spirv: Implement alpha test

src/shader_recompiler/profile.h

@@ -5,8 +5,8 @@
 #pragma once
 
 #include <array>
-#include <vector>
 #include <optional>
+#include <vector>
 
 #include "common/common_types.h"
 
@@ -27,6 +27,17 @@ enum class InputTopology {
     TrianglesAdjacency,
 };
 
+enum class CompareFunction {
+    Never,
+    Less,
+    Equal,
+    LessThanEqual,
+    Greater,
+    NotEqual,
+    GreaterThanEqual,
+    Always,
+};
+
 struct TransformFeedbackVarying {
     u32 buffer{};
     u32 stride{};
@@ -66,6 +77,8 @@ struct Profile {
     InputTopology input_topology{};
 
     std::optional<float> fixed_state_point_size;
+    std::optional<CompareFunction> alpha_test_func;
+    float alpha_test_reference{};
 
     std::vector<TransformFeedbackVarying> xfb_varyings;
 };