GPU: Implement interlaced VRAM fills

src/core/gpu.cpp

@@ -893,7 +893,7 @@ void GPU::ReadVRAM(u32 x, u32 y, u32 width, u32 height) {}
 void GPU::FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color)
 {
   const u16 color16 = RGBA8888ToRGBA5551(color);
-  if ((x + width) <= VRAM_WIDTH)
+  if ((x + width) <= VRAM_WIDTH && !IsInterlacedRenderingEnabled())
   {
     for (u32 yoffs = 0; yoffs < height; yoffs++)
     {
@@ -901,6 +901,26 @@ void GPU::FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color)
       std::fill_n(&m_vram_ptr[row * VRAM_WIDTH + x], width, color16);
     }
   }
+  else if (IsInterlacedRenderingEnabled())
+  {
+    // Hardware tests show that fills seem to break on the first two lines when the offset matches the displayed field.
+    if (IsRasterScanlinePending())
+      Synchronize();
+    const u32 active_field = GetInterlacedField();
+    for (u32 yoffs = 0; yoffs < height; yoffs++)
+    {
+      const u32 row = (y + yoffs) % VRAM_HEIGHT;
+      if ((row & u32(1)) == active_field)
+        continue;
+
+      u16* row_ptr = &m_vram_ptr[row * VRAM_WIDTH];
+      for (u32 xoffs = 0; xoffs < width; xoffs++)
+      {
+        const u32 col = (x + xoffs) % VRAM_WIDTH;
+        row_ptr[col] = color16;
+      }
+    }
+  }
   else
   {
     for (u32 yoffs = 0; yoffs < height; yoffs++)

src/core/gpu.h

@@ -330,7 +330,16 @@ protected:
   void Execute(TickCount ticks);
 
   /// Returns true if scanout should be interlaced.
-  bool IsDisplayInterlaced() const { return !m_force_progressive_scan && m_GPUSTAT.In480iMode(); }
+  ALWAYS_INLINE bool IsInterlacedDisplayEnabled() const { return (!m_force_progressive_scan) & m_GPUSTAT.In480iMode(); }
+
+  /// Returns true if interlaced rendering is enabled and force progressive scan is disabled.
+  ALWAYS_INLINE bool IsInterlacedRenderingEnabled() const
+  {
+    return (!m_force_progressive_scan) & m_GPUSTAT.SkipDrawingToActiveField();
+  }
+
+  /// Returns 0 if the currently-rendered field is even, otherwise 1.
+  ALWAYS_INLINE u32 GetInterlacedField() const { return BoolToUInt32(m_GPUSTAT.displaying_odd_line); }
 
   /// Sets/decodes GP0(E1h) (set draw mode).
   void SetDrawMode(u16 bits);

src/core/gpu_commands.cpp

@@ -306,7 +306,7 @@ bool GPU::HandleRenderCommand(const u32*& command_ptr, u32 command_size)
                   primitive_names[static_cast<u8>(rc.primitive.GetValue())], ZeroExtend32(num_vertices),
                   ZeroExtend32(words_per_vertex));
 
-  if (m_GPUSTAT.SkipDrawingToActiveField() && IsRasterScanlinePending())
+  if (IsInterlacedRenderingEnabled() && IsRasterScanlinePending())
     Synchronize();
 
   DispatchRenderCommand(rc, num_vertices, command_ptr);

src/core/gpu_hw.cpp

@@ -541,10 +541,10 @@ void GPU_HW::DispatchRenderCommand(RenderCommand rc, u32 num_vertices, const u32
     m_batch_ubo_dirty = true;
   }
 
-  m_batch.interlacing = m_GPUSTAT.SkipDrawingToActiveField();
+  m_batch.interlacing = IsInterlacedRenderingEnabled();
   if (m_batch.interlacing)
   {
-    const u32 displayed_field = BoolToUInt32(m_GPUSTAT.displaying_odd_line);
+    const u32 displayed_field = GetInterlacedField();
     m_batch_ubo_dirty |= (m_batch_ubo_data.u_interlaced_displayed_field != displayed_field);
     m_batch_ubo_data.u_interlaced_displayed_field = displayed_field;
   }

src/core/gpu_hw_d3d11.cpp

@@ -377,8 +377,13 @@ bool GPU_HW_D3D11::CompileShaders()
   if (!m_copy_pixel_shader)
     return false;
 
-  m_fill_pixel_shader = m_shader_cache.GetPixelShader(m_device.Get(), shadergen.GenerateFillFragmentShader());
+  m_vram_fill_pixel_shader = m_shader_cache.GetPixelShader(m_device.Get(), shadergen.GenerateFillFragmentShader());
-  if (!m_fill_pixel_shader)
+  if (!m_vram_fill_pixel_shader)
+    return false;
+
+  m_vram_interlaced_fill_pixel_shader =
+    m_shader_cache.GetPixelShader(m_device.Get(), shadergen.GenerateInterlacedFillFragmentShader());
+  if (!m_vram_interlaced_fill_pixel_shader)
     return false;
 
   m_vram_read_pixel_shader = m_shader_cache.GetPixelShader(m_device.Get(), shadergen.GenerateVRAMReadFragmentShader());
@@ -542,7 +547,7 @@ void GPU_HW_D3D11::UpdateDisplay()
     const u32 display_height = m_crtc_state.display_vram_height;
     const u32 scaled_display_width = display_width * m_resolution_scale;
     const u32 scaled_display_height = display_height * m_resolution_scale;
-    const bool interlaced = IsDisplayInterlaced();
+    const bool interlaced = IsInterlacedDisplayEnabled();
 
     if (m_GPUSTAT.display_disable)
     {
@@ -559,7 +564,7 @@ void GPU_HW_D3D11::UpdateDisplay()
       m_context->OMSetRenderTargets(1, m_display_texture.GetD3DRTVArray(), nullptr);
       m_context->PSSetShaderResources(0, 1, m_vram_texture.GetD3DSRVArray());
 
-      const u32 reinterpret_field_offset = BoolToUInt32(m_GPUSTAT.displaying_odd_line);
+      const u32 reinterpret_field_offset = GetInterlacedField();
       const u32 reinterpret_start_x = m_crtc_state.regs.X * m_resolution_scale;
       const u32 reinterpret_width = scaled_display_width + (m_crtc_state.display_vram_left - m_crtc_state.regs.X);
       const u32 uniforms[4] = {reinterpret_field_offset, reinterpret_start_x};
@@ -634,12 +639,21 @@ void GPU_HW_D3D11::FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color)
   if (!m_true_color)
     color = RGBA5551ToRGBA8888(RGBA8888ToRGBA5551(color));
 
-  float uniforms[4];
+  struct Uniforms
-  std::tie(uniforms[0], uniforms[1], uniforms[2], uniforms[3]) = RGBA8ToFloat(color);
+  {
+    float u_fill_color[4];
+    u32 u_interlaced_displayed_field;
+  };
+  Uniforms uniforms;
+  std::tie(uniforms.u_fill_color[0], uniforms.u_fill_color[1], uniforms.u_fill_color[2], uniforms.u_fill_color[3]) =
+    RGBA8ToFloat(color);
+  uniforms.u_interlaced_displayed_field = GetInterlacedField();
 
   SetViewportAndScissor(x * m_resolution_scale, y * m_resolution_scale, width * m_resolution_scale,
                         height * m_resolution_scale);
-  DrawUtilityShader(m_fill_pixel_shader.Get(), uniforms, sizeof(uniforms));
+  DrawUtilityShader(IsInterlacedRenderingEnabled() ? m_vram_interlaced_fill_pixel_shader.Get() :
+                                                     m_vram_fill_pixel_shader.Get(),
+                    &uniforms, sizeof(uniforms));
 
   RestoreGraphicsAPIState();
 }

src/core/gpu_hw_d3d11.h

@@ -109,7 +109,8 @@ private:
 
   ComPtr<ID3D11VertexShader> m_screen_quad_vertex_shader;
   ComPtr<ID3D11PixelShader> m_copy_pixel_shader;
-  ComPtr<ID3D11PixelShader> m_fill_pixel_shader;
+  ComPtr<ID3D11PixelShader> m_vram_fill_pixel_shader;
+  ComPtr<ID3D11PixelShader> m_vram_interlaced_fill_pixel_shader;
   ComPtr<ID3D11PixelShader> m_vram_read_pixel_shader;
   ComPtr<ID3D11PixelShader> m_vram_write_pixel_shader;
   std::array<std::array<ComPtr<ID3D11PixelShader>, 2>, 2> m_display_pixel_shaders; // [depth_24][interlaced]

src/core/gpu_hw_opengl.cpp

@@ -367,23 +367,34 @@ bool GPU_HW_OpenGL::CompilePrograms()
 
       prog->Bind();
       prog->Uniform1i("samp0", 0);
-
       m_display_programs[depth_24bit][interlaced] = std::move(*prog);
     }
   }
 
-  std::optional<GL::Program> prog = m_shader_cache.GetProgram(
+  std::optional<GL::Program> prog =
-    shadergen.GenerateScreenQuadVertexShader(), shadergen.GenerateVRAMReadFragmentShader(), [this](GL::Program& prog) {
+    m_shader_cache.GetProgram(shadergen.GenerateScreenQuadVertexShader(),
-      if (!m_is_gles)
+                              shadergen.GenerateInterlacedFillFragmentShader(), [this](GL::Program& prog) {
-        prog.BindFragData(0, "o_col0");
+                                if (!m_is_gles)
-    });
+                                  prog.BindFragData(0, "o_col0");
+                              });
+  if (!prog)
+    return false;
+
+  prog->BindUniformBlock("UBOBlock", 1);
+  prog->Bind();
+  m_vram_interlaced_fill_program = std::move(*prog);
+
+  prog = m_shader_cache.GetProgram(shadergen.GenerateScreenQuadVertexShader(),
+                                   shadergen.GenerateVRAMReadFragmentShader(), [this](GL::Program& prog) {
+                                     if (!m_is_gles)
+                                       prog.BindFragData(0, "o_col0");
+                                   });
   if (!prog)
     return false;
 
   prog->BindUniformBlock("UBOBlock", 1);
   prog->Bind();
   prog->Uniform1i("samp0", 0);
-
   m_vram_read_program = std::move(*prog);
 
   if (m_supports_texture_buffer)
@@ -399,7 +410,6 @@ bool GPU_HW_OpenGL::CompilePrograms()
     prog->BindUniformBlock("UBOBlock", 1);
     prog->Bind();
     prog->Uniform1i("samp0", 0);
-
     m_vram_write_program = std::move(*prog);
   }
 
@@ -490,7 +500,7 @@ void GPU_HW_OpenGL::UpdateDisplay()
     const u32 display_height = m_crtc_state.display_vram_height;
     const u32 scaled_display_width = display_width * m_resolution_scale;
     const u32 scaled_display_height = display_height * m_resolution_scale;
-    const bool interlaced = IsDisplayInterlaced();
+    const bool interlaced = IsInterlacedDisplayEnabled();
 
     if (m_GPUSTAT.display_disable)
     {
@@ -516,7 +526,7 @@ void GPU_HW_OpenGL::UpdateDisplay()
       const u32 scaled_flipped_vram_offset_y =
         m_vram_texture.GetHeight() - scaled_vram_offset_y - scaled_display_height;
 
-      const u32 reinterpret_field_offset = BoolToUInt32(m_GPUSTAT.displaying_odd_line);
+      const u32 reinterpret_field_offset = GetInterlacedField();
       const u32 reinterpret_start_x = m_crtc_state.regs.X * m_resolution_scale;
       const u32 reinterpret_width = scaled_display_width + (m_crtc_state.display_vram_left - m_crtc_state.regs.X);
       const u32 uniforms[4] = {reinterpret_field_offset, reinterpret_start_x};
@@ -600,11 +610,32 @@ void GPU_HW_OpenGL::FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color)
   if (!m_true_color)
     color = RGBA5551ToRGBA8888(RGBA8888ToRGBA5551(color));
 
-  const auto [r, g, b, a] = RGBA8ToFloat(color);
+  // fast path when not using interlaced rendering
-  glClearColor(r, g, b, a);
+  if (!IsInterlacedRenderingEnabled())
-  glClear(GL_COLOR_BUFFER_BIT);
+  {
+    const auto [r, g, b, a] = RGBA8ToFloat(color);
+    glClearColor(r, g, b, a);
+    glClear(GL_COLOR_BUFFER_BIT);
+    SetScissorFromDrawingArea();
+  }
+  else
+  {
+    struct Uniforms
+    {
+      float u_fill_color[4];
+      u32 u_interlaced_displayed_field;
+    };
+    Uniforms uniforms;
+    std::tie(uniforms.u_fill_color[0], uniforms.u_fill_color[1], uniforms.u_fill_color[2], uniforms.u_fill_color[3]) =
+      RGBA8ToFloat(color);
+    uniforms.u_interlaced_displayed_field = GetInterlacedField();
 
-  SetScissorFromDrawingArea();
+    m_vram_interlaced_fill_program.Bind();
+    UploadUniformBlock(&uniforms, sizeof(uniforms));
+    glDrawArrays(GL_TRIANGLES, 0, 3);
+
+    RestoreGraphicsAPIState();
+  }
 }
 
 void GPU_HW_OpenGL::UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data)

src/core/gpu_hw_opengl.h

@@ -79,6 +79,7 @@ private:
   std::array<std::array<std::array<std::array<GL::Program, 2>, 2>, 9>, 4>
     m_render_programs;                                          // [render_mode][texture_mode][dithering][interlacing]
   std::array<std::array<GL::Program, 2>, 2> m_display_programs; // [depth_24][interlaced]
+  GL::Program m_vram_interlaced_fill_program;
   GL::Program m_vram_read_program;
   GL::Program m_vram_write_program;
 

src/core/gpu_hw_opengl_es.cpp

@@ -253,7 +253,17 @@ bool GPU_HW_OpenGL_ES::CompilePrograms()
     }
   }
 
-  std::optional<GL::Program> prog =
+  std::optional<GL::Program> prog = m_shader_cache.GetProgram(shadergen.GenerateScreenQuadVertexShader(),
+                                                              shadergen.GenerateInterlacedFillFragmentShader());
+  if (!prog)
+    return false;
+
+  prog->Bind();
+  prog->RegisterUniform("u_fill_color");
+  prog->RegisterUniform("u_u_interlaced_displayed_field");
+  m_vram_interlaced_fill_program = std::move(*prog);
+
+  prog =
     m_shader_cache.GetProgram(shadergen.GenerateScreenQuadVertexShader(), shadergen.GenerateVRAMReadFragmentShader());
   if (!prog)
     return false;
@@ -357,7 +367,7 @@ void GPU_HW_OpenGL_ES::UpdateDisplay()
     const u32 display_height = m_crtc_state.display_vram_height;
     const u32 scaled_display_width = display_width * m_resolution_scale;
     const u32 scaled_display_height = display_height * m_resolution_scale;
-    const bool interlaced = IsDisplayInterlaced();
+    const bool interlaced = IsInterlacedDisplayEnabled();
 
     if (m_GPUSTAT.display_disable)
     {
@@ -385,7 +395,7 @@ void GPU_HW_OpenGL_ES::UpdateDisplay()
       const u32 scaled_flipped_vram_offset_y =
         m_vram_texture.GetHeight() - scaled_vram_offset_y - scaled_display_height;
 
-      const u32 reinterpret_field_offset = BoolToUInt32(m_GPUSTAT.displaying_odd_line);
+      const u32 reinterpret_field_offset = GetInterlacedField();
       const u32 reinterpret_start_x = m_crtc_state.regs.X * m_resolution_scale;
       const u32 reinterpret_width = scaled_display_width + (m_crtc_state.display_vram_left - m_crtc_state.regs.X);
 
@@ -469,10 +479,21 @@ void GPU_HW_OpenGL_ES::FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color)
     color = RGBA5551ToRGBA8888(RGBA8888ToRGBA5551(color));
 
   const auto [r, g, b, a] = RGBA8ToFloat(color);
-  glClearColor(r, g, b, a);
-  glClear(GL_COLOR_BUFFER_BIT);
 
-  SetScissorFromDrawingArea();
+  if (!IsInterlacedRenderingEnabled())
+  {
+    glClearColor(r, g, b, a);
+    glClear(GL_COLOR_BUFFER_BIT);
+    SetScissorFromDrawingArea();
+  }
+  else
+  {
+    m_vram_interlaced_fill_program.Bind();
+    m_vram_interlaced_fill_program.Uniform4f(0, r, g, b, a);
+    m_vram_interlaced_fill_program.Uniform1i(1, GetInterlacedField());
+    glDrawArrays(GL_TRIANGLES, 0, 3);
+    RestoreGraphicsAPIState();
+  }
 }
 
 void GPU_HW_OpenGL_ES::UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data)

src/core/gpu_hw_opengl_es.h

@@ -67,5 +67,6 @@ private:
   std::array<std::array<std::array<std::array<GL::Program, 2>, 2>, 9>, 4>
     m_render_programs;                                          // [render_mode][texture_mode][dithering][interlacing]
   std::array<std::array<GL::Program, 2>, 2> m_display_programs; // [depth_24][interlaced]
+  GL::Program m_vram_interlaced_fill_program;
   GL::Program m_vram_read_program;
 };

src/core/gpu_hw_shadergen.cpp

@@ -523,7 +523,7 @@ float4 SampleFromVRAM(int4 texpage, int2 icoord)
   float oalpha;
 
   #if INTERLACING
-    if (((int(v_pos.y) / RESOLUTION_SCALE) & 1) == u_interlaced_displayed_field)
+    if (((fixYCoord(int(v_pos.y)) / RESOLUTION_SCALE) & 1) == u_interlaced_displayed_field)
       discard;
   #endif
 
@@ -732,6 +732,26 @@ std::string GPU_HW_ShaderGen::GenerateFillFragmentShader()
   return ss.str();
 }
 
+std::string GPU_HW_ShaderGen::GenerateInterlacedFillFragmentShader()
+{
+  std::stringstream ss;
+  WriteHeader(ss);
+  WriteCommonFunctions(ss);
+  DeclareUniformBuffer(ss, {"float4 u_fill_color", "int u_interlaced_displayed_field"});
+  DeclareFragmentEntryPoint(ss, 0, 1, {}, true, false);
+
+  ss << R"(
+{
+  if (((fixYCoord(int(v_pos.y)) / RESOLUTION_SCALE) & 1) == u_interlaced_displayed_field)
+    discard;
+
+  o_col0 = u_fill_color;
+}
+)";
+
+  return ss.str();
+}
+
 std::string GPU_HW_ShaderGen::GenerateCopyFragmentShader()
 {
   std::stringstream ss;
@@ -767,7 +787,7 @@ std::string GPU_HW_ShaderGen::GenerateDisplayFragmentShader(bool depth_24bit, bo
   int2 icoords = int2(v_pos.xy);
 
   #if INTERLACED
-    if (((icoords.y / RESOLUTION_SCALE) & 1) != u_field_offset)
+    if (((fixYCoord(icoords.y) / RESOLUTION_SCALE) & 1) != u_field_offset)
       discard;
   #endif
 

src/core/gpu_hw_shadergen.h

@@ -17,6 +17,7 @@ public:
   std::string GenerateBatchLineExpandGeometryShader();
   std::string GenerateScreenQuadVertexShader();
   std::string GenerateFillFragmentShader();
+  std::string GenerateInterlacedFillFragmentShader();
   std::string GenerateCopyFragmentShader();
   std::string GenerateDisplayFragmentShader(bool depth_24bit, bool interlaced);
   std::string GenerateVRAMReadFragmentShader();

src/core/gpu_sw.cpp

@@ -574,11 +574,8 @@ void GPU_SW::ShadePixel(u32 x, u32 y, u8 color_r, u8 color_g, u8 color_b, u8 tex
   if ((bg_color.bits & mask_and) != 0)
     return;
 
-  if (m_GPUSTAT.SkipDrawingToActiveField() &&
+  if (IsInterlacedRenderingEnabled() && GetInterlacedField() == (static_cast<u32>(y) & 1u))
-      BoolToUInt32(m_GPUSTAT.displaying_odd_line) == (static_cast<u32>(y) & 1u))
-  {
     return;
-  }
 
   SetPixel(static_cast<u32>(x), static_cast<u32>(y), color.bits | m_GPUSTAT.GetMaskOR());
 }