three.js/examples/js/shaders/SMAAShader.js

( function () {

	/**
 * WebGL port of Subpixel Morphological Antialiasing (SMAA) v2.8
 * Preset: SMAA 1x Medium (with color edge detection)
 * https://github.com/iryoku/smaa/releases/tag/v2.8
 */

	var SMAAEdgesShader = {
		defines: {
			'SMAA_THRESHOLD': '0.1'
		},
		uniforms: {
			'tDiffuse': {
				value: null
			},
			'resolution': {
				value: new THREE.Vector2( 1 / 1024, 1 / 512 )
			}
		},
		vertexShader: [ 'uniform vec2 resolution;', 'varying vec2 vUv;', 'varying vec4 vOffset[ 3 ];', 'void SMAAEdgeDetectionVS( vec2 texcoord ) {', '	vOffset[ 0 ] = texcoord.xyxy + resolution.xyxy * vec4( -1.0, 0.0, 0.0,	1.0 );', // WebGL port note: Changed sign in W component
			'	vOffset[ 1 ] = texcoord.xyxy + resolution.xyxy * vec4(	1.0, 0.0, 0.0, -1.0 );', // WebGL port note: Changed sign in W component
			'	vOffset[ 2 ] = texcoord.xyxy + resolution.xyxy * vec4( -2.0, 0.0, 0.0,	2.0 );', // WebGL port note: Changed sign in W component
			'}', 'void main() {', '	vUv = uv;', '	SMAAEdgeDetectionVS( vUv );', '	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );', '}' ].join( '\n' ),
		fragmentShader: [ 'uniform sampler2D tDiffuse;', 'varying vec2 vUv;', 'varying vec4 vOffset[ 3 ];', 'vec4 SMAAColorEdgeDetectionPS( vec2 texcoord, vec4 offset[3], sampler2D colorTex ) {', '	vec2 threshold = vec2( SMAA_THRESHOLD, SMAA_THRESHOLD );', // Calculate color deltas:
			'	vec4 delta;', '	vec3 C = texture2D( colorTex, texcoord ).rgb;', '	vec3 Cleft = texture2D( colorTex, offset[0].xy ).rgb;', '	vec3 t = abs( C - Cleft );', '	delta.x = max( max( t.r, t.g ), t.b );', '	vec3 Ctop = texture2D( colorTex, offset[0].zw ).rgb;', '	t = abs( C - Ctop );', '	delta.y = max( max( t.r, t.g ), t.b );', // We do the usual threshold:
			'	vec2 edges = step( threshold, delta.xy );', // Then discard if there is no edge:
			'	if ( dot( edges, vec2( 1.0, 1.0 ) ) == 0.0 )', '		discard;', // Calculate right and bottom deltas:
			'	vec3 Cright = texture2D( colorTex, offset[1].xy ).rgb;', '	t = abs( C - Cright );', '	delta.z = max( max( t.r, t.g ), t.b );', '	vec3 Cbottom	= texture2D( colorTex, offset[1].zw ).rgb;', '	t = abs( C - Cbottom );', '	delta.w = max( max( t.r, t.g ), t.b );', // Calculate the maximum delta in the direct neighborhood:
			'	float maxDelta = max( max( max( delta.x, delta.y ), delta.z ), delta.w );', // Calculate left-left and top-top deltas:
			'	vec3 Cleftleft	= texture2D( colorTex, offset[2].xy ).rgb;', '	t = abs( C - Cleftleft );', '	delta.z = max( max( t.r, t.g ), t.b );', '	vec3 Ctoptop = texture2D( colorTex, offset[2].zw ).rgb;', '	t = abs( C - Ctoptop );', '	delta.w = max( max( t.r, t.g ), t.b );', // Calculate the final maximum delta:
			'	maxDelta = max( max( maxDelta, delta.z ), delta.w );', // Local contrast adaptation in action:
			'	edges.xy *= step( 0.5 * maxDelta, delta.xy );', '	return vec4( edges, 0.0, 0.0 );', '}', 'void main() {', '	gl_FragColor = SMAAColorEdgeDetectionPS( vUv, vOffset, tDiffuse );', '}' ].join( '\n' )
	};
	var SMAAWeightsShader = {
		defines: {
			'SMAA_MAX_SEARCH_STEPS': '8',
			'SMAA_AREATEX_MAX_DISTANCE': '16',
			'SMAA_AREATEX_PIXEL_SIZE': '( 1.0 / vec2( 160.0, 560.0 ) )',
			'SMAA_AREATEX_SUBTEX_SIZE': '( 1.0 / 7.0 )'
		},
		uniforms: {
			'tDiffuse': {
				value: null
			},
			'tArea': {
				value: null
			},
			'tSearch': {
				value: null
			},
			'resolution': {
				value: new THREE.Vector2( 1 / 1024, 1 / 512 )
			}
		},
		vertexShader: [ 'uniform vec2 resolution;', 'varying vec2 vUv;', 'varying vec4 vOffset[ 3 ];', 'varying vec2 vPixcoord;', 'void SMAABlendingWeightCalculationVS( vec2 texcoord ) {', '	vPixcoord = texcoord / resolution;', // We will use these offsets for the searches later on (see @PSEUDO_GATHER4):
			'	vOffset[ 0 ] = texcoord.xyxy + resolution.xyxy * vec4( -0.25, 0.125, 1.25, 0.125 );', // WebGL port note: Changed sign in Y and W components
			'	vOffset[ 1 ] = texcoord.xyxy + resolution.xyxy * vec4( -0.125, 0.25, -0.125, -1.25 );', // WebGL port note: Changed sign in Y and W components
			// And these for the searches, they indicate the ends of the loops:
			'	vOffset[ 2 ] = vec4( vOffset[ 0 ].xz, vOffset[ 1 ].yw ) + vec4( -2.0, 2.0, -2.0, 2.0 ) * resolution.xxyy * float( SMAA_MAX_SEARCH_STEPS );', '}', 'void main() {', '	vUv = uv;', '	SMAABlendingWeightCalculationVS( vUv );', '	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );', '}' ].join( '\n' ),
		fragmentShader: [ '#define SMAASampleLevelZeroOffset( tex, coord, offset ) texture2D( tex, coord + float( offset ) * resolution, 0.0 )', 'uniform sampler2D tDiffuse;', 'uniform sampler2D tArea;', 'uniform sampler2D tSearch;', 'uniform vec2 resolution;', 'varying vec2 vUv;', 'varying vec4 vOffset[3];', 'varying vec2 vPixcoord;', '#if __VERSION__ == 100', 'vec2 round( vec2 x ) {', '	return sign( x ) * floor( abs( x ) + 0.5 );', '}', '#endif', 'float SMAASearchLength( sampler2D searchTex, vec2 e, float bias, float scale ) {', // Not required if searchTex accesses are set to point:
			// float2 SEARCH_TEX_PIXEL_SIZE = 1.0 / float2(66.0, 33.0);
			// e = float2(bias, 0.0) + 0.5 * SEARCH_TEX_PIXEL_SIZE +
			//		 e * float2(scale, 1.0) * float2(64.0, 32.0) * SEARCH_TEX_PIXEL_SIZE;
			'	e.r = bias + e.r * scale;', '	return 255.0 * texture2D( searchTex, e, 0.0 ).r;', '}', 'float SMAASearchXLeft( sampler2D edgesTex, sampler2D searchTex, vec2 texcoord, float end ) {',
			/**
		* @PSEUDO_GATHER4
		* This texcoord has been offset by (-0.25, -0.125) in the vertex shader to
		* sample between edge, thus fetching four edges in a row.
		* Sampling with different offsets in each direction allows to disambiguate
		* which edges are active from the four fetched ones.
		*/
			'	vec2 e = vec2( 0.0, 1.0 );', '	for ( int i = 0; i < SMAA_MAX_SEARCH_STEPS; i ++ ) {', // WebGL port note: Changed while to for
			'		e = texture2D( edgesTex, texcoord, 0.0 ).rg;', '		texcoord -= vec2( 2.0, 0.0 ) * resolution;', '		if ( ! ( texcoord.x > end && e.g > 0.8281 && e.r == 0.0 ) ) break;', '	}', // We correct the previous (-0.25, -0.125) offset we applied:
			'	texcoord.x += 0.25 * resolution.x;', // The searches are bias by 1, so adjust the coords accordingly:
			'	texcoord.x += resolution.x;', // Disambiguate the length added by the last step:
			'	texcoord.x += 2.0 * resolution.x;', // Undo last step
			'	texcoord.x -= resolution.x * SMAASearchLength(searchTex, e, 0.0, 0.5);', '	return texcoord.x;', '}', 'float SMAASearchXRight( sampler2D edgesTex, sampler2D searchTex, vec2 texcoord, float end ) {', '	vec2 e = vec2( 0.0, 1.0 );', '	for ( int i = 0; i < SMAA_MAX_SEARCH_STEPS; i ++ ) {', // WebGL port note: Changed while to for
			'		e = texture2D( edgesTex, texcoord, 0.0 ).rg;', '		texcoord += vec2( 2.0, 0.0 ) * resolution;', '		if ( ! ( texcoord.x < end && e.g > 0.8281 && e.r == 0.0 ) ) break;', '	}', '	texcoord.x -= 0.25 * resolution.x;', '	texcoord.x -= resolution.x;', '	texcoord.x -= 2.0 * resolution.x;', '	texcoord.x += resolution.x * SMAASearchLength( searchTex, e, 0.5, 0.5 );', '	return texcoord.x;', '}', 'float SMAASearchYUp( sampler2D edgesTex, sampler2D searchTex, vec2 texcoord, float end ) {', '	vec2 e = vec2( 1.0, 0.0 );', '	for ( int i = 0; i < SMAA_MAX_SEARCH_STEPS; i ++ ) {', // WebGL port note: Changed while to for
			'		e = texture2D( edgesTex, texcoord, 0.0 ).rg;', '		texcoord += vec2( 0.0, 2.0 ) * resolution;', // WebGL port note: Changed sign
			'		if ( ! ( texcoord.y > end && e.r > 0.8281 && e.g == 0.0 ) ) break;', '	}', '	texcoord.y -= 0.25 * resolution.y;', // WebGL port note: Changed sign
			'	texcoord.y -= resolution.y;', // WebGL port note: Changed sign
			'	texcoord.y -= 2.0 * resolution.y;', // WebGL port note: Changed sign
			'	texcoord.y += resolution.y * SMAASearchLength( searchTex, e.gr, 0.0, 0.5 );', // WebGL port note: Changed sign
			'	return texcoord.y;', '}', 'float SMAASearchYDown( sampler2D edgesTex, sampler2D searchTex, vec2 texcoord, float end ) {', '	vec2 e = vec2( 1.0, 0.0 );', '	for ( int i = 0; i < SMAA_MAX_SEARCH_STEPS; i ++ ) {', // WebGL port note: Changed while to for
			'		e = texture2D( edgesTex, texcoord, 0.0 ).rg;', '		texcoord -= vec2( 0.0, 2.0 ) * resolution;', // WebGL port note: Changed sign
			'		if ( ! ( texcoord.y < end && e.r > 0.8281 && e.g == 0.0 ) ) break;', '	}', '	texcoord.y += 0.25 * resolution.y;', // WebGL port note: Changed sign
			'	texcoord.y += resolution.y;', // WebGL port note: Changed sign
			'	texcoord.y += 2.0 * resolution.y;', // WebGL port note: Changed sign
			'	texcoord.y -= resolution.y * SMAASearchLength( searchTex, e.gr, 0.5, 0.5 );', // WebGL port note: Changed sign
			'	return texcoord.y;', '}', 'vec2 SMAAArea( sampler2D areaTex, vec2 dist, float e1, float e2, float offset ) {', // Rounding prevents precision errors of bilinear filtering:
			'	vec2 texcoord = float( SMAA_AREATEX_MAX_DISTANCE ) * round( 4.0 * vec2( e1, e2 ) ) + dist;', // We do a scale and bias for mapping to texel space:
			'	texcoord = SMAA_AREATEX_PIXEL_SIZE * texcoord + ( 0.5 * SMAA_AREATEX_PIXEL_SIZE );', // Move to proper place, according to the subpixel offset:
			'	texcoord.y += SMAA_AREATEX_SUBTEX_SIZE * offset;', '	return texture2D( areaTex, texcoord, 0.0 ).rg;', '}', 'vec4 SMAABlendingWeightCalculationPS( vec2 texcoord, vec2 pixcoord, vec4 offset[ 3 ], sampler2D edgesTex, sampler2D areaTex, sampler2D searchTex, ivec4 subsampleIndices ) {', '	vec4 weights = vec4( 0.0, 0.0, 0.0, 0.0 );', '	vec2 e = texture2D( edgesTex, texcoord ).rg;', '	if ( e.g > 0.0 ) {', // Edge at north
			'		vec2 d;', // Find the distance to the left:
			'		vec2 coords;', '		coords.x = SMAASearchXLeft( edgesTex, searchTex, offset[ 0 ].xy, offset[ 2 ].x );', '		coords.y = offset[ 1 ].y;', // offset[1].y = texcoord.y - 0.25 * resolution.y (@CROSSING_OFFSET)
			'		d.x = coords.x;', // Now fetch the left crossing edges, two at a time using bilinear
			// filtering. Sampling at -0.25 (see @CROSSING_OFFSET) enables to
			// discern what value each edge has:
			'		float e1 = texture2D( edgesTex, coords, 0.0 ).r;', // Find the distance to the right:
			'		coords.x = SMAASearchXRight( edgesTex, searchTex, offset[ 0 ].zw, offset[ 2 ].y );', '		d.y = coords.x;', // We want the distances to be in pixel units (doing this here allow to
			// better interleave arithmetic and memory accesses):
			'		d = d / resolution.x - pixcoord.x;', // SMAAArea below needs a sqrt, as the areas texture is compressed
			// quadratically:
			'		vec2 sqrt_d = sqrt( abs( d ) );', // Fetch the right crossing edges:
			'		coords.y -= 1.0 * resolution.y;', // WebGL port note: Added
			'		float e2 = SMAASampleLevelZeroOffset( edgesTex, coords, ivec2( 1, 0 ) ).r;', // Ok, we know how this pattern looks like, now it is time for getting
			// the actual area:
			'		weights.rg = SMAAArea( areaTex, sqrt_d, e1, e2, float( subsampleIndices.y ) );', '	}', '	if ( e.r > 0.0 ) {', // Edge at west
			'		vec2 d;', // Find the distance to the top:
			'		vec2 coords;', '		coords.y = SMAASearchYUp( edgesTex, searchTex, offset[ 1 ].xy, offset[ 2 ].z );', '		coords.x = offset[ 0 ].x;', // offset[1].x = texcoord.x - 0.25 * resolution.x;
			'		d.x = coords.y;', // Fetch the top crossing edges:
			'		float e1 = texture2D( edgesTex, coords, 0.0 ).g;', // Find the distance to the bottom:
			'		coords.y = SMAASearchYDown( edgesTex, searchTex, offset[ 1 ].zw, offset[ 2 ].w );', '		d.y = coords.y;', // We want the distances to be in pixel units:
			'		d = d / resolution.y - pixcoord.y;', // SMAAArea below needs a sqrt, as the areas texture is compressed
			// quadratically:
			'		vec2 sqrt_d = sqrt( abs( d ) );', // Fetch the bottom crossing edges:
			'		coords.y -= 1.0 * resolution.y;', // WebGL port note: Added
			'		float e2 = SMAASampleLevelZeroOffset( edgesTex, coords, ivec2( 0, 1 ) ).g;', // Get the area for this direction:
			'		weights.ba = SMAAArea( areaTex, sqrt_d, e1, e2, float( subsampleIndices.x ) );', '	}', '	return weights;', '}', 'void main() {', '	gl_FragColor = SMAABlendingWeightCalculationPS( vUv, vPixcoord, vOffset, tDiffuse, tArea, tSearch, ivec4( 0.0 ) );', '}' ].join( '\n' )
	};
	var SMAABlendShader = {
		uniforms: {
			'tDiffuse': {
				value: null
			},
			'tColor': {
				value: null
			},
			'resolution': {
				value: new THREE.Vector2( 1 / 1024, 1 / 512 )
			}
		},
		vertexShader: [ 'uniform vec2 resolution;', 'varying vec2 vUv;', 'varying vec4 vOffset[ 2 ];', 'void SMAANeighborhoodBlendingVS( vec2 texcoord ) {', '	vOffset[ 0 ] = texcoord.xyxy + resolution.xyxy * vec4( -1.0, 0.0, 0.0, 1.0 );', // WebGL port note: Changed sign in W component
			'	vOffset[ 1 ] = texcoord.xyxy + resolution.xyxy * vec4( 1.0, 0.0, 0.0, -1.0 );', // WebGL port note: Changed sign in W component
			'}', 'void main() {', '	vUv = uv;', '	SMAANeighborhoodBlendingVS( vUv );', '	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );', '}' ].join( '\n' ),
		fragmentShader: [ 'uniform sampler2D tDiffuse;', 'uniform sampler2D tColor;', 'uniform vec2 resolution;', 'varying vec2 vUv;', 'varying vec4 vOffset[ 2 ];', 'vec4 SMAANeighborhoodBlendingPS( vec2 texcoord, vec4 offset[ 2 ], sampler2D colorTex, sampler2D blendTex ) {', // Fetch the blending weights for current pixel:
			'	vec4 a;', '	a.xz = texture2D( blendTex, texcoord ).xz;', '	a.y = texture2D( blendTex, offset[ 1 ].zw ).g;', '	a.w = texture2D( blendTex, offset[ 1 ].xy ).a;', // Is there any blending weight with a value greater than 0.0?
			'	if ( dot(a, vec4( 1.0, 1.0, 1.0, 1.0 )) < 1e-5 ) {', '		return texture2D( colorTex, texcoord, 0.0 );', '	} else {', // Up to 4 lines can be crossing a pixel (one through each edge). We
			// favor blending by choosing the line with the maximum weight for each
			// direction:
			'		vec2 offset;', '		offset.x = a.a > a.b ? a.a : -a.b;', // left vs. right
			'		offset.y = a.g > a.r ? -a.g : a.r;', // top vs. bottom // WebGL port note: Changed signs
			// Then we go in the direction that has the maximum weight:
			'		if ( abs( offset.x ) > abs( offset.y )) {', // horizontal vs. vertical
			'			offset.y = 0.0;', '		} else {', '			offset.x = 0.0;', '		}', // Fetch the opposite color and lerp by hand:
			'		vec4 C = texture2D( colorTex, texcoord, 0.0 );', '		texcoord += sign( offset ) * resolution;', '		vec4 Cop = texture2D( colorTex, texcoord, 0.0 );', '		float s = abs( offset.x ) > abs( offset.y ) ? abs( offset.x ) : abs( offset.y );', // WebGL port note: Added gamma correction
			'		C.xyz = pow(C.xyz, vec3(2.2));', '		Cop.xyz = pow(Cop.xyz, vec3(2.2));', '		vec4 mixed = mix(C, Cop, s);', '		mixed.xyz = pow(mixed.xyz, vec3(1.0 / 2.2));', '		return mixed;', '	}', '}', 'void main() {', '	gl_FragColor = SMAANeighborhoodBlendingPS( vUv, vOffset, tColor, tDiffuse );', '}' ].join( '\n' )
	};

	THREE.SMAABlendShader = SMAABlendShader;
	THREE.SMAAEdgesShader = SMAAEdgesShader;
	THREE.SMAAWeightsShader = SMAAWeightsShader;

} )();