Cocos2dx中的像素完美碰撞检测

Question

我试图在Cocos2d-x中移植像素完美碰撞检测,原始版本是为Cocos2D制作的,可以在这里找到:http://www.cocos2d-iphone.org/forums/topic/pixel-perfect-collision-detection -使用色混/

这是我的Cocos2d-x版本的代码

bool CollisionDetection::areTheSpritesColliding(cocos2d::CCSprite *spr1, cocos2d::CCSprite *spr2, bool pp, CCRenderTexture* _rt) {
    bool isColliding = false;
    CCRect intersection;
    CCRect r1 = spr1->boundingBox();
    CCRect r2 = spr2->boundingBox();
    intersection = CCRectMake(fmax(r1.getMinX(),r2.getMinX()), fmax( r1.getMinY(), r2.getMinY()) ,0,0);
    intersection.size.width = fmin(r1.getMaxX(), r2.getMaxX() - intersection.getMinX());
    intersection.size.height = fmin(r1.getMaxY(), r2.getMaxY() - intersection.getMinY());

    // Look for simple bounding box collision
    if ( (intersection.size.width>0) && (intersection.size.height>0) ) {
        // If we're not checking for pixel perfect collisions, return true
        if (!pp) {
            return true;
        }

        unsigned int x = intersection.origin.x;
        unsigned int y = intersection.origin.y;
        unsigned int w = intersection.size.width;
        unsigned int h = intersection.size.height;
        unsigned int numPixels = w * h;
        //CCLog("Intersection X and Y %d, %d", x, y);
        //CCLog("Number of pixels %d", numPixels);

        // Draw into the RenderTexture
        _rt->beginWithClear( 0, 0, 0, 0);

        // Render both sprites: first one in RED and second one in GREEN
        glColorMask(1, 0, 0, 1);
        spr1->visit();
        glColorMask(0, 1, 0, 1);
        spr2->visit();
        glColorMask(1, 1, 1, 1);

        // Get color values of intersection area
        ccColor4B *buffer = (ccColor4B *)malloc( sizeof(ccColor4B) * numPixels );
        glReadPixels(x, y, w, h, GL_RGBA, GL_UNSIGNED_BYTE, buffer);

        _rt->end();

        // Read buffer
        unsigned int step = 1;
        for(unsigned int i=0; i 0 && color.g > 0) {
                isColliding = true;
                break;
            }
        }

        // Free buffer memory
        free(buffer);
    }


    return isColliding;
}

如果我将"pp"参数发送为false,我的代码将完美运行.也就是说,如果我做的只是一个边框碰撞,但我不能让它正常工作的情况下,当我需要像素完美碰撞.我认为opengl掩码代码没有按照我的意图运行.

这是"_rt"的代码

    _rt = CCRenderTexture::create(visibleSize.width, visibleSize.height);
    _rt->setPosition(ccp(origin.x + visibleSize.width * 0.5f, origin.y + visibleSize.height * 0.5f));
    this->addChild(_rt, 1000000);
    _rt->setVisible(true); //For testing

我认为我在执行这个CCRenderTexture时犯了一个错误

任何人都可以指导我做错的事吗？

感谢您的时间 :)

Answer 1

您没有正确单步通过缓冲区。

// Read buffer
unsigned int step = 1;
for(unsigned int i=0; i<numPixels; i+=step)
{
    ccColor4B color = buffer;

    if (color.r > 0 && color.g > 0)
    {
        isCollision = YES;
        break;
    }
}

来源：http ://www.cocos2d-iphone.org/forums/topic/pixel-perfect-collision-detection-using-color-blending/#post-337907