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improve area calculation by a shift width to simulate fragments

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This commit is contained in:
Rudolf Polzer 2010-09-01 07:51:01 +02:00
parent 76e61abc01
commit 1875137f28
1 changed files with 36 additions and 3 deletions
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39
tools/quake3/q3map2/surface_meta.c
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@ -421,10 +421,43 @@ int MaxAreaIndexes(bspDrawVert_t *vert, int cnt, int *indexes)
double A, bestA = -1, V, bestV = -1;
vec3_t ab, ac, bc, cross;
bspDrawVert_t *buf;
double shiftWidth;
if(cnt < 3)
return 0;
/* calculate total area */
A = 0;
for(i = 1; i+1 < cnt; ++i)
{
VectorSubtract(vert[i].xyz, vert[0].xyz, ab);
VectorSubtract(vert[i+1].xyz, vert[0].xyz, ac);
CrossProduct(ab, ac, cross);
A += VectorLength(cross);
}
V = 0;
for(i = 0; i < cnt; ++i)
{
VectorSubtract(vert[(i+1)%cnt].xyz, vert[i].xyz, ab);
V += VectorLength(ab);
}
/* calculate shift width from the area sensibly, assuming the polygon
* fits about 25% of the screen in both dimensions
* we assume 1280x1024
* 1 pixel is then about sqrt(A) / (0.25 * screenwidth)
* 8 pixels are then about sqrt(A) / (0.25 * 1280) * 8
* 8 pixels are then about sqrt(A) * 0.025
* */
shiftWidth = sqrt(A) * 0.0125;
/* 3->1 6->2 12->3 ... */
if(A - ceil(log(cnt/1.5) / log(2)) * V * shiftWidth * 2 < 0)
{
/* printf("Small triangle detected (area %f, circumference %f), adjusting shiftWidth from %f to ", A, V, shiftWidth); */
shiftWidth = A / (ceil(log(cnt/1.5) / log(2)) * V * 2);
/* printf("%f\n", shiftWidth); */
}
/* find the triangle with highest area */
for(r = 0; r+2 < cnt; ++r)
for(s = r+1; s+1 < cnt; ++s)
@ -436,9 +469,9 @@ int MaxAreaIndexes(bspDrawVert_t *vert, int cnt, int *indexes)
CrossProduct(ab, ac, cross);
A = VectorLength(cross);
V = A - (VectorLength(ab) - VectorLength(ac) - VectorLength(bc)) * 0.2;
/* value = A - circumference * 0.2, i.e. we back out by 0.2 units from each side, to prevent too acute triangles */
/* this kind of simulates "number of 0.2x0.2 fragments in the triangle not touched by an edge" */
V = A - (VectorLength(ab) - VectorLength(ac) - VectorLength(bc)) * shiftWidth;
/* value = A - circumference * shiftWidth, i.e. we back out by shiftWidth units from each side, to prevent too acute triangles */
/* this kind of simulates "number of shiftWidth*shiftWidth fragments in the triangle not touched by an edge" */
if(bestA < 0 || V > bestV)
{