diff --git a/source/Irrlicht/COpenGLDriver.cpp b/source/Irrlicht/COpenGLDriver.cpp
index 14d19314..93d52820 100644
--- a/source/Irrlicht/COpenGLDriver.cpp
+++ b/source/Irrlicht/COpenGLDriver.cpp
@@ -3425,7 +3425,7 @@ bool COpenGLDriver::setRenderTarget(const core::array<video::IRenderTarget>& tar
 	if (targets.size()==0)
 		return setRenderTarget(0, clearBackBuffer, clearZBuffer, color);
 
-	u32 maxMultipleRTTs = core::min_(16u, targets.size());
+	u32 maxMultipleRTTs = core::min_(static_cast<u32>(MaxMultipleRenderTargets), targets.size());
 
 	// determine common size
 	core::dimension2du rttSize = CurrentRendertargetSize;
diff --git a/source/Irrlicht/COpenGLExtensionHandler.cpp b/source/Irrlicht/COpenGLExtensionHandler.cpp
index 8f37bb57..c272e0dc 100644
--- a/source/Irrlicht/COpenGLExtensionHandler.cpp
+++ b/source/Irrlicht/COpenGLExtensionHandler.cpp
@@ -452,7 +452,7 @@ void COpenGLExtensionHandler::initExtensions(bool stencilBuffer)
 #endif
 	glGetIntegerv(GL_MAX_TEXTURE_SIZE, &num);
 	MaxTextureSize=static_cast<u32>(num);
-#ifdef EXT_texture_lod_bias
+#ifdef GL_EXT_texture_lod_bias
 	if (FeatureAvailable[IRR_EXT_texture_lod_bias])
 		glGetFloatv(GL_MAX_TEXTURE_LOD_BIAS_EXT, &MaxTextureLODBias);
 #endif
@@ -460,17 +460,17 @@ void COpenGLExtensionHandler::initExtensions(bool stencilBuffer)
 	MaxUserClipPlanes=static_cast<u8>(num);
 	glGetIntegerv(GL_AUX_BUFFERS, &num);
 	MaxAuxBuffers=static_cast<u8>(num);
-#ifdef ARB_draw_buffers
+#ifdef GL_ARB_draw_buffers
 	if (FeatureAvailable[IRR_ARB_draw_buffers])
 	{
-		glGetIntegerv(GL_MAX_DRAW_BUFFERS_ARB, reinterpret_cast<GLint*>(&MaxUserClipPlanes));
-		MaxMultipleRenderTargets = static_cast<u8>(MaxUserClipPlanes);
+		glGetIntegerv(GL_MAX_DRAW_BUFFERS_ARB, &num);
+		MaxMultipleRenderTargets = static_cast<u8>(num);
 	}
-#elif defined(ATI_draw_buffers)
+#elif defined(GL_ATI_draw_buffers)
 	if (FeatureAvailable[IRR_ATI_draw_buffers])
 	{
-		glGetIntegerv(GL_MAX_DRAW_BUFFERS_ATI, reinterpret_cast<GLint*>(&MaxUserClipPlanes));
-		MaxMultipleRenderTargets = static_cast<u8>(MaxUserClipPlanes);
+		glGetIntegerv(GL_MAX_DRAW_BUFFERS_ATI, &num);
+		MaxMultipleRenderTargets = static_cast<u8>(num);
 	}
 #endif
 	glGetFloatv(GL_ALIASED_LINE_WIDTH_RANGE, DimAliasedLine);