Cocos2d-x 不规则按钮处理

处理不规则按钮

问题描述

在Cocos2d-x实际项目中,经常会遇到不规则按钮的情况,或是因为项目需要,或是美术切图问题.由于按钮的响应区域是根据图片的实际尺寸来的,所以会出现透明区域也能响应的情况,这时候,就需要我们想办法屏蔽掉透明区域的触摸.

解决思路

由于Cocos2d-x本身没有做这方面的处理,我自己通过查阅资料找到了一个解决办法,那就是：复写Button类,在创建按钮的时候获取按钮正常形态的图片,根据其alpha通道值维护一个二维Bool型数组,如果像素点的透明度值为1,则该点为false,点击按钮的时候,根据点击的坐标去判断当前位置是否透明,透明则不予响应.

代码

加载函数loadNormalTransparentInfo()

#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    auto start = std::chrono::steady_clock::now();
#endif

#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    auto stepStart = std::chrono::steady_clock::now();
#endif
    Sprite* normalRenderer = static_cast<Sprite*>(_buttonNormalRenderer);
    auto normalTexture = normalRenderer->getTexture();
    const Size& s = normalTexture->getContentSizeInPixels();
#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    auto stepEnd = std::chrono::steady_clock::now();
    auto stepTime = std::chrono::duration_cast<std::chrono::milliseconds>(stepEnd - stepStart);
    CCLOG("Sprite::getTexture: %lld ms\n", stepTime.count());
#endif

    int savedBufferWidth = (int)s.width;
    int savedBufferHeight = (int)s.height;
#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    CCLOG("image: %s, savedBuffWidth: %d, savedBuffHeight: %d\n", _normalFileName.c_str(), savedBufferWidth, savedBufferHeight);
#endif

    GLubyte *buffer = nullptr;

    // the FBO which cocos2dx used is not window-system-provided (non-zero id)
    GLint oldFBO;
    glGetIntegerv(GL_FRAMEBUFFER_BINDING, &oldFBO);
#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    CCLOG("oldFBO: %d\n", oldFBO);
#endif

    GLuint framebuffer;
    glGenFramebuffers(1, &framebuffer);
    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);

#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    stepStart = std::chrono::steady_clock::now();
#endif
    glBindTexture(GL_TEXTURE_2D, normalTexture->getName());
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA4, savedBufferWidth, savedBufferHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, normalTexture->getName(), 0);
#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    stepEnd = std::chrono::steady_clock::now();
    stepTime = std::chrono::duration_cast<std::chrono::milliseconds>(stepEnd - stepStart);
    CCLOG("bind texture: %lld ms\n", stepTime.count());
#endif

    CCASSERT(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE, "Could not attach texture to framebuffer");

    buffer = new (std::nothrow) GLubyte[savedBufferWidth * savedBufferHeight * 4];

#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    stepStart = std::chrono::steady_clock::now();
#endif
    glPixelStorei(GL_PACK_ALIGNMENT, 1);
    glReadPixels(0, 0, savedBufferWidth, savedBufferHeight, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
    glBindFramebuffer(GL_FRAMEBUFFER, oldFBO);
#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    stepEnd = std::chrono::steady_clock::now();
    stepTime = std::chrono::duration_cast<std::chrono::milliseconds>(stepEnd - stepStart);
    CCLOG("glReadPixels: %lld ms\n", stepTime.count());
#endif

#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    stepStart = std::chrono::steady_clock::now();
#endif
    auto dataLen = savedBufferWidth * savedBufferHeight * 4;
    if (normalTransparent_ != nullptr) {
        delete[] normalTransparent_;
    }
    normalImageWidth_ = savedBufferWidth;
    normalImageHeight_ = savedBufferHeight;
    normalTransparent_ = new bool[dataLen / (sizeof(unsigned char) * 4)];
    for (auto i = 0; i < normalImageHeight_; i++) {
        for (auto j = 0; j < normalImageWidth_; j++) {
            normalTransparent_[i * normalImageWidth_ + j] = (buffer[(i * normalImageWidth_ + j) * 4] == 0);
        }
    }
#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    stepEnd = std::chrono::steady_clock::now();
    stepTime = std::chrono::duration_cast<std::chrono::milliseconds>(stepEnd - stepStart);
    CCLOG("init normalTransparent_: %lld ms\n", stepTime.count());
#endif

    CC_SAFE_DELETE_ARRAY(buffer);

#if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0)
    auto end = std::chrono::steady_clock::now();
    auto totalTime = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
    CCLOG("load from memory: %lld ms\n", totalTime.count());
#endif

判断函数getIsTransparentAtPoint(cocos2d::Vec2 point)

point.y = _buttonNormalRenderer->getContentSize().height - point.y;
   int x = (int) point.x - 1;
   if (x < 0) {
       x = 0;
   } else if (x >= normalImageWidth_) {
       x = normalImageWidth_ - 1;
   }
   int y = (int) point.y - 1;
   if (y < 0) {
       y = 0;
   } else if (y >= normalImageHeight_) {
       y = normalImageHeight_ - 1;
   }
   return normalTransparent_[normalImageWidth_ * y + x];

响应函数hitTest(const Vec2 &pt)

Vec2 localLocation = _buttonNormalRenderer->convertToNodeSpace(pt);
 Rect validTouchedRect;
 validTouchedRect.size = _buttonNormalRenderer->getContentSize();
 if (validTouchedRect.containsPoint(localLocation) && getIsTransparentAtPoint(localLocation) == false)
 {
     return true;
 }
 return false;

需要注意的地方

alpha通道值存储的位置问题