如何用 Cocos2d-iPhone 画线 [英] How to draw a line with Cocos2d-iPhone

问题描述

我试图通过完成简单的事情来掌握 Cocos2d.此时，我有一个场景，该场景有一个背景精灵和一个图层.我正在尝试使用 drawLine 绘制到图层上.这是我目前的尝试.

I'm trying to get to grips with Cocos2d by trying to accomplish simple things. At this point, I have a scene, that scene has a background sprite, and a Layer. I'm trying to draw onto the Layer using drawLine. Here's my current attempt.

@implementation MyLayer
-(id)init{
    self = [super init];
    if(self != nil){
        glColor4f(0.8, 1.0, 0.76, 1.0);  
        glLineWidth(2.0f);
        CocosNode *line = drawLine(10.0f, 100.0f,400.0f,27.0f);
        [self addChild:line z:1];
    }
    return self;
}
@end

这会产生错误空值没有被忽略，因为它应该是".所以很明显我做错了，但希望你能看到我的推理.

Which generates the error "void value not ignored as it ought to be". So obviously I'm doing it wrong, but hopefully you can see my reasoning.

我也试过了

-(id)init{
    self = [super init];
    if(self != nil){
        glColor4f(0.8, 1.0, 0.76, 1.0);  
        glLineWidth(2.0f);
        drawLine(10.0f, 100.0f,400.0f,27.0f);
    }
    return self;
}

这不会给我一个错误，但它也不起作用.我意识到我没有理解一些基本的东西，但是谁能引导我朝着正确的方向前进?

Which doesn't give me an error, but it doesn't work either. I realise I'm not understanding something fundamental, but can anyone steer me in the right direction?

推荐答案

来自cocos2d drawPrimitivesTest.m:

From the cocos2d drawPrimitivesTest.m:

- (void)draw {
  // ...

  // draw a simple line
  // The default state is:
  // Line Width: 1
  // color: 255,255,255,255 (white, non-transparent)
  // Anti-Aliased
  glEnable(GL_LINE_SMOOTH);
  ccDrawLine( ccp(0, 0), ccp(s.width, s.height) );

  // ...
}

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