VideoCommon: add custom pixel shader constants as a buffer of data to be passed to all backends

Source/Core/VideoCommon/PixelShaderManager.h

@@ -3,6 +3,8 @@
 
 #pragma once
 
+#include <span>
+
 #include "Common/CommonTypes.h"
 #include "VideoCommon/ConstantManager.h"
 
@@ -52,6 +54,10 @@ public:
   PixelShaderConstants constants{};
   bool dirty = false;
 
+  // Constants for custom shaders
+  std::span<u8> custom_constants;
+  bool custom_constants_dirty = false;
+
 private:
   bool m_fog_range_adjusted_changed = false;
   bool m_viewport_changed = false;

Source/Core/VideoCommon/VertexManagerBase.cpp

@@ -595,6 +595,7 @@ void VertexManagerBase::Flush()
     CustomPixelShaderContents custom_pixel_shader_contents;
     std::optional<CustomPixelShader> custom_pixel_shader;
     std::vector<std::string> custom_pixel_texture_names;
+    std::span<u8> custom_pixel_shader_uniforms;
     for (int i = 0; i < texture_names.size(); i++)
     {
       const std::string& texture_name = texture_names[i];
@@ -644,6 +645,12 @@ void VertexManagerBase::Flush()
     // Now we can upload uniforms, as nothing else will override them.
     geometry_shader_manager.SetConstants(m_current_primitive_type);
     pixel_shader_manager.SetConstants();
+    if (!custom_pixel_shader_uniforms.empty() &&
+        pixel_shader_manager.custom_constants.data() != custom_pixel_shader_uniforms.data())
+    {
+      pixel_shader_manager.custom_constants_dirty = true;
+    }
+    pixel_shader_manager.custom_constants = custom_pixel_shader_uniforms;
     UploadUniforms();
 
     // Update the pipeline, or compile one if needed.
@@ -1052,7 +1059,8 @@ void VertexManagerBase::OnEndFrame()
     return;
 
   // In order to reduce CPU readback latency, we want to kick a command buffer roughly halfway
-  // between the draw counters that invoked the readback, or every 250 draws, whichever is smaller.
+  // between the draw counters that invoked the readback, or every 250 draws, whichever is
+  // smaller.
   if (g_ActiveConfig.iCommandBufferExecuteInterval > 0)
   {
     u32 last_draw_counter = 0;