text: import {
  	Vector2
  } from "../../../build/three.module.js";
  
  /**
   * 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 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 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 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' )
  
  };
  
  export { SMAAEdgesShader, SMAAWeightsShader, SMAABlendShader };
  