Add human readable error strings when creating the Fbo failed

src/modules/graphics/opengl/Fbo.cpp

@@ -8,9 +8,35 @@ namespace graphics
 namespace opengl
 {
 
+	std::map<GLenum, const char*> Fbo::status_to_string;
+
 	Fbo::Fbo(int width, int height) :
 		width(width), height(height)
 	{
+		// maybe create status code messages
+		if (status_to_string.empty()) {
+			status_to_string[GL_FRAMEBUFFER_UNSUPPORTED] // the most important one
+				= "your opengl implementation does not support framebuffer objects";
+
+			status_to_string[GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT]
+				= "framebuffer has incomplete attachments";
+			status_to_string[GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER]
+				= "incomplete draw buffer";
+
+			// the ones that should never, ever happen:
+			status_to_string[GL_FRAMEBUFFER_UNDEFINED]
+				= "default framebuffer does not exist";
+			status_to_string[GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT]
+				= "framebuffer needs at least one image attached";
+			status_to_string[GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER]
+				= "incomplete read buffer";
+			status_to_string[GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE]
+				= "number of samples mismatch in attached buffers";
+			// "Additionally, if an error occurs, zero is returned." and
+			// "GL_INVALID_ENUM is generated if target is not GL_DRAW_FRAMEBUFFER, GL_READ_FRAMEBUFFER or GL_FRAMEBUFFER."
+			status_to_string[0] = "Framebuffer hijacked by aliens";
+		}
+
 		// world coordinates
 		vertices[0].x = 0;     vertices[0].y = 0;
 		vertices[1].x = 0;     vertices[1].y = height;
@@ -58,9 +84,9 @@ namespace opengl
 		glDeleteFramebuffers(1, &img);
 	}
 
-	GLenum Fbo::status() const
+	const char* Fbo::statusMessage() const
 	{
-		return status_;
+		status_to_string[statusCode()];
 	}
 
 	void Fbo::bind()

src/modules/graphics/opengl/Fbo.h

@@ -4,6 +4,7 @@
 #include <graphics/Drawable.h>
 #include <graphics/Volatile.h>
 #include <common/math.h>
+#include <map>
 #include "GLee.h"
 
 namespace love
@@ -19,7 +20,9 @@ namespace opengl
 		Fbo(int width, int height);
 		virtual ~Fbo();
 
-		GLenum status() const; //SERIOUS DISLIKE HERE
+		// for internal use (w_newFbo <-> love.graphics.newFbo) only
+		GLenum statusCode() const { return status_; } //SERIOUS DISLIKE HERE
+		const char* statusMessage() const;
 
 		void bind(); //DOUBTFUL ABOUT NAME
 		void unbind(); //Maybe start/stop?
@@ -37,6 +40,8 @@ namespace opengl
 		GLenum status_;
 
 		vertex vertices[4];
+
+		static std::map<GLenum, const char*> status_to_string;
 	};
 
 } // opengl

src/modules/graphics/opengl/wrap_Graphics.cpp

@@ -300,9 +300,8 @@ namespace opengl
 		Fbo * fbo = instance->newFbo(width, height);
 
 		//and there we go with the status... still disliked
-		GLenum status = fbo->status();
-		if (status != GL_FRAMEBUFFER_COMPLETE_EXT)
-			return luaL_error(L, "Cannot create FBO: %d", status);
+		if (fbo->statusCode() != GL_FRAMEBUFFER_COMPLETE_EXT)
+			return luaL_error(L, "Cannot create FBO: %s", fbo->statusMessage());
 		luax_newtype(L, "Fbo", GRAPHICS_FBO_T, (void*)fbo);
 		return 1;
 	}