Snap output window to framebuffer pixel grid

Author: drhelius

platforms/shared/desktop/gui.cpp

@@ -609,7 +609,18 @@ static void main_window(void)
     float tex_h = (float)runtime.screen_width / (float)(SYSTEM_TEXTURE_WIDTH);
     float tex_v = ((float)runtime.screen_height * (float)ogl_renderer_output_scale) / (float)(FRAME_BUFFER_HEIGHT);
 
-    ImGui::Image((ImTextureID)(intptr_t)ogl_renderer_emu_texture, ImVec2(window_width, window_height), ImVec2(0, 0), ImVec2(tex_h, tex_v));
+    if (fractional_fb_scale)
+    {
+        float uv_x0 = 0.5f / (float)FRAME_BUFFER_WIDTH;
+        float uv_y0 = 0.5f / (float)FRAME_BUFFER_HEIGHT;
+        float uv_x1 = ((float)runtime.screen_width - 0.5f) / (float)FRAME_BUFFER_WIDTH;
+        float uv_y1 = (((float)runtime.screen_height * (float)ogl_renderer_output_scale) - 0.5f) / (float)FRAME_BUFFER_HEIGHT;
+        ImGui::Image((ImTextureID)(intptr_t)ogl_renderer_emu_texture, ImVec2(window_width, window_height), ImVec2(uv_x0, uv_y0), ImVec2(uv_x1, uv_y1));
+    }
+    else
+    {
+        ImGui::Image((ImTextureID)(intptr_t)ogl_renderer_emu_texture, ImVec2(window_width, window_height), ImVec2(0, 0), ImVec2(tex_h, tex_v));
+    }
 
     if (config_video.fps)
         gui_show_fps();