WebGLRenderer: Add transmission render target scale (#1442)

* WebGLRenderer: Add transmission render target scale

* Update three.js

* Add examples

* Update patch and delete examples

Author: Methuselah96

examples-testing/changes.patch

@@ -8437,19 +8437,19 @@ index 408fd992..dc782ea9 100644
  init();
 
 diff --git a/examples-testing/examples/webgl_materials_physical_transmission.ts b/examples-testing/examples/webgl_materials_physical_transmission.ts
-index d4596797..6464232e 100644
+index 08c73894..45b0f9ba 100644
 --- a/examples-testing/examples/webgl_materials_physical_transmission.ts
 +++ b/examples-testing/examples/webgl_materials_physical_transmission.ts
-@@ -19,7 +19,7 @@ const params = {
-     exposure: 1,
+@@ -20,7 +20,7 @@ const params = {
+     transmissionResolutionScale: 1,
  };
 
 -let camera, scene, renderer;
 +let camera: THREE.PerspectiveCamera, scene: THREE.Scene, renderer: THREE.WebGLRenderer;
 
  let mesh;
 
-@@ -170,7 +170,7 @@ function generateTexture() {
+@@ -178,7 +178,7 @@ function generateTexture() {
      canvas.width = 2;
      canvas.height = 2;
 

three.js

@@ -198,6 +198,13 @@ export class WebGLRenderer implements Renderer {
      */
     toneMappingExposure: number;
 
+    /**
+     * The normalized resolution scale for the transmission render target, measured in percentage of viewport
+     * dimensions. Lowering this value can result in significant improvements to {@link MeshPhysicalMaterial}
+     * transmission performance. Default is `1`.
+     */
+    transmissionResolutionScale: number;
+
     info: WebGLInfo;
 
     shadowMap: WebGLShadowMap;