Add implementation for color filling.

TODO: Get LCD Color Fill data from GPU

src/video_core/renderer_opengl/renderer_opengl.cpp

@@ -61,18 +61,28 @@ void RendererOpenGL::SwapBuffers() {
     for(int i : {0, 1}) {
         const auto& framebuffer = GPU::g_regs.framebuffer_config[i];
 
-        if (textures[i].width != framebuffer.width || textures[i].height != framebuffer.height) {
+        u32 lcd_color_fill = 0;
-            // Reallocate texture if the framebuffer size has changed.
+        // TODO: Get LCD Color Fill data from GPU (main: 0x202204, sub: 0x202A04)
-            // This is expected to not happen very often and hence should not be a
-            // performance problem.
-            glBindTexture(GL_TEXTURE_2D, textures[i].handle);
-            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, framebuffer.width, framebuffer.height, 0,
-                GL_BGR, GL_UNSIGNED_BYTE, nullptr);
-            textures[i].width = framebuffer.width;
-            textures[i].height = framebuffer.height;
-        }
 
-        LoadFBToActiveGLTexture(GPU::g_regs.framebuffer_config[i], textures[i]);
+        if (lcd_color_fill & 1 << 24) { //Enabled
+            u8 r = (lcd_color_fill >> 0) & 0xFF;
+            u8 g = (lcd_color_fill >> 8) & 0xFF;
+            u8 b = (lcd_color_fill >> 16) & 0xFF;
+            LoadColorToActiveGLTexture(r, g, b, &textures[i]);
+        } else {
+            if (textures[i].width != framebuffer.width || textures[i].height != framebuffer.height) {
+                // Reallocate texture if the framebuffer size has changed.
+                // This is expected to not happen very often and hence should not be a
+                // performance problem.
+                glBindTexture(GL_TEXTURE_2D, textures[i].handle);
+                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, framebuffer.width, framebuffer.height, 0,
+                             GL_BGR, GL_UNSIGNED_BYTE, nullptr);
+                textures[i].width = framebuffer.width;
+                textures[i].height = framebuffer.height;
+            }
+
+            LoadFBToActiveGLTexture(GPU::g_regs.framebuffer_config[i], textures[i]);
+        }
     }
 
     DrawScreens();
@@ -124,6 +134,31 @@ void RendererOpenGL::LoadFBToActiveGLTexture(const GPU::Regs::FramebufferConfig&
     glBindTexture(GL_TEXTURE_2D, 0);
 }
 
+/**
+ * Creates 1x1 framebuffer from color, loads into the active OpenGL texture.
+ * Since the color is solid, the texture can be 1x1 but will stretch across whatever it's rendered on.
+ * This has the added benefit of being *really fast*.
+ */
+void RendererOpenGL::LoadColorToActiveGLTexture(u8 color_r, u8 color_g, u8 color_b, TextureInfo* texture) {
+    glBindTexture(GL_TEXTURE_2D, texture->handle);
+
+    u8 framebuffer_data[3] = { color_r, color_g, color_b };
+
+    if (texture->width != 1 || texture->height != 1) {
+        // Reallocate texture if the framebuffer size has changed.
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 1, 1, 0,
+                     GL_RGB, GL_UNSIGNED_BYTE, framebuffer_data);
+        texture->width = 1;
+        texture->height = 1;
+    } else {
+        // Update existing texture
+        glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, texture->width, texture->height,
+                        GL_RGB, GL_UNSIGNED_BYTE, framebuffer_data);
+    }
+    
+    glBindTexture(GL_TEXTURE_2D, 0);
+}
+
 /**
  * Initializes the OpenGL state and creates persistent objects.
  */

src/video_core/renderer_opengl/renderer_opengl.h

@@ -51,6 +51,8 @@ private:
     // Loads framebuffer from emulated memory into the active OpenGL texture.
     static void LoadFBToActiveGLTexture(const GPU::Regs::FramebufferConfig& framebuffer,
                                         const TextureInfo& texture);
+    // Creates 1x1 framebuffer from color, loads into the active OpenGL texture.
+    static void LoadColorToActiveGLTexture(u8 color_r, u8 color_g, u8 color_b, TextureInfo* texture);
 
     EmuWindow*  render_window;                    ///< Handle to render window
     u32         last_mode;                        ///< Last render mode
@@ -62,7 +64,7 @@ private:
     GLuint vertex_array_handle;
     GLuint vertex_buffer_handle;
     GLuint program_id;
-    std::array<TextureInfo, 2> textures;
+    std::array<TextureInfo, 2> textures; // main, sub respectively
     // Shader uniform location indices
     GLuint uniform_modelview_matrix;
     GLuint uniform_color_texture;