axmol/tests/cpp-tests/Source/ChipmunkTestBed/demo/OneWay.c

/* Copyright (c) 2007 Scott Lembcke
 *
 * 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.
 */

#include "chipmunk/chipmunk.h"
#include "ChipmunkDemo.h"

enum CollisionTypes
{
    COLLISION_TYPE_ONE_WAY = 1,
};

typedef struct OneWayPlatform
{
    cpVect n;  // direction objects may pass through
} OneWayPlatform;

static OneWayPlatform platformInstance;

static cpBool PreSolve(cpArbiter* arb, cpSpace* space, void* ignore)
{
    CP_ARBITER_GET_SHAPES(arb, a, b);
    OneWayPlatform* platform = (OneWayPlatform*)cpShapeGetUserData(a);

    if (cpvdot(cpArbiterGetNormal(arb), platform->n) < 0)
    {
        return cpArbiterIgnore(arb);
    }

    return cpTrue;
}

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

static cpSpace* init(void)
{
    ChipmunkDemoMessageString = "One way platforms are trivial in Chipmunk using a very simple collision callback.";

    cpSpace* space = cpSpaceNew();
    cpSpaceSetIterations(space, 10);
    cpSpaceSetGravity(space, cpv(0, -100));

    cpBody *body, *staticBody = cpSpaceGetStaticBody(space);
    cpShape* shape;

    // Create segments around the edge of the screen.
    shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320, -240), cpv(-320, 240), 0.0f));
    cpShapeSetElasticity(shape, 1.0f);
    cpShapeSetFriction(shape, 1.0f);
    cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);

    shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(320, -240), cpv(320, 240), 0.0f));
    cpShapeSetElasticity(shape, 1.0f);
    cpShapeSetFriction(shape, 1.0f);
    cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);

    shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320, -240), cpv(320, -240), 0.0f));
    cpShapeSetElasticity(shape, 1.0f);
    cpShapeSetFriction(shape, 1.0f);
    cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);

    // Add our one way segment
    shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-160, -100), cpv(160, -100), 10.0f));
    cpShapeSetElasticity(shape, 1.0f);
    cpShapeSetFriction(shape, 1.0f);
    cpShapeSetCollisionType(shape, COLLISION_TYPE_ONE_WAY);
    cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);

    // We'll use the data pointer for the OneWayPlatform struct
    platformInstance.n = cpv(0, 1);  // let objects pass upwards
    cpShapeSetUserData(shape, &platformInstance);

    // Add a ball to test it out
    cpFloat radius = 15.0f;
    body           = cpSpaceAddBody(space, cpBodyNew(10.0f, cpMomentForCircle(10.0f, 0.0f, radius, cpvzero)));
    cpBodySetPosition(body, cpv(0, -200));
    cpBodySetVelocity(body, cpv(0, 170));

    shape = cpSpaceAddShape(space, cpCircleShapeNew(body, radius, cpvzero));
    cpShapeSetElasticity(shape, 0.0f);
    cpShapeSetFriction(shape, 0.9f);
    cpShapeSetCollisionType(shape, 2);

    cpCollisionHandler* handler = cpSpaceAddWildcardHandler(space, COLLISION_TYPE_ONE_WAY);
    handler->preSolveFunc       = PreSolve;

    return space;
}

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

ChipmunkDemo OneWay = {
    "One Way Platforms", 1.0 / 60.0, init, update, ChipmunkDemoDefaultDrawImpl, destroy,
};