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/* Copyright (c) 1997 Silicon Graphics, Inc. */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ SGI"; |
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#endif |
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|
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/* |
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* Routines for converting holodeck coordinates, etc. |
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* |
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* 10/22/97 GWLarson |
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*/ |
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|
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#include "holo.h" |
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|
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float hd_depthmap[DCINF-DCLIN]; |
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|
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static double logstep; |
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|
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static int wg0[6] = {1,1,2,2,0,0}; |
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static int wg1[6] = {2,2,0,0,1,1}; |
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|
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|
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hdcompgrid(hp) /* compute derived grid vector and index */ |
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register HOLO *hp; |
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{ |
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FVECT AxB; |
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double d; |
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register FLOAT *v; |
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register int i, j; |
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/* initialize depth map */ |
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if (hd_depthmap[0] < 1.) { |
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d = 1. + .5/DCLIN; |
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for (i = 0; i < DCINF-DCLIN; i++) { |
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hd_depthmap[i] = d; |
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d *= 1. + 1./DCLIN; |
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} |
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logstep = log(1. + 1./DCLIN); |
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} |
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/* compute grid coordinate vectors */ |
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for (i = 0; i < 3; i++) { |
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fcross(AxB, hp->xv[(i+1)%3], v=hp->xv[(i+2)%3]); |
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VCOPY(hp->wn[i], AxB); |
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if (normalize(hp->wn[i]) == 0.) |
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error(USER, "degenerate holodeck section"); |
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hp->wo[i<<1] = DOT(hp->wn[i],hp->orig); |
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hp->wo[i<<1|1] = hp->wo[i<<1] + DOT(hp->wn[i],hp->xv[i]); |
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fcross(hp->gv[i][0], v, AxB); |
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d = DOT(v,v) / DOT(hp->gv[i][0],hp->gv[i][0]) * |
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hp->grid[(i+1)%3]; |
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for (j = 0; j < 3; j++) |
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hp->gv[i][0][j] *= d; |
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fcross(hp->gv[i][1], AxB, v=hp->xv[(i+1)%3]); |
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d = DOT(v,v) / DOT(hp->gv[i][1],hp->gv[i][1]) * |
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hp->grid[(i+2)%3]; |
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for (j = 0; j < 3; j++) |
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hp->gv[i][1][j] *= d; |
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} |
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/* compute linear depth range */ |
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hp->tlin = VLEN(hp->xv[0]) + VLEN(hp->xv[1]) + VLEN(hp->xv[2]); |
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/* compute wall super-indices from grid */ |
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hp->wi[0] = 1; /**** index values begin at 1 ****/ |
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for (i = 1; i < 6; i++) { |
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hp->wi[i] = 0; |
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for (j = i; j < 6; j++) |
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hp->wi[i] += hp->grid[wg0[j]] * hp->grid[wg1[j]]; |
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hp->wi[i] *= hp->grid[wg0[i-1]] * hp->grid[wg1[i-1]]; |
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hp->wi[i] += hp->wi[i-1]; |
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} |
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} |
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|
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|
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HOLO * |
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hdalloc(hproto) /* allocate and set holodeck section based on grid */ |
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HDGRID *hproto; |
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{ |
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HOLO hdhead; |
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register HOLO *hp; |
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int n; |
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/* copy grid to temporary header */ |
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bcopy((char *)hproto, (char *)&hdhead, sizeof(HDGRID)); |
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/* compute grid vectors and sizes */ |
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hdcompgrid(&hdhead); |
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/* allocate header with directory */ |
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n = sizeof(HOLO)+nbeams(&hdhead)*sizeof(BEAMI); |
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if ((hp = (HOLO *)malloc(n)) == NULL) |
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return(NULL); |
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/* copy header information */ |
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copystruct(hp, &hdhead); |
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/* allocate and clear beam list */ |
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hp->bl = (BEAM **)malloc((nbeams(hp)+1)*sizeof(BEAM *)+sizeof(BEAM)); |
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if (hp->bl == NULL) { |
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free((char *)hp); |
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return(NULL); |
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} |
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bzero((char *)hp->bl, (nbeams(hp)+1)*sizeof(BEAM *)+sizeof(BEAM)); |
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hp->bl[0] = (BEAM *)(hp->bl+nbeams(hp)+1); /* set blglob(hp) */ |
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hp->fd = -1; |
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hp->dirty = 0; |
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hp->priv = NULL; |
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/* clear beam directory */ |
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bzero((char *)hp->bi, (nbeams(hp)+1)*sizeof(BEAMI)); |
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return(hp); /* all is well */ |
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} |
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|
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|
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hdbcoord(gc, hp, i) /* compute beam coordinates from index */ |
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GCOORD gc[2]; /* returned */ |
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register HOLO *hp; |
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register int i; |
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{ |
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register int j, n; |
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int n2, reverse; |
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GCOORD g2[2]; |
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/* check range */ |
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if (i < 1 | i > nbeams(hp)) |
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return(0); |
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if (reverse = i >= hp->wi[5]) |
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i -= hp->wi[5] - 1; |
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for (j = 0; j < 5; j++) /* find w0 */ |
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if (hp->wi[j+1] > i) |
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break; |
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i -= hp->wi[gc[0].w=j]; |
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/* find w1 */ |
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n2 = hp->grid[wg0[j]] * hp->grid[wg1[j]]; |
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while (++j < 5) { |
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n = n2 * hp->grid[wg0[j]] * hp->grid[wg1[j]]; |
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if (n > i) |
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break; |
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i -= n; |
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} |
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gc[1].w = j; |
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/* find position on w0 */ |
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n2 = hp->grid[wg0[j]] * hp->grid[wg1[j]]; |
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n = i / n2; |
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gc[0].i[1] = n / hp->grid[wg0[gc[0].w]]; |
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gc[0].i[0] = n - gc[0].i[1]*hp->grid[wg0[gc[0].w]]; |
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i -= n*n2; |
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/* find position on w1 */ |
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gc[1].i[1] = i / hp->grid[wg0[gc[1].w]]; |
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gc[1].i[0] = i - gc[1].i[1]*hp->grid[wg0[gc[1].w]]; |
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if (reverse) { |
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copystruct(g2, gc+1); |
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copystruct(gc+1, gc); |
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copystruct(gc, g2); |
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} |
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return(1); /* we're done */ |
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} |
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|
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|
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int |
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hdbindex(hp, gc) /* compute index from beam coordinates */ |
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register HOLO *hp; |
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register GCOORD gc[2]; |
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{ |
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GCOORD g2[2]; |
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int reverse; |
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register int i, j; |
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/* check ordering and limits */ |
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if (reverse = gc[0].w > gc[1].w) { |
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copystruct(g2, gc+1); |
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copystruct(g2+1, gc); |
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gc = g2; |
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} else if (gc[0].w == gc[1].w) |
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return(0); |
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if (gc[0].w < 0 | gc[1].w > 5) |
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return(0); |
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i = 0; /* compute index */ |
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for (j = gc[0].w+1; j < gc[1].w; j++) |
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i += hp->grid[wg0[j]] * hp->grid[wg1[j]]; |
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i *= hp->grid[wg0[gc[0].w]] * hp->grid[wg1[gc[0].w]]; |
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i += hp->wi[gc[0].w]; |
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i += (hp->grid[wg0[gc[0].w]]*gc[0].i[1] + gc[0].i[0]) * |
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hp->grid[wg0[gc[1].w]] * hp->grid[wg1[gc[1].w]] ; |
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i += hp->grid[wg0[gc[1].w]]*gc[1].i[1] + gc[1].i[0]; |
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if (reverse) |
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i += hp->wi[5] - 1; |
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return(i); |
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} |
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|
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|
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hdcell(cp, hp, gc) /* compute cell coordinates */ |
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register FVECT cp[4]; /* returned (may be passed as FVECT cp[2][2]) */ |
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HOLO *hp; |
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register GCOORD *gc; |
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{ |
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register int i; |
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register FLOAT *v; |
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double d; |
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/* compute each corner */ |
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for (i = 0; i < 4; i++) { |
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VCOPY(cp[i], hp->orig); |
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if (gc->w & 1) { |
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v = hp->xv[gc->w>>1]; |
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cp[i][0] += *v++; cp[i][1] += *v++; cp[i][2] += *v; |
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} |
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d = (double)( gc->i[0] + (i&1) ) / hp->grid[wg0[gc->w]]; |
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v = hp->xv[wg0[gc->w]]; |
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cp[i][0] += d * *v++; cp[i][1] += d * *v++; cp[i][2] += d * *v; |
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|
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d = (double)( gc->i[1] + (i>>1) ) / hp->grid[wg1[gc->w]]; |
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v = hp->xv[wg1[gc->w]]; |
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cp[i][0] += d * *v++; cp[i][1] += d * *v++; cp[i][2] += d * *v; |
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} |
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} |
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|
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|
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hdlseg(lseg, hp, i) /* compute line segment for beam */ |
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register int lseg[2][3]; |
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register HOLO *hp; |
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int i; |
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{ |
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GCOORD gc[2]; |
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register int k; |
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|
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if (!hdbcoord(gc, hp, i)) /* compute grid coordinates */ |
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return(0); |
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for (k = 0; k < 2; k++) { /* compute end points */ |
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lseg[k][gc[k].w>>1] = gc[k].w&1 ? hp->grid[gc[k].w>>1]-1 : 0 ; |
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lseg[k][wg0[gc[k].w]] = gc[k].i[0]; |
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lseg[k][wg1[gc[k].w]] = gc[k].i[1]; |
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} |
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return(1); |
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} |
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|
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|
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unsigned |
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hdcode(hp, d) /* compute depth code for d */ |
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HOLO *hp; |
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double d; |
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{ |
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double tl = hp->tlin; |
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register unsigned c; |
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|
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if (d <= 0.) |
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return(0); |
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if (d >= .99*FHUGE) |
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return(DCINF); |
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if (d < tl) |
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return((unsigned)(d*DCLIN/tl)); |
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c = (unsigned)(log(d/tl)/logstep) + DCLIN; |
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return(c > DCINF ? DCINF : c); |
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} |
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|
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|
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double |
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hdray(ro, rd, hp, gc, r) /* compute ray within a beam */ |
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FVECT ro, rd; /* returned */ |
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register HOLO *hp; |
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register GCOORD gc[2]; |
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BYTE r[2][2]; |
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{ |
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FVECT p[2]; |
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register int i; |
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register FLOAT *v; |
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double d; |
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/* compute entry and exit points */ |
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for (i = 0; i < 2; i++) { |
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VCOPY(p[i], hp->orig); |
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if (gc[i].w & 1) { |
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v = hp->xv[gc[i].w>>1]; |
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p[i][0] += *v++; p[i][1] += *v++; p[i][2] += *v; |
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} |
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d = ( gc[i].i[0] + (1./256.)*(r[i][0]+.5) ) / |
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hp->grid[wg0[gc[i].w]]; |
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v = hp->xv[wg0[gc[i].w]]; |
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p[i][0] += d * *v++; p[i][1] += d * *v++; p[i][2] += d * *v; |
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d = ( gc[i].i[1] + (1./256.)*(r[i][1]+.5) ) / |
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hp->grid[wg1[gc[i].w]]; |
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v = hp->xv[wg1[gc[i].w]]; |
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p[i][0] += d * *v++; p[i][1] += d * *v++; p[i][2] += d * *v; |
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} |
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VCOPY(ro, p[0]); /* assign ray origin and direction */ |
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rd[0] = p[1][0] - p[0][0]; |
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rd[1] = p[1][1] - p[0][1]; |
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rd[2] = p[1][2] - p[0][2]; |
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return(normalize(rd)); /* return maximum inside distance */ |
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} |
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|
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|
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double |
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hdinter(gc, r, hp, ro, rd) /* compute ray intersection with section */ |
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register GCOORD gc[2]; /* returned */ |
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BYTE r[2][2]; /* returned */ |
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register HOLO *hp; |
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FVECT ro, rd; /* rd should be normalized */ |
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{ |
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FVECT p[2], vt; |
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double d, t0, t1, d0, d1; |
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register FLOAT *v; |
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register int i; |
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/* first, intersect walls */ |
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gc[0].w = gc[1].w = -1; |
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t0 = -FHUGE; t1 = FHUGE; |
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for (i = 0; i < 3; i++) { /* for each wall pair */ |
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d = -DOT(rd, hp->wn[i]); /* plane distance */ |
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if (d <= FTINY && d >= -FTINY) /* check for parallel */ |
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continue; |
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d1 = DOT(ro, hp->wn[i]); /* ray distances */ |
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d0 = (d1 - hp->wo[i<<1]) / d; |
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d1 = (d1 - hp->wo[i<<1|1]) / d; |
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if (d0 < d1) { /* check against best */ |
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if (d0 > t0) { |
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t0 = d0; |
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gc[0].w = i<<1; |
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} |
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if (d1 < t1) { |
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t1 = d1; |
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gc[1].w = i<<1 | 1; |
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} |
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} else { |
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if (d1 > t0) { |
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t0 = d1; |
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gc[0].w = i<<1 | 1; |
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} |
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if (d0 < t1) { |
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t1 = d0; |
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gc[1].w = i<<1; |
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} |
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} |
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} |
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if (gc[0].w < 0 | gc[1].w < 0) /* paranoid check */ |
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return(FHUGE); |
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/* compute intersections */ |
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for (i = 0; i < 3; i++) { |
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p[0][i] = ro[i] + rd[i]*t0; |
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p[1][i] = ro[i] + rd[i]*t1; |
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} |
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/* now, compute grid coordinates */ |
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for (i = 0; i < 2; i++) { |
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vt[0] = p[i][0] - hp->orig[0]; |
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vt[1] = p[i][1] - hp->orig[1]; |
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vt[2] = p[i][2] - hp->orig[2]; |
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if (gc[i].w & 1) { |
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v = hp->xv[gc[i].w>>1]; |
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vt[0] -= *v++; vt[1] -= *v++; vt[2] -= *v; |
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} |
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v = hp->gv[gc[i].w>>1][0]; |
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d = DOT(vt, v); |
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if (d < 0. || (gc[i].i[0] = d) >= hp->grid[wg0[gc[i].w]]) |
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return(FHUGE); /* outside wall */ |
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r[i][0] = 256. * (d - gc[i].i[0]); |
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v = hp->gv[gc[i].w>>1][1]; |
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d = DOT(vt, v); |
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if (d < 0. || (gc[i].i[1] = d) >= hp->grid[wg1[gc[i].w]]) |
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return(FHUGE); /* outside wall */ |
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r[i][1] = 256. * (d - gc[i].i[1]); |
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} |
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/* return distance from entry point */ |
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vt[0] = ro[0] - p[0][0]; |
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vt[1] = ro[1] - p[0][1]; |
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vt[2] = ro[2] - p[0][2]; |
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return(DOT(vt,rd)); |
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} |
