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{ RCSid $Id: ambpos.cal,v 2.3 2014/05/01 03:00:59 greg Exp $ } |
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{ |
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Compute patterns for ambient position markers |
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} |
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odd(n) : .5*n - floor(.5*n) - .25; |
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posangle(a) : if(-a, a + 2*PI, a) / DEGREE; |
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{ Relative hit point } |
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rpx = Px - arg(1); |
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rpy = Py - arg(2); |
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rpz = Pz - arg(3); |
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{ Calculation of directional gradient pattern } |
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ndx = arg(4); ndy = arg(5); ndz = arg(6); |
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dgx = arg(7); dgy = arg(8); dgz = arg(9); |
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rdx = ndy*rpz - ndz*rpy; |
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rdy = ndz*rpx - ndx*rpz; |
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rdz = ndx*rpy - ndy*rpx; |
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dgrad = (rdx*dgx + rdy*dgy + rdz*dgz)/sqrt(rpx*rpx + rpy*rpy + rpz*rpz); |
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dirfunc = bound(0, 1 + dgrad, 2); |
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|
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{ Calculation of positional gradient pattern } |
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pgx = arg(4); pgy = arg(5); pgz = arg(6); |
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posfunc = bound(0, 1 + (pgx*rpx + pgy*rpy + pgz*rpz), 2); |
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{ corral flags and associated pattern } |
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ux = arg(4); uy = arg(5); uz = arg(6); |
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cflags = arg(7); |
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vx = Ny*uz - Nz*uy; |
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vy = Nz*ux - Nx*uz; |
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vz = Nx*uy - Ny*ux; |
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cflg(i) = if(odd(floor( cflags / 2^i )), 1, -1); |
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corralled = cflg(floor(32/360*posangle( |
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atan2(rpx*vx+rpy*vy+rpz*vz, rpx*ux+rpy*uy+rpz*uz) ))); |
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|
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{ Calculation of ellipse stencil for base } |
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usx = arg(4); usy = arg(5); usz = arg(6); |
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vsx = arg(7); vsy = arg(8); vsz = arg(9); |
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ellipstencil = if(1 - sq(usx*rpx + usy*rpy + usz*rpz) - sq(vsx*rpx + vsy*rpy + vsz*rpz), |
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1, 0); |
