bool Renderer::checkVisibility(const kmMat4 &transform, const Size &size)
{
// half size of the screen
Size screen_half = Director::getInstance()->getWinSize();
screen_half.width /= 2;
screen_half.height /= 2;
float hSizeX = size.width/2;
float hSizeY = size.height/2;
kmVec4 v4world, v4local;
kmVec4Fill(&v4local, hSizeX, hSizeY, 0, 1);
kmVec4MultiplyMat4(&v4world, &v4local, &transform);
// center of screen is (0,0)
v4world.x -= screen_half.width;
v4world.y -= screen_half.height;
// convert content size to world coordinates
float wshw = std::max(fabsf(hSizeX * transform.mat[0] + hSizeY * transform.mat[4]), fabsf(hSizeX * transform.mat[0] - hSizeY * transform.mat[4]));
float wshh = std::max(fabsf(hSizeX * transform.mat[1] + hSizeY * transform.mat[5]), fabsf(hSizeX * transform.mat[1] - hSizeY * transform.mat[5]));
// compare if it in the positive quadrant of the screen
float tmpx = (fabsf(v4world.x)-wshw);
float tmpy = (fabsf(v4world.y)-wshh);
bool ret = (tmpx < screen_half.width && tmpy < screen_half.height);
return ret;
}
kmVec4* kmVec4Transform(kmVec4* pOut, const kmVec4* pV, const kmMat4* pM) {
return kmVec4MultiplyMat4(pOut, pV, pM);
}
