// written in the D programming language

module samples.Query;

import chipmunkd.chipmunk;

import samples.ChipmunkDemo;
import gameApp;

import std.math;

//extern cpVect			mousePos;

static cpSpace *space;

static cpShape *querySeg = null;


static void
update(int ticks)
{
	//messageString[0] = '\0';
	
	cpVect start = cpvzero;
	cpVect end = /*cpv(0, 85);//*/mousePos;
	cpVect lineEnd = end;
	
	//{
	//	char infoString[1024];
	//	sprintf(infoString, "Query: Dist(%f) Point%s, ", cpvdist(start, end), cpvstr(end));
	//	strcat(messageString, infoString);
	//}
	
	cpSegmentQueryInfo info = {};
	if(cpSpaceSegmentQueryFirst(space, start, end, CP_ALL_LAYERS, CP_NO_GROUP, &info)){
		cpVect point = cpSegmentQueryHitPoint(start, end, info);
		lineEnd = cpvadd(point, cpvzero);//cpvmult(info.n, 4.0f));
		
		//char infoString[1024];
		//sprintf(infoString, "Segment Query: Dist(%f) Normal%s", cpSegmentQueryHitDist(start, end, info), cpvstr(info.n));
		//strcat(messageString, infoString);
	} else {
		//strcat(messageString, "Segment Query (None)");
	}
	
	cpSegmentShapeSetEndpoints(querySeg, start, lineEnd);
	cpShapeCacheBB(querySeg); // force it to update it's collision detection data so it will draw
	
	// normal other stuff.
	int steps = 1;
	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.elasticIterations = 0;
	space.iterations = 5;

	cpSpaceResizeStaticHash(space, 40.0f, 999);
	cpSpaceResizeActiveHash(space, 30.0f, 2999);

	cpBody *staticBody = &space.staticBody;
	cpShape *shape;
	
	// add a non-collidable segment as a quick and dirty way to draw the query line
	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpvzero, cpv(100.0f, 0.0f), 4.0f));
	shape.layers = 0;
	querySeg = shape;
	
	{ // add a fat segment
		cpFloat mass = 1.0f;
		cpFloat length = 100.0f;
		cpVect a = cpv(-length/2.0f, 0.0f), b = cpv(length/2.0f, 0.0f);
		
		cpBody *_body = cpSpaceAddBody(space, cpBodyNew(mass, cpMomentForSegment(mass, a, b)));
		_body.p = cpv(0.0f, 100.0f);
		
		cpSpaceAddShape(space, cpSegmentShapeNew(_body, a, b, 20.0f));
	}
	
	{ // add a static segment
		cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(0, 300), cpv(300, 0), 0.0f));
	}
	
	{ // add a pentagon
		cpFloat mass = 1.0f;
		const int NUM_VERTS = 5;
		
		cpVect verts[NUM_VERTS];
		for(int i=0; i<NUM_VERTS; i++){
			cpFloat angle = -2*PI*i/(cast(cpFloat) NUM_VERTS);
			verts[i] = cpv(30*cos(angle), 30*sin(angle));
		}
		
		cpBody *_body = cpSpaceAddBody(space, cpBodyNew(mass, cpMomentForPoly(mass, NUM_VERTS, verts.ptr, cpvzero)));
		_body.p = cpv(50.0f, 50.0f);
		
		cpSpaceAddShape(space, cpPolyShapeNew(_body, NUM_VERTS, verts.ptr, cpvzero));
	}
	
	{ // add a circle
		cpFloat mass = 1.0f;
		cpFloat r = 20.0f;
		
		cpBody *_body = cpSpaceAddBody(space, cpBodyNew(mass, cpMomentForCircle(mass, 0.0f, r, cpvzero)));
		_body.p = cpv(100.0f, 100.0f);
		
		cpSpaceAddShape(space, cpCircleShapeNew(_body, r, cpvzero));
	}
	
	return space;
}

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

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