static void
draw(void)
{
ChipmunkDemoDefaultDrawImpl();
cpVect start = QUERY_START;
cpVect end = ChipmunkDemoMouse;
ChipmunkDebugDrawSegment(start, end, RGBAColor(0,1,0,1));
ChipmunkDemoPrintString("Query: Dist(%f) Point%s, ", cpvdist(start, end), cpvstr(end));
cpSegmentQueryInfo segInfo = {};
if(cpSpaceSegmentQueryFirst(space, start, end, CP_ALL_LAYERS, CP_NO_GROUP, &segInfo)){
cpVect point = cpSegmentQueryHitPoint(start, end, segInfo);
// Draw red over the occluded part of the query
ChipmunkDebugDrawSegment(point, end, RGBAColor(1,0,0,1));
// Draw a little blue surface normal
ChipmunkDebugDrawSegment(point, cpvadd(point, cpvmult(segInfo.n, 16)), RGBAColor(0,0,1,1));
// Draw a little red dot on the hit point.
ChipmunkDebugDrawPoints(3, 1, &point, RGBAColor(1,0,0,1));
ChipmunkDemoPrintString("Segment Query: Dist(%f) Normal%s", cpSegmentQueryHitDist(start, end, segInfo), cpvstr(segInfo.n));
} else {
ChipmunkDemoPrintString("Segment Query (None)");
}
cpNearestPointQueryInfo nearestInfo = {};
cpSpaceNearestPointQueryNearest(space, ChipmunkDemoMouse, 100.0, CP_ALL_LAYERS, CP_NO_GROUP, &nearestInfo);
if(nearestInfo.shape){
// Draw a grey line to the closest shape.
ChipmunkDebugDrawPoints(3, 1, &ChipmunkDemoMouse, RGBAColor(0.5, 0.5, 0.5, 1.0));
ChipmunkDebugDrawSegment(ChipmunkDemoMouse, nearestInfo.p, RGBAColor(0.5, 0.5, 0.5, 1.0));
// Draw a red bounding box around the shape under the mouse.
if(nearestInfo.d < 0) ChipmunkDebugDrawBB(cpShapeGetBB(nearestInfo.shape), RGBAColor(1,0,0,1));
}
}
static void
update(cpSpace *space, double dt)
{
cpSpaceStep(space, dt);
ChipmunkDemoPrintString("Place objects on the scale to weigh them. The ball marks the shapes it's sitting on.\n");
// Sum the total impulse applied to the scale from all collision pairs in the contact graph.
// If your compiler supports blocks, your life is a little easier.
// You can use the "Block" versions of the functions without needing the callbacks above.
#if USE_BLOCKS
__block cpVect impulseSum = cpvzero;
cpBodyEachArbiter_b(scaleStaticBody, ^(cpArbiter *arb) {
impulseSum = cpvadd(impulseSum, cpArbiterTotalImpulse(arb));
});