// written in the D programming language

module samples.Bounce;

import chipmunkd.chipmunk;

import samples.ChipmunkDemo;

static cpSpace *space;

static void
update(int ticks)
{
	enum int steps = 3;
	enum cpFloat dt = 1.0f/60.0f/cast(cpFloat)steps;
	
	for(int i=0; i<steps; i++){
		cpSpaceStep(space, dt);
	}
}

static void
add_box()
{
	enum cpFloat size = 10.0f;
	enum cpFloat mass = 1.0f;
	
	cpVect verts[] = [
		cpv(-size,-size),
		cpv(-size, size),
		cpv( size, size),
		cpv( size,-size),
	];
	
	cpFloat radius = cpvlength(cpv(size, size));

	cpBody *_body = cpSpaceAddBody(space, cpBodyNew(mass, cpMomentForPoly(mass, 4, verts.ptr, cpvzero)));
	_body.p = cpv(frand()*(640 - 2*radius) - (320 - radius), frand()*(480 - 2*radius) - (240 - radius));
	_body.v = cpvmult(cpv(2*frand() - 1, 2*frand() - 1), 200);
	
	cpShape *shape = cpSpaceAddShape(space, cpPolyShapeNew(_body, 4, verts.ptr, cpvzero));
	shape.e = 1.0f; shape.u = 0.0f;
}

static cpSpace *
init()
{
	cpResetShapeIdCounter();
	
	space = cpSpaceNew();
	cpSpaceResizeActiveHash(space, 30.0f, 1000);
	space.iterations = 10;

	cpBody *_body;
	cpBody *staticBody = &space.staticBody;
	cpShape *shape;

	// Create segments around the edge of the screen.
	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,-240), cpv(-320,240), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(320,-240), cpv(320,240), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,-240), cpv(320,-240), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,240), cpv(320,240), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;
	
	for(int i=0; i<10; i++)
		add_box();
	
	_body = cpSpaceAddBody(space, cpBodyNew(100.0f, 10000.0f));

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(_body, cpv(-75,0), cpv(75,0), 5.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	
	cpSpaceAddConstraint(space, cpPivotJointNew2(_body, staticBody, cpvzero, cpvzero));
	
	return space;
}

static void
destroy()
{
	cpSpaceFreeChildren(space);
	cpSpaceFree(space);
}

chipmunkDemo Bounce = {
	"Bounce",
	null,
	&init,
	&update,
	&destroy,
};