bd34f9 100644
--- a/src/video_core/renderer_opengl/gl_shader_gen.h
+++ b/src/video_core/renderer_opengl/gl_shader_gen.h
@@ -4,9 +4,12 @@
 
 #pragma once
 
+#include <array>
+#include <cstring>
+#include <functional>
 #include <string>
-
-union PicaShaderConfig;
+#include <type_traits>
+#include "video_core/regs.h"
 
 namespace GLShader {
 
@@ -22,6 +25,101 @@ enum Attributes {
 };
 
 /**
+ * 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.
+ *
+ * We use a union because "implicitly-defined copy/move constructor for a union X copies the object
+ * representation of X." and "implicitly-defined copy assignment operator for a union X copies the
+ * object representation (3.9) of X." = Bytewise copy instead of memberwise copy. This is important
+ * because the padding bytes are included in the hash and comparison between objects.
+ */
+union PicaShaderConfig {
+
+    /// Construct a PicaShaderConfig with the current Pica register configuration.
+    static PicaShaderConfig CurrentConfig();
+
+    bool TevStageUpdatesCombinerBufferColor(unsigned stage_index) const {
+        return (stage_index < 4) && (state.combiner_buffer_input & (1 << stage_index));
+    }
+
+    bool TevStageUpdatesCombinerBufferAlpha(unsigned stage_index) const {
+        return (stage_index < 4) && ((state.combiner_buffer_input >> 4) & (1 << stage_index));
+    }
+
+    bool operator==(const PicaShaderConfig& o) const {
+        return std::memcmp(&state, &o.state, sizeof(PicaShaderConfig::State)) == 0;
+    };
+
+    // NOTE: MSVC15 (Update 2) doesn't think `delete`'d constructors and operators are TC.
+    //       This makes BitField not TC when used in a union or struct so we have to resort
+    //       to this ugly hack.
+    //       Once that bug is fixed we can use Pica::Regs::TevStageConfig here.
+    //       Doesn't include const_color because we don't sync it, see comment in CurrentConfig()
+    struct TevStageConfigRaw {
+        u32 sources_raw;
+        u32 modifiers_raw;
+        u32 ops_raw;
+        u32 scales_raw;
+        explicit operator Pica::TexturingRegs::TevStageConfig() const noexcept {
+            Pica::TexturingRegs::TevStageConfig stage;
+            stage.sources_raw = sources_raw;
+            stage.modifiers_raw = modifiers_raw;
+            stage.ops_raw = ops_raw;
+            stage.const_color = 0;
+            stage.scales_raw = scales_raw;
+            return stage;
+        }
+    };
+
+    struct State {
+        Pica::FramebufferRegs::CompareFunc alpha_test_func;
+        Pica::RasterizerRegs::ScissorMode scissor_test_mode;
+        Pica::TexturingRegs::TextureConfig::TextureType texture0_type;
+        std::array<TevStageConfigRaw, 6> tev_stages;
+        u8 combiner_buffer_input;
+
+        Pica::RasterizerRegs::DepthBuffering depthmap_enable;
+        Pica::TexturingRegs::FogMode fog_mode;
+        bool fog_flip;
+
+        struct {
+            struct {
+                unsigned num;
+                bool directional;
+                bool two_sided_diffuse;
+                bool dist_atten_enable;
+            } light[8];
+
+            bool enable;
+            unsigned src_num;
+            Pica::LightingRegs::LightingBumpMode bump_mode;
+            unsigned bump_selector;
+            bool bump_renorm;
+            bool clamp_highlights;
+
+            Pica::LightingRegs::LightingConfig config;
+            Pica::LightingRegs::LightingFresnelSelector fresnel_selector;
+
+            struct {
+                bool enable;
+                bool abs_input;
+                Pica::LightingRegs::LightingLutInput type;
+                float scale;
+            } lut_d0, lut_d1, lut_fr, lut_rr, lut_rg, lut_rb;
+        } lighting;
+
+    } state;
+};
+#if (__GNUC__ >= 5) || defined(__clang__) || defined(_MSC_VER)
+static_assert(std::is_trivially_copyable<PicaShaderConfig::State>::value,
+              "PicaShaderConfig::State must be trivially copyable");
+#endif
+
+/**
  * Generates the GLSL vertex shader program source code for the current Pica state
  * @returns String of the shader source code
  */
@@ -36,3 +134,12 @@ std::string GenerateVertexShader();
 std::string GenerateFragmentShader(const PicaShaderConfig& config);
 
 } // namespace GLShader
+
+namespace std {
+template <>
+struct hash<GLShader::PicaShaderConfig> {
+    size_t operator()(const GLShader::PicaShaderConfig& k) const {
+        return Common::ComputeHash64(&k.state, sizeof(GLShader::PicaShaderConfig::State));
+    }
+};
+} // namespace std