/*
 * Copyright (c) 2007-2013 Scott Lembcke and Howling Moon Software
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
module demo.RollBall;

/**
    Taken from the Chipmunk manual, the hello-world with a ball rolling down a slope.
*/

import demo.dchip;

import demo.ChipmunkDebugDraw;
import demo.ChipmunkDemo;
import demo.types;

void update(cpSpace* space, double dt)
{
    cpSpaceStep(space, dt);
}

cpSpace* init()
{
    // cpVect is a 2D vector and cpv() is a shortcut for initializing them.
    cpVect gravity = cpv(0, -100);

    // Create an empty space.
    cpSpace *space = cpSpaceNew();
    cpSpaceSetGravity(space, gravity);

    // Add a static line segment shape for the ground.
    // We'll make it slightly tilted so the ball will roll off.
    // We attach it to space.staticBody to tell Chipmunk it shouldn't be movable.
    cpShape *ground = cpSegmentShapeNew(space.staticBody, cpv(-200, 0), cpv(200, -100), 0);
    cpShapeSetFriction(ground, 1);
    cpSpaceAddShape(space, ground);

    // Now let's make a ball that falls onto the line and rolls off.
    // First we need to make a cpBody to hold the physical properties of the object.
    // These include the mass, position, velocity, angle, etc. of the object.
    // Then we attach collision shapes to the cpBody to give it a size and shape.

    cpFloat radius = 20;
    cpFloat mass = 1;

    // The moment of inertia is like mass for rotation
    // Use the cpMomentFor*() functions to help you approximate it.
    cpFloat moment = cpMomentForCircle(mass, 0, radius, cpvzero);

    // The cpSpaceAdd*() functions return the thing that you are adding.
    // It's convenient to create and add an object in one line.
    cpBody *ballBody = cpSpaceAddBody(space, cpBodyNew(mass, moment));
    cpBodySetPos(ballBody, cpv(0, 15));

    // Now we create the collision shape for the ball.
    // You can create multiple collision shapes that point to the same body.
    // They will all be attached to the body and move around to follow it.
    cpShape *ballShape = cpSpaceAddShape(space, cpCircleShapeNew(ballBody, radius, cpvzero));
    cpShapeSetFriction(ballShape, 0.7);

    return space;
}

void destroy(cpSpace* space)
{
    ChipmunkDemoFreeSpaceChildren(space);
    cpSpaceFree(space);
}

ChipmunkDemo RollBall = {
    "RollBall",
    1.0 / 180.0,
    &init,
    &update,
    &ChipmunkDemoDefaultDrawImpl,
    &destroy,
};