WebGLTexture: Fix disposal of multisampled RT.

src/renderers/webgl/WebGLTextures.js

@@ -278,6 +278,9 @@ function WebGLTextures( _gl, extensions, state, properties, capabilities, utils,
 
 			_gl.deleteFramebuffer( renderTargetProperties.__webglFramebuffer );
 			if ( renderTargetProperties.__webglDepthbuffer ) _gl.deleteRenderbuffer( renderTargetProperties.__webglDepthbuffer );
+			if ( renderTargetProperties.__webglMultisampledFramebuffer ) _gl.deleteFramebuffer( renderTargetProperties.__webglMultisampledFramebuffer );
+			if ( renderTargetProperties.__webglColorRenderbuffer ) _gl.deleteRenderbuffer( renderTargetProperties.__webglColorRenderbuffer );
+			if ( renderTargetProperties.__webglDepthRenderbuffer ) _gl.deleteRenderbuffer( renderTargetProperties.__webglDepthRenderbuffer );
 
 		}