Function ShatterCell

tests/cpp-tests/Source/ChipmunkTestBed/demo/Shatter.cpp:117–164

}

static void ShatterCell(cpSpace* space,
                        cpShape* shape,
                        cpVect cell,
                        int cell_i,
                        int cell_j,
                        struct WorleyContex* context)
{
    //	printf("cell %dx%d: (% 5.2f, % 5.2f)\n", cell_i, cell_j, cell.x, cell.y);

    cpBody* body = cpShapeGetBody(shape);

    cpVect* ping = (cpVect*)alloca(MAX_VERTEXES_PER_VORONOI * sizeof(cpVect));
    cpVect* pong = (cpVect*)alloca(MAX_VERTEXES_PER_VORONOI * sizeof(cpVect));

    int count = cpPolyShapeGetCount(shape);
    count     = (count > MAX_VERTEXES_PER_VORONOI ? MAX_VERTEXES_PER_VORONOI : count);

    for (int i = 0; i < count; i++)
    {
        ping[i] = cpBodyLocalToWorld(body, cpPolyShapeGetVert(shape, i));
    }

    for (int i = 0; i < context->width; i++)
    {
        for (int j = 0; j < context->height; j++)
        {
            if (!(i == cell_i && j == cell_j) && cpShapePointQuery(shape, cell, NULL) < 0.0f)
            {
                count = ClipCell(shape, cell, i, j, context, ping, pong, count);
                memcpy(ping, pong, count * sizeof(cpVect));
            }
        }
    }

    cpVect centroid = cpCentroidForPoly(count, ping);
    cpFloat mass    = cpAreaForPoly(count, ping, 0.0f) * DENSITY;
    cpFloat moment  = cpMomentForPoly(mass, count, ping, cpvneg(centroid), 0.0f);

    cpBody* new_body = cpSpaceAddBody(space, cpBodyNew(mass, moment));
    cpBodySetPosition(new_body, centroid);
    cpBodySetVelocity(new_body, cpBodyGetVelocityAtWorldPoint(body, centroid));
    cpBodySetAngularVelocity(new_body, cpBodyGetAngularVelocity(body));

    cpTransform transform = cpTransformTranslate(cpvneg(centroid));
    cpShape* new_shape    = cpSpaceAddShape(space, cpPolyShapeNew(new_body, count, ping, transform, 0.0));
    // Copy whatever properties you have set on the original shape that are important
    cpShapeSetFriction(new_shape, cpShapeGetFriction(shape));
}

static void ShatterShape(cpSpace* space, cpShape* shape, cpFloat cellSize, cpVect focus)
{