更新iPad Retina的OpenGL ES Touch Detection（光线追踪）？

Question

我有我正在使用的光线跟踪下面的代码。该代码可以在非视网膜iPad上成功运行，但不能在视网膜iPad上运行。触摸被检测到，但是转换后的点向左和向下偏离应该位置。任何人都可以建议我如何更新下面以适应视网膜屏幕？

- (void)handleTap: (UITapGestureRecognizer *)recognizer 
{ 

    CGPoint tapLoc = [recognizer locationInView:self.view]; 

    bool testResult; 

    GLint viewport[4]; 
    glGetIntegerv(GL_VIEWPORT, viewport); 

    float uiKitOffset = 113; //Need to factor in the height of the nav bar + the height of the tab bar at the bottom in the storyboard. 

    GLKVector3 nearPt = GLKMathUnproject(GLKVector3Make(tapLoc.x, (tapLoc.y-1024+uiKitOffset)*-1, 0.0), modelViewMatrix, projectionMatrix, &viewport[0] , &testResult); 

    GLKVector3 farPt = GLKMathUnproject(GLKVector3Make(tapLoc.x, (tapLoc.y-1024+uiKitOffset)*-1, 1.0), modelViewMatrix, projectionMatrix, &viewport[0] , &testResult); 

    farPt = GLKVector3Subtract(farPt, nearPt); 

    for (Object * Object in self.objectArray) { 

     ... 

} 

Answer 1

上[UIScreen mainScreen]简单地乘以tapLoc的X和Y .scale 和1024 * [UIScreen mainScreen] .scale或视替换[3]

我觉得是这样的：

- (void)handleTap: (UITapGestureRecognizer *)recognizer 
{ 

    CGPoint tapLoc = [recognizer locationInView:self.view]; 
    tapLoc.x *= [UIScreen mainScreen].scale; 
    tapLoc.y *= [UIScreen mainScreen].scale; 

    bool testResult; 

    GLint viewport[4]; 
    glGetIntegerv(GL_VIEWPORT, viewport); 

    float uiKitOffset = 113; //Need to factor in the height of the nav bar + the height of the tab bar at the bottom in the storyboard. 

    GLKVector3 nearPt = GLKMathUnproject(GLKVector3Make(tapLoc.x, (tapLoc.y-viewport[3]+uiKitOffset)*-1, 0.0), modelViewMatrix, projectionMatrix, &viewport[0] , &testResult); 

    GLKVector3 farPt = GLKMathUnproject(GLKVector3Make(tapLoc.x, (tapLoc.y-viewport[3]+uiKitOffset)*-1, 1.0), modelViewMatrix, projectionMatrix, &viewport[0] , &testResult); 

    farPt = GLKVector3Subtract(farPt, nearPt); 

    .... 
}