declare const shader = "\nconst MAX_STRENGTH = 65535f;\n\n// Workgroup size - X*Y*Z must be multiple of 32 for better performance\noverride workGroupSizeX = 1u;\noverride workGroupSizeY = 1u;\noverride workGroupSizeZ = 1u;\n\n// Compare the current voxel to neighbors using a 9x9x9 window\noverride windowSize = 9i;\n\nstruct Params {\n  size: vec3u,\n  iteration: u32,\n}\n\n// New structure to track bounds of modified voxels\nstruct Bounds {\n  minX: atomic<i32>,\n  minY: atomic<i32>,\n  minZ: atomic<i32>,\n  maxX: atomic<i32>,\n  maxY: atomic<i32>,\n  maxZ: atomic<i32>,\n}\n\n@group(0) @binding(0) var<uniform> params: Params;\n@group(0) @binding(1) var<storage> volumePixelData: array<f32>;\n@group(0) @binding(2) var<storage, read_write> labelmap: array<u32>;\n@group(0) @binding(3) var<storage, read_write> strengthData: array<f32>;\n@group(0) @binding(4) var<storage> prevLabelmap: array<u32>;\n@group(0) @binding(5) var<storage> prevStrengthData: array<f32>;\n@group(0) @binding(6) var<storage, read_write> updatedVoxelsCounter: array<atomic<u32>>;\n@group(0) @binding(7) var<storage, read_write> modifiedBounds: Bounds;\n\nfn getPixelIndex(ijkPos: vec3u) -> u32 {\n  let numPixelsPerSlice = params.size.x * params.size.y;\n  return ijkPos.x + ijkPos.y * params.size.x + ijkPos.z * numPixelsPerSlice;\n}\n\nfn updateBounds(position: vec3i) {\n  // Atomically update min bounds (use min operation)\n  let oldMinX = atomicMin(&modifiedBounds.minX, position.x);\n  let oldMinY = atomicMin(&modifiedBounds.minY, position.y);\n  let oldMinZ = atomicMin(&modifiedBounds.minZ, position.z);\n\n  // Atomically update max bounds (use max operation)\n  let oldMaxX = atomicMax(&modifiedBounds.maxX, position.x);\n  let oldMaxY = atomicMax(&modifiedBounds.maxY, position.y);\n  let oldMaxZ = atomicMax(&modifiedBounds.maxZ, position.z);\n}\n\n@compute @workgroup_size(workGroupSizeX, workGroupSizeY, workGroupSizeZ)\nfn main(\n  @builtin(global_invocation_id) globalId: vec3u,\n) {\n  // Make sure it will not get out of bounds for volume with sizes that\n  // are not multiple of workGroupSize\n  if (\n    globalId.x >= params.size.x ||\n    globalId.y >= params.size.y ||\n    globalId.z >= params.size.z\n  ) {\n    return;\n  }\n\n  // Initialize bounds for the first iteration\n  if (params.iteration == 0 && globalId.x == 0 && globalId.y == 0 && globalId.z == 0) {\n    // Initialize to opposite extremes to ensure any update will improve the bounds\n    atomicStore(&modifiedBounds.minX, i32(params.size.x));\n    atomicStore(&modifiedBounds.minY, i32(params.size.y));\n    atomicStore(&modifiedBounds.minZ, i32(params.size.z));\n    atomicStore(&modifiedBounds.maxX, -1);\n    atomicStore(&modifiedBounds.maxY, -1);\n    atomicStore(&modifiedBounds.maxZ, -1);\n  }\n\n  let currentCoord = vec3i(globalId);\n  let currentPixelIndex = getPixelIndex(globalId);\n\n  let numPixels = arrayLength(&volumePixelData);\n  let currentPixelValue = volumePixelData[currentPixelIndex];\n\n  if (params.iteration == 0) {\n    // All non-zero initial labels are given maximum strength\n    strengthData[currentPixelIndex] = select(MAX_STRENGTH, 0., labelmap[currentPixelIndex] == 0);\n\n    // Update bounds for non-zero initial labels\n    if (labelmap[currentPixelIndex] != 0) {\n      updateBounds(currentCoord);\n    }\n    return;\n  }\n\n  // It should at least copy the values from previous state\n  var newLabel = prevLabelmap[currentPixelIndex];\n  var newStrength = prevStrengthData[currentPixelIndex];\n\n  let window = i32(ceil(f32(windowSize - 1) * .5));\n  let minWindow = -1i * window;\n  let maxWindow = 1i * window;\n\n  for (var k = minWindow; k <= maxWindow; k++) {\n    for (var j = minWindow; j <= maxWindow; j++) {\n      for (var i = minWindow; i <= maxWindow; i++) {\n        // Skip current voxel\n        if (i == 0 && j == 0 && k == 0) {\n          continue;\n        }\n\n        let neighborCoord = currentCoord + vec3i(i, j, k);\n\n        //  Boundary conditions. Do not grow outside of the volume\n        if (\n          neighborCoord.x < 0i || neighborCoord.x >= i32(params.size.x) ||\n          neighborCoord.y < 0i || neighborCoord.y >= i32(params.size.y) ||\n          neighborCoord.z < 0i || neighborCoord.z >= i32(params.size.z)\n        ) {\n          continue;\n        }\n\n        let neighborIndex = getPixelIndex(vec3u(neighborCoord));\n        let neighborPixelValue = volumePixelData[neighborIndex];\n        let prevNeighborStrength = prevStrengthData[neighborIndex];\n        let strengthCost = abs(neighborPixelValue - currentPixelValue);\n        let takeoverStrength = prevNeighborStrength - strengthCost;\n\n        if (takeoverStrength > newStrength) {\n          newLabel = prevLabelmap[neighborIndex];\n          newStrength = takeoverStrength;\n        }\n      }\n    }\n  }\n\n  if (labelmap[currentPixelIndex] != newLabel) {\n    atomicAdd(&updatedVoxelsCounter[params.iteration], 1u);\n\n    // Update bounds for modified voxels\n    updateBounds(currentCoord);\n  }\n\n  labelmap[currentPixelIndex] = newLabel;\n  strengthData[currentPixelIndex] = newStrength;\n}\n";
export default shader;