Iphone检测每个手指和画线（使用cocos2d / openGL进行绘图）

Question

我了解多点触控事件的基本工作原理

1. 当一个文件触及视图/屏幕时，该视图将通过一组ccTouchesBegan收到UITouch。
2. UITouch将保留位置（CGPoint），并且每个手指都有唯一的位置。
3. 如果同时有多个手指触摸视图，则会向视图发送2 UITouch。
4. 有时候视图会收到ccTouchesBegan次UITouch次，ccTouchesBegan会被称为twise，每次手指触摸一个接一个。
5. 如果finger1正在移动，则视图将会收到ccTouchesMoved一个UITouch。

我的问题是如何用每个手指单独划线来画线，将1或2个手指放在屏幕上并为每个手指触摸开始/移动/结束画线？

以下代码仅在单次触摸时起作用，但对于多点触控，由于上述第3点和第4点，它不起作用。

正是这样的

-(void) ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    if ([touches count] > 0) {

        // handle multi touch
        UITouch *touch1 = [[touches allObjects] objectAtIndex:0];
        CGPoint touchLocation1 = [touch1 locationInView: [touch1 view]];
        touchLocation1 = [[CCDirector sharedDirector] convertToGL: touchLocation1];

        Edge *temEdge1 = (Edge*)[temEdges objectAtIndex:0];
        [[temEdge1 end] updateXY:touchLocation1];
        [[temEdge1 start] updateXY:touchLocation1];

        if ([touches count] > 1) {
            UITouch *touch2 = [[touches allObjects] objectAtIndex:1];
            CGPoint touchLocation2 = [touch2 locationInView: [touch2 view]];
            touchLocation2 = [[CCDirector sharedDirector] convertToGL: touchLocation2];

            Edge *temEdge2 = (Edge*)[temEdges objectAtIndex:1];
            [[temEdge2 end] updateXY:touchLocation2];
            [[temEdge2 start] updateXY:touchLocation2];

        }

    }
}

-(void) ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{

    if ([touches count] > 0) {

        // handle multi touch
        UITouch *touch1 = [[touches allObjects] objectAtIndex:0];
        CGPoint touchLocation1 = [touch1 locationInView: [touch1 view]];
        touchLocation1 = [[CCDirector sharedDirector] convertToGL: touchLocation1];

        Edge *temEdge1 = (Edge*)[temEdges objectAtIndex:0];
        [[temEdge1 end] updateXY:touchLocation1];


        if ([touches count] > 1) {
            UITouch *touch2 = [[touches allObjects] objectAtIndex:1];
            CGPoint touchLocation2 = [touch2 locationInView: [touch2 view]];
            touchLocation2 = [[CCDirector sharedDirector] convertToGL: touchLocation2];

            Edge *temEdge2 = (Edge*)[temEdges objectAtIndex:1];
            [[temEdge2 end] updateXY:touchLocation2];
        }

    }

}

-(void) ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    if ([touches count] > 0) {

        // handle multi touch
        UITouch *touch1 = [[touches allObjects] objectAtIndex:0];
        CGPoint touchLocation1 = [touch1 locationInView: [touch1 view]];
        touchLocation1 = [[CCDirector sharedDirector] convertToGL: touchLocation1];

        Edge *temEdge1 = (Edge*)[temEdges objectAtIndex:0];
        [[temEdge1 end] updateXY:touchLocation1];

        if ([touches count] > 1) {

            UITouch *touch2 = [[touches allObjects] objectAtIndex:1];
            CGPoint touchLocation2 = [touch2 locationInView: [touch2 view]];
            touchLocation2 = [[CCDirector sharedDirector] convertToGL: touchLocation2];

            Edge *temEdge2 = (Edge*)[temEdges objectAtIndex:1];
            [[temEdge2 end] updateXY:touchLocation2];
        }
    }

}
-(void)draw
{
    [super draw];
    glLineWidth(5.f);
    ccDrawColor4B(0, 0, 255, 255);
    for (Edge *temEdge in temEdges) {
        CGPoint start = [[temEdge start] toCCP];
        CGPoint end   = [[temEdge end] toCCP];
        ccDrawLine(start , end);
    }

}

Answer 1

您可以尝试将触摸位置的数组与不同的触摸相关联（类似于NSDictionary，UITouches作为键，NSArrays作为值）。然后，如果使用ccDrawLine方法，您可以使用draw或任何其他方式绘制这些行。只是不要忘记将这些数组存储在当前触摸结束的地方。