Ogre-捏脸-三维坐标投影到屏幕坐标

详细原理可查看博客:

https://blog.csdn.net/miyu1994/article/details/106554004

 

bool World2Screen(Vector3 objPos, Vector2& screenPos)
{
    //视图矩阵
	Matrix4 viewMat = m_camera->getViewMatrix();
    //透视投影矩阵
	Matrix4 projMat = m_camera->getProjectionMatrix();
 
 
	Vector4 inP = Vector4(objPos.x, objPos.y, objPos.z ,1.0);
    //先做视图变换
	Vector4 outP = viewMat * inP;
    //再做投影变换
	outP = projMat * outP;
 
	if(outP.w <= 0.0f)
		return false;
 
    //齐次坐标
	outP.x /= outP.w;
	outP.y /= outP.w;
	outP.z /= outP.w;
 
    //[-1,1]->[0,1]
	outP.x = outP.x*0.5 + 0.5;
	outP.y = outP.y*0.5 + 0.5;
	outP.z = outP.z*0.5 + 0.5;
 
	outP.x = outP.x;
	outP.y = (1-outP.y);
 
	// outP.x = outP.x * mWindow->getWidth();
	// outP.y = (1-outP.y) * mWindow->getHeight();

    //返回归一后的坐标
	screenPos.x = outP.x;
	screenPos.y = outP.y;

	return true;
}