Draw line or rectangle on cocos2d Layer

Can you let me know what is the best way to draw a line or rectangle on a scene layer using Cocos2d ios4 iphone.

So far have tried Texture2d, but it is more like a paint brush and is not so good. Tried drawing a line using draw method, but previous line disappears on drawing another line.

Basically want to draw multiple horizontal ,vertical, oblique beams. Please suggest. Any code would help a lot .

The code to draw using texture is below:

CGPoint start = edge.start;
            CGPoint end = edge.end;
            // begin drawing to the render texture
            [target begin];

            // for extra points, we'll draw this smoothly from the last position and vary the sprite's
            // scale/rotation/offset
            float distance = ccpDistance(start, end);
            if (distance > 1)
            {
                int d = (int)distance;
                for (int i = 0; i < d; i++)
                {
                    float difx = end.x - start.x;
                    float dify = end.y - start.y;
                    float delta = (float)i / distance;
                    [brush setPosition:ccp(start.x + (difx * delta), start.y + (dify * delta))];
                    [brush setScale:0.3];
                    // Call visit to draw the brush, don't call draw..
                    [brush visit];
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            }
            // finish drawing and return context back to the screen
            [target end];

The rendering is not good esp. with oblique lines as the scaling affects the quality.

Cheers

You could create a separate layer and call the draw method like this:

-(void) draw
{
    CGSize s = [[Director sharedDirector] winSize];

    drawCircle( ccp(s.width/2,  s.height/2), circleSize, 0, 50, NO);

It's for a circle but the principle is the same. This is from a project I made a while back and it worked then. Don't know if anything has changed since.

You need to add draw method to your layer:

-(void) draw {
    // ...
}

Inside it you can use some openGL like functions and cocos2d wrapper methods for openGL.

Hint: other methods can be called inside draw method. But keep in mind that using other name for method containing openGL instructions, that's not called inside draw mentioned above simply won't work. Even when called from update method or other method used by scheduleUpdate selector.

So you will end up with something like this:

-(void) draw {
    glEnable(GL_LINE_SMOOTH);
    glColor4ub(255, 0, 100, 255);
    glLineWidth(4);
    CGPoint verts[] = { ccp(0,200), ccp(300,200) };
    ccDrawLine(verts[0], verts[1]);

    [self drawSomething];
    [self drawSomeOtherStuffFrom:ccp(a,b) to:ccp(c,d)];

    [someObject doSomeDrawingAsWell];
}

For more information check out cocos2d-iphone programming guide :

http://www.cocos2d-iphone.org/wiki/doku.php/prog_guide:draw_update?s[]=schedule#draw