98 lines
2.0 KiB
C++
98 lines
2.0 KiB
C++
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#ifndef B3_REDUCE_CONTACTS_H
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#define B3_REDUCE_CONTACTS_H
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inline int b3ReduceContacts(const b3Float4* p, int nPoints, const b3Float4& nearNormal, b3Int4* contactIdx)
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{
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if( nPoints == 0 )
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return 0;
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if (nPoints <=4)
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return nPoints;
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if (nPoints >64)
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nPoints = 64;
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b3Float4 center = b3MakeFloat4(0,0,0,0);
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{
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for (int i=0;i<nPoints;i++)
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center += p[i];
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center /= (float)nPoints;
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}
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// sample 4 directions
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b3Float4 aVector = p[0] - center;
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b3Float4 u = b3Cross3( nearNormal, aVector );
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b3Float4 v = b3Cross3( nearNormal, u );
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u = b3FastNormalized3( u );
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v = b3FastNormalized3( v );
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//keep point with deepest penetration
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float minW= FLT_MAX;
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int minIndex=-1;
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b3Float4 maxDots;
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maxDots.x = FLT_MIN;
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maxDots.y = FLT_MIN;
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maxDots.z = FLT_MIN;
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maxDots.w = FLT_MIN;
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// idx, distance
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for(int ie = 0; ie<nPoints; ie++ )
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{
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if (p[ie].w<minW)
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{
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minW = p[ie].w;
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minIndex=ie;
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}
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float f;
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b3Float4 r = p[ie]-center;
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f = b3Dot3F4( u, r );
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if (f<maxDots.x)
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{
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maxDots.x = f;
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contactIdx[0].x = ie;
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}
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f = b3Dot3F4( -u, r );
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if (f<maxDots.y)
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{
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maxDots.y = f;
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contactIdx[0].y = ie;
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}
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f = b3Dot3F4( v, r );
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if (f<maxDots.z)
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{
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maxDots.z = f;
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contactIdx[0].z = ie;
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}
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f = b3Dot3F4( -v, r );
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if (f<maxDots.w)
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{
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maxDots.w = f;
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contactIdx[0].w = ie;
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}
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}
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if (contactIdx[0].x != minIndex && contactIdx[0].y != minIndex && contactIdx[0].z != minIndex && contactIdx[0].w != minIndex)
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{
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//replace the first contact with minimum (todo: replace contact with least penetration)
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contactIdx[0].x = minIndex;
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}
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return 4;
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}
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#endif //B3_REDUCE_CONTACTS_H
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