Created
September 9, 2012 19:30
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| # smallest positive t such that s+t*ds is an integer | |
| intbound = (s, ds) -> | |
| if ds < 0 | |
| intbound -s, -ds | |
| else | |
| s = mod s, 1 | |
| return (1 - s) / ds | |
| signum = (x) -> if x > 0 then 1 else (if x < 0 then -1 else 0) | |
| mod = (value, modulus) -> (value % modulus + modulus) % modulus | |
| wx = wy = wz = 128 | |
| module.exports = raycast = (origin, direction, callback, radius = 30) -> | |
| x = Math.floor origin[0] | |
| y = Math.floor origin[1] | |
| z = Math.floor origin[2] | |
| [dx, dy, dz] = direction | |
| stepX = signum dx | |
| stepY = signum dy | |
| stepZ = signum dz | |
| tMaxX = intbound origin[0], dx | |
| tMaxY = intbound origin[1], dy | |
| tMaxZ = intbound origin[2], dz | |
| tDeltaX = stepX / dx | |
| tDeltaY = stepY / dy | |
| tDeltaZ = stepZ / dz | |
| face = vec3.create() | |
| if dx is 0 and dy is 0 and dz is 0 | |
| throw new Error 'Raycast in zero direction!' | |
| radius /= Math.sqrt (dx * dx) + (dy * dy) + (dz * dz) | |
| while true # ((if stepX > 0 then x < wx else x >= 0)) and ((if stepY > 0 then y < wy else y >= 0)) and ((if stepZ > 0 then z < wz else z >= 0)) | |
| # check inside world | |
| # unless x < 0 or y < 0 or z < 0 or x >= wx or y >= wy or z >= wz | |
| break if callback x, y, z, face | |
| if tMaxX < tMaxY | |
| if tMaxX < tMaxZ | |
| break if tMaxX > radius | |
| x += stepX | |
| tMaxX += tDeltaX | |
| face[0] = -stepX | |
| face[1] = 0 | |
| face[2] = 0 | |
| else | |
| break if tMaxZ > radius | |
| z += stepZ | |
| tMaxZ += tDeltaZ | |
| face[0] = 0 | |
| face[1] = 0 | |
| face[2] = -stepZ | |
| else | |
| if tMaxY < tMaxZ | |
| break if tMaxY > radius | |
| y += stepY | |
| tMaxY += tDeltaY | |
| face[0] = 0 | |
| face[1] = -stepY | |
| face[2] = 0 | |
| else | |
| break if tMaxZ > radius | |
| z += stepZ | |
| tMaxZ += tDeltaZ | |
| face[0] = 0 | |
| face[1] = 0 | |
| face[2] = -stepZ |
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