GPU: Partially implemented texture support

src/common/gl_program.cpp

@@ -121,7 +121,7 @@ bool Program::Link()
   return true;
 }
 
-void Program::Bind()
+void Program::Bind() const
 {
   glUseProgram(m_program_id);
 }
@@ -152,15 +152,95 @@ u32 Program::RegisterUniform(const char* name)
   return id;
 }
 
-void Program::Uniform1ui(u32 index, u32 value)
+void Program::Uniform1ui(u32 index, u32 x) const
 {
   Assert(index < m_uniform_locations.size());
   const int location = m_uniform_locations[index];
   if (location >= 0)
-    glUniform1ui(location, value);
+    glUniform1ui(location, x);
 }
 
-void Program::Uniform4f(u32 index, float x, float y, float z, float w)
+void Program::Uniform2ui(u32 index, u32 x, u32 y) const
+{
+  Assert(index < m_uniform_locations.size());
+  const int location = m_uniform_locations[index];
+  if (location >= 0)
+    glUniform2ui(location, x, y);
+}
+
+void Program::Uniform3ui(u32 index, u32 x, u32 y, u32 z) const
+{
+  Assert(index < m_uniform_locations.size());
+  const int location = m_uniform_locations[index];
+  if (location >= 0)
+    glUniform3ui(location, x, y, z);
+}
+
+void Program::Uniform4ui(u32 index, u32 x, u32 y, u32 z, u32 w) const
+{
+  Assert(index < m_uniform_locations.size());
+  const int location = m_uniform_locations[index];
+  if (location >= 0)
+    glUniform4ui(location, x, y, z, w);
+}
+
+void Program::Uniform1i(u32 index, s32 x) const
+{
+  Assert(index < m_uniform_locations.size());
+  const int location = m_uniform_locations[index];
+  if (location >= 0)
+    glUniform1i(location, x);
+}
+
+void Program::Uniform2i(u32 index, s32 x, s32 y) const
+{
+  Assert(index < m_uniform_locations.size());
+  const int location = m_uniform_locations[index];
+  if (location >= 0)
+    glUniform2i(location, x, y);
+}
+
+void Program::Uniform3i(u32 index, s32 x, s32 y, s32 z) const
+{
+  Assert(index < m_uniform_locations.size());
+  const int location = m_uniform_locations[index];
+  if (location >= 0)
+    glUniform3i(location, x, y, z);
+}
+
+void Program::Uniform4i(u32 index, s32 x, s32 y, s32 z, s32 w) const
+{
+  Assert(index < m_uniform_locations.size());
+  const int location = m_uniform_locations[index];
+  if (location >= 0)
+    glUniform4i(location, x, y, z, w);
+}
+
+void Program::Uniform1f(u32 index, float x) const
+{
+  Assert(index < m_uniform_locations.size());
+  const int location = m_uniform_locations[index];
+  if (location >= 0)
+    glUniform1f(location, x);
+}
+
+void Program::Uniform2f(u32 index, float x, float y) const
+{
+  Assert(index < m_uniform_locations.size());
+  const int location = m_uniform_locations[index];
+  if (location >= 0)
+    glUniform2f(location, x, y);
+}
+
+void Program::Uniform3f(u32 index, float x, float y, float z) const
+{
+  Assert(index < m_uniform_locations.size());
+  const int location = m_uniform_locations[index];
+  if (location >= 0)
+    glUniform3f(location, x, y, z);
+}
+
+void Program::Uniform4f(u32 index, float x, float y, float z, float w) const
 {
   Assert(index < m_uniform_locations.size());
   const int location = m_uniform_locations[index];

src/common/gl_program.h

@@ -23,13 +23,23 @@ public:
 
   bool Link();
 
-  void Bind();
+  void Bind() const;
 
   void Destroy();
 
   u32 RegisterUniform(const char* name);
-  void Uniform1ui(u32 index, u32 value);
+  void Uniform1ui(u32 index, u32 x) const;
-  void Uniform4f(u32 index, float x, float y, float z, float w);
+  void Uniform2ui(u32 index, u32 x, u32 y) const;
+  void Uniform3ui(u32 index, u32 x, u32 y, u32 z) const;
+  void Uniform4ui(u32 index, u32 x, u32 y, u32 z, u32 w) const;
+  void Uniform1i(u32 index, s32 x) const;
+  void Uniform2i(u32 index, s32 x, s32 y) const;
+  void Uniform3i(u32 index, s32 x, s32 y, s32 z) const;
+  void Uniform4i(u32 index, s32 x, s32 y, s32 z, s32 w) const;
+  void Uniform1f(u32 index, float x) const;
+  void Uniform2f(u32 index, float x, float y) const;
+  void Uniform3f(u32 index, float x, float y, float z) const;
+  void Uniform4f(u32 index, float x, float y, float z, float w) const;
 
 private:
   GLuint m_program_id = 0;

src/common/gl_texture.cpp

@@ -26,4 +26,9 @@ void Texture::Bind()
   glBindTexture(GL_TEXTURE_2D, m_id);
 }
 
+void Texture::Unbind()
+{
+  glBindTexture(GL_TEXTURE_2D, 0);
+}
+
 } // namespace GL

src/common/gl_texture.h

@@ -14,6 +14,7 @@ public:
   u32 GetHeight() const { return m_height; }
 
   void Bind();
+  static void Unbind();
 
 private:
   GLuint m_id;

src/pse-sdl/sdl_interface.cpp

@@ -77,6 +77,7 @@ bool SDLInterface::CreateGLContext()
     glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS);
   }
 
+  SDL_GL_SetSwapInterval(0);
   return true;
 }
 
@@ -132,7 +133,7 @@ void main()
 
   m_display_program.RegisterUniform("samp0");
   m_display_program.Bind();
-  m_display_program.Uniform1ui(0, 0);
+  m_display_program.Uniform1i(0, 0);
 
   glGenVertexArrays(1, &m_display_vao);
   return true;
@@ -410,8 +411,6 @@ void SDLInterface::SetDisplayTexture(GL::Texture* texture, u32 offset_x, u32 off
   m_display_texture_width = width;
   m_display_texture_height = height;
   m_display_texture_changed = true;
-
-  Render();
 }
 
 void SDLInterface::RenderOSDMessages()
@@ -476,8 +475,6 @@ void SDLInterface::DoSaveState(u32 index)
 
 void SDLInterface::Run()
 {
-  Timer last_render_time;
-
   while (m_running)
   {
     for (;;)
@@ -489,12 +486,7 @@ void SDLInterface::Run()
         break;
     }
 
-    while (!m_display_texture_changed || last_render_time.GetTimeSeconds() < (1.0f / 60.0f))
+    m_system->RunFrame();
-    {
+    Render();
-      m_system->RunFrame();
-    }
-
-    // Render();
-    last_render_time.Reset();
   }
 }

src/pse/dma.cpp

@@ -116,8 +116,10 @@ void DMA::WriteRegister(u32 offset, u32 value)
 void DMA::SetRequest(Channel channel, bool request)
 {
   ChannelState& cs = m_state[static_cast<u32>(channel)];
-  cs.request = request;
+  if (cs.request == request)
+    return;
 
+  cs.request = request;
   if (CanRunChannel(channel))
     RunDMA(channel);
 }
@@ -199,7 +201,7 @@ void DMA::RunDMA(Channel channel)
 
           const u32 word_count = header >> 24;
           const u32 next_address = header & UINT32_C(0xFFFFFF);
-          Log_DebugPrintf(" .. linked list entry at 0x%08X size=%u(%u words) next=0x%08X", current_address,
+          Log_TracePrintf(" .. linked list entry at 0x%08X size=%u(%u words) next=0x%08X", current_address,
                           word_count * UINT32_C(4), word_count, next_address);
           current_address += sizeof(header);
 

src/pse/gpu.cpp

@@ -2,6 +2,7 @@
 #include "YBaseLib/Log.h"
 #include "bus.h"
 #include "dma.h"
+#include "system.h"
 Log_SetChannel(GPU);
 
 GPU::GPU() = default;
@@ -24,14 +25,40 @@ void GPU::Reset()
 void GPU::SoftReset()
 {
   m_GPUSTAT.bits = 0x14802000;
-  UpdateDMARequest();
+  UpdateGPUSTAT();
 }
 
-void GPU::UpdateDMARequest()
+void GPU::UpdateGPUSTAT()
 {
-  const bool request = m_GPUSTAT.dma_direction != DMADirection::Off;
+  m_GPUSTAT.ready_to_send_vram = !m_GPUREAD_buffer.empty();
-  m_GPUSTAT.dma_data_request = request;
+  m_GPUSTAT.ready_to_recieve_cmd = m_GPUREAD_buffer.empty();
-  m_dma->SetRequest(DMA::Channel::GPU, request);
+  m_GPUSTAT.ready_to_recieve_dma = m_GPUREAD_buffer.empty();
+
+  bool dma_request;
+  switch (m_GPUSTAT.dma_direction)
+  {
+    case DMADirection::Off:
+      dma_request = false;
+      break;
+
+    case DMADirection::FIFO:
+      dma_request = true; // FIFO not full/full
+      break;
+
+    case DMADirection::CPUtoGP0:
+      dma_request = m_GPUSTAT.ready_to_recieve_dma;
+      break;
+
+    case DMADirection::GPUREADtoCPU:
+      dma_request = m_GPUSTAT.ready_to_send_vram;
+      break;
+
+    default:
+      dma_request = false;
+      break;
+  }
+  m_GPUSTAT.dma_data_request = dma_request;
+  m_dma->SetRequest(DMA::Channel::GPU, dma_request);
 }
 
 u32 GPU::ReadRegister(u32 offset)
@@ -96,8 +123,16 @@ void GPU::DMAWrite(u32 value)
 
 u32 GPU::ReadGPUREAD()
 {
-  Log_ErrorPrintf("GPUREAD not implemented");
+  if (m_GPUREAD_buffer.empty())
-  return UINT32_C(0xFFFFFFFF);
+  {
+    Log_ErrorPrintf("GPUREAD read while buffer is empty");
+    return UINT32_C(0xFFFFFFFF);
+  }
+
+  const u32 value = m_GPUREAD_buffer.front();
+  m_GPUREAD_buffer.pop_front();
+  UpdateGPUSTAT();
+  return value;
 }
 
 void GPU::WriteGP0(u32 value)
@@ -107,6 +142,7 @@ void GPU::WriteGP0(u32 value)
 
   const u8 command = Truncate8(m_GP0_command[0] >> 24);
   const u32 param = m_GP0_command[0] & UINT32_C(0x00FFFFFF);
+  UpdateGPUSTAT();
 
   if (command >= 0x20 && command <= 0x7F)
   {
@@ -128,6 +164,13 @@ void GPU::WriteGP0(u32 value)
       }
       break;
 
+      case 0xC0: // Copy Rectnagle VRAM->CPU
+      {
+        if (!HandleCopyRectangleVRAMToCPUCommand())
+          return;
+      }
+      break;
+
       case 0xE1: // Set draw mode
       {
         // 0..10 bits match GPUSTAT
@@ -136,6 +179,7 @@ void GPU::WriteGP0(u32 value)
         m_GPUSTAT.texture_disable = (param & (UINT32_C(1) << 11)) != 0;
         m_texture_config.x_flip = (param & (UINT32_C(1) << 12)) != 0;
         m_texture_config.y_flip = (param & (UINT32_C(1) << 13)) != 0;
+        m_texture_config.SetColorMode(m_GPUSTAT.texture_color_mode);
         Log_DebugPrintf("Set draw mode %08X", param);
       }
       break;
@@ -195,6 +239,7 @@ void GPU::WriteGP0(u32 value)
   }
 
   m_GP0_command.clear();
+  UpdateGPUSTAT();
 }
 
 void GPU::WriteGP1(u32 value)
@@ -207,7 +252,15 @@ void GPU::WriteGP1(u32 value)
     {
       m_GPUSTAT.dma_direction = static_cast<DMADirection>(param);
       Log_DebugPrintf("DMA direction <- 0x%02X", static_cast<u32>(m_GPUSTAT.dma_direction.GetValue()));
-      UpdateDMARequest();
+      UpdateGPUSTAT();
+    }
+    break;
+
+    case 0x05: // Set display start address
+    {
+      // TODO: Remove this later..
+      FlushRender();
+      UpdateDisplay();
     }
     break;
 
@@ -319,12 +372,90 @@ bool GPU::HandleCopyRectangleCPUToVRAMCommand()
     return true;
   }
 
+  FlushRender();
   UpdateVRAM(dst_x, dst_y, copy_width, copy_height, &m_GP0_command[3]);
   return true;
 }
 
+bool GPU::HandleCopyRectangleVRAMToCPUCommand()
+{
+  if (m_GP0_command.size() < 3)
+    return false;
+
+  const u32 width = m_GP0_command[2] & UINT32_C(0xFFFF);
+  const u32 height = m_GP0_command[2] >> 16;
+  const u32 num_pixels = width * height;
+  const u32 num_words = ((num_pixels + 1) / 2);
+  const u32 src_x = m_GP0_command[1] & UINT32_C(0xFFFF);
+  const u32 src_y = m_GP0_command[1] >> 16;
+
+  Log_DebugPrintf("Copy rectangle from VRAM to CPU offset=(%u,%u), size=(%u,%u)", src_x, src_y, width, height);
+
+  if ((src_x + width) > VRAM_WIDTH || (src_x + height) > VRAM_HEIGHT)
+  {
+    Panic("Out of bounds VRAM copy");
+    return true;
+  }
+
+  // TODO: Implement.
+  for (u32 i = 0; i < num_words; i++)
+    m_GPUREAD_buffer.push_back(0);
+
+  // Is this correct?
+  return true;
+}
+
+void GPU::UpdateDisplay()
+{
+  m_texture_config.page_changed = true;
+  m_system->IncrementFrameNumber();
+}
+
 void GPU::UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data) {}
 
 void GPU::DispatchRenderCommand(RenderCommand rc, u32 num_vertices) {}
 
-void GPU::FlushRender() {}
+void GPU::FlushRender() {}
+
+void GPU::TextureConfig::SetColorMode(TextureColorMode new_color_mode)
+{
+  if (new_color_mode == TextureColorMode::Reserved_Direct16Bit)
+    new_color_mode = TextureColorMode::Direct16Bit;
+
+  if (color_mode == new_color_mode)
+    return;
+
+  color_mode = new_color_mode;
+}
+
+void GPU::TextureConfig::SetFromPolygonTexcoord(u32 texcoord0, u32 texcoord1)
+{
+  SetFromPaletteAttribute(Truncate16(texcoord0 >> 16));
+  SetFromPageAttribute(Truncate16(texcoord1 >> 16));
+}
+
+void GPU::TextureConfig::SetFromRectangleTexcoord(u32 texcoord)
+{
+  SetFromPaletteAttribute(Truncate16(texcoord >> 16));
+}
+
+void GPU::TextureConfig::SetFromPageAttribute(u16 value)
+{
+  value &= PAGE_ATTRIBUTE_MASK;
+  if (page_attribute == value)
+    return;
+
+  base_x = static_cast<s32>(ZeroExtend32(value & UINT16_C(0x1FF)) * UINT32_C(64));
+  base_y = static_cast<s32>(ZeroExtend32((value >> 11) & UINT16_C(1)) * UINT32_C(512));
+  page_changed = true;
+}
+
+void GPU::TextureConfig::SetFromPaletteAttribute(u16 value)
+{
+  value &= PALETTE_ATTRIBUTE_MASK;
+  if (palette_attribute == value)
+    return;
+
+  palette_x = static_cast<s32>(ZeroExtend32(value & UINT16_C(0x3F)) * UINT32_C(16));
+  palette_y = static_cast<s32>(ZeroExtend32((value >> 6) & UINT16_C(0x1FF)));
+}

src/pse/gpu.h

@@ -2,6 +2,8 @@
 #include "common/bitfield.h"
 #include "types.h"
 #include <array>
+#include <deque>
+#include <vector>
 
 class System;
 class Bus;
@@ -30,6 +32,8 @@ protected:
   static constexpr u32 VRAM_WIDTH = 1024;
   static constexpr u32 VRAM_HEIGHT = 512;
   static constexpr u32 VRAM_SIZE = VRAM_WIDTH * VRAM_HEIGHT * sizeof(u16);
+  static constexpr u32 TEXTURE_PAGE_WIDTH = 256;
+  static constexpr u32 TEXTURE_PAGE_HEIGHT = 256;
 
   static constexpr s32 S11ToS32(u32 value)
   {
@@ -63,17 +67,26 @@ protected:
     R16x16 = 3
   };
 
+  enum class TextureColorMode : u8
+  {
+    Palette4Bit = 0,
+    Palette8Bit = 1,
+    Direct16Bit = 2,
+    Reserved_Direct16Bit = 3
+  };
+
   union RenderCommand
   {
     u32 bits;
 
     BitField<u32, u32, 0, 23> color_for_first_vertex;
-    BitField<u32, bool, 24, 1> texture_enable; // not valid for lines
+    BitField<u32, bool, 24, 1> texture_blending_raw; // not valid for lines
     BitField<u32, bool, 25, 1> transparency_enable;
+    BitField<u32, bool, 26, 1> texture_enable;
     BitField<u32, DrawRectangleSize, 27, 2> rectangle_size; // only for rectangles
     BitField<u32, bool, 27, 1> quad_polygon;                // only for polygons
     BitField<u32, bool, 27, 1> polyline;                    // only for lines
-    BitField<u32, bool, 28, 1> shading_enable;                     // 0 - flat, 1 = gouroud
+    BitField<u32, bool, 28, 1> shading_enable;              // 0 - flat, 1 = gouroud
     BitField<u32, Primitive, 29, 21> primitive;
   };
 
@@ -90,7 +103,10 @@ protected:
   };
 
   void SoftReset();
-  void UpdateDMARequest();
+
+  // Updates dynamic bits in GPUSTAT (ready to send VRAM/ready to receive DMA)
+  void UpdateGPUSTAT();
+
   u32 ReadGPUREAD();
   void WriteGP0(u32 value);
   void WriteGP1(u32 value);
@@ -98,8 +114,10 @@ protected:
   // Rendering commands, returns false if not enough data is provided
   bool HandleRenderCommand();
   bool HandleCopyRectangleCPUToVRAMCommand();
+  bool HandleCopyRectangleVRAMToCPUCommand();
 
   // Rendering in the backend
+  virtual void UpdateDisplay();
   virtual void UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data);
   virtual void DispatchRenderCommand(RenderCommand rc, u32 num_vertices);
   virtual void FlushRender();
@@ -114,7 +132,7 @@ protected:
     BitField<u32, u8, 0, 4> texture_page_x_base;
     BitField<u32, u8, 4, 1> texture_page_y_base;
     BitField<u32, u8, 5, 2> semi_transparency;
-    BitField<u32, u8, 7, 2> texture_page_colors;
+    BitField<u32, TextureColorMode, 7, 2> texture_color_mode;
     BitField<u32, bool, 9, 1> dither_enable;
     BitField<u32, bool, 10, 1> draw_to_display_area;
     BitField<u32, bool, 11, 1> draw_set_mask_bit;
@@ -140,6 +158,33 @@ protected:
 
   struct TextureConfig
   {
+    static constexpr u16 PAGE_ATTRIBUTE_MASK = UINT16_C(0b0000100111111111);
+    static constexpr u16 PALETTE_ATTRIBUTE_MASK = UINT16_C(0b0111111111111111);
+
+    // decoded values
+    s32 base_x;
+    s32 base_y;
+    s32 palette_x;
+    s32 palette_y;
+
+    // original values
+    u16 page_attribute;          // from register in rectangle modes/vertex in polygon modes
+    u16 palette_attribute;       // from vertex
+    TextureColorMode color_mode; // from register/vertex in polygon modes
+
+    bool page_changed = false;
+
+    bool IsPageChanged() const { return page_changed; }
+    void ClearPageChangedFlag() { page_changed = false; }
+
+    void SetColorMode(TextureColorMode new_color_mode);
+
+    void SetFromPolygonTexcoord(u32 texcoord0, u32 texcoord1);
+    void SetFromRectangleTexcoord(u32 texcoord);
+
+    void SetFromPageAttribute(u16 value);
+    void SetFromPaletteAttribute(u16 value);
+
     u8 window_mask_x;   // in 8 pixel steps
     u8 window_mask_y;   // in 8 pixel steps
     u8 window_offset_x; // in 8 pixel steps
@@ -160,5 +205,11 @@ protected:
     s32 y;
   } m_drawing_offset = {};
 
+  struct TexturePageConfig
+  {
+
+  } m_texture_page_config = {};
+
   std::vector<u32> m_GP0_command;
+  std::deque<u32> m_GPUREAD_buffer;
 };

src/pse/gpu_hw.cpp

@@ -17,8 +17,8 @@ void GPU_HW::LoadVertices(RenderCommand rc, u32 num_vertices)
       const bool textured = rc.texture_enable;
 
       // if we're drawing quads, we need to create a degenerate triangle to restart the triangle strip
-      if (rc.quad_polygon && !m_vertex_staging.empty())
+      if (rc.quad_polygon && !m_batch_vertices.empty())
-        m_vertex_staging.push_back(m_vertex_staging.back());
+        m_batch_vertices.push_back(m_batch_vertices.back());
 
       u32 buffer_pos = 1;
       for (u32 i = 0; i < num_vertices; i++)
@@ -30,12 +30,20 @@ void GPU_HW::LoadVertices(RenderCommand rc, u32 num_vertices)
         hw_vert.x = vp.x();
         hw_vert.y = vp.y();
 
+        // excluding lower-right coordinates
+        if ((i & UINT32_C(1)) != 0)
+          hw_vert.x--;
+        if ((i & UINT32_C(2)) != 0)
+          hw_vert.y--;
+
         if (textured)
-          hw_vert.texcoord = (m_GP0_command[buffer_pos++] & UINT32_C(0x0000FFFF));
+          hw_vert.texcoord = Truncate16(m_GP0_command[buffer_pos++]);
         else
           hw_vert.texcoord = 0;
 
-        m_vertex_staging.push_back(hw_vert);
+        hw_vert.padding = 0;
+
+        m_batch_vertices.push_back(hw_vert);
       }
     }
     break;
@@ -62,35 +70,73 @@ void GPU_HW::CalcScissorRect(int* left, int* top, int* right, int* bottom)
   *bottom = m_drawing_area.bottom_right_y;
 }
 
+static void DefineMacro(std::stringstream& ss, const char* name, bool enabled)
+{
+  if (enabled)
+    ss << "#define " << name << " 1\n";
+  else
+    ss << "/* #define " << name << " 0 */\n";
+}
+
+void GPU_HW::GenerateShaderHeader(std::stringstream& ss)
+{
+  ss << "#version 330 core\n\n";
+  ss << "const vec2 vram_size = vec2(float(" << VRAM_WIDTH << "), float(" << VRAM_HEIGHT << "));\n";
+  ss << "const vec2 rcp_vram_size = vec2(1.0, 1.0) / vram_size;\n";
+  ss << R"(
+
+float fixYCoord(float y)
+{
+  return 1.0 - rcp_vram_size.y - y;
+}
+
+uint RGBA8ToRGBA5551(vec4 v)
+{
+  uint r = uint(v.r * 255.0) >> 3;
+  uint g = uint(v.g * 255.0) >> 3;
+  uint b = uint(v.b * 255.0) >> 3;
+  uint a = (v.a != 0.0) ? 1u : 0u;
+  return (r) | (g << 5) | (b << 10) | (a << 15);
+}
+
+vec4 RGBA5551ToRGBA8(uint v)
+{
+  uint r = (v & 0x1Fu);
+  uint g = ((v >> 5) & 0x1Fu);
+  uint b = ((v >> 10) & 0x1Fu);
+  uint a = ((v >> 15) & 0x01u);
+
+  return vec4(float(r) * 255.0, float(g) * 255.0, float(b) * 255.0, float(a) * 255.0);
+}
+)";
+}
+
 std::string GPU_HW::GenerateVertexShader(bool textured)
 {
   std::stringstream ss;
-  ss << "#version 330 core\n";
+  GenerateShaderHeader(ss);
-  if (textured)
+  DefineMacro(ss, "TEXTURED", textured);
-    ss << "#define TEXTURED 1\n";
-  else
-    ss << "/* #define TEXTURED 0 */\n";
 
   ss << R"(
-in ivec2 a_position;
+in ivec2 a_pos;
-in vec4 a_color;
+in vec4 a_col0;
-in uint a_texcoord;
+in vec2 a_tex0;
 
-out vec4 v_color;
+out vec4 v_col0;
 #if TEXTURED
-  out vec2 v_texcoord;
+  out vec2 v_tex0;
 #endif
 
 void main()
 {
   // 0..+1023 -> -1..1
-  float pos_x = (float(a_position.x) / 511.5) - 1.0;
+  float pos_x = (float(a_pos.x) / 511.5) - 1.0;
-  float pos_y = (float(a_position.y) / -255.5) + 1.0;
+  float pos_y = (float(a_pos.y) / -255.5) + 1.0;
   gl_Position = vec4(pos_x, pos_y, 0.0, 1.0);
 
-  v_color = a_color;
+  v_col0 = a_col0;
   #if TEXTURED
-    v_texcoord = vec2(float(a_texcoord & 0xFFu) / 256.0, float((a_texcoord >> 8) & 0xFFu) / 256.0);
+    v_tex0 = vec2(a_tex0.x / 4, a_tex0.y);
   #endif
 }
 )";
@@ -98,29 +144,154 @@ void main()
   return ss.str();
 }
 
-std::string GPU_HW::GenerateFragmentShader(bool textured)
+std::string GPU_HW::GenerateFragmentShader(bool textured, bool blending)
 {
   std::stringstream ss;
-  ss << "#version 330 core\n";
+  GenerateShaderHeader(ss);
-  if (textured)
+  DefineMacro(ss, "TEXTURED", textured);
-    ss << "#define TEXTURED 1\n";
+  DefineMacro(ss, "BLENDING", blending);
-  else
-    ss << "/* #define TEXTURED 0 */\n";
 
   ss << R"(
-in vec4 v_color;
+in vec4 v_col0;
 #if TEXTURED
-  in vec2 v_texcoord;
+  in vec2 v_tex0;
+  uniform sampler2D samp0;
 #endif
 
-out vec4 ocol0;
+out vec4 o_col0;
 
 void main()
 {
-  ocol0 = v_color;
+  #if TEXTURED
-  //ocol0 = vec4(1.0, 0.5, 0.5, 1.0);
+    vec4 texcol = texture(samp0, v_tex0);
+    #if BLENDING
+      o_col0 = v_col0 * texcol;
+    #else
+      o_col0 = /*v_col0 + */texcol;
+    #endif
+  #else
+    o_col0 = v_col0;
+  #endif
 }
 )";
 
   return ss.str();
 }
+
+std::string GPU_HW::GenerateScreenQuadVertexShader()
+{
+  std::stringstream ss;
+  GenerateShaderHeader(ss);
+  ss << R"(
+
+out vec2 v_tex0;
+
+void main()
+{
+  v_tex0 = vec2(float((gl_VertexID << 1) & 2), float(gl_VertexID & 2));
+  gl_Position = vec4(v_tex0 * vec2(2.0f, -2.0f) + vec2(-1.0f, 1.0f), 0.0f, 1.0f);
+  gl_Position.y = -gl_Position.y;
+}
+)";
+
+  return ss.str();
+}
+
+std::string GPU_HW::GenerateTexturePageProgram(TextureColorMode mode)
+{
+  const bool is_palette = (mode == GPU::TextureColorMode::Palette4Bit || mode == GPU::TextureColorMode::Palette8Bit);
+
+  std::stringstream ss;
+  GenerateShaderHeader(ss);
+  DefineMacro(ss, "PALETTE", is_palette);
+  DefineMacro(ss, "PALETTE_4_BIT", mode == GPU::TextureColorMode::Palette4Bit);
+  DefineMacro(ss, "PALETTE_8_BIT", mode == GPU::TextureColorMode::Palette8Bit);
+
+  ss << R"(
+uniform sampler2D samp0;
+uniform vec2 base_offset;
+
+#if PALETTE
+uniform vec2 palette_offset;
+#endif
+
+in vec2 v_tex0;
+out vec4 o_col0;
+
+void main()
+{
+  #if PALETTE_4_BIT
+    vec2 local_coords = vec2(v_tex0.x / 4.0, v_tex0.y);
+  #elif PALETTE_8_BIT
+    vec2 local_coords = vec2(v_tex0.x / 2.0, v_tex0.y);
+  #else
+    vec2 local_coords = v_tex0;
+  #endif
+
+  // fixup coords
+  vec2 coords = vec2(local_coords.x + base_offset.x, fixYCoord(local_coords.y + base_offset.y));
+
+  // load colour/palette
+  vec4 color = texture(samp0, coords);
+
+  // apply palette
+  #if PALETTE
+    #if PALETTE_4_BIT
+      uint subpixel = uint(gl_FragCoord.x) & 3u;
+      uint vram_value = RGBA8ToRGBA5551(color);
+      float palette_index = float((vram_value >> (subpixel * 4u)) & 0x0Fu) * rcp_vram_size.x;
+    #elif PALETTE_8_BIT
+      // TODO: Still has precision issues here
+      uint subpixel = uint(gl_FragCoord.x) & 1u;
+      float palette_index = ((subpixel == 0u) ? color.x : color.y) * (255.0 * rcp_vram_size.x);
+    #endif
+    vec2 palette_coords = vec2(palette_offset.x + palette_index, fixYCoord(palette_offset.y));
+    color = texture(samp0, palette_coords);
+  #endif
+
+  o_col0 = color;
+}
+)";
+
+  return ss.str();
+}
+
+void GPU_HW::UpdateTexturePageTexture() {}
+
+void GPU_HW::DispatchRenderCommand(RenderCommand rc, u32 num_vertices)
+{
+  if (rc.texture_enable)
+  {
+    // extract texture lut/page
+    switch (rc.primitive)
+    {
+      case Primitive::Polygon:
+      {
+        if (rc.shading_enable)
+          m_texture_config.SetFromPolygonTexcoord(m_GP0_command[2], m_GP0_command[5]);
+        else
+          m_texture_config.SetFromPolygonTexcoord(m_GP0_command[2], m_GP0_command[4]);
+      }
+      break;
+
+      default:
+        break;
+    }
+
+    if (m_texture_config.IsPageChanged())
+    {
+      if (!m_batch_vertices.empty())
+        FlushRender();
+
+      UpdateTexturePageTexture();
+      m_texture_config.ClearPageChangedFlag();
+    }
+  }
+
+  // flush when the command changes
+  if (!m_batch_vertices.empty()) // && m_batch_command.bits != rc.bits)
+    FlushRender();
+
+  m_batch_command = rc;
+  LoadVertices(rc, num_vertices);
+}

src/pse/gpu_hw.h

@@ -1,6 +1,7 @@
 #pragma once
 #include "gpu.h"
 #include <string>
+#include <sstream>
 #include <vector>
 
 class GPU_HW : public GPU
@@ -15,17 +16,30 @@ protected:
     s32 x;
     s32 y;
     u32 color;
-    u32 texcoord;
+    u16 texcoord;
+    u16 padding;
   };
 
-  void LoadVertices(RenderCommand rc, u32 num_vertices);
+  virtual void UpdateTexturePageTexture();
+
+  bool IsFlushed() const { return !m_batch_vertices.empty(); }
+
+  void DispatchRenderCommand(RenderCommand rc, u32 num_vertices) override;
 
   void CalcViewport(int* x, int* y, int* width, int* height);
   void CalcScissorRect(int* left, int* top, int* right, int* bottom);
 
   std::string GenerateVertexShader(bool textured);
-  std::string GenerateFragmentShader(bool textured);
+  std::string GenerateFragmentShader(bool textured, bool blending);
+  std::string GenerateScreenQuadVertexShader();
+  std::string GenerateTexturePageProgram(TextureColorMode mode);
 
-  std::vector<HWVertex> m_vertex_staging;
+  std::vector<HWVertex> m_batch_vertices;
+  RenderCommand m_batch_command = {};
+
+private:
+  void GenerateShaderHeader(std::stringstream& ss);
+
+  void LoadVertices(RenderCommand rc, u32 num_vertices);
 };
 

src/pse/gpu_hw_opengl.cpp

@@ -32,6 +32,11 @@ void GPU_HW_OpenGL::Reset()
   ClearFramebuffer();
 }
 
+std::tuple<s32, s32> GPU_HW_OpenGL::ConvertToFramebufferCoordinates(s32 x, s32 y)
+{
+  return std::make_tuple(x, static_cast<s32>(static_cast<s32>(VRAM_HEIGHT) - y));
+}
+
 void GPU_HW_OpenGL::CreateFramebuffer()
 {
   m_framebuffer_texture =
@@ -41,6 +46,13 @@ void GPU_HW_OpenGL::CreateFramebuffer()
   glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer_fbo_id);
   glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_framebuffer_texture->GetGLId(), 0);
   Assert(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE);
+
+  m_texture_page_texture =
+    std::make_unique<GL::Texture>(TEXTURE_PAGE_WIDTH, TEXTURE_PAGE_HEIGHT, GL_RGBA, GL_UNSIGNED_BYTE, nullptr, false);
+  glGenFramebuffers(1, &m_texture_page_fbo_id);
+  glBindFramebuffer(GL_FRAMEBUFFER, m_texture_page_fbo_id);
+  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_texture_page_texture->GetGLId(), 0);
+  Assert(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE);
 }
 
 void GPU_HW_OpenGL::ClearFramebuffer()
@@ -51,14 +63,17 @@ void GPU_HW_OpenGL::ClearFramebuffer()
   glClear(GL_COLOR_BUFFER_BIT);
   glBindFramebuffer(GL_FRAMEBUFFER, 0);
 
-  //m_system->GetHostInterface()->SetDisplayTexture(m_framebuffer_texture.get(), 0, 0, VRAM_WIDTH, VRAM_HEIGHT);
+  m_system->GetHostInterface()->SetDisplayTexture(m_framebuffer_texture.get(), 0, 0, VRAM_WIDTH, VRAM_HEIGHT);
 }
 
 void GPU_HW_OpenGL::DestroyFramebuffer()
 {
+  glDeleteFramebuffers(1, &m_texture_page_fbo_id);
+  m_texture_page_fbo_id = 0;
+  m_texture_page_texture.reset();
+
   glDeleteFramebuffers(1, &m_framebuffer_fbo_id);
   m_framebuffer_fbo_id = 0;
-
   m_framebuffer_texture.reset();
 }
 
@@ -70,52 +85,86 @@ void GPU_HW_OpenGL::CreateVertexBuffer()
 
   glGenVertexArrays(1, &m_vao_id);
   glBindVertexArray(m_vao_id);
-  glVertexAttribIPointer(0, 2, GL_INT, sizeof(HWVertex), reinterpret_cast<void*>(offsetof(HWVertex, x)));
-  glVertexAttribPointer(1, 4, GL_UNSIGNED_BYTE, true, sizeof(HWVertex),
-                        reinterpret_cast<void*>(offsetof(HWVertex, color)));
-  glVertexAttribIPointer(2, 1, GL_UNSIGNED_INT, sizeof(HWVertex), reinterpret_cast<void*>(offsetof(HWVertex, color)));
   glEnableVertexAttribArray(0);
   glEnableVertexAttribArray(1);
   glEnableVertexAttribArray(2);
+  glVertexAttribIPointer(0, 2, GL_INT, sizeof(HWVertex), reinterpret_cast<void*>(offsetof(HWVertex, x)));
+  glVertexAttribPointer(1, 4, GL_UNSIGNED_BYTE, true, sizeof(HWVertex),
+                        reinterpret_cast<void*>(offsetof(HWVertex, color)));
+  glVertexAttribPointer(2, 2, GL_UNSIGNED_BYTE, true, sizeof(HWVertex),
+                        reinterpret_cast<void*>(offsetof(HWVertex, texcoord)));
   glBindVertexArray(0);
+
+  glGenVertexArrays(1, &m_attributeless_vao_id);
 }
 
 bool GPU_HW_OpenGL::CompilePrograms()
 {
-  for (u32 texture_enable_i = 0; texture_enable_i < 2; texture_enable_i++)
+  bool result = true;
-  {
+  result &= CompileProgram(m_color_program, false, false);
-    const bool texture_enable = ConvertToBool(texture_enable_i);
+  result &= CompileProgram(m_texture_program, true, false);
-    const std::string vs = GenerateVertexShader(texture_enable);
+  result &= CompileProgram(m_blended_texture_program, true, true);
-    const std::string fs = GenerateFragmentShader(texture_enable);
+  if (!result)
+    return false;
 
-    GL::Program& prog = texture_enable ? m_texture_program : m_color_program;
+  const std::string screen_quad_vs = GenerateScreenQuadVertexShader();
-    if (!prog.Compile(vs.c_str(), fs.c_str()))
+  for (u32 palette_size = 0; palette_size < static_cast<u32>(m_texture_page_programs.size()); palette_size++)
+  {
+    const std::string fs = GenerateTexturePageProgram(static_cast<TextureColorMode>(palette_size));
+
+    GL::Program& prog = m_texture_page_programs[palette_size];
+    if (!prog.Compile(screen_quad_vs.c_str(), fs.c_str()))
       return false;
 
-    prog.BindAttribute(0, "a_position");
+    prog.BindFragData(0, "o_col0");
-    prog.BindAttribute(1, "a_color");
-    if (texture_enable)
-      prog.BindAttribute(2, "a_texcoord");
-
-    prog.BindFragData(0, "ocol0");
 
     if (!prog.Link())
       return false;
+
+    prog.RegisterUniform("samp0");
+    prog.RegisterUniform("base_offset");
+    prog.RegisterUniform("palette_offset");
+    prog.Bind();
+    prog.Uniform1i(0, 0);
   }
 
   return true;
 }
 
-bool GPU_HW_OpenGL::SetProgram(bool texture_enable)
+bool GPU_HW_OpenGL::CompileProgram(GL::Program& prog, bool textured, bool blending)
 {
-  GL::Program& prog = texture_enable ? m_texture_program : m_color_program;
+  const std::string vs = GenerateVertexShader(textured);
-  if (!prog.IsVaild())
+  const std::string fs = GenerateFragmentShader(textured, blending);
+  if (!prog.Compile(vs.c_str(), fs.c_str()))
+    return false;
+
+  prog.BindAttribute(0, "a_pos");
+  prog.BindAttribute(1, "a_col0");
+  if (textured)
+    prog.BindAttribute(2, "a_tex0");
+
+  prog.BindFragData(0, "o_col0");
+
+  if (!prog.Link())
     return false;
 
   prog.Bind();
+
+  if (textured)
+  {
+    prog.RegisterUniform("samp0");
+    prog.Uniform1i(0, 0);
+  }
+
   return true;
 }
 
+void GPU_HW_OpenGL::SetProgram(bool textured, bool blending)
+{
+  const GL::Program& prog = textured ? (blending ? m_blended_texture_program : m_texture_program) : m_color_program;
+  prog.Bind();
+}
+
 void GPU_HW_OpenGL::SetViewport()
 {
   int x, y, width, height;
@@ -144,70 +193,100 @@ inline u32 ConvertRGBA5551ToRGBA8888(u16 color)
   return ZeroExtend32(r) | (ZeroExtend32(g) << 8) | (ZeroExtend32(b) << 16) | (ZeroExtend32(a) << 24);
 }
 
-void GPU_HW_OpenGL::UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data)
+void GPU_HW_OpenGL::UpdateDisplay()
 {
-  const u32 pixel_count = width * height;
+  GPU_HW::UpdateDisplay();
-  std::vector<u32> rgba_data;
-  rgba_data.reserve(pixel_count);
-
-  const u8* source_ptr = static_cast<const u8*>(data);
-  for (u32 i = 0; i < pixel_count; i++)
-  {
-    u16 src_col;
-    std::memcpy(&src_col, source_ptr, sizeof(src_col));
-    source_ptr += sizeof(src_col);
-
-    const u32 dst_col = ConvertRGBA5551ToRGBA8888(src_col);
-    rgba_data.push_back(dst_col);
-  }
-
-  m_framebuffer_texture->Bind();
-  glTexSubImage2D(GL_TEXTURE_2D, 0, x, y, width, height, GL_RGBA, GL_UNSIGNED_BYTE,
-                  rgba_data.data());
   m_system->GetHostInterface()->SetDisplayTexture(m_framebuffer_texture.get(), 0, 0, VRAM_WIDTH, VRAM_HEIGHT);
 }
 
-void GPU_HW_OpenGL::DispatchRenderCommand(RenderCommand rc, u32 num_vertices)
+void GPU_HW_OpenGL::UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data)
 {
-  LoadVertices(rc, num_vertices);
+  std::vector<u32> rgba_data;
-  if (m_vertex_staging.empty())
+  rgba_data.reserve(width * height);
-    return;
 
-  if (!SetProgram(rc.texture_enable))
+  // reverse copy the rows so it matches opengl's lower-left origin
+  const u32 source_stride = width * sizeof(u16);
+  const u8* source_ptr = static_cast<const u8*>(data) + (source_stride * (height - 1));
+  for (u32 row = 0; row < height; row++)
   {
-    Log_ErrorPrintf("Failed to set GL program");
+    const u8* source_row_ptr = source_ptr;
-    m_vertex_staging.clear();
+
-    return;
+    for (u32 col = 0; col < width; col++)
+    {
+      u16 src_col;
+      std::memcpy(&src_col, source_row_ptr, sizeof(src_col));
+      source_row_ptr += sizeof(src_col);
+
+      const u32 dst_col = ConvertRGBA5551ToRGBA8888(src_col);
+      rgba_data.push_back(dst_col);
+    }
+
+    source_ptr -= source_stride;
   }
 
+  m_framebuffer_texture->Bind();
+
+  // lower-left origin flip happens here
+  glTexSubImage2D(GL_TEXTURE_2D, 0, x, VRAM_HEIGHT - y - height, width, height, GL_RGBA, GL_UNSIGNED_BYTE,
+                  rgba_data.data());
+}
+
+void GPU_HW_OpenGL::UpdateTexturePageTexture()
+{
+  glBindFramebuffer(GL_FRAMEBUFFER, m_texture_page_fbo_id);
+  m_framebuffer_texture->Bind();
+
+  glDisable(GL_BLEND);
+  glViewport(0, 0, TEXTURE_PAGE_WIDTH, TEXTURE_PAGE_HEIGHT);
+  glBindVertexArray(m_attributeless_vao_id);
+
+  const GL::Program& prog = m_texture_page_programs[static_cast<u8>(m_texture_config.color_mode)];
+  prog.Bind();
+
+  const float base_x = static_cast<float>(m_texture_config.base_x) * (1.0f / static_cast<float>(VRAM_WIDTH));
+  const float base_y = static_cast<float>(m_texture_config.base_y) * (1.0f / static_cast<float>(VRAM_HEIGHT));
+  prog.Uniform2f(1, base_x, base_y);
+
+  if (m_texture_config.color_mode >= GPU::TextureColorMode::Palette4Bit)
+  {
+    const float palette_x = static_cast<float>(m_texture_config.palette_x) * (1.0f / static_cast<float>(VRAM_WIDTH));
+    const float palette_y = static_cast<float>(m_texture_config.palette_y) * (1.0f / static_cast<float>(VRAM_HEIGHT));
+    prog.Uniform2f(2, palette_x, palette_y);
+  }
+
+  glDrawArrays(GL_TRIANGLES, 0, 3);
+
+  m_framebuffer_texture->Unbind();
+  glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer_fbo_id);
+}
+
+void GPU_HW_OpenGL::FlushRender()
+{
+  if (m_batch_vertices.empty())
+    return;
+
+  SetProgram(m_batch_command.texture_enable, m_batch_command.texture_blending_raw);
   SetViewport();
 
+  if (m_batch_command.texture_enable)
+    m_texture_page_texture->Bind();
+
   glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer_fbo_id);
   glBindVertexArray(m_vao_id);
 
   glBindBuffer(GL_ARRAY_BUFFER, m_vertex_buffer);
-  glBufferData(GL_ARRAY_BUFFER, static_cast<GLsizei>(sizeof(HWVertex) * m_vertex_staging.size()),
+  glBufferData(GL_ARRAY_BUFFER, static_cast<GLsizei>(sizeof(HWVertex) * m_batch_vertices.size()),
-               m_vertex_staging.data(), GL_STREAM_DRAW);
+               m_batch_vertices.data(), GL_STREAM_DRAW);
-  glEnableVertexAttribArray(0);
   glVertexAttribIPointer(0, 2, GL_INT, sizeof(HWVertex), reinterpret_cast<void*>(offsetof(HWVertex, x)));
-  glEnableVertexAttribArray(1);
   glVertexAttribPointer(1, 4, GL_UNSIGNED_BYTE, true, sizeof(HWVertex),
                         reinterpret_cast<void*>(offsetof(HWVertex, color)));
-  glEnableVertexAttribArray(2);
+  glVertexAttribPointer(2, 2, GL_UNSIGNED_BYTE, true, sizeof(HWVertex),
-  glVertexAttribIPointer(2, 1, GL_UNSIGNED_INT, sizeof(HWVertex), reinterpret_cast<void*>(offsetof(HWVertex, color)));
+                        reinterpret_cast<void*>(offsetof(HWVertex, texcoord)));
 
-  glDrawArrays(rc.quad_polygon ? GL_TRIANGLE_STRIP : GL_TRIANGLES, 0, static_cast<GLsizei>(m_vertex_staging.size()));
+  glDrawArrays(m_batch_command.quad_polygon ? GL_TRIANGLE_STRIP : GL_TRIANGLES, 0,
+               static_cast<GLsizei>(m_batch_vertices.size()));
 
-  m_system->GetHostInterface()->SetDisplayTexture(m_framebuffer_texture.get(), 0, 0, VRAM_WIDTH, VRAM_HEIGHT);
+  m_batch_vertices.clear();
-  m_vertex_staging.clear();
-}
-
-void GPU_HW_OpenGL::FlushRender()
-{
-  if (m_vertex_staging.empty())
-    return;
-
-  m_vertex_staging.clear();
 }
 
 std::unique_ptr<GPU> GPU::CreateHardwareOpenGLRenderer()

src/pse/gpu_hw_opengl.h

@@ -5,6 +5,7 @@
 #include "gpu_hw.h"
 #include <array>
 #include <memory>
+#include <tuple>
 
 class GPU_HW_OpenGL : public GPU_HW
 {
@@ -16,11 +17,14 @@ public:
   void Reset() override;
 
 protected:
+  void UpdateDisplay() override;
   void UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data) override;
-  void DispatchRenderCommand(RenderCommand rc, u32 num_vertices) override;
+  void UpdateTexturePageTexture() override;
   void FlushRender() override;
 
 private:
+  std::tuple<s32, s32> ConvertToFramebufferCoordinates(s32 x, s32 y);
+
   void CreateFramebuffer();
   void ClearFramebuffer();
   void DestroyFramebuffer();
@@ -28,17 +32,24 @@ private:
   void CreateVertexBuffer();
 
   bool CompilePrograms();
+  bool CompileProgram(GL::Program& prog, bool textured, bool blending);
 
-  bool SetProgram(bool texture_enable);
+  void SetProgram(bool textured, bool blending);
   void SetViewport();
   void SetScissor();
 
   std::unique_ptr<GL::Texture> m_framebuffer_texture;
   GLuint m_framebuffer_fbo_id = 0;
 
+  std::unique_ptr<GL::Texture> m_texture_page_texture;
+  GLuint m_texture_page_fbo_id = 0;
+
   GLuint m_vertex_buffer = 0;
   GLuint m_vao_id = 0;
+  GLuint m_attributeless_vao_id = 0;
 
   GL::Program m_texture_program;
   GL::Program m_color_program;
+  GL::Program m_blended_texture_program;
+  std::array<GL::Program, 3> m_texture_page_programs;
 };

src/pse/system.cpp

@@ -38,9 +38,12 @@ void System::Reset()
   m_bus->Reset();
   m_dma->Reset();
   m_gpu->Reset();
+  m_frame_number = 1;
 }
 
 void System::RunFrame()
 {
-  m_cpu->Execute();
+  u32 current_frame_number = m_frame_number;
+  while (current_frame_number == m_frame_number)
+    m_cpu->Execute();
 }

src/pse/system.h

@@ -20,6 +20,9 @@ public:
 
   HostInterface* GetHostInterface() const { return m_host_interface; }
 
+  u32 GetFrameNumber() const { return m_frame_number; }
+  void IncrementFrameNumber() { m_frame_number++; }
+
   bool Initialize();
   void Reset();
 
@@ -31,4 +34,5 @@ private:
   std::unique_ptr<Bus> m_bus;
   std::unique_ptr<DMA> m_dma;
   std::unique_ptr<GPU> m_gpu;
+  u32 m_frame_number = 1;
 };