OpenGLES 2.0由touchesMoved旋转

Question

我想使用touchesMoved方法在屏幕上旋转图像。 因此，如果我将手指从右侧移动到左侧，我想要我的手指 图像从左向右旋转。

这有可能吗？

Answer 1

找到解决方案！

- (void)handleDragFrom:(CGPoint)start to:(CGPoint)end
{
    [super handleDragFrom:start to:end];

    float rotationCenterX = self.player.position.x - (self.player.contentSize.width / 2);
    float rotationCenterY = self.player.position.y - (self.player.contentSize.height / 2);

    float dXStart = start.x - rotationCenterX;
    float dYStart = start.y - rotationCenterY;
    float radianStart = atan2(dYStart, dXStart);

    float dXEnd = end.x - rotationCenterX;
    float dYEnd = end.y - rotationCenterY;
    float radianEnd = atan2(dYEnd, dXEnd);

    float radian = GLKMathRadiansToDegrees(radianEnd - radianStart);

    self.player.rotation -= radian;
}

“开始”和“结束”是移动触摸给出的两点：

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [[event allTouches] anyObject];

    CGPoint end = [touch locationInView:self.view];
    CGPoint start = [touch previousLocationInView:self.view];

    [self.scene handleDragFrom:start to:end];
}