/**
 * Slightly adapted from https://github.com/mrdoob/three.js
 * MIT License Copyright (c) 2010-2020 three.js authors
 *
 * 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
 */
export declare const blend_frag = "\nprecision highp float;\nprecision highp int;\nprecision highp sampler2D;\n\nuniform sampler2D tWeights;\nuniform sampler2D tColor;\nuniform vec2 uTexSizeInv;\n\nvarying vec2 vUv;\nvarying vec4 vOffset[2];\n\nvec4 SMAANeighborhoodBlendingPS(vec2 texCoord, vec4 offset[2], sampler2D colorTex, sampler2D blendTex) {\n    // Fetch the blending weights for current pixel:\n    vec4 a;\n    a.xz = texture2D(blendTex, texCoord).xz;\n    a.y = texture2D(blendTex, offset[1].zw).g;\n    a.w = texture2D(blendTex, offset[1].xy).a;\n\n    // Is there any blending weight with a value greater than 0.0?\n    if (dot(a, vec4(1.0, 1.0, 1.0, 1.0)) < 1e-5) {\n        return texture2D(colorTex, texCoord, 0.0);\n    } else {\n        // Up to 4 lines can be crossing a pixel (one through each edge). We\n        // favor blending by choosing the line with the maximum weight for each\n        // direction:\n        vec2 offset;\n        offset.x = a.a > a.b ? a.a : -a.b; // left vs. right\n        offset.y = a.g > a.r ? -a.g : a.r; // top vs. bottom // WebGL port note: Changed signs\n\n        // Then we go in the direction that has the maximum weight:\n        if (abs(offset.x) > abs(offset.y)) { // horizontal vs. vertical\n            offset.y = 0.0;\n        } else {\n            offset.x = 0.0;\n        }\n\n        // Fetch the opposite color and lerp by hand:\n        vec4 C = texture2D(colorTex, texCoord, 0.0);\n        texCoord += sign(offset) * uTexSizeInv;\n        vec4 Cop = texture2D(colorTex, texCoord, 0.0);\n        float s = abs(offset.x) > abs(offset.y) ? abs(offset.x) : abs(offset.y);\n\n        // WebGL port note: Added gamma correction\n        C.xyz = pow(C.xyz, vec3(2.2));\n        Cop.xyz = pow(Cop.xyz, vec3(2.2));\n        vec4 mixed = mix(C, Cop, s);\n        mixed.xyz = pow(mixed.xyz, vec3(1.0 / 2.2));\n\n        return mixed;\n    }\n}\n\nvoid main() {\n    gl_FragColor = SMAANeighborhoodBlendingPS(vUv, vOffset, tColor, tWeights);\n}\n";