renderer_opengl: Fix sRGB blits

Removes the sRGB hack of tracking if a frame used an sRGB rendertarget
to apply at least once to blit the final texture as sRGB. Instead of
doing this apply sRGB if the presented image has sRGB.

Also enable sRGB by default on Maxwell3D registers as some games seem to
assume this.

src/video_core/engines/maxwell_3d.cpp

@@ -89,6 +89,9 @@ void Maxwell3D::InitializeRegisterDefaults() {
 
     // Commercial games seem to assume this value is enabled and nouveau sets this value manually.
     regs.rt_separate_frag_data = 1;
+
+    // Some games (like Super Mario Odyssey) assume that SRGB is enabled.
+    regs.framebuffer_srgb = 1;
 }
 
 #define DIRTY_REGS_POS(field_name) (offsetof(Maxwell3D::DirtyRegs, field_name))

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -485,15 +485,6 @@ std::pair<bool, bool> RasterizerOpenGL::ConfigureFramebuffers(
             View color_surface{
                 texture_cache.GetColorBufferSurface(*single_color_target, preserve_contents)};
 
-            if (color_surface) {
-                // Assume that a surface will be written to if it is used as a framebuffer, even if
-                // the shader doesn't actually write to it.
-                texture_cache.MarkColorBufferInUse(*single_color_target);
-                // Workaround for and issue in nvidia drivers
-                // https://devtalk.nvidia.com/default/topic/776591/opengl/gl_framebuffer_srgb-functions-incorrectly/
-                state.framebuffer_srgb.enabled |= color_surface->GetSurfaceParams().srgb_conversion;
-            }
-
             fbkey.is_single_buffer = true;
             fbkey.color_attachments[0] =
                 GL_COLOR_ATTACHMENT0 + static_cast<GLenum>(*single_color_target);
@@ -508,17 +499,6 @@ std::pair<bool, bool> RasterizerOpenGL::ConfigureFramebuffers(
             for (std::size_t index = 0; index < Maxwell::NumRenderTargets; ++index) {
                 View color_surface{texture_cache.GetColorBufferSurface(index, preserve_contents)};
 
-                if (color_surface) {
-                    // Assume that a surface will be written to if it is used as a framebuffer, even
-                    // if the shader doesn't actually write to it.
-                    texture_cache.MarkColorBufferInUse(index);
-                    // Enable sRGB only for supported formats
-                    // Workaround for and issue in nvidia drivers
-                    // https://devtalk.nvidia.com/default/topic/776591/opengl/gl_framebuffer_srgb-functions-incorrectly/
-                    state.framebuffer_srgb.enabled |=
-                        color_surface->GetSurfaceParams().srgb_conversion;
-                }
-
                 fbkey.color_attachments[index] =
                     GL_COLOR_ATTACHMENT0 + regs.rt_control.GetMap(index);
                 fbkey.colors[index] = color_surface;
@@ -906,6 +886,7 @@ bool RasterizerOpenGL::AccelerateDisplay(const Tegra::FramebufferConfig& config,
     }
 
     screen_info.display_texture = surface->GetTexture();
+    screen_info.display_srgb = surface->GetSurfaceParams().srgb_conversion;
 
     return true;
 }

src/video_core/renderer_opengl/gl_state.cpp

@@ -16,7 +16,6 @@ namespace OpenGL {
 using Maxwell = Tegra::Engines::Maxwell3D::Regs;
 
 OpenGLState OpenGLState::cur_state;
-bool OpenGLState::s_rgb_used;
 
 namespace {
 
@@ -282,8 +281,6 @@ void OpenGLState::ApplySRgb() const {
         return;
     cur_state.framebuffer_srgb.enabled = framebuffer_srgb.enabled;
     if (framebuffer_srgb.enabled) {
-        // Track if sRGB is used
-        s_rgb_used = true;
         glEnable(GL_FRAMEBUFFER_SRGB);
     } else {
         glDisable(GL_FRAMEBUFFER_SRGB);

src/video_core/renderer_opengl/gl_state.h

@@ -175,14 +175,6 @@ public:
         return cur_state;
     }
 
-    static bool GetsRGBUsed() {
-        return s_rgb_used;
-    }
-
-    static void ClearsRGBUsed() {
-        s_rgb_used = false;
-    }
-
     void SetDefaultViewports();
     /// Apply this state as the current OpenGL state
     void Apply();
@@ -253,8 +245,6 @@ public:
 private:
     static OpenGLState cur_state;
 
-    // Workaround for sRGB problems caused by QT not supporting srgb output
-    static bool s_rgb_used;
     struct {
         bool blend_state;
         bool stencil_state;

src/video_core/renderer_opengl/renderer_opengl.cpp

@@ -264,7 +264,6 @@ void RendererOpenGL::CreateRasterizer() {
     if (rasterizer) {
         return;
     }
-    OpenGLState::ClearsRGBUsed();
     rasterizer = std::make_unique<RasterizerOpenGL>(system, emu_window, screen_info);
 }
 
@@ -342,10 +341,8 @@ void RendererOpenGL::DrawScreenTriangles(const ScreenInfo& screen_info, float x,
         ScreenRectVertex(x + w, y + h, texcoords.bottom * scale_u, right * scale_v),
     }};
 
-    state.textures[0] = screen_info.display_texture;
-    // Workaround brigthness problems in SMO by enabling sRGB in the final output
-    // if it has been used in the frame. Needed because of this bug in QT: QTBUG-50987
-    state.framebuffer_srgb.enabled = OpenGLState::GetsRGBUsed();
+    state.textures[0].texture = screen_info.display_texture;
+    state.framebuffer_srgb.enabled = screen_info.display_srgb;
     state.AllDirty();
     state.Apply();
     glNamedBufferSubData(vertex_buffer.handle, 0, sizeof(vertices), vertices.data());
@@ -355,8 +352,6 @@ void RendererOpenGL::DrawScreenTriangles(const ScreenInfo& screen_info, float x,
     state.textures[0] = 0;
     state.AllDirty();
     state.Apply();
-    // Clear sRGB state for the next frame
-    OpenGLState::ClearsRGBUsed();
 }
 
 /**
@@ -406,8 +401,8 @@ void RendererOpenGL::CaptureScreenshot() {
     GLuint renderbuffer;
     glGenRenderbuffers(1, &renderbuffer);
     glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
-    glRenderbufferStorage(GL_RENDERBUFFER, state.GetsRGBUsed() ? GL_SRGB8 : GL_RGB8, layout.width,
-                          layout.height);
+    glRenderbufferStorage(GL_RENDERBUFFER, screen_info.display_srgb ? GL_SRGB8 : GL_RGB8,
+                          layout.width, layout.height);
     glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, renderbuffer);
 
     DrawScreen(layout);

src/video_core/renderer_opengl/renderer_opengl.h

@@ -38,7 +38,8 @@ struct TextureInfo {
 
 /// Structure used for storing information about the display target for the Switch screen
 struct ScreenInfo {
-    GLuint display_texture;
+    GLuint display_texture{};
+    bool display_srgb{};
     const Common::Rectangle<float> display_texcoords{0.0f, 0.0f, 1.0f, 1.0f};
     TextureInfo texture;
 };