gl_rasterizer: Skip framebuffer configuration if rendertargets have not been changed

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -488,7 +488,19 @@ void RasterizerOpenGL::ConfigureFramebuffers(OpenGLState& current_state, bool us
                                              bool using_depth_fb, bool preserve_contents,
                                              std::optional<std::size_t> single_color_target) {
     MICROPROFILE_SCOPE(OpenGL_Framebuffer);
-    const auto& regs = Core::System::GetInstance().GPU().Maxwell3D().regs;
+    const auto& gpu = Core::System::GetInstance().GPU().Maxwell3D();
+    const auto& regs = gpu.regs;
+
+    const FramebufferConfigState fb_config_state{using_color_fb, using_depth_fb, preserve_contents,
+                                                 single_color_target};
+    if (fb_config_state == current_framebuffer_config_state && gpu.dirty_flags.color_buffer == 0 &&
+        !gpu.dirty_flags.zeta_buffer) {
+        // Only skip if the previous ConfigureFramebuffers call was from the same kind (multiple or
+        // single color targets). This is done because the guest registers may not change but the
+        // host framebuffer may contain different attachments
+        return;
+    }
+    current_framebuffer_config_state = fb_config_state;
 
     Surface depth_surface;
     if (using_depth_fb) {

src/video_core/renderer_opengl/gl_rasterizer.h

@@ -94,6 +94,23 @@ private:
         float max_anisotropic = 1.0f;
     };
 
+    struct FramebufferConfigState {
+        bool using_color_fb{};
+        bool using_depth_fb{};
+        bool preserve_contents{};
+        std::optional<std::size_t> single_color_target;
+
+        bool operator==(const FramebufferConfigState& rhs) const {
+            return std::tie(using_color_fb, using_depth_fb, preserve_contents,
+                            single_color_target) == std::tie(rhs.using_color_fb, rhs.using_depth_fb,
+                                                             rhs.preserve_contents,
+                                                             rhs.single_color_target);
+        }
+        bool operator!=(const FramebufferConfigState& rhs) const {
+            return !operator==(rhs);
+        }
+    };
+
     /**
      * Configures the color and depth framebuffer states.
      * @param use_color_fb If true, configure color framebuffers.
@@ -197,6 +214,7 @@ private:
         vertex_array_cache;
 
     std::map<FramebufferCacheKey, OGLFramebuffer> framebuffer_cache;
+    FramebufferConfigState current_framebuffer_config_state;
 
     std::array<SamplerInfo, Tegra::Engines::Maxwell3D::Regs::NumTextureSamplers> texture_samplers;