vis, qbsp: improve robustness of ClipWinding/DivideWinding
Carry over some correctness fixes from recent changes to vis into the qbsp versions of ClipWinding and make the implementations more consistent overall. Most importantly: * Ensure we always have allocated one extra dists/sides slot for wrap around * Check we have space for a new vertex every time we try to add one Signed-off-by: Kevin Shanahan <kmshanah@disenchant.net>
This commit is contained in:
Kevin Shanahan
parent
dddae057d6
commit
37f87a28be
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@ -164,16 +164,20 @@ it will be clipped away.
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winding_t *
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ClipWinding(winding_t *in, const plane_t *split, bool keepon)
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{
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vec_t dists[MAX_POINTS_ON_WINDING];
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int sides[MAX_POINTS_ON_WINDING];
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vec_t dists[MAX_POINTS_ON_WINDING + 1];
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int sides[MAX_POINTS_ON_WINDING + 1];
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int counts[3];
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vec_t dot;
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vec_t fraction;
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int i, j;
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vec_t *p1, *p2;
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vec3_t mid;
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winding_t *neww;
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int maxpts;
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if (in->numpoints > MAX_POINTS_ON_WINDING)
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Error("Internal error: in->numpoints > MAX (%s: %d > %d)",
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__func__, in->numpoints, MAX_POINTS_ON_WINDING);
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CalcSides(in, split, sides, dists, counts);
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if (keepon && !counts[SIDE_FRONT] && !counts[SIDE_BACK])
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@ -187,20 +191,24 @@ ClipWinding(winding_t *in, const plane_t *split, bool keepon)
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if (!counts[SIDE_BACK])
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return in;
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maxpts = in->numpoints + 4; // can't use counts[0]+2 because
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// of fp grouping errors
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/* can't use maxpoints = counts[0] + 2 because of fp grouping errors */
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maxpts = in->numpoints + 4;
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neww = AllocMem(WINDING, maxpts, true);
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for (i = 0; i < in->numpoints; i++) {
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p1 = in->points[i];
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if (sides[i] == SIDE_ON) {
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if (neww->numpoints == maxpts)
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goto noclip;
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VectorCopy(p1, neww->points[neww->numpoints]);
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neww->numpoints++;
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continue;
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}
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if (sides[i] == SIDE_FRONT) {
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if (neww->numpoints == maxpts)
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goto noclip;
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VectorCopy(p1, neww->points[neww->numpoints]);
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neww->numpoints++;
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}
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@ -208,31 +216,31 @@ ClipWinding(winding_t *in, const plane_t *split, bool keepon)
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if (sides[i + 1] == SIDE_ON || sides[i + 1] == sides[i])
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continue;
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// generate a split point
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/* generate a split point */
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p2 = in->points[(i + 1) % in->numpoints];
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dot = dists[i] / (dists[i] - dists[i + 1]);
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fraction = dists[i] / (dists[i] - dists[i + 1]);
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for (j = 0; j < 3; j++) {
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// avoid round off error when possible
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/* avoid round off error when possible */
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if (split->normal[j] == 1)
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mid[j] = split->dist;
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else if (split->normal[j] == -1)
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mid[j] = -split->dist;
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else
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mid[j] = p1[j] + dot * (p2[j] - p1[j]);
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mid[j] = p1[j] + fraction * (p2[j] - p1[j]);
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}
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if (neww->numpoints == maxpts)
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goto noclip;
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VectorCopy(mid, neww->points[neww->numpoints]);
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neww->numpoints++;
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}
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if (neww->numpoints > maxpts)
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Error("Internal error: excess clipped points (%s)", __func__);
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// free the original winding
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FreeMem(in, WINDING, 1);
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return neww;
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noclip:
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Error("Internal error: new->numpoints > MAX (%s: %d > %d)",
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__func__, neww->numpoints, maxpts);
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}
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@ -250,17 +258,19 @@ void
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DivideWinding(winding_t *in, const plane_t *split, winding_t **front,
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winding_t **back)
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{
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vec_t dists[MAX_POINTS_ON_WINDING];
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int sides[MAX_POINTS_ON_WINDING];
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vec_t dists[MAX_POINTS_ON_WINDING + 1];
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int sides[MAX_POINTS_ON_WINDING + 1];
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int counts[3];
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vec_t dot;
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vec_t fraction;
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int i, j;
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vec_t *p1, *p2;
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vec3_t mid;
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winding_t *f, *b;
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int maxpts;
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counts[0] = counts[1] = counts[2] = 0;
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if (in->numpoints > MAX_POINTS_ON_WINDING)
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Error("Internal error: in->numpoints > MAX (%s: %d > %d)",
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__func__, in->numpoints, MAX_POINTS_ON_WINDING);
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CalcSides(in, split, sides, dists, counts);
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@ -275,9 +285,8 @@ DivideWinding(winding_t *in, const plane_t *split, winding_t **front,
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return;
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}
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maxpts = in->numpoints + 4; // can't use counts[0]+2 because
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// of fp grouping errors
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/* can't use maxpoints = counts[0] + 2 because of fp grouping errors */
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maxpts = in->numpoints + 4;
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*front = f = AllocMem(WINDING, maxpts, true);
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*back = b = AllocMem(WINDING, maxpts, true);
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@ -285,18 +294,26 @@ DivideWinding(winding_t *in, const plane_t *split, winding_t **front,
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p1 = in->points[i];
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if (sides[i] == SIDE_ON) {
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if (f->numpoints == maxpts)
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goto noclip_front;
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VectorCopy(p1, f->points[f->numpoints]);
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f->numpoints++;
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if (b->numpoints == maxpts)
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goto noclip_back;
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VectorCopy(p1, b->points[b->numpoints]);
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b->numpoints++;
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continue;
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}
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if (sides[i] == SIDE_FRONT) {
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if (f->numpoints == maxpts)
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goto noclip_front;
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VectorCopy(p1, f->points[f->numpoints]);
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f->numpoints++;
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}
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if (sides[i] == SIDE_BACK) {
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if (b->numpoints == maxpts)
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goto noclip_back;
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VectorCopy(p1, b->points[b->numpoints]);
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b->numpoints++;
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}
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@ -304,27 +321,37 @@ DivideWinding(winding_t *in, const plane_t *split, winding_t **front,
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if (sides[i + 1] == SIDE_ON || sides[i + 1] == sides[i])
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continue;
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// generate a split point
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/* generate a split point */
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p2 = in->points[(i + 1) % in->numpoints];
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dot = dists[i] / (dists[i] - dists[i + 1]);
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for (j = 0; j < 3; j++) { // avoid round off error when possible
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fraction = dists[i] / (dists[i] - dists[i + 1]);
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for (j = 0; j < 3; j++) {
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/* avoid round off error when possible */
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if (split->normal[j] == 1)
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mid[j] = split->dist;
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else if (split->normal[j] == -1)
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mid[j] = -split->dist;
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else
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mid[j] = p1[j] + dot * (p2[j] - p1[j]);
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mid[j] = p1[j] + fraction * (p2[j] - p1[j]);
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}
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if (f->numpoints == maxpts)
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goto noclip_front;
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VectorCopy(mid, f->points[f->numpoints]);
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f->numpoints++;
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if (b->numpoints == maxpts)
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goto noclip_back;
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VectorCopy(mid, b->points[b->numpoints]);
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b->numpoints++;
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}
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return;
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if (f->numpoints > maxpts || b->numpoints > maxpts)
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Error("Internal error: excess clipped points (%s)", __func__);
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noclip_front:
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Error("Internal error: front->numpoints > MAX (%s: %d > %d)",
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__func__, f->numpoints, maxpts);
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noclip_back:
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Error("Internal error: back->numpoints > MAX (%s: %d > %d)",
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__func__, b->numpoints, maxpts);
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}
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45
vis/vis.c
45
vis/vis.c
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@ -239,7 +239,7 @@ ClipStackWinding(winding_t *in, pstack_t *stack, plane_t *split)
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vec_t dists[MAX_WINDING + 1];
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int sides[MAX_WINDING + 1];
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int counts[3];
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vec_t dot;
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vec_t dot, fraction;
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int i, j;
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vec_t *p1, *p2;
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vec3_t mid;
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@ -254,9 +254,13 @@ ClipStackWinding(winding_t *in, pstack_t *stack, plane_t *split)
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return in;
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}
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if (in->numpoints > MAX_WINDING)
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Error("%s: in->numpoints > MAX_WINDING (%d > %d)",
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__func__, in->numpoints, MAX_WINDING);
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counts[0] = counts[1] = counts[2] = 0;
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// determine sides for each point
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/* determine sides for each point */
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for (i = 0; i < in->numpoints; i++) {
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dot = DotProduct(in->points[i], split->normal);
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dot -= split->dist;
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@ -288,20 +292,16 @@ ClipStackWinding(winding_t *in, pstack_t *stack, plane_t *split)
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for (i = 0; i < in->numpoints; i++) {
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p1 = in->points[i];
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if (neww->numpoints == MAX_WINDING_FIXED) {
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/* Can't clip, fall back to original */
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FreeStackWinding(neww, stack);
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c_noclip++;
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return in;
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}
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if (sides[i] == SIDE_ON) {
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VectorCopy(p1, neww->points[neww->numpoints]);
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if (neww->numpoints == MAX_WINDING_FIXED)
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goto noclip;
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neww->numpoints++;
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continue;
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}
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if (sides[i] == SIDE_FRONT) {
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if (neww->numpoints == MAX_WINDING_FIXED)
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goto noclip;
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VectorCopy(p1, neww->points[neww->numpoints]);
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neww->numpoints++;
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}
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@ -309,34 +309,33 @@ ClipStackWinding(winding_t *in, pstack_t *stack, plane_t *split)
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if (sides[i + 1] == SIDE_ON || sides[i + 1] == sides[i])
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continue;
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if (neww->numpoints == MAX_WINDING_FIXED) {
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/* Can't clip, fall back to original */
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FreeStackWinding(neww, stack);
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c_noclip++;
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return in;
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}
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// generate a split point
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/* generate a split point */
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p2 = in->points[(i + 1) % in->numpoints];
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dot = dists[i] / (dists[i] - dists[i + 1]);
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for (j = 0; j < 3; j++) { // avoid round off error when possible
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fraction = dists[i] / (dists[i] - dists[i + 1]);
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for (j = 0; j < 3; j++) {
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/* avoid round off error when possible */
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if (split->normal[j] == 1)
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mid[j] = split->dist;
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else if (split->normal[j] == -1)
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mid[j] = -split->dist;
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else
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mid[j] = p1[j] + dot * (p2[j] - p1[j]);
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mid[j] = p1[j] + fraction * (p2[j] - p1[j]);
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}
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if (neww->numpoints == MAX_WINDING_FIXED)
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goto noclip;
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VectorCopy(mid, neww->points[neww->numpoints]);
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neww->numpoints++;
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}
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FreeStackWinding(in, stack);
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return neww;
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}
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noclip:
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FreeStackWinding(neww, stack);
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c_noclip++;
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return in;
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}
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//============================================================================
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