Fixed discrepancy between ANGLE and OpenGL when rendering to texture.

Had to set viewport to make it work in OpenGL.

Also made it easier to see texture orientation in the example.

Now it's visible that there is indeed flipping. At least now it's consistent ;).

examples/render_to_texture.html

@@ -53,7 +53,13 @@
 			
             void main(void)
             {
-                gl_FragColor = vec4( time, vUv.x, vUv.y, 1.0 );
+                //gl_FragColor = vec4( time, vUv.x, vUv.y, 1.0 );
+				float r = vUv.x;
+				if( vUv.y < 0.5 ) r = 0.0;
+				float g = vUv.y;
+				if( vUv.x < 0.5 ) g = 0.0;
+				
+				gl_FragColor = vec4( r, g, 0.25, 1.0 );
             }
         </script>
 
@@ -94,6 +100,13 @@
 				light.position.normalize();
 				scene.addLight( light );
 
+				light = new THREE.DirectionalLight( 0xffaaaa, 0.5 );
+				light.position.x = -1;
+				light.position.y = 0;
+				light.position.z = -1;
+				light.position.normalize();
+				scene.addLight( light );
+
                 rtTexture = new THREE.RenderTarget( 256, 256 );
 
                 material = new THREE.MeshShaderMaterial( {

src/renderers/WebGLRenderer.js

@@ -22,6 +22,7 @@ THREE.WebGLRenderer = function ( parameters ) {
 
 	var _canvas = document.createElement( 'canvas' ), _gl,
 	_oldProgram = null,
+	_oldFramebuffer = null,
 	_modelViewMatrix = new THREE.Matrix4(), _normalMatrix,
 
 	_viewMatrixArray = new Float32Array(16),
@@ -1484,8 +1485,30 @@ THREE.WebGLRenderer = function ( parameters ) {
 			
 		}
 
-		var framebuffer = renderTexture ? renderTexture.__webGLFramebuffer : null;
-		_gl.bindFramebuffer( _gl.FRAMEBUFFER, framebuffer );
+		var framebuffer, width, height;
+		
+		if ( renderTexture ) {
+			
+			framebuffer = renderTexture.__webGLFramebuffer;
+			width = renderTexture.width;
+			height = renderTexture.height;
+			
+		} else {
+			
+			framebuffer = null;
+			width = _canvas.width;
+			height = _canvas.height;
+			
+		}
+		
+		if( framebuffer != _oldFramebuffer ) {
+			
+			_gl.bindFramebuffer( _gl.FRAMEBUFFER, framebuffer );
+			_gl.viewport( 0, 0, width, height );
+			
+			_oldFramebuffer = framebuffer;
+			
+		}
 
 	};