Merge pull request #16671 from WestLangley/dev_from_equirect

WebGLRenderTargetCube: added fromEquirectangularTexture() method

src/renderers/WebGLRenderTargetCube.js

@@ -2,6 +2,7 @@ import { WebGLRenderTarget } from './WebGLRenderTarget.js';
 
 /**
  * @author alteredq / http://alteredqualia.com
+ * @author WestLangley / http://github.com/WestLangley
  */
 
 function WebGLRenderTargetCube( width, height, options ) {
@@ -15,5 +16,97 @@ WebGLRenderTargetCube.prototype.constructor = WebGLRenderTargetCube;
 
 WebGLRenderTargetCube.prototype.isWebGLRenderTargetCube = true;
 
+WebGLRenderTargetCube.prototype.fromEquirectangularTexture = function ( renderer, texture ) {
+
+	this.texture.type = texture.type;
+	this.texture.format = texture.format;
+	this.texture.encoding = texture.encoding;
+
+	var scene = new THREE.Scene();
+
+	var shader = {
+
+		uniforms: {
+			tEquirect: { value: null },
+		},
+
+		vertexShader:
+
+			`
+			varying vec3 vWorldDirection;
+
+			vec3 transformDirection( in vec3 dir, in mat4 matrix ) {
+
+				return normalize( ( matrix * vec4( dir, 0.0 ) ).xyz );
+
+			}
+
+			void main() {
+
+				vWorldDirection = transformDirection( position, modelMatrix );
+
+				#include <begin_vertex>
+				#include <project_vertex>
+
+			}
+			`,
+
+		fragmentShader:
+
+			`
+			uniform sampler2D tEquirect;
+
+			varying vec3 vWorldDirection;
+
+			#define RECIPROCAL_PI 0.31830988618
+			#define RECIPROCAL_PI2 0.15915494
+
+			void main() {
+
+				vec3 direction = normalize( vWorldDirection );
+
+				vec2 sampleUV;
+
+				sampleUV.y = asin( clamp( direction.y, - 1.0, 1.0 ) ) * RECIPROCAL_PI + 0.5;
+
+				sampleUV.x = atan( direction.z, direction.x ) * RECIPROCAL_PI2 + 0.5;
+
+				gl_FragColor = texture2D( tEquirect, sampleUV );
+
+			}
+			`
+	};
+
+	var material = new THREE.ShaderMaterial( {
+
+		type: 'CubemapFromEquirect',
+
+		uniforms: THREE.UniformsUtils.clone( shader.uniforms ),
+		vertexShader: shader.vertexShader,
+		fragmentShader: shader.fragmentShader,
+		side: THREE.BackSide,
+		blending: THREE.NoBlending
+
+	} );
+
+	material.uniforms.tEquirect.value = texture;
+
+	var mesh = new THREE.Mesh( new THREE.BoxBufferGeometry( 5, 5, 5 ), material );
+
+	scene.add( mesh );
+
+	var camera = new THREE.CubeCamera( 1, 10, 1 );
+
+	camera.renderTarget = this;
+	camera.renderTarget.texture.name = 'CubeCameraTexture';
+
+	camera.update( renderer, scene );
+
+	mesh.geometry.dispose();
+	mesh.material.dispose();
+
+	return this;
+
+};
 
 export { WebGLRenderTargetCube };