311 lines
11 KiB
C
311 lines
11 KiB
C
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/*
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Polygon clipping routines written by Forest Hale and placed into public domain.
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*/
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#include <math.h>
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#include "polygon.h"
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void PolygonF_QuadForPlane(float *outpoints, float planenormalx, float planenormaly, float planenormalz, float planedist, float quadsize)
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{
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float d, quadright[3], quadup[3];
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if (fabs(planenormalz) > fabs(planenormalx) && fabs(planenormalz) > fabs(planenormaly))
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{
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quadup[0] = 1;
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quadup[1] = 0;
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quadup[2] = 0;
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}
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else
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{
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quadup[0] = 0;
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quadup[1] = 0;
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quadup[2] = 1;
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}
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// d = -DotProduct(quadup, planenormal);
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d = -(quadup[0] * planenormalx + quadup[1] * planenormaly + quadup[2] * planenormalz);
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// VectorMA(quadup, d, planenormal, quadup);
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quadup[0] += d * planenormalx;
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quadup[1] += d * planenormaly;
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quadup[2] += d * planenormalz;
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// VectorNormalize(quadup);
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d = (float)(1.0 / sqrt(quadup[0] * quadup[0] + quadup[1] * quadup[1] + quadup[2] * quadup[2]));
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quadup[0] *= d;
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quadup[1] *= d;
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quadup[2] *= d;
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// CrossProduct(quadup,planenormal,quadright);
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quadright[0] = quadup[1] * planenormalz - quadup[2] * planenormaly;
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quadright[1] = quadup[2] * planenormalx - quadup[0] * planenormalz;
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quadright[2] = quadup[0] * planenormaly - quadup[1] * planenormalx;
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// make the points
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outpoints[0] = planedist * planenormalx - quadsize * quadright[0] + quadsize * quadup[0];
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outpoints[1] = planedist * planenormaly - quadsize * quadright[1] + quadsize * quadup[1];
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outpoints[2] = planedist * planenormalz - quadsize * quadright[2] + quadsize * quadup[2];
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outpoints[3] = planedist * planenormalx + quadsize * quadright[0] + quadsize * quadup[0];
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outpoints[4] = planedist * planenormaly + quadsize * quadright[1] + quadsize * quadup[1];
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outpoints[5] = planedist * planenormalz + quadsize * quadright[2] + quadsize * quadup[2];
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outpoints[6] = planedist * planenormalx + quadsize * quadright[0] - quadsize * quadup[0];
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outpoints[7] = planedist * planenormaly + quadsize * quadright[1] - quadsize * quadup[1];
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outpoints[8] = planedist * planenormalz + quadsize * quadright[2] - quadsize * quadup[2];
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outpoints[9] = planedist * planenormalx - quadsize * quadright[0] - quadsize * quadup[0];
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outpoints[10] = planedist * planenormaly - quadsize * quadright[1] - quadsize * quadup[1];
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outpoints[11] = planedist * planenormalz - quadsize * quadright[2] - quadsize * quadup[2];
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}
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void PolygonD_QuadForPlane(double *outpoints, double planenormalx, double planenormaly, double planenormalz, double planedist, double quadsize)
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{
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double d, quadright[3], quadup[3];
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if (fabs(planenormalz) > fabs(planenormalx) && fabs(planenormalz) > fabs(planenormaly))
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{
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quadup[0] = 1;
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quadup[1] = 0;
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quadup[2] = 0;
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}
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else
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{
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quadup[0] = 0;
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quadup[1] = 0;
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quadup[2] = 1;
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}
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// d = -DotProduct(quadup, planenormal);
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d = -(quadup[0] * planenormalx + quadup[1] * planenormaly + quadup[2] * planenormalz);
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// VectorMA(quadup, d, planenormal, quadup);
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quadup[0] += d * planenormalx;
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quadup[1] += d * planenormaly;
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quadup[2] += d * planenormalz;
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// VectorNormalize(quadup);
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d = 1.0 / sqrt(quadup[0] * quadup[0] + quadup[1] * quadup[1] + quadup[2] * quadup[2]);
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quadup[0] *= d;
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quadup[1] *= d;
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quadup[2] *= d;
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// CrossProduct(quadup,planenormal,quadright);
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quadright[0] = quadup[1] * planenormalz - quadup[2] * planenormaly;
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quadright[1] = quadup[2] * planenormalx - quadup[0] * planenormalz;
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quadright[2] = quadup[0] * planenormaly - quadup[1] * planenormalx;
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// make the points
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outpoints[0] = planedist * planenormalx - quadsize * quadright[0] + quadsize * quadup[0];
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outpoints[1] = planedist * planenormaly - quadsize * quadright[1] + quadsize * quadup[1];
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outpoints[2] = planedist * planenormalz - quadsize * quadright[2] + quadsize * quadup[2];
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outpoints[3] = planedist * planenormalx + quadsize * quadright[0] + quadsize * quadup[0];
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outpoints[4] = planedist * planenormaly + quadsize * quadright[1] + quadsize * quadup[1];
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outpoints[5] = planedist * planenormalz + quadsize * quadright[2] + quadsize * quadup[2];
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outpoints[6] = planedist * planenormalx + quadsize * quadright[0] - quadsize * quadup[0];
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outpoints[7] = planedist * planenormaly + quadsize * quadright[1] - quadsize * quadup[1];
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outpoints[8] = planedist * planenormalz + quadsize * quadright[2] - quadsize * quadup[2];
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outpoints[9] = planedist * planenormalx - quadsize * quadright[0] - quadsize * quadup[0];
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outpoints[10] = planedist * planenormaly - quadsize * quadright[1] - quadsize * quadup[1];
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outpoints[11] = planedist * planenormalz - quadsize * quadright[2] - quadsize * quadup[2];
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}
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int PolygonF_Clip(int innumpoints, const float *inpoints, float planenormalx, float planenormaly, float planenormalz, float planedist, float epsilon, int outfrontmaxpoints, float *outfrontpoints)
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{
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int i, frontcount = 0;
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const float *n, *p;
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float frac, pdist, ndist;
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if (innumpoints < 1)
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return 0;
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n = inpoints;
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ndist = n[0] * planenormalx + n[1] * planenormaly + n[2] * planenormalz - planedist;
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for(i = 0;i < innumpoints;i++)
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{
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p = n;
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pdist = ndist;
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n = inpoints + ((i + 1) < innumpoints ? (i + 1) : 0) * 3;
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ndist = n[0] * planenormalx + n[1] * planenormaly + n[2] * planenormalz - planedist;
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if (pdist >= -epsilon)
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{
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if (frontcount < outfrontmaxpoints)
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{
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*outfrontpoints++ = p[0];
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*outfrontpoints++ = p[1];
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*outfrontpoints++ = p[2];
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}
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frontcount++;
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}
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if ((pdist > epsilon && ndist < -epsilon) || (pdist < -epsilon && ndist > epsilon))
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{
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frac = pdist / (pdist - ndist);
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if (frontcount < outfrontmaxpoints)
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{
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*outfrontpoints++ = p[0] + frac * (n[0] - p[0]);
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*outfrontpoints++ = p[1] + frac * (n[1] - p[1]);
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*outfrontpoints++ = p[2] + frac * (n[2] - p[2]);
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}
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frontcount++;
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}
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}
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return frontcount;
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}
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int PolygonD_Clip(int innumpoints, const double *inpoints, double planenormalx, double planenormaly, double planenormalz, double planedist, double epsilon, int outfrontmaxpoints, double *outfrontpoints)
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{
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int i, frontcount = 0;
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const double *n, *p;
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double frac, pdist, ndist;
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if (innumpoints < 1)
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return 0;
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n = inpoints;
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ndist = n[0] * planenormalx + n[1] * planenormaly + n[2] * planenormalz - planedist;
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for(i = 0;i < innumpoints;i++)
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{
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p = n;
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pdist = ndist;
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n = inpoints + ((i + 1) < innumpoints ? (i + 1) : 0) * 3;
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ndist = n[0] * planenormalx + n[1] * planenormaly + n[2] * planenormalz - planedist;
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if (pdist >= -epsilon)
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{
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if (frontcount < outfrontmaxpoints)
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{
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*outfrontpoints++ = p[0];
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*outfrontpoints++ = p[1];
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*outfrontpoints++ = p[2];
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}
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frontcount++;
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}
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if ((pdist > epsilon && ndist < -epsilon) || (pdist < -epsilon && ndist > epsilon))
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{
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frac = pdist / (pdist - ndist);
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if (frontcount < outfrontmaxpoints)
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{
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*outfrontpoints++ = p[0] + frac * (n[0] - p[0]);
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*outfrontpoints++ = p[1] + frac * (n[1] - p[1]);
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*outfrontpoints++ = p[2] + frac * (n[2] - p[2]);
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}
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frontcount++;
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}
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}
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return frontcount;
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}
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void PolygonF_Divide(int innumpoints, const float *inpoints, float planenormalx, float planenormaly, float planenormalz, float planedist, float epsilon, int outfrontmaxpoints, float *outfrontpoints, int *neededfrontpoints, int outbackmaxpoints, float *outbackpoints, int *neededbackpoints, int *oncountpointer)
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{
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int i, frontcount = 0, backcount = 0, oncount = 0;
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const float *n, *p;
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float frac, pdist, ndist;
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if (innumpoints)
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{
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n = inpoints;
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ndist = n[0] * planenormalx + n[1] * planenormaly + n[2] * planenormalz - planedist;
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for(i = 0;i < innumpoints;i++)
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{
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p = n;
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pdist = ndist;
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n = inpoints + ((i + 1) < innumpoints ? (i + 1) : 0) * 3;
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ndist = n[0] * planenormalx + n[1] * planenormaly + n[2] * planenormalz - planedist;
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if (pdist >= -epsilon)
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{
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if (pdist <= epsilon)
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oncount++;
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if (frontcount < outfrontmaxpoints)
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{
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*outfrontpoints++ = p[0];
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*outfrontpoints++ = p[1];
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*outfrontpoints++ = p[2];
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}
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frontcount++;
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}
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if (pdist <= epsilon)
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{
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if (backcount < outbackmaxpoints)
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{
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*outbackpoints++ = p[0];
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*outbackpoints++ = p[1];
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*outbackpoints++ = p[2];
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}
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backcount++;
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}
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if ((pdist > epsilon && ndist < -epsilon) || (pdist < -epsilon && ndist > epsilon))
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{
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oncount++;
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frac = pdist / (pdist - ndist);
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if (frontcount < outfrontmaxpoints)
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{
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*outfrontpoints++ = p[0] + frac * (n[0] - p[0]);
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*outfrontpoints++ = p[1] + frac * (n[1] - p[1]);
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*outfrontpoints++ = p[2] + frac * (n[2] - p[2]);
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}
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frontcount++;
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if (backcount < outbackmaxpoints)
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{
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*outbackpoints++ = p[0] + frac * (n[0] - p[0]);
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*outbackpoints++ = p[1] + frac * (n[1] - p[1]);
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*outbackpoints++ = p[2] + frac * (n[2] - p[2]);
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}
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backcount++;
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}
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}
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}
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if (neededfrontpoints)
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*neededfrontpoints = frontcount;
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if (neededbackpoints)
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*neededbackpoints = backcount;
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if (oncountpointer)
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*oncountpointer = oncount;
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}
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void PolygonD_Divide(int innumpoints, const double *inpoints, double planenormalx, double planenormaly, double planenormalz, double planedist, double epsilon, int outfrontmaxpoints, double *outfrontpoints, int *neededfrontpoints, int outbackmaxpoints, double *outbackpoints, int *neededbackpoints, int *oncountpointer)
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{
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int i = 0, frontcount = 0, backcount = 0, oncount = 0;
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const double *n, *p;
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double frac, pdist, ndist;
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if (innumpoints)
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{
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n = inpoints;
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ndist = n[0] * planenormalx + n[1] * planenormaly + n[2] * planenormalz - planedist;
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for(i = 0;i < innumpoints;i++)
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{
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p = n;
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pdist = ndist;
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n = inpoints + ((i + 1) < innumpoints ? (i + 1) : 0) * 3;
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ndist = n[0] * planenormalx + n[1] * planenormaly + n[2] * planenormalz - planedist;
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if (pdist >= -epsilon)
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{
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if (pdist <= epsilon)
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oncount++;
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if (frontcount < outfrontmaxpoints)
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{
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*outfrontpoints++ = p[0];
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*outfrontpoints++ = p[1];
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*outfrontpoints++ = p[2];
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}
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frontcount++;
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}
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if (pdist <= epsilon)
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{
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if (backcount < outbackmaxpoints)
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{
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*outbackpoints++ = p[0];
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*outbackpoints++ = p[1];
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*outbackpoints++ = p[2];
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}
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backcount++;
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}
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if ((pdist > epsilon && ndist < -epsilon) || (pdist < -epsilon && ndist > epsilon))
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{
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oncount++;
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frac = pdist / (pdist - ndist);
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if (frontcount < outfrontmaxpoints)
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{
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*outfrontpoints++ = p[0] + frac * (n[0] - p[0]);
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*outfrontpoints++ = p[1] + frac * (n[1] - p[1]);
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*outfrontpoints++ = p[2] + frac * (n[2] - p[2]);
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}
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frontcount++;
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if (backcount < outbackmaxpoints)
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{
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*outbackpoints++ = p[0] + frac * (n[0] - p[0]);
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*outbackpoints++ = p[1] + frac * (n[1] - p[1]);
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*outbackpoints++ = p[2] + frac * (n[2] - p[2]);
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}
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backcount++;
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}
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}
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}
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if (neededfrontpoints)
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*neededfrontpoints = frontcount;
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if (neededbackpoints)
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*neededbackpoints = backcount;
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if (oncountpointer)
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*oncountpointer = oncount;
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}
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