Removed restrictions preventing sRGB and non-sRGB canvases from being used together when doing multi-canvas rendering.

src/modules/graphics/opengl/Canvas.cpp

@@ -397,15 +397,6 @@ void Canvas::setupGrab()
 
 	// Set up the projection matrix
 	gl.matrices.projection.push_back(Matrix::ortho(0.0, (float) width, 0.0, (float) height));
-
-	// Make sure the correct sRGB setting is used when drawing to the canvas.
-	if (GLAD_VERSION_1_0 || GLAD_EXT_sRGB_write_control)
-	{
-		if (format == FORMAT_SRGB)
-			glEnable(GL_FRAMEBUFFER_SRGB);
-		else if (screenHasSRGB)
-			glDisable(GL_FRAMEBUFFER_SRGB);
-	}
 }
 
 void Canvas::startGrab(const std::vector<Canvas *> &canvases)
@@ -413,6 +404,7 @@ void Canvas::startGrab(const std::vector<Canvas *> &canvases)
 	// Whether the new canvas list is different from the old one.
 	// A more thorough check is done below.
 	bool canvaseschanged = canvases.size() != attachedCanvases.size();
+	bool hasSRGBcanvas = (format == FORMAT_SRGB);
 
 	if (canvases.size() > 0)
 	{
@@ -435,26 +427,32 @@ void Canvas::startGrab(const std::vector<Canvas *> &canvases)
 
 		Format otherformat = canvases[i]->getTextureFormat();
 
-		if (otherformat != format)
-		{
-			if (!multiformatsupported)
-				throw love::Exception("This system doesn't support multi-canvas rendering with different canvas formats.");
-			else if (otherformat == FORMAT_SRGB || format == FORMAT_SRGB)
-				// Driver bugs related to enabling GL_FRAMEBUFFER_SRGB...
-				throw love::Exception("sRGB and non-sRGB canvas formats cannot be mixed when using multi-canvas rendering.");
-		}
+		if (otherformat != format && !multiformatsupported)
+			throw love::Exception("This system doesn't support multi-canvas rendering with different canvas formats.");
 
 		if (canvases[i]->getMSAA() != 0)
 			throw love::Exception("Multi-canvas rendering is not supported with MSAA.");
 
 		if (!canvaseschanged && canvases[i] != attachedCanvases[i])
 			canvaseschanged = true;
+
+		if (otherformat == FORMAT_SRGB)
+			hasSRGBcanvas = true;
 	}
 
 	OpenGL::TempDebugGroup debuggroup("Canvas set");
 
 	setupGrab();
 
+	// Make sure the correct sRGB setting is used when drawing to the canvases.
+	if (GLAD_VERSION_1_0 || GLAD_EXT_sRGB_write_control)
+	{
+		if (hasSRGBcanvas && !gl.hasFramebufferSRGB())
+			gl.setFramebufferSRGB(true);
+		else if (!hasSRGBcanvas && gl.hasFramebufferSRGB())
+			gl.setFramebufferSRGB(false);
+	}
+
 	// Don't attach anything if there's nothing to change.
 	if (!canvaseschanged)
 		return;
@@ -489,10 +487,19 @@ void Canvas::startGrab()
 
 	setupGrab();
 
+	// Make sure the correct sRGB setting is used when drawing to the canvas.
+	if (GLAD_VERSION_1_0 || GLAD_EXT_sRGB_write_control)
+	{
+		if (format == FORMAT_SRGB && !gl.hasFramebufferSRGB())
+			gl.setFramebufferSRGB(true);
+		else if (format != FORMAT_SRGB && gl.hasFramebufferSRGB())
+			gl.setFramebufferSRGB(false);
+	}
+
 	if (attachedCanvases.size() == 0)
 		return;
 
-	// make sure the FBO is only using a single draw buffer
+	// Make sure the FBO is only using a single draw buffer.
 	glDrawBuffer(GL_COLOR_ATTACHMENT0);
 
 	attachedCanvases.clear();
@@ -511,15 +518,7 @@ void Canvas::stopGrab(bool switchingToOtherCanvas)
 
 	gl.matrices.projection.pop_back();
 
-	if (switchingToOtherCanvas)
-	{
-		if (GLAD_VERSION_1_0 || GLAD_EXT_sRGB_write_control)
-		{
-			if (format == FORMAT_SRGB)
-				glDisable(GL_FRAMEBUFFER_SRGB);
-		}
-	}
-	else
+	if (!switchingToOtherCanvas)
 	{
 		// bind system framebuffer.
 		gl.bindFramebuffer(GL_FRAMEBUFFER, gl.getDefaultFBO());
@@ -528,10 +527,10 @@ void Canvas::stopGrab(bool switchingToOtherCanvas)
 
 		if (GLAD_VERSION_1_0 || GLAD_EXT_sRGB_write_control)
 		{
-			if (format == FORMAT_SRGB && !screenHasSRGB)
-				glDisable(GL_FRAMEBUFFER_SRGB);
-			else if (format != FORMAT_SRGB && screenHasSRGB)
-				glEnable(GL_FRAMEBUFFER_SRGB);
+			if (screenHasSRGB && !gl.hasFramebufferSRGB())
+				gl.setFramebufferSRGB(true);
+			else if (!screenHasSRGB && gl.hasFramebufferSRGB())
+				gl.setFramebufferSRGB(false);
 		}
 	}
 }
@@ -631,6 +630,8 @@ bool Canvas::resolveMSAA(bool restoreprev)
 	if (resolve_fbo == 0 || msaa_buffer == 0)
 		return false;
 
+	OpenGL::TempDebugGroup debuggroup("Canvas MSAA resolve");
+
 	GLint w = width;
 	GLint h = height;
 

src/modules/graphics/opengl/Graphics.cpp

@@ -270,12 +270,7 @@ bool Graphics::setMode(int width, int height, bool &sRGB)
 		|| GLAD_ES_VERSION_3_0 || GLAD_EXT_sRGB)
 	{
 		if (GLAD_VERSION_1_0 || GLAD_EXT_sRGB_write_control)
-		{
-			if (sRGB)
-				glEnable(GL_FRAMEBUFFER_SRGB);
-			else
-				glDisable(GL_FRAMEBUFFER_SRGB);
-		}
+			gl.setFramebufferSRGB(sRGB);
 	}
 	else
 		sRGB = false;

src/modules/graphics/opengl/OpenGL.cpp

@@ -103,6 +103,14 @@ void OpenGL::setupContext()
 	else
 		state.pointSize = 1.0f;
 
+	if (GLAD_VERSION_3_0 || GLAD_ARB_framebuffer_sRGB || GLAD_EXT_framebuffer_sRGB
+		|| GLAD_EXT_sRGB_write_control)
+	{
+		state.framebufferSRGBEnabled = (glIsEnabled(GL_FRAMEBUFFER_SRGB) == GL_TRUE);
+	}
+	else
+		state.framebufferSRGBEnabled = false;
+
 	// Initialize multiple texture unit support for shaders.
 	state.boundTextures.clear();
 	state.boundTextures.resize(maxTextureUnits, 0);
@@ -427,6 +435,21 @@ float OpenGL::getPointSize() const
 	return state.pointSize;
 }
 
+void OpenGL::setFramebufferSRGB(bool enable)
+{
+	if (enable)
+		glEnable(GL_FRAMEBUFFER_SRGB);
+	else
+		glDisable(GL_FRAMEBUFFER_SRGB);
+
+	state.framebufferSRGBEnabled = enable;
+}
+
+bool OpenGL::hasFramebufferSRGB() const
+{
+	return state.framebufferSRGBEnabled;
+}
+
 void OpenGL::bindFramebuffer(GLenum target, GLuint framebuffer)
 {
 	glBindFramebuffer(target, framebuffer);

src/modules/graphics/opengl/OpenGL.h

@@ -238,6 +238,16 @@ public:
 	 **/
 	float getPointSize() const;
 
+	/**
+	 * Calls glEnable/glDisable(GL_FRAMEBUFFER_SRGB).
+	 **/
+	void setFramebufferSRGB(bool enable);
+
+	/**
+	 * Equivalent to glIsEnabled(GL_FRAMEBUFFER_SRGB).
+	 **/
+	bool hasFramebufferSRGB() const;
+
 	/**
 	 * Binds a Framebuffer Object to the specified target.
 	 **/
@@ -360,6 +370,8 @@ private:
 
 		float pointSize;
 
+		bool framebufferSRGBEnabled;
+
 		GLuint defaultTexture;
 
 		Matrix lastProjectionMatrix;