Validate level index before validating level itself.

src/OpenGL/libGLES_CM/libGLES_CM.cpp

@@ -1526,11 +1526,6 @@ void FramebufferTexture2DOES(GLenum target, GLenum attachment, GLenum textarget,
 				return error(GL_INVALID_OPERATION);
 			}
 
-			if(tex->isCompressed(textarget, level))
-			{
-				return error(GL_INVALID_OPERATION);
-			}
-
 			switch(textarget)
 			{
 			case GL_TEXTURE_2D:
@@ -1547,6 +1542,11 @@ void FramebufferTexture2DOES(GLenum target, GLenum attachment, GLenum textarget,
 			{
 				return error(GL_INVALID_VALUE);
 			}
+
+			if(tex->isCompressed(textarget, level))
+			{
+				return error(GL_INVALID_OPERATION);
+			}
 		}
 
 		es1::Framebuffer *framebuffer = context->getFramebuffer();

src/OpenGL/libGLESv2/libGLESv2.cpp

@@ -2098,11 +2098,6 @@ void FramebufferTexture2D(GLenum target, GLenum attachment, GLenum textarget, GL
 				return error(GL_INVALID_ENUM);
 			}
 
-			if(tex->isCompressed(textarget, level))
-			{
-				return error(GL_INVALID_OPERATION);
-			}
-
 			if((level != 0) && (context->getClientVersion() < 3))
 			{
 				return error(GL_INVALID_VALUE);
@@ -2112,6 +2107,11 @@ void FramebufferTexture2D(GLenum target, GLenum attachment, GLenum textarget, GL
 			{
 				return error(GL_INVALID_VALUE);
 			}
+
+			if(tex->isCompressed(textarget, level))
+			{
+				return error(GL_INVALID_OPERATION);
+			}
 		}
 
 		es2::Framebuffer *framebuffer = nullptr;