remove _forceViewport (#31189)

src/renderers/common/Renderer.js

@@ -314,8 +314,6 @@ class Renderer {
 		 */
 		this._scissor = new Vector4( 0, 0, this._width, this._height );
 
-		this._forceViewport = false;
-
 		/**
 		 * Whether the scissor test should be enabled or not.
 		 *
@@ -1245,7 +1243,16 @@ class Renderer {
 
 		frameBufferTarget.depthBuffer = depth;
 		frameBufferTarget.stencilBuffer = stencil;
-		frameBufferTarget.setSize( width, height, outputRenderTarget !== null ? outputRenderTarget.depth : 1 );
+		if ( outputRenderTarget !== null ) {
+
+			frameBufferTarget.setSize( outputRenderTarget.width, outputRenderTarget.height, outputRenderTarget.depth );
+
+		} else {
+
+			frameBufferTarget.setSize( width, height, 1 );
+
+		}
+
 		frameBufferTarget.viewport.copy( this._viewport );
 		frameBufferTarget.scissor.copy( this._scissor );
 		frameBufferTarget.viewport.multiplyScalar( this._pixelRatio );
@@ -1383,7 +1390,7 @@ class Renderer {
 		renderContext.viewportValue.height >>= activeMipmapLevel;
 		renderContext.viewportValue.minDepth = minDepth;
 		renderContext.viewportValue.maxDepth = maxDepth;
-		renderContext.viewport = renderContext.viewportValue.equals( _screen ) === false || this._forceViewport;
+		renderContext.viewport = renderContext.viewportValue.equals( _screen ) === false;
 
 		renderContext.scissorValue.copy( scissor ).multiplyScalar( pixelRatio ).floor();
 		renderContext.scissor = this._scissorTest && renderContext.scissorValue.equals( _screen ) === false;
@@ -1513,8 +1520,6 @@ class Renderer {
 		this._width = width;
 		this._height = height;
 
-		this._forceViewport = true;
-
 		this.setViewport( 0, 0, width, height );
 
 	}
@@ -1702,7 +1707,6 @@ class Renderer {
 
 		this.domElement.width = Math.floor( width * pixelRatio );
 		this.domElement.height = Math.floor( height * pixelRatio );
-		this._forceViewport = false;
 
 		this.setViewport( 0, 0, width, height );
 
@@ -1728,8 +1732,6 @@ class Renderer {
 		this.domElement.width = Math.floor( width * this._pixelRatio );
 		this.domElement.height = Math.floor( height * this._pixelRatio );
 
-		this._forceViewport = false;
-
 		if ( updateStyle === true ) {
 
 			this.domElement.style.width = width + 'px';

src/renderers/webgl-fallback/WebGLBackend.js

@@ -13,8 +13,11 @@ import { WebGLBufferRenderer } from './WebGLBufferRenderer.js';
 
 import { warnOnce } from '../../utils.js';
 import { WebGLCoordinateSystem } from '../../constants.js';
+import { Vector2 } from '../../math/Vector2.js';
 import WebGLTimestampQueryPool from './utils/WebGLTimestampQueryPool.js';
 
+const _drawingBufferSize = /*@__PURE__*/ new Vector2();
+
 /**
  * A backend implementation targeting WebGL 2.
  *
@@ -441,7 +444,7 @@ class WebGLBackend extends Backend {
 	 */
 	beginRender( renderContext ) {
 
-		const { state, gl } = this;
+		const { state } = this;
 		const renderContextData = this.get( renderContext );
 
 		//
@@ -452,7 +455,8 @@ class WebGLBackend extends Backend {
 
 		} else {
 
-			state.viewport( 0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight );
+			const { width, height } = this.getDrawingBufferSize( _drawingBufferSize );
+			state.viewport( 0, 0, width, height );
 
 		}
 
@@ -611,7 +615,8 @@ class WebGLBackend extends Backend {
 
 			} else {
 
-				state.viewport( 0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight );
+				const { width, height } = this.getDrawingBufferSize( _drawingBufferSize );
+				state.viewport( 0, 0, width, height );
 
 			}