molstar/lib/commonjs/mol-gl/shader/marching-cubes/isosurface.frag.js

A comprehensive macromolecular library.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.isosurface_frag = void 0;
exports.isosurface_frag = "\nprecision highp float;\nprecision highp int;\nprecision highp sampler2D;\n\n#if __VERSION__ == 100\n    uniform sampler2D tActiveVoxelsPyramid;\n#else\n    precision highp isampler2D;\n    uniform isampler2D tActiveVoxelsPyramid;\n#endif\n\nuniform sampler2D tActiveVoxelsBase;\nuniform sampler2D tVolumeData;\nuniform sampler2D tTriIndices;\n\nuniform float uIsoValue;\nuniform float uLevels;\nuniform float uSize;\nuniform float uCount;\nuniform bool uInvert;\n\nuniform vec3 uGridDim;\nuniform vec3 uGridTexDim;\nuniform mat4 uGridTransform;\n\n// scale to volume data coord\nuniform vec2 uScale;\n\n#include common\n\n// cube corners (excluding origin)\nconst vec3 c1 = vec3(1., 0., 0.);\nconst vec3 c2 = vec3(1., 1., 0.);\nconst vec3 c3 = vec3(0., 1., 0.);\nconst vec3 c4 = vec3(0., 0., 1.);\nconst vec3 c5 = vec3(1., 0., 1.);\nconst vec3 c6 = vec3(1., 1., 1.);\nconst vec3 c7 = vec3(0., 1., 1.);\n\nvec3 index3dFrom2d(vec2 coord) {\n    vec2 gridTexPos = coord * uGridTexDim.xy;\n    vec2 columnRow = ivec2Div(gridTexPos, uGridDim.xy);\n    vec2 posXY = gridTexPos - columnRow * uGridDim.xy;\n    float posZ = columnRow.y * intDiv(uGridTexDim.x, uGridDim.x) + columnRow.x;\n    return vec3(posXY, posZ);\n}\n\nvec4 texture3dFrom2dNearest(sampler2D tex, vec3 pos, vec3 gridDim, vec2 texDim) {\n    float zSlice = floor(pos.z * gridDim.z + 0.5); // round to nearest z-slice\n    float column = intDiv(intMod(zSlice * gridDim.x, texDim.x), gridDim.x);\n    float row = intDiv(zSlice * gridDim.x, texDim.x);\n    vec2 coord = (vec2(column * gridDim.x, row * gridDim.y) + (pos.xy * gridDim.xy)) / (texDim / uScale);\n    return texture2D(tex, coord + 0.5 / (texDim / uScale));\n}\n\nvec4 voxel(vec3 pos) {\n    pos = min(max(vec3(0.0), pos), uGridDim - vec3(1.0));\n    return texture3dFrom2dNearest(tVolumeData, pos / uGridDim, uGridDim, uGridTexDim.xy);\n}\n\nvec4 voxelPadded(vec3 pos) {\n    pos = min(max(vec3(0.0), pos), uGridDim - vec3(vec2(2.0), 1.0)); // remove xy padding\n    return texture3dFrom2dNearest(tVolumeData, pos / uGridDim, uGridDim, uGridTexDim.xy);\n}\n\nint idot2(const in ivec2 a, const in ivec2 b) {\n    return a.x * b.x + a.y * b.y;\n}\n\nint idot4(const in ivec4 a, const in ivec4 b) {\n    return a.x * b.x + a.y * b.y + a.z * b.z + a.w * b.w;\n}\n\n#if __VERSION__ == 100\n    int pyramidVoxel(vec2 pos) {\n        return int(decodeFloatRGB(texture2D(tActiveVoxelsPyramid, pos / (vec2(1.0, 0.5) * uSize)).rgb));\n    }\n#else\n    int pyramidVoxel(vec2 pos) {\n        return texture2D(tActiveVoxelsPyramid, pos / (vec2(1.0, 0.5) * uSize)).r;\n    }\n#endif\n\nvec4 baseVoxel(vec2 pos) {\n    return texture2D(tActiveVoxelsBase, pos / uSize);\n}\n\nvoid main(void) {\n    // get 1D index\n    int vI = int(gl_FragCoord.x) + int(gl_FragCoord.y) * int(uSize);\n\n    // ignore 1D indices outside of the grid\n    if(vI >= int(uCount)) discard;\n\n    ivec2 offset = ivec2(int(uSize) - 2, 0);\n\n    int start = 0;\n    ivec4 starts = ivec4(0);\n    ivec4 ends = ivec4(0);\n    int diff = 2;\n    ivec4 m = ivec4(0);\n    ivec2 position = ivec2(0);\n    ivec4 vI4 = ivec4(vI);\n\n    ivec2 relativePosition = ivec2(0);\n    int end = 0;\n    ivec2 pos1 = ivec2(0);\n    ivec2 pos2 = ivec2(0);\n    ivec2 pos3 = ivec2(0);\n    ivec2 pos4 = ivec2(0);\n    ivec3 vI3 = ivec3(vI);\n    ivec3 mask = ivec3(0);\n\n    // traverse the different levels of the pyramid\n    for(int i = 1; i < 14; i++) {\n        if(float(i) >= uLevels) break;\n\n        offset.x -= diff;\n        diff *= 2;\n        relativePosition = position + offset;\n\n        end = start + pyramidVoxel(vec2(relativePosition));\n        pos1 = ivec2(relativePosition);\n        starts.x = start;\n        ends.x = end;\n        pos2 = ivec2(relativePosition + ivec2(1, 0));\n        starts.y = ends.x;\n        ends.y = ends.x + pyramidVoxel(vec2(pos2));\n        pos3 = relativePosition + ivec2(0, 1);\n        starts.z = ends.y;\n        ends.z = ends.y + pyramidVoxel(vec2(pos3));\n        pos4 = relativePosition + ivec2(1, 1);\n        starts.w = ends.z;\n        mask = ivec3(greaterThanEqual(vI3, starts.rgb)) * ivec3(lessThan(vI3, ends.rgb));\n        m = ivec4(mask, 1 - int(any(bvec3(mask))));\n\n        relativePosition = m.x * pos1 + m.y * pos2 + m.z * pos3 + m.w * pos4;\n        start = idot4(m, starts);\n        position = 2 * (relativePosition - offset);\n    }\n\n    end = start + int(baseVoxel(vec2(position)).r * 255.0);\n    pos1 = position;\n    starts.x = start;\n    ends.x = end;\n    pos2 = position + ivec2(1, 0);\n    starts.y = ends.x;\n    ends.y = ends.x + int(baseVoxel(vec2(pos2)).r * 255.0);\n    pos3 = position + ivec2(0, 1);\n    starts.z = ends.y;\n    ends.z = ends.y + int(baseVoxel(vec2(pos3)).r * 255.0);\n    pos4 = position + ivec2(1, 1);\n    starts.w = ends.z;\n    mask = ivec3(greaterThanEqual(vI3, starts.rgb)) * ivec3(lessThan(vI3, ends.rgb));\n    m = ivec4(mask, 1 - int(any(bvec3(mask))));\n    position = m.x * pos1 + m.y * pos2 + m.z * pos3 + m.w * pos4;\n\n    vec2 coord2d = (vec2(position) / uSize) / uScale;\n    vec3 coord3d = floor(index3dFrom2d(coord2d) + 0.5);\n\n    float edgeIndex = floor(baseVoxel(vec2(position)).a * 255.0 + 0.5);\n\n    // current vertex for the up to 15 MC cases\n    int currentVertex = vI - idot4(m, starts);\n\n    // ensure winding-order is the same for negative and positive iso-levels\n    if (uInvert) {\n        int v = imod(currentVertex + 1, 3);\n        if (v == 1) currentVertex += 2;\n        else if (v == 0) currentVertex -= 2;\n    }\n\n    // get index into triIndices table\n    int mcIndex = 16 * int(edgeIndex) + currentVertex;\n    vec4 mcData = texture2D(tTriIndices, vec2(imod(mcIndex, 64), mcIndex / 64) / 64.);\n\n    // bit mask to avoid conditionals (see comment below) for getting MC case corner\n    vec4 m0 = vec4(floor(mcData.a * 255.0 + 0.5));\n\n    // get edge value masks\n    vec4 m1 = vec4(equal(m0, vec4(0., 1., 2., 3.)));\n    vec4 m2 = vec4(equal(m0, vec4(4., 5., 6., 7.)));\n    vec4 m3 = vec4(equal(m0, vec4(8., 9., 10., 11.)));\n\n    // apply bit masks\n    vec3 b0 = coord3d +\n                m1.y * c1 +\n                m1.z * c2 +\n                m1.w * c3 +\n                m2.x * c4 +\n                m2.y * c5 +\n                m2.z * c6 +\n                m2.w * c7 +\n                m3.y * c1 +\n                m3.z * c2 +\n                m3.w * c3;\n    vec3 b1 = coord3d +\n                m1.x * c1 +\n                m1.y * c2 +\n                m1.z * c3 +\n                m2.x * c5 +\n                m2.y * c6 +\n                m2.z * c7 +\n                m2.w * c4 +\n                m3.x * c4 +\n                m3.y * c5 +\n                m3.z * c6 +\n                m3.w * c7;\n\n    // the conditionals that are avoided by above bitmasks\n    // vec3 b0 = coord3d;\n    // vec3 b1 = coord3d;\n    // if (mcIndex == 0.0) {\n    //     b1 += c1;\n    // } else if (mcIndex == 1.0) {\n    //     b0 += c1; b1 += c2;\n    // } else if (mcIndex == 2.0) {\n    //     b0 += c2; b1 += c3;\n    // } else if (mcIndex == 3.0) {\n    //     b0 += c3;\n    // } else if (mcIndex == 4.0) {\n    //     b0 += c4; b1 += c5;\n    // } else if (mcIndex == 5.0) {\n    //     b0 += c5; b1 += c6;\n    // } else if (mcIndex == 6.0) {\n    //     b0 += c6; b1 += c7;\n    // } else if (mcIndex == 7.0) {\n    //     b0 += c7; b1 += c4;\n    // } else if (mcIndex == 8.0) {\n    //     b1 += c4;\n    // } else if (mcIndex == 9.0) {\n    //     b0 += c1; b1 += c5;\n    // } else if (mcIndex == 10.0) {\n    //     b0 += c2; b1 += c6;\n    // } else if (mcIndex == 11.0) {\n    //     b0 += c3; b1 += c7;\n    // }\n    // b0 = floor(b0 + 0.5);\n    // b1 = floor(b1 + 0.5);\n\n    vec4 d0 = voxel(b0);\n    vec4 d1 = voxel(b1);\n\n    float v0 = d0.a;\n    float v1 = d1.a;\n\n    float t = (uIsoValue - v0) / (v0 - v1);\n    gl_FragData[0].xyz = (uGridTransform * vec4(b0 + t * (b0 - b1), 1.0)).xyz;\n\n    // group id\n    #if __VERSION__ == 100\n        // webgl1 does not support 'flat' interpolation (i.e. no interpolation)\n        // so we ensure a constant group id per triangle here\n        #ifdef dPackedGroup\n            gl_FragData[1] = vec4(voxel(coord3d).rgb, 1.0);\n        #else\n            vec3 gridDim = uGridDim - vec3(1.0, 1.0, 0.0); // remove xy padding\n            float group = coord3d.z + coord3d.y * gridDim.z + coord3d.x * gridDim.z * gridDim.y;\n            gl_FragData[1] = vec4(group > 16777215.5 ? vec3(1.0) : encodeFloatRGB(group), 1.0);\n        #endif\n    #else\n        #ifdef dPackedGroup\n            gl_FragData[1] = vec4(t < 0.5 ? d0.rgb : d1.rgb, 1.0);\n        #else\n            vec3 b = t < 0.5 ? b0 : b1;\n            vec3 gridDim = uGridDim - vec3(1.0, 1.0, 0.0); // remove xy padding\n            float group = b.z + b.y * gridDim.z + b.x * gridDim.z * gridDim.y;\n            gl_FragData[1] = vec4(group > 16777215.5 ? vec3(1.0) : encodeFloatRGB(group), 1.0);\n        #endif\n    #endif\n\n    // normals from gradients\n    vec3 n0 = -normalize(vec3(\n        voxelPadded(b0 - c1).a - voxelPadded(b0 + c1).a,\n        voxelPadded(b0 - c3).a - voxelPadded(b0 + c3).a,\n        voxelPadded(b0 - c4).a - voxelPadded(b0 + c4).a\n    ));\n    vec3 n1 = -normalize(vec3(\n        voxelPadded(b1 - c1).a - voxelPadded(b1 + c1).a,\n        voxelPadded(b1 - c3).a - voxelPadded(b1 + c3).a,\n        voxelPadded(b1 - c4).a - voxelPadded(b1 + c4).a\n    ));\n    gl_FragData[2].xyz = -vec3(\n        n0.x + t * (n0.x - n1.x),\n        n0.y + t * (n0.y - n1.y),\n        n0.z + t * (n0.z - n1.z)\n    );\n\n    // ensure normal-direction is the same for negative and positive iso-levels\n    if (uInvert) {\n        gl_FragData[2].xyz *= -1.0;\n    }\n\n    // apply normal matrix\n    gl_FragData[2].xyz *= transpose3(inverse3(mat3(uGridTransform)));\n}\n";
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