LensFlarePlugin: Use THREE.Box2 for area check

src/renderers/webgl/plugins/LensFlarePlugin.js

@@ -193,7 +193,10 @@ THREE.LensFlarePlugin = function ( renderer, flares ) {
 		var screenPosition = new THREE.Vector3( 1, 1, 0 ),
 			screenPositionPixels = new THREE.Vector2( 1, 1 );
 
-		var areaToCopy = new THREE.Vector2();
+		var validArea = new THREE.Box2();
+
+		validArea.min.set( 0, 0 );
+		validArea.max.set( viewport.z - 16, viewport.w - 16 );
 
 		if ( program === undefined ) {
 
@@ -241,18 +244,14 @@ THREE.LensFlarePlugin = function ( renderer, flares ) {
 
 			screenPosition.copy( tempPosition );
 
-			screenPositionPixels.x = screenPosition.x * halfViewportWidth + halfViewportWidth;
-			screenPositionPixels.y = screenPosition.y * halfViewportHeight + halfViewportHeight;
+			// horizontal and vertical coordinate of the lower left corner of the pixels to copy
 
-			areaToCopy.x = viewport.x + screenPositionPixels.x - 8; // horizontal coordinate of the lower left corner of the pixels to copy
-			areaToCopy.y = viewport.y + screenPositionPixels.y - 8; // vertical coordinate of the lower left corner of the pixels to copy
+			screenPositionPixels.x = viewport.x + ( screenPosition.x * halfViewportWidth ) + halfViewportWidth - 8;
+			screenPositionPixels.y = viewport.y + ( screenPosition.y * halfViewportHeight ) + halfViewportHeight - 8;
 
 			// screen cull
 
-			if ( areaToCopy.x > 0 &&
-				areaToCopy.x < ( viewport.z - 16 ) &&
-				areaToCopy.y > 0 &&
-				areaToCopy.y < ( viewport.w - 16 ) ) {
+			if ( validArea.containsPoint( screenPositionPixels ) === true ) {
 
 				// save current RGB to temp texture
 
@@ -260,7 +259,7 @@ THREE.LensFlarePlugin = function ( renderer, flares ) {
 				state.bindTexture( gl.TEXTURE_2D, null );
 				state.activeTexture( gl.TEXTURE1 );
 				state.bindTexture( gl.TEXTURE_2D, tempTexture );
-				gl.copyTexImage2D( gl.TEXTURE_2D, 0, gl.RGB, areaToCopy.x, areaToCopy.y, 16, 16, 0 );
+				gl.copyTexImage2D( gl.TEXTURE_2D, 0, gl.RGB, screenPositionPixels.x, screenPositionPixels.y, 16, 16, 0 );
 
 
 				// render pink quad
@@ -279,7 +278,7 @@ THREE.LensFlarePlugin = function ( renderer, flares ) {
 
 				state.activeTexture( gl.TEXTURE0 );
 				state.bindTexture( gl.TEXTURE_2D, occlusionTexture );
-				gl.copyTexImage2D( gl.TEXTURE_2D, 0, gl.RGBA, areaToCopy.x, areaToCopy.y, 16, 16, 0 );
+				gl.copyTexImage2D( gl.TEXTURE_2D, 0, gl.RGBA, screenPositionPixels.x, screenPositionPixels.y, 16, 16, 0 );
 
 
 				// restore graphics