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public/sdk/three/jsm/objects/Refractor.js

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+import {
+	Color,
+	Matrix4,
+	Mesh,
+	PerspectiveCamera,
+	Plane,
+	Quaternion,
+	ShaderMaterial,
+	UniformsUtils,
+	Vector3,
+	Vector4,
+	WebGLRenderTarget,
+	HalfFloatType
+} from 'three';
+
+class Refractor extends Mesh {
+
+	constructor( geometry, options = {} ) {
+
+		super( geometry );
+
+		this.isRefractor = true;
+
+		this.type = 'Refractor';
+		this.camera = new PerspectiveCamera();
+
+		const scope = this;
+
+		const color = ( options.color !== undefined ) ? new Color( options.color ) : new Color( 0x7F7F7F );
+		const textureWidth = options.textureWidth || 512;
+		const textureHeight = options.textureHeight || 512;
+		const clipBias = options.clipBias || 0;
+		const shader = options.shader || Refractor.RefractorShader;
+		const multisample = ( options.multisample !== undefined ) ? options.multisample : 4;
+
+		//
+
+		const virtualCamera = this.camera;
+		virtualCamera.matrixAutoUpdate = false;
+		virtualCamera.userData.refractor = true;
+
+		//
+
+		const refractorPlane = new Plane();
+		const textureMatrix = new Matrix4();
+
+		// render target
+
+		const renderTarget = new WebGLRenderTarget( textureWidth, textureHeight, { samples: multisample, type: HalfFloatType } );
+
+		// material
+
+		this.material = new ShaderMaterial( {
+			name: ( shader.name !== undefined ) ? shader.name : 'unspecified',
+			uniforms: UniformsUtils.clone( shader.uniforms ),
+			vertexShader: shader.vertexShader,
+			fragmentShader: shader.fragmentShader,
+			transparent: true // ensures, refractors are drawn from farthest to closest
+		} );
+
+		this.material.uniforms[ 'color' ].value = color;
+		this.material.uniforms[ 'tDiffuse' ].value = renderTarget.texture;
+		this.material.uniforms[ 'textureMatrix' ].value = textureMatrix;
+
+		// functions
+
+		const visible = ( function () {
+
+			const refractorWorldPosition = new Vector3();
+			const cameraWorldPosition = new Vector3();
+			const rotationMatrix = new Matrix4();
+
+			const view = new Vector3();
+			const normal = new Vector3();
+
+			return function visible( camera ) {
+
+				refractorWorldPosition.setFromMatrixPosition( scope.matrixWorld );
+				cameraWorldPosition.setFromMatrixPosition( camera.matrixWorld );
+
+				view.subVectors( refractorWorldPosition, cameraWorldPosition );
+
+				rotationMatrix.extractRotation( scope.matrixWorld );
+
+				normal.set( 0, 0, 1 );
+				normal.applyMatrix4( rotationMatrix );
+
+				return view.dot( normal ) < 0;
+
+			};
+
+		} )();
+
+		const updateRefractorPlane = ( function () {
+
+			const normal = new Vector3();
+			const position = new Vector3();
+			const quaternion = new Quaternion();
+			const scale = new Vector3();
+
+			return function updateRefractorPlane() {
+
+				scope.matrixWorld.decompose( position, quaternion, scale );
+				normal.set( 0, 0, 1 ).applyQuaternion( quaternion ).normalize();
+
+				// flip the normal because we want to cull everything above the plane
+
+				normal.negate();
+
+				refractorPlane.setFromNormalAndCoplanarPoint( normal, position );
+
+			};
+
+		} )();
+
+		const updateVirtualCamera = ( function () {
+
+			const clipPlane = new Plane();
+			const clipVector = new Vector4();
+			const q = new Vector4();
+
+			return function updateVirtualCamera( camera ) {
+
+				virtualCamera.matrixWorld.copy( camera.matrixWorld );
+				virtualCamera.matrixWorldInverse.copy( virtualCamera.matrixWorld ).invert();
+				virtualCamera.projectionMatrix.copy( camera.projectionMatrix );
+				virtualCamera.far = camera.far; // used in WebGLBackground
+
+				// The following code creates an oblique view frustum for clipping.
+				// see: Lengyel, Eric. “Oblique View Frustum Depth Projection and Clipping”.
+				// Journal of Game Development, Vol. 1, No. 2 (2005), Charles River Media, pp. 5–16
+
+				clipPlane.copy( refractorPlane );
+				clipPlane.applyMatrix4( virtualCamera.matrixWorldInverse );
+
+				clipVector.set( clipPlane.normal.x, clipPlane.normal.y, clipPlane.normal.z, clipPlane.constant );
+
+				// calculate the clip-space corner point opposite the clipping plane and
+				// transform it into camera space by multiplying it by the inverse of the projection matrix
+
+				const projectionMatrix = virtualCamera.projectionMatrix;
+
+				q.x = ( Math.sign( clipVector.x ) + projectionMatrix.elements[ 8 ] ) / projectionMatrix.elements[ 0 ];
+				q.y = ( Math.sign( clipVector.y ) + projectionMatrix.elements[ 9 ] ) / projectionMatrix.elements[ 5 ];
+				q.z = - 1.0;
+				q.w = ( 1.0 + projectionMatrix.elements[ 10 ] ) / projectionMatrix.elements[ 14 ];
+
+				// calculate the scaled plane vector
+
+				clipVector.multiplyScalar( 2.0 / clipVector.dot( q ) );
+
+				// replacing the third row of the projection matrix
+
+				projectionMatrix.elements[ 2 ] = clipVector.x;
+				projectionMatrix.elements[ 6 ] = clipVector.y;
+				projectionMatrix.elements[ 10 ] = clipVector.z + 1.0 - clipBias;
+				projectionMatrix.elements[ 14 ] = clipVector.w;
+
+			};
+
+		} )();
+
+		// This will update the texture matrix that is used for projective texture mapping in the shader.
+		// see: http://developer.download.nvidia.com/assets/gamedev/docs/projective_texture_mapping.pdf
+
+		function updateTextureMatrix( camera ) {
+
+			// this matrix does range mapping to [ 0, 1 ]
+
+			textureMatrix.set(
+				0.5, 0.0, 0.0, 0.5,
+				0.0, 0.5, 0.0, 0.5,
+				0.0, 0.0, 0.5, 0.5,
+				0.0, 0.0, 0.0, 1.0
+			);
+
+			// we use "Object Linear Texgen", so we need to multiply the texture matrix T
+			// (matrix above) with the projection and view matrix of the virtual camera
+			// and the model matrix of the refractor
+
+			textureMatrix.multiply( camera.projectionMatrix );
+			textureMatrix.multiply( camera.matrixWorldInverse );
+			textureMatrix.multiply( scope.matrixWorld );
+
+		}
+
+		//
+
+		function render( renderer, scene, camera ) {
+
+			scope.visible = false;
+
+			const currentRenderTarget = renderer.getRenderTarget();
+			const currentXrEnabled = renderer.xr.enabled;
+			const currentShadowAutoUpdate = renderer.shadowMap.autoUpdate;
+
+			renderer.xr.enabled = false; // avoid camera modification
+			renderer.shadowMap.autoUpdate = false; // avoid re-computing shadows
+
+			renderer.setRenderTarget( renderTarget );
+			if ( renderer.autoClear === false ) renderer.clear();
+			renderer.render( scene, virtualCamera );
+
+			renderer.xr.enabled = currentXrEnabled;
+			renderer.shadowMap.autoUpdate = currentShadowAutoUpdate;
+			renderer.setRenderTarget( currentRenderTarget );
+
+			// restore viewport
+
+			const viewport = camera.viewport;
+
+			if ( viewport !== undefined ) {
+
+				renderer.state.viewport( viewport );
+
+			}
+
+			scope.visible = true;
+
+		}
+
+		//
+
+		this.onBeforeRender = function ( renderer, scene, camera ) {
+
+			// ensure refractors are rendered only once per frame
+
+			if ( camera.userData.refractor === true ) return;
+
+			// avoid rendering when the refractor is viewed from behind
+
+			if ( ! visible( camera ) === true ) return;
+
+			// update
+
+			updateRefractorPlane();
+
+			updateTextureMatrix( camera );
+
+			updateVirtualCamera( camera );
+
+			render( renderer, scene, camera );
+
+		};
+
+		this.getRenderTarget = function () {
+
+			return renderTarget;
+
+		};
+
+		this.dispose = function () {
+
+			renderTarget.dispose();
+			scope.material.dispose();
+
+		};
+
+	}
+
+}
+
+Refractor.RefractorShader = {
+
+	name: 'RefractorShader',
+
+	uniforms: {
+
+		'color': {
+			value: null
+		},
+
+		'tDiffuse': {
+			value: null
+		},
+
+		'textureMatrix': {
+			value: null
+		}
+
+	},
+
+	vertexShader: /* glsl */`
+
+		uniform mat4 textureMatrix;
+
+		varying vec4 vUv;
+
+		void main() {
+
+			vUv = textureMatrix * vec4( position, 1.0 );
+			gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
+
+		}`,
+
+	fragmentShader: /* glsl */`
+
+		uniform vec3 color;
+		uniform sampler2D tDiffuse;
+
+		varying vec4 vUv;
+
+		float blendOverlay( float base, float blend ) {
+
+			return( base < 0.5 ? ( 2.0 * base * blend ) : ( 1.0 - 2.0 * ( 1.0 - base ) * ( 1.0 - blend ) ) );
+
+		}
+
+		vec3 blendOverlay( vec3 base, vec3 blend ) {
+
+			return vec3( blendOverlay( base.r, blend.r ), blendOverlay( base.g, blend.g ), blendOverlay( base.b, blend.b ) );
+
+		}
+
+		void main() {
+
+			vec4 base = texture2DProj( tDiffuse, vUv );
+			gl_FragColor = vec4( blendOverlay( base.rgb, color ), 1.0 );
+
+			#include <tonemapping_fragment>
+			#include <colorspace_fragment>
+
+		}`
+
+};
+
+export { Refractor };