cpPolyShape *
cpPolyShapeInitRaw(cpPolyShape *poly, cpBody *body, int count, const cpVect *verts, cpFloat radius)
{
cpShapeInit((cpShape *)poly, &polyClass, body, cpPolyShapeMassInfo(0.0f, count, verts, radius));
SetVerts(poly, count, verts);
poly->r = radius;
return poly;
}
void
cpPolyShapeSetVertsRaw(cpShape *shape, int count, cpVect *verts)
{
cpAssertHard(shape->klass == &polyClass, "Shape is not a poly shape.");
cpPolyShape *poly = (cpPolyShape *)shape;
cpPolyShapeDestroy(poly);
SetVerts(poly, count, verts);
cpFloat mass = shape->massInfo.m;
shape->massInfo = cpPolyShapeMassInfo(shape->massInfo.m, count, verts, poly->r);
if(mass > 0.0f) cpBodyAccumulateMassFromShapes(shape->body);
}
double CompArea1(double *eqn, double *corner)
{
double val, area, minVal, maxVal;
int i, minIndex, maxIndex;
double cos_phi, top_area, bottom_area;
if((corner[0] < EPS) || (corner[1] < EPS) || (corner[2] < EPS))
{
return -1.0;
}
if(eqn[2] < 1.0)
{ // vertical plane
return -2.0;
}
// cos of angle between plane perpendicular and z axis
cos_phi = eqn[2]/getNorm(&(eqn[0]));
maxVal = 0.0;
minVal = 0.0;
minIndex = maxIndex = -1;
area = 0.0;
SetVerts(corner[0], corner[1], corner[2]);
for(i = 0; i < 8; i++)
{
val = applyEqn(eqn, &(vert[i][0]));
vertVals[i] = val;
if(val > maxVal)
{
maxVal = val;
maxIndex = i;
}
if(val < minVal)
{
minVal = val;
minIndex = i;
}
}
/* sanity check */
if((minIndex == -1) || (maxIndex == -1))
{ // all veritces below plane or all above
return -3.0;
}
area = 0.0;
// see if plane hits top of box
if((vertVals[1] >= 0.0) && (vertVals[3] >= 0.0) &&
(vertVals[5] >= 0.0) && (vertVals[7] >= 0.0)) {
/* plane does not hit top of box */
top_area = 0.0;
} else {
top_area = FindFaceArea(topFaceVerts);
}
if((vertVals[0] <= 0.0) && (vertVals[2] <= 0.0) &&
(vertVals[4] <= 0.0) && (vertVals[6] <= 0.0)) {
/* does not hit bottom, arrea is whole base */
bottom_area = corner[0] * corner[1];
} else {
bottom_area = FindFaceArea(bottomFaceVerts);
}
area = top_area + (bottom_area - top_area)/cos_phi;
return area;
}
