axmol/tests/cpp-tests/Source/ChipmunkTestBed/demo/Convex.cpp

111 lines
4.0 KiB
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 "chipmunk/chipmunk_unsafe.h"
#include "ChipmunkDemo.h"
#define DENSITY (1.0 / 10000.0)
static cpShape* shape;
static void update(cpSpace* space, double dt)
{
cpFloat tolerance = 2.0;
if (ChipmunkDemoRightClick && cpShapePointQuery(shape, ChipmunkDemoMouse, NULL) > tolerance)
{
cpBody* body = cpShapeGetBody(shape);
int count = cpPolyShapeGetCount(shape);
// Allocate the space for the new vertexes on the stack.
cpVect* verts = (cpVect*)alloca((count + 1) * sizeof(cpVect));
for (int i = 0; i < count; i++)
{
verts[i] = cpPolyShapeGetVert(shape, i);
}
verts[count] = cpBodyWorldToLocal(body, ChipmunkDemoMouse);
// This function builds a convex hull for the vertexes.
// Because the result array is the same as verts, it will reduce it in place.
int hullCount = cpConvexHull(count + 1, verts, verts, NULL, tolerance);
// Figure out how much to shift the body by.
cpVect centroid = cpCentroidForPoly(hullCount, verts);
// Recalculate the body properties to match the updated shape.
cpFloat mass = cpAreaForPoly(hullCount, verts, 0.0f) * DENSITY;
cpBodySetMass(body, mass);
cpBodySetMoment(body, cpMomentForPoly(mass, hullCount, verts, cpvneg(centroid), 0.0f));
cpBodySetPosition(body, cpBodyLocalToWorld(body, centroid));
// Use the setter function from chipmunk_unsafe.h.
// You could also remove and recreate the shape if you wanted.
cpPolyShapeSetVerts(shape, hullCount, verts, cpTransformTranslate(cpvneg(centroid)));
}
cpSpaceStep(space, dt);
}
static cpSpace* init(void)
{
ChipmunkDemoMessageString = "Right click and drag to change the blocks's shape.";
cpSpace* space = cpSpaceNew();
cpSpaceSetIterations(space, 30);
cpSpaceSetGravity(space, cpv(0, -500));
cpSpaceSetSleepTimeThreshold(space, 0.5f);
cpSpaceSetCollisionSlop(space, 0.5f);
cpBody *body, *staticBody = cpSpaceGetStaticBody(space);
// 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);
cpFloat width = 50.0f;
cpFloat height = 70.0f;
cpFloat mass = width * height * DENSITY;
cpFloat moment = cpMomentForBox(mass, width, height);
body = cpSpaceAddBody(space, cpBodyNew(mass, moment));
shape = cpSpaceAddShape(space, cpBoxShapeNew(body, width, height, 0.0));
cpShapeSetFriction(shape, 0.6f);
return space;
}
static void destroy(cpSpace* space)
{
ChipmunkDemoFreeSpaceChildren(space);
cpSpaceFree(space);
}
ChipmunkDemo Convex = {
"Convex.", 1.0 / 60.0, init, update, ChipmunkDemoDefaultDrawImpl, destroy,
};