Changed ReadBuffer to be always the front buffer. Hence, screenshots under...

Changed ReadBuffer to be always the front buffer. Hence, screenshots under OpenGL will now also reflect the currently visible image, whatever render calls have been made in between.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@1380 dfc29bdd-3216-0410-991c-e03cc46cb475

source/Irrlicht/COpenGLDriver.cpp

@@ -299,25 +299,37 @@ bool COpenGLDriver::genericDriverInit(const core::dimension2d<s32>& screenSize,
 	else
 		os::Printer::log("GLSL not available.", ELL_INFORMATION);
 
-	glViewport(0, 0, screenSize.Width, screenSize.Height); // Reset The Current Viewport
-	setAmbientLight(SColorf(0.0f,0.0f,0.0f,0.0f));
+	// We want to read the front buffer to get the latest render finished.
+	glReadBuffer(GL_FRONT);
+
+	// Reset The Current Viewport
+	glViewport(0, 0, screenSize.Width, screenSize.Height);
+
 // This needs an SMaterial flag to enable/disable later on, but should become default sometimes
 //	glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE);
 //	glEnable(GL_COLOR_MATERIAL);
+
+	setAmbientLight(SColorf(0.0f,0.0f,0.0f,0.0f));
 #ifdef GL_EXT_separate_specular_color
 	if (FeatureAvailable[IRR_EXT_separate_specular_color])
 		glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SEPARATE_SPECULAR_COLOR);
 #endif
 	glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, 1);
+
 // This is a fast replacement for NORMALIZE_NORMALS
 //	if ((Version>101) || FeatureAvailable[IRR_EXT_rescale_normal])
 //		glEnable(GL_RESCALE_NORMAL_EXT);
+
 	glClearDepth(1.0);
 	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
 	glDepthFunc(GL_LEQUAL);
 	glFrontFace( GL_CW );
+
 	if (AntiAlias)
 	{
+		if (MultiSamplingExtension)
+			glEnable(GL_MULTISAMPLE_ARB);
+
 		glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
 		glEnable(GL_LINE_SMOOTH);
 	}
@@ -325,9 +337,6 @@ bool COpenGLDriver::genericDriverInit(const core::dimension2d<s32>& screenSize,
 //	glHint(GL_POINT_SMOOTH_HINT, GL_FASTEST);
 //	glEnable(GL_POINT_SMOOTH);
 
-	if (AntiAlias && MultiSamplingExtension)
-		glEnable(GL_MULTISAMPLE_ARB);
-
 	UserClipPlane.reallocate(MaxUserClipPlanes);
 	UserClipPlaneEnabled.reallocate(MaxUserClipPlanes);
 	for (i=0; i<MaxUserClipPlanes; ++i)