Add basic software GPU renderer

src/core/gpu_sw.h

@@ -0,0 +1,71 @@
+#pragma once
+#include "common/gl_texture.h"
+#include "gpu.h"
+#include <array>
+#include <memory>
+#include <vector>
+
+namespace GL {
+class Texture;
+}
+
+class GPU_SW final : public GPU
+{
+public:
+  GPU_SW();
+  ~GPU_SW() override;
+
+  bool Initialize(System* system, DMA* dma, InterruptController* interrupt_controller, Timers* timers) override;
+  void Reset() override;
+
+  u16 GetPixel(u32 x, u32 y) const { return m_vram[VRAM_WIDTH * y + x]; }
+  const u16* GetPixelPtr(u32 x, u32 y) const { return &m_vram[VRAM_WIDTH * y + x]; }
+  u16* GetPixelPtr(u32 x, u32 y) { return &m_vram[VRAM_WIDTH * y + x]; }
+  void SetPixel(u32 x, u32 y, u16 value) { m_vram[VRAM_WIDTH * y + x] = value; }
+
+protected:
+  enum : u32
+  {
+    MAX_VERTICES_PER_POLYGON = 4
+  };
+
+  struct SWVertex
+  {
+    s32 x, y;
+    u8 color_r, color_g, color_b;
+    u8 texcoord_x, texcoord_y;
+  };
+
+  void ReadVRAM(u32 x, u32 y, u32 width, u32 height, void* buffer) override;
+  void FillVRAM(u32 x, u32 y, u32 width, u32 height, u16 color) override;
+  void UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data) override;
+  void CopyVRAM(u32 src_x, u32 src_y, u32 dst_x, u32 dst_y, u32 width, u32 height) override;
+
+  //////////////////////////////////////////////////////////////////////////
+  // Scanout
+  //////////////////////////////////////////////////////////////////////////
+  static void CopyOut15Bit(const u16* src_ptr, u32 src_stride, u32* dst_ptr, u32 dst_stride, u32 width, u32 height);
+
+  static void CopyOut24Bit(const u16* src_ptr, u32 src_stride, u32* dst_ptr, u32 dst_stride, u32 width, u32 height);
+
+  void UpdateDisplay() override;
+
+  //////////////////////////////////////////////////////////////////////////
+  // Rasterization
+  //////////////////////////////////////////////////////////////////////////
+
+  void DispatchRenderCommand(RenderCommand rc, u32 num_vertices, const u32* command_ptr) override;
+
+  static bool IsClockwiseWinding(const SWVertex* v0, const SWVertex* v1, const SWVertex* v2);
+
+  void ShadePixel(RenderCommand rc, u32 x, u32 y, u8 color_r, u8 color_g, u8 color_b, u8 texcoord_x, u8 texcoord_y);
+  void DrawTriangle(RenderCommand rc, const SWVertex* v0, const SWVertex* v1, const SWVertex* v2);
+  void DrawRectangle(RenderCommand rc, s32 origin_x, s32 origin_y, u32 width, u32 height, u8 r, u8 g, u8 b,
+                     u8 origin_texcoord_x, u8 origin_texcoord_y);
+
+  std::unique_ptr<GL::Texture> m_display_texture;
+  std::vector<u32> m_display_texture_buffer;
+
+  std::array<SWVertex, MAX_VERTICES_PER_POLYGON> m_vertex_buffer;
+  std::array<u16, VRAM_WIDTH * VRAM_HEIGHT> m_vram;
+};