rasterizer_cache: Clear null surface to transparent

* Causes visual regressions in Pokemon with RADV

src/video_core/pica/pica_core.cpp

@@ -256,10 +256,6 @@ void PicaCore::WriteInternalReg(u32 id, u32 value, u32 mask) {
 
     case PICA_REG_INDEX(vs.bool_uniforms):
         vs_setup.WriteUniformBoolReg(regs.internal.vs.bool_uniforms.Value());
-        if (!regs.internal.pipeline.gs_unit_exclusive_configuration &&
-            regs.internal.pipeline.use_gs == PipelineRegs::UseGS::No) {
-            gs_setup.WriteUniformBoolReg(regs.internal.vs.bool_uniforms.Value());
-        }
         break;
 
     case PICA_REG_INDEX(vs.int_uniforms[0]):
@@ -268,10 +264,6 @@ void PicaCore::WriteInternalReg(u32 id, u32 value, u32 mask) {
     case PICA_REG_INDEX(vs.int_uniforms[3]): {
         const u32 index = (id - PICA_REG_INDEX(vs.int_uniforms[0]));
         vs_setup.WriteUniformIntReg(index, regs.internal.vs.GetIntUniform(index));
-        if (!regs.internal.pipeline.gs_unit_exclusive_configuration &&
-            regs.internal.pipeline.use_gs == PipelineRegs::UseGS::No) {
-            gs_setup.WriteUniformIntReg(index, regs.internal.vs.GetIntUniform(index));
-        }
         break;
     }
 
@@ -283,11 +275,7 @@ void PicaCore::WriteInternalReg(u32 id, u32 value, u32 mask) {
     case PICA_REG_INDEX(vs.uniform_setup.set_value[5]):
     case PICA_REG_INDEX(vs.uniform_setup.set_value[6]):
     case PICA_REG_INDEX(vs.uniform_setup.set_value[7]): {
-        const auto index = vs_setup.WriteUniformFloatReg(regs.internal.vs, value);
-        if (!regs.internal.pipeline.gs_unit_exclusive_configuration &&
-            regs.internal.pipeline.use_gs == PipelineRegs::UseGS::No && index) {
-            gs_setup.uniforms.f[index.value()] = vs_setup.uniforms.f[index.value()];
-        }
+        vs_setup.WriteUniformFloatReg(regs.internal.vs, value);
         break;
     }
 

src/video_core/pica/shader_setup.cpp

@@ -27,23 +27,21 @@ void ShaderSetup::WriteUniformIntReg(u32 index, const Common::Vec4<u8> values) {
     uniforms.i[index] = values;
 }
 
-std::optional<u32> ShaderSetup::WriteUniformFloatReg(ShaderRegs& config, u32 value) {
+void ShaderSetup::WriteUniformFloatReg(ShaderRegs& config, u32 value) {
     auto& uniform_setup = config.uniform_setup;
     const bool is_float32 = uniform_setup.IsFloat32();
     if (!uniform_queue.Push(value, is_float32)) {
-        return std::nullopt;
+        return;
     }
 
     const auto uniform = uniform_queue.Get(is_float32);
     if (uniform_setup.index >= uniforms.f.size()) {
         LOG_ERROR(HW_GPU, "Invalid float uniform index {}", uniform_setup.index.Value());
-        return std::nullopt;
+        return;
     }
 
-    const u32 index = uniform_setup.index.Value();
-    uniforms.f[index] = uniform;
-    uniform_setup.index.Assign(index + 1);
-    return index;
+    uniforms.f[uniform_setup.index] = uniform;
+    uniform_setup.index.Assign(uniform_setup.index + 1);
 }
 
 u64 ShaderSetup::GetProgramCodeHash() {

src/video_core/pica/shader_setup.h

@@ -4,7 +4,6 @@
 
 #pragma once
 
-#include <optional>
 #include "common/vector_math.h"
 #include "video_core/pica/packed_attribute.h"
 #include "video_core/pica_types.h"
@@ -59,7 +58,7 @@ public:
 
     void WriteUniformIntReg(u32 index, const Common::Vec4<u8> values);
 
-    std::optional<u32> WriteUniformFloatReg(ShaderRegs& config, u32 value);
+    void WriteUniformFloatReg(ShaderRegs& config, u32 value);
 
     u64 GetProgramCodeHash();
 

src/video_core/rasterizer_cache/rasterizer_cache.h

@@ -67,6 +67,16 @@ RasterizerCache<T>::RasterizerCache(Memory::MemorySystem& memory_,
                                            .wrap_s = TextureConfig::WrapMode::ClampToBorder,
                                            .wrap_t = TextureConfig::WrapMode::ClampToBorder,
                                        }));
+
+    auto& null_surface = slot_surfaces[NULL_SURFACE_ID];
+    runtime.ClearTexture(null_surface, {
+                                           .texture_level = 0,
+                                           .texture_rect = null_surface.GetScaledRect(),
+                                           .value =
+                                               {
+                                                   .color = {0.f, 0.f, 0.f, 0.f},
+                                               },
+                                       });
 }
 
 template <class T>

src/video_core/shader/generator/glsl_shader_gen.cpp

@@ -63,7 +63,13 @@ static std::string GetVertexInterfaceDeclaration(bool is_output, bool use_clip_p
     if (is_output && separable_shader) {
         // gl_PerVertex redeclaration is required for separate shader object
         out += "out gl_PerVertex {\n";
+        // Apple Silicon GPU drivers optimize more aggressively, which can create
+        // too much variance and cause visual artifacting in games like Pokemon.
+#ifdef __APPLE__
         out += "    invariant vec4 gl_Position;\n";
+#else
+        out += "    vec4 gl_Position;\n";
+#endif
         if (use_clip_planes) {
             out += "    float gl_ClipDistance[2];\n";
         }