static void
cpMarchCellHard(
cpFloat t, cpFloat a, cpFloat b, cpFloat c, cpFloat d,
cpFloat x0, cpFloat x1, cpFloat y0, cpFloat y1,
cpMarchSegmentFunc segment, void *segment_data
){
// midpoints
cpFloat xm = cpflerp(x0, x1, 0.5f);
cpFloat ym = cpflerp(y0, y1, 0.5f);
switch((a>t)<<0 | (b>t)<<1 | (c>t)<<2 | (d>t)<<3){
case 0x1: segs(cpv(x0, ym), cpv(xm, ym), cpv(xm, y0), segment, segment_data); break;
case 0x2: segs(cpv(xm, y0), cpv(xm, ym), cpv(x1, ym), segment, segment_data); break;
case 0x3: seg(cpv(x0, ym), cpv(x1, ym), segment, segment_data); break;
case 0x4: segs(cpv(xm, y1), cpv(xm, ym), cpv(x0, ym), segment, segment_data); break;
case 0x5: seg(cpv(xm, y1), cpv(xm, y0), segment, segment_data); break;
case 0x6: segs(cpv(xm, y0), cpv(xm, ym), cpv(x0, ym), segment, segment_data);
segs(cpv(xm, y1), cpv(xm, ym), cpv(x1, ym), segment, segment_data); break;
case 0x7: segs(cpv(xm, y1), cpv(xm, ym), cpv(x1, ym), segment, segment_data); break;
case 0x8: segs(cpv(x1, ym), cpv(xm, ym), cpv(xm, y1), segment, segment_data); break;
case 0x9: segs(cpv(x1, ym), cpv(xm, ym), cpv(xm, y0), segment, segment_data);
segs(cpv(x0, ym), cpv(xm, ym), cpv(xm, y1), segment, segment_data); break;
case 0xA: seg(cpv(xm, y0), cpv(xm, y1), segment, segment_data); break;
case 0xB: segs(cpv(x0, ym), cpv(xm, ym), cpv(xm, y1), segment, segment_data); break;
case 0xC: seg(cpv(x1, ym), cpv(x0, ym), segment, segment_data); break;
case 0xD: segs(cpv(x1, ym), cpv(xm, ym), cpv(xm, y0), segment, segment_data); break;
case 0xE: segs(cpv(xm, y0), cpv(xm, ym), cpv(x0, ym), segment, segment_data); break;
default: break; // 0x0 and 0xF
}
}
static cpSpace *
init(void)
{
ChipmunkDemoMessageString = "Sticky collisions using the cpArbiter data pointer.";
cpSpace *space = cpSpaceNew();
cpSpaceSetIterations(space, 10);
cpSpaceSetGravity(space, cpv(0, -1000));
cpSpaceSetCollisionSlop(space, 2.0);
cpBody *staticBody = cpSpaceGetStaticBody(space);
cpShape *shape;
// Create segments around the edge of the screen.
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-340,-260), cpv(-340, 260), 20.0f));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetCollisionType(shape, COLLIDE_STICK_SENSOR);
cpShapeSetLayers(shape, NOT_GRABABLE_MASK);
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv( 340,-260), cpv( 340, 260), 20.0f));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetCollisionType(shape, COLLIDE_STICK_SENSOR);
cpShapeSetLayers(shape, NOT_GRABABLE_MASK);
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-340,-260), cpv( 340,-260), 20.0f));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetCollisionType(shape, COLLIDE_STICK_SENSOR);
cpShapeSetLayers(shape, NOT_GRABABLE_MASK);
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-340, 260), cpv( 340, 260), 20.0f));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetCollisionType(shape, COLLIDE_STICK_SENSOR);
cpShapeSetLayers(shape, NOT_GRABABLE_MASK);
for(int i=0; i<200; i++){
cpFloat mass = 0.15f;
cpFloat radius = 10.0f;
cpBody *body = cpSpaceAddBody(space, cpBodyNew(mass, cpMomentForCircle(mass, 0.0f, radius, cpvzero)));
cpBodySetPos(body, cpv(cpflerp(-150.0f, 150.0f, frand()), cpflerp(-150.0f, 150.0f, frand())));
cpShape *shape = cpSpaceAddShape(space, cpCircleShapeNew(body, radius + STICK_SENSOR_THICKNESS, cpvzero));
cpShapeSetFriction(shape, 0.9f);
cpShapeSetCollisionType(shape, COLLIDE_STICK_SENSOR);
}
cpSpaceAddCollisionHandler(space, COLLIDE_STICK_SENSOR, COLLIDE_STICK_SENSOR, NULL, StickyPreSolve, NULL, StickySeparate, NULL);
return space;
}
// The looping and sample caching code is shared between cpMarchHard() and cpMarchSoft().
static void
cpMarchCells(
cpBB bb, unsigned long x_samples, unsigned long y_samples, cpFloat t,
cpMarchSegmentFunc segment, void *segment_data,
cpMarchSampleFunc sample, void *sample_data,
cpMarchCellFunc cell
){
cpFloat x_denom = 1.0/(cpFloat)(x_samples - 1);
cpFloat y_denom = 1.0/(cpFloat)(y_samples - 1);
// TODO range assertions and short circuit for 0 sized windows.
// Keep a copy of the previous row to avoid double lookups.
cpFloat *buffer = (cpFloat *)cpcalloc(x_samples, sizeof(cpFloat));
for(unsigned long i=0; i<x_samples; i++) buffer[i] = sample(cpv(cpflerp(bb.l, bb.r, i*x_denom), bb.b), sample_data);
for(unsigned long j=0; j<y_samples-1; j++){
cpFloat y0 = cpflerp(bb.b, bb.t, (j+0)*y_denom);
cpFloat y1 = cpflerp(bb.b, bb.t, (j+1)*y_denom);
cpFloat a, b = buffer[0];
cpFloat c, d = sample(cpv(bb.l, y1), sample_data);
buffer[0] = d;
for(unsigned long i=0; i<x_samples-1; i++){
cpFloat x0 = cpflerp(bb.l, bb.r, (i+0)*x_denom);
cpFloat x1 = cpflerp(bb.l, bb.r, (i+1)*x_denom);
a = b, b = buffer[i + 1];
c = d, d = sample(cpv(x1, y1), sample_data);
buffer[i + 1] = d;
cell(t, a, b, c, d, x0, x1, y0, y1, segment, segment_data);
}
}
cpfree(buffer);
}
static void DrawShape(cpShape *shape, DrawNode *renderer)
{
cpBody *body = cpShapeGetBody(shape);
Color4F color = ColorForBody(body);
switch (shape->CP_PRIVATE(klass)->type)
{
case CP_CIRCLE_SHAPE:
{
cpCircleShape *circle = (cpCircleShape *)shape;
cpVect center = circle->tc;
cpFloat radius = circle->r;
renderer->drawDot(cpVert2Point(center), cpfmax(radius, 1.0), color);
renderer->drawSegment(cpVert2Point(center), cpVert2Point(cpvadd(center, cpvmult(cpBodyGetRotation(body), radius))), 1.0, color);
}
break;
case CP_SEGMENT_SHAPE:
{
cpSegmentShape *seg = (cpSegmentShape *)shape;
renderer->drawSegment(cpVert2Point(seg->ta), cpVert2Point(seg->tb), cpfmax(seg->r, 2.0), color);
}
break;
case CP_POLY_SHAPE:
{
cpPolyShape* poly = (cpPolyShape*)shape;
Color4F line = color;
line.a = cpflerp(color.a, 1.0, 0.5);
int num = poly->count;
Vec2* pPoints = new (std::nothrow) Vec2[num];
for(int i=0;i<num;++i)
pPoints[i] = cpVert2Point(poly->planes[i].v0);
renderer->drawPolygon(pPoints, num, color, 1.0, line);
CC_SAFE_DELETE_ARRAY(pPoints);
}
break;
default:
cpAssertHard(false, "Bad assertion in DrawShape()");
}
}
static void DrawShape(cpShape *shape, DrawNode *renderer)
{
cpBody *body = shape->body;
Color4F color = ColorForBody(body);
switch (shape->CP_PRIVATE(klass)->type)
{
case CP_CIRCLE_SHAPE:
{
cpCircleShape *circle = (cpCircleShape *)shape;
cpVect center = circle->tc;
cpFloat radius = circle->r;
renderer->drawDot(cpVert2Point(center), cpfmax(radius, 1.0), color);
renderer->drawSegment(cpVert2Point(center), cpVert2Point(cpvadd(center, cpvmult(body->rot, radius))), 1.0, color);
}
break;
case CP_SEGMENT_SHAPE:
{
cpSegmentShape *seg = (cpSegmentShape *)shape;
renderer->drawSegment(cpVert2Point(seg->ta), cpVert2Point(seg->tb), cpfmax(seg->r, 2.0), color);
}
break;
case CP_POLY_SHAPE:
{
cpPolyShape *poly = (cpPolyShape *)shape;
Color4F line = color;
line.a = cpflerp(color.a, 1.0, 0.5);
Vec2* pPoints = cpVertArray2ccpArrayN(poly->tVerts, poly->numVerts);
renderer->drawPolygon(pPoints, poly->numVerts, color, 1.0, line);
CC_SAFE_DELETE_ARRAY(pPoints);
}
break;
default:
cpAssertHard(false, "Bad assertion in DrawShape()");
}
}
// Lerps between two positions based on their sample values.
static inline cpFloat
midlerp(cpFloat x0, cpFloat x1, cpFloat s0, cpFloat s1, cpFloat t)
{
return cpflerp(x0, x1, (t - s0)/(s1 - s0));
}
static VALUE
rb_cpflerp(VALUE self, VALUE f1, VALUE f2, VALUE t) {
cpFloat result = cpflerp(NUM2DBL(f1), NUM2DBL(f2), NUM2DBL(t));
return rb_float_new(result);
}
