// written in the D programming language

module samples.PyramidTopple;

import chipmunkd.chipmunk;

import samples.ChipmunkDemo;

import std.math:PI;

static cpSpace *space;

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

static cpSpace *
init()
{
	cpResetShapeIdCounter();
	
	space = cpSpaceNew();
	space.iterations = 30;
	cpSpaceResizeActiveHash(space, 30.0f, 2999);
	cpSpaceResizeStaticHash(space, 30.0f, 999);
	space.gravity = cpv(0, -300);
	space.sleepTimeThreshold = 0.5f;
	
	cpBody *_body;
	
	cpShape *shape;
	
	// Vertexes for the dominos.
	int num = 4;
	cpVect verts[] = [
		cpv(-3,-20),
		cpv(-3, 20),
		cpv( 3, 20),
		cpv( 3,-20),
	];
	
	// Add a floor.
	shape = cpSpaceAddShape(space, cpSegmentShapeNew(&space.staticBody, cpv(-600,-240), cpv(600,-240), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;
	
	// Shared friction constant.
	cpFloat u = 0.6f;
	
	// Add the dominoes. Skim over this. It doesn't do anything fancy, and it's hard to follow.
	int n = 9;
	for(int i=1; i<=n; i++){
		cpVect offset = cpv(-i*60/2.0f, (n - i)*52);
		
		for(int j=0; j<i; j++){
			_body = cpSpaceAddBody(space, cpBodyNew(1.0f, cpMomentForPoly(1.0f, num, verts.ptr, cpvzero)));
			_body.p = cpvadd(cpv(j*60, -220), offset);
			
			shape = cpSpaceAddShape(space, cpPolyShapeNew(_body, num, verts.ptr, cpvzero));
			shape.e = 0.0f; shape.u = u;
			

			_body = cpSpaceAddBody(space, cpBodyNew(1.0f, cpMomentForPoly(1.0f, num, verts.ptr, cpvzero)));
			_body.p = cpvadd(cpv(j*60, -197), offset);
			cpBodySetAngle(_body, cast(float)PI/2.0f);
			
			shape = cpSpaceAddShape(space, cpPolyShapeNew(_body, num, verts.ptr, cpvzero));
			shape.e = 0.0f; shape.u = u;
			
			
			if(j == (i - 1)) continue;
			_body = cpSpaceAddBody(space, cpBodyNew(1.0f, cpMomentForPoly(1.0f, num, verts.ptr, cpvzero)));
			_body.p = cpvadd(cpv(j*60 + 30, -191), offset);
			cpBodySetAngle(_body, cast(float)PI/2.0f);
			
			shape = cpSpaceAddShape(space, cpPolyShapeNew(_body, num, verts.ptr, cpvzero));
			shape.e = 0.0f; shape.u = u;
		}

		_body = cpSpaceAddBody(space, cpBodyNew(1.0f, cpMomentForPoly(1.0f, num, verts.ptr, cpvzero)));
		_body.p = cpvadd(cpv(-17, -174), offset);
		
		shape = cpSpaceAddShape(space, cpPolyShapeNew(_body, num, verts.ptr, cpvzero));
		shape.e = 0.0f; shape.u = u;
		

		_body = cpSpaceAddBody(space, cpBodyNew(1.0f, cpMomentForPoly(1.0f, num, verts.ptr, cpvzero)));
		_body.p = cpvadd(cpv((i - 1)*60 + 17, -174), offset);
		
		shape = cpSpaceAddShape(space, cpPolyShapeNew(_body, num, verts.ptr, cpvzero));
		shape.e = 0.0f; shape.u = u;
	}
	
	// Give the last domino a little tap.
//	body.w = -1;
//	body.v = cpv(-body.w*20, 0);
	return space;
}

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

chipmunkDemo PyramidTopple = {
	"Pyramid Topple",
	null,
	&init,
	&update,
	&destroy,
};