--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/trunk/tests/ChipmunkDemos/samples/Joints.d	Sat Dec 04 02:02:29 2010 +0100
@@ -0,0 +1,277 @@
+
+// written in the D programming language
+
+module samples.Joints;
+
+import chipmunkd.chipmunk;
+
+import samples.ChipmunkDemo;
+
+import std.math;
+
+static cpSpace *space;
+
+enum M_PI = PI;
+enum M_PI_2 = PI*0.5f;
+
+static cpBody *
+addBall(cpVect pos, cpVect boxOffset)
+{
+	cpFloat radius = 15.0f;
+	cpFloat mass = 1.0f;
+	cpBody *_body = cpSpaceAddBody(space, cpBodyNew(mass, cpMomentForCircle(mass, 0.0f, radius, cpvzero)));
+	_body.p = cpvadd(pos, boxOffset);
+	
+	cpShape *shape = cpSpaceAddShape(space, cpCircleShapeNew(_body, radius, cpvzero));
+	shape.e = 0.0f; shape.u = 0.7f;
+	
+	return _body;
+}
+
+static cpBody *
+addLever(cpVect pos, cpVect boxOffset)
+{
+	cpFloat mass = 1.0f;
+	cpVect a = cpv(0,  15);
+	cpVect b = cpv(0, -15);
+	
+	cpBody *_body = cpSpaceAddBody(space, cpBodyNew(mass, cpMomentForSegment(mass, a, b)));
+	_body.p = cpvadd(pos, cpvadd(boxOffset, cpv(0, -15)));
+	
+	cpShape *shape = cpSpaceAddShape(space, cpSegmentShapeNew(_body, a, b, 5.0f));
+	shape.e = 0.0f; shape.u = 0.7f;
+	
+	return _body;
+}
+
+static cpBody *
+addBar(cpVect pos, cpVect boxOffset)
+{
+	cpFloat mass = 2.0f;
+	cpVect a = cpv(0,  30);
+	cpVect b = cpv(0, -30);
+	
+	cpBody *_body = cpSpaceAddBody(space, cpBodyNew(mass, cpMomentForSegment(mass, a, b)));
+	_body.p = cpvadd(pos, boxOffset);
+	
+	cpShape *shape = cpSpaceAddShape(space, cpSegmentShapeNew(_body, a, b, 5.0f));
+	shape.e = 0.0f; shape.u = 0.7f;
+	
+	return _body;
+}
+
+static cpBody *
+addWheel(cpVect pos, cpVect boxOffset)
+{
+	cpFloat radius = 15.0f;
+	cpFloat mass = 1.0f;
+	cpBody *_body = cpSpaceAddBody(space, cpBodyNew(mass, cpMomentForCircle(mass, 0.0f, radius, cpvzero)));
+	_body.p = cpvadd(pos, boxOffset);
+	
+	cpShape *shape = cpSpaceAddShape(space, cpCircleShapeNew(_body, radius, cpvzero));
+	shape.e = 0.0f; shape.u = 0.7f;
+	shape.group = 1; // use a group to keep the car parts from colliding
+	
+	return _body;
+}
+
+static cpBody *
+addChassis(cpVect pos, cpVect boxOffset)
+{
+	int num = 4;
+	cpVect verts[] = [
+		cpv(-40,-15),
+		cpv(-40, 15),
+		cpv( 40, 15),
+		cpv( 40,-15),
+	];
+
+	
+	cpFloat mass = 5.0f;
+	cpBody *_body = cpSpaceAddBody(space, cpBodyNew(mass, cpMomentForPoly(mass, num, verts.ptr, cpvzero)));
+	_body.p = cpvadd(pos, boxOffset);
+	
+	cpShape *shape = cpSpaceAddShape(space, cpPolyShapeNew(_body, num, verts.ptr, cpvzero));
+	shape.e = 0.0f; shape.u = 0.7f;
+	shape.group = 1; // use a group to keep the car parts from colliding
+	
+	return _body;
+}
+
+static cpSpace *
+init()
+{
+	space = cpSpaceNew();
+	space.iterations = 10;
+	space.gravity = cpv(0, -100);
+	space.sleepTimeThreshold = 0.5f;
+	
+	cpBody *staticBody = &space.staticBody;
+	cpShape *shape;
+	
+	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(-320,120), cpv(320,120), 0.0f));
+	shape.e = 1.0f; shape.u = 1.0f;
+	shape.layers = NOT_GRABABLE_MASK;
+	
+	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,0), cpv(320,0), 0.0f));
+	shape.e = 1.0f; shape.u = 1.0f;
+	shape.layers = NOT_GRABABLE_MASK;
+	
+	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,-120), cpv(320,-120), 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(-160,-240), cpv(-160,240), 0.0f));
+	shape.e = 1.0f; shape.u = 1.0f;
+	shape.layers = NOT_GRABABLE_MASK;
+	
+	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(0,-240), cpv(0,240), 0.0f));
+	shape.e = 1.0f; shape.u = 1.0f;
+	shape.layers = NOT_GRABABLE_MASK;
+	
+	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(160,-240), cpv(160,240), 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;
+	
+	cpVect boxOffset;
+	cpBody *body1;
+	cpBody *body2;
+	
+	cpVect posA = cpv( 50, 60);
+	cpVect posB = cpv(110, 60);
+	
+	// Pin Joints - Link shapes with a solid bar or pin.
+	// Keeps the anchor points the same distance apart from when the joint was created.
+	boxOffset = cpv(-320, -240);
+	body1 = addBall(posA, boxOffset);
+	body2 = addBall(posB, boxOffset);
+	cpSpaceAddConstraint(space, cpPinJointNew(body1, body2, cpv(15,0), cpv(-15,0)));
+	
+	// Slide Joints - Like pin joints but with a min/max distance.
+	// Can be used for a cheap approximation of a rope.
+	boxOffset = cpv(-160, -240);
+	body1 = addBall(posA, boxOffset);
+	body2 = addBall(posB, boxOffset);
+	cpSpaceAddConstraint(space, cpSlideJointNew(body1, body2, cpv(15,0), cpv(-15,0), 20.0f, 40.0f));
+	
+	// Pivot Joints - Holds the two anchor points together. Like a swivel.
+	boxOffset = cpv(0, -240);
+	body1 = addBall(posA, boxOffset);
+	body2 = addBall(posB, boxOffset);
+	cpSpaceAddConstraint(space, cpPivotJointNew(body1, body2, cpvadd(boxOffset, cpv(80,60))));
+	// cpPivotJointNew() takes it's anchor parameter in world coordinates. The anchors are calculated from that
+	// cpPivotJointNew2() lets you specify the two anchor points explicitly
+	
+	// Groove Joints - Like a pivot joint, but one of the anchors is a line segment that the pivot can slide in
+	boxOffset = cpv(160, -240);
+	body1 = addBall(posA, boxOffset);
+	body2 = addBall(posB, boxOffset);
+	cpSpaceAddConstraint(space, cpGrooveJointNew(body1, body2, cpv(30,30), cpv(30,-30), cpv(-30,0)));
+	
+	// Damped Springs
+	boxOffset = cpv(-320, -120);
+	body1 = addBall(posA, boxOffset);
+	body2 = addBall(posB, boxOffset);
+	cpSpaceAddConstraint(space, cpDampedSpringNew(body1, body2, cpv(15,0), cpv(-15,0), 20.0f, 5.0f, 0.3f));
+	
+	// Damped Rotary Springs
+	boxOffset = cpv(-160, -120);
+	body1 = addBar(posA, boxOffset);
+	body2 = addBar(posB, boxOffset);
+	// Add some pin joints to hold the circles in place.
+	cpSpaceAddConstraint(space, cpPivotJointNew(body1, staticBody, cpvadd(boxOffset, posA)));
+	cpSpaceAddConstraint(space, cpPivotJointNew(body2, staticBody, cpvadd(boxOffset, posB)));
+	cpSpaceAddConstraint(space, cpDampedRotarySpringNew(body1, body2, 0.0f, 3000.0f, 60.0f));
+	
+	// Rotary Limit Joint
+	boxOffset = cpv(0, -120);
+	body1 = addLever(posA, boxOffset);
+	body2 = addLever(posB, boxOffset);
+	// Add some pin joints to hold the circles in place.
+	cpSpaceAddConstraint(space, cpPivotJointNew(body1, staticBody, cpvadd(boxOffset, posA)));
+	cpSpaceAddConstraint(space, cpPivotJointNew(body2, staticBody, cpvadd(boxOffset, posB)));
+	// Hold their rotation within 90 degrees of each other.
+	cpSpaceAddConstraint(space, cpRotaryLimitJointNew(body1, body2, -M_PI_2, M_PI_2));
+	
+	// Ratchet Joint - A rotary ratchet, like a socket wrench
+	boxOffset = cpv(160, -120);
+	body1 = addLever(posA, boxOffset);
+	body2 = addLever(posB, boxOffset);
+	// Add some pin joints to hold the circles in place.
+	cpSpaceAddConstraint(space, cpPivotJointNew(body1, staticBody, cpvadd(boxOffset, posA)));
+	cpSpaceAddConstraint(space, cpPivotJointNew(body2, staticBody, cpvadd(boxOffset, posB)));
+	// Ratchet every 90 degrees
+	cpSpaceAddConstraint(space, cpRatchetJointNew(body1, body2, 0.0f, M_PI_2));
+	
+	// Gear Joint - Maintain a specific angular velocity ratio
+	boxOffset = cpv(-320, 0);
+	body1 = addBar(posA, boxOffset);
+	body2 = addBar(posB, boxOffset);
+	// Add some pin joints to hold the circles in place.
+	cpSpaceAddConstraint(space, cpPivotJointNew(body1, staticBody, cpvadd(boxOffset, posA)));
+	cpSpaceAddConstraint(space, cpPivotJointNew(body2, staticBody, cpvadd(boxOffset, posB)));
+	// Force one to sping 2x as fast as the other
+	cpSpaceAddConstraint(space, cpGearJointNew(body1, body2, 0.0f, 2.0f));
+	
+	// Simple Motor - Maintain a specific angular relative velocity
+	boxOffset = cpv(-160, 0);
+	body1 = addBar(posA, boxOffset);
+	body2 = addBar(posB, boxOffset);
+	// Add some pin joints to hold the circles in place.
+	cpSpaceAddConstraint(space, cpPivotJointNew(body1, staticBody, cpvadd(boxOffset, posA)));
+	cpSpaceAddConstraint(space, cpPivotJointNew(body2, staticBody, cpvadd(boxOffset, posB)));
+	// Make them spin at 1/2 revolution per second in relation to each other.
+	cpSpaceAddConstraint(space, cpSimpleMotorNew(body1, body2, M_PI));
+	
+	// Make a car with some nice soft suspension
+	boxOffset = cpv(0, 0);
+	cpBody *wheel1 = addWheel(posA, boxOffset);
+	cpBody *wheel2 = addWheel(posB, boxOffset);
+	cpBody *chassis = addChassis(cpv(80, 100), boxOffset);
+	
+	cpSpaceAddConstraint(space, cpGrooveJointNew(chassis, wheel1, cpv(-30, -10), cpv(-30, -40), cpvzero));
+	cpSpaceAddConstraint(space, cpGrooveJointNew(chassis, wheel2, cpv( 30, -10), cpv( 30, -40), cpvzero));
+	
+	cpSpaceAddConstraint(space, cpDampedSpringNew(chassis, wheel1, cpv(-30, 0), cpvzero, 50.0f, 20.0f, 1.5f));
+	cpSpaceAddConstraint(space, cpDampedSpringNew(chassis, wheel2, cpv( 30, 0), cpvzero, 50.0f, 20.0f, 1.5f));
+	
+	return space;
+}
+
+static void
+update(int ticks)
+{
+	cpSpaceStep(space, 1.0f/60.0f);
+}
+
+static void
+destroy()
+{
+	cpSpaceFreeChildren(space);
+	cpSpaceFree(space);
+}
+
+chipmunkDemo Joints = {
+	"Joints and Constraints",
+	null,
+	&init,
+	&update,
+	&destroy,
+};