text: import {
  	Vector2
  } from "../../../build/three.module.js";
  
  /**
   * Normal map shader
   * - compute normals from heightmap
   */
  
  var NormalMapShader = {
  
  	uniforms: {
  
  		"heightMap": { value: null },
  		"resolution": { value: new Vector2( 512, 512 ) },
  		"scale": { value: new Vector2( 1, 1 ) },
  		"height": { value: 0.05 }
  
  	},
  
  	vertexShader: [
  
  		"varying vec2 vUv;",
  
  		"void main() {",
  
  		"	vUv = uv;",
  		"	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",
  
  		"}"
  
  	].join( "\n" ),
  
  	fragmentShader: [
  
  		"uniform float height;",
  		"uniform vec2 resolution;",
  		"uniform sampler2D heightMap;",
  
  		"varying vec2 vUv;",
  
  		"void main() {",
  
  		"	float val = texture2D( heightMap, vUv ).x;",
  
  		"	float valU = texture2D( heightMap, vUv + vec2( 1.0 / resolution.x, 0.0 ) ).x;",
  		"	float valV = texture2D( heightMap, vUv + vec2( 0.0, 1.0 / resolution.y ) ).x;",
  
  		"	gl_FragColor = vec4( ( 0.5 * normalize( vec3( val - valU, val - valV, height  ) ) + 0.5 ), 1.0 );",
  
  		"}"
  
  	].join( "\n" )
  
  };
  
  export { NormalMapShader };
  