three-shaders/shaders/ToneMapShader.js

three-shaders - a library of shaders included with Three.js library

/**
 * @author miibond
 *
 * Full-screen tone-mapping shader based on http://www.graphics.cornell.edu/~jaf/publications/sig02_paper.pdf
 */

function ToneMapShader() {

	return {

	uniforms: {

		tDiffuse: { value: null },
		averageLuminance:  { value: 1.0 },
		luminanceMap:  { value: null },
		maxLuminance:  { value: 16.0 },
		middleGrey:  { value: 0.6 }
	},

	vertexShader: `

		varying vec2 vUv;

		void main() {

			vUv = uv;
			gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

		}

	`,

	fragmentShader: `

		uniform sampler2D tDiffuse;

		varying vec2 vUv;

		uniform float middleGrey;
		uniform float maxLuminance;
		#ifdef ADAPTED_LUMINANCE
			uniform sampler2D luminanceMap;
		#else
			uniform float averageLuminance;
		#endif
		
		const vec3 LUM_CONVERT = vec3(0.299, 0.587, 0.114);

		vec3 ToneMap( vec3 vColor ) {
			#ifdef ADAPTED_LUMINANCE
				// Get the calculated average luminance 
				float fLumAvg = texture2D(luminanceMap, vec2(0.5, 0.5)).r;
			#else
				float fLumAvg = averageLuminance;
			#endif
			
			// Calculate the luminance of the current pixel
			float fLumPixel = dot(vColor, LUM_CONVERT);

			// Apply the modified operator (Eq. 4)
			float fLumScaled = (fLumPixel * middleGrey) / fLumAvg;

			float fLumCompressed = (fLumScaled * (1.0 + (fLumScaled / (maxLuminance * maxLuminance)))) / (1.0 + fLumScaled);
			return fLumCompressed * vColor;
		}

		void main() {

			vec4 texel = texture2D( tDiffuse, vUv );
			
			gl_FragColor = vec4( ToneMap( texel.xyz ), texel.w );

		}

	`
	}

};

module.exports = ToneMapShader;