Rewrite host GPU abstraction

- Don't have to repeat the same thing for 4 renderers.
 - Add native Metal renderer.

src/util/postprocessing_shader.h

@@ -1,24 +1,28 @@
-// SPDX-FileCopyrightText: 2019-2022 Connor McLaughlin <stenzek@gmail.com>
+// SPDX-FileCopyrightText: 2019-2023 Connor McLaughlin <stenzek@gmail.com>
 // SPDX-License-Identifier: (GPL-3.0 OR CC-BY-NC-ND-4.0)
 
 #pragma once
+
 #include "common/rectangle.h"
-#include "core/types.h"
+#include "common/timer.h"
+#include "common/types.h"
+#include "gpu_device.h"
+
 #include <array>
 #include <string>
 #include <string_view>
 #include <vector>
 
-namespace FrontendCommon {
+class GPUPipeline;
+class GPUTexture;
+
+class PostProcessingChain;
 
 class PostProcessingShader
 {
-public:
-  enum : u32
-  {
-    PUSH_CONSTANT_SIZE_THRESHOLD = 128
-  };
+  friend PostProcessingChain;
 
+public:
   struct Option
   {
     enum : u32
@@ -49,6 +53,8 @@ public:
     std::string dependent_option;
     Type type;
     u32 vector_size;
+    u32 buffer_size;
+    u32 buffer_offset;
     ValueVector default_value;
     ValueVector min_value;
     ValueVector max_value;
@@ -57,21 +63,15 @@ public:
   };
 
   PostProcessingShader();
-  PostProcessingShader(std::string name, std::string code);
-  PostProcessingShader(const PostProcessingShader& copy);
-  PostProcessingShader(PostProcessingShader& move);
-  ~PostProcessingShader();
-
-  PostProcessingShader& operator=(const PostProcessingShader& copy);
-  PostProcessingShader& operator=(PostProcessingShader& move);
+  PostProcessingShader(std::string name);
+  virtual ~PostProcessingShader();
 
   ALWAYS_INLINE const std::string& GetName() const { return m_name; }
-  ALWAYS_INLINE const std::string& GetCode() const { return m_code; }
   ALWAYS_INLINE const std::vector<Option>& GetOptions() const { return m_options; }
   ALWAYS_INLINE std::vector<Option>& GetOptions() { return m_options; }
   ALWAYS_INLINE bool HasOptions() const { return !m_options.empty(); }
 
-  bool IsValid() const;
+  virtual bool IsValid() const = 0;
 
   const Option* GetOptionByName(const std::string_view& name) const;
   Option* GetOptionByName(const std::string_view& name);
@@ -79,35 +79,21 @@ public:
   std::string GetConfigString() const;
   void SetConfigString(const std::string_view& str);
 
-  bool LoadFromFile(std::string name, const char* filename);
-  bool LoadFromString(std::string name, std::string code);
+  virtual bool ResizeOutput(GPUTexture::Format format, u32 width, u32 height) = 0;
 
-  bool UsePushConstants() const;
-  u32 GetUniformsSize() const;
-  void FillUniformBuffer(void* buffer, u32 texture_width, s32 texture_height, s32 texture_view_x, s32 texture_view_y,
-                         s32 texture_view_width, s32 texture_view_height, u32 window_width, u32 window_height,
-                         s32 original_width, s32 original_height, float time) const;
+  virtual bool CompilePipeline(GPUTexture::Format format, u32 width, u32 height) = 0;
 
-private:
-  struct CommonUniforms
-  {
-    float src_rect[4];
-    float src_size[2];
-    float resolution[2];
-    float rcp_resolution[2];
-    float window_resolution[2];
-    float rcp_window_resolution[2];
-    float original_size[2];
-    float padded_original_size[2];
-    float time;
-    float padding;
-  };
+  virtual bool Apply(GPUTexture* input, GPUFramebuffer* final_target, s32 final_left, s32 final_top, s32 final_width,
+                     s32 final_height, s32 orig_width, s32 orig_height, u32 target_width, u32 target_height) = 0;
 
-  void LoadOptions();
+protected:
+  static void ParseKeyValue(const std::string_view& line, std::string_view* key, std::string_view* value);
+
+  template<typename T>
+  static u32 ParseVector(const std::string_view& line, PostProcessingShader::Option::ValueVector* values);
 
   std::string m_name;
-  std::string m_code;
   std::vector<Option> m_options;
-};
 
-} // namespace FrontendCommon
+  Common::Timer m_timer;
+};