cocos2d 绘制虚线

//
//  XLDashedLine.h
//  XLDashedLine
//
//  Created by Richard Wei on 11-8-31.
//  Copyright 2011 Xinranmsn Labs. All rights reserved.
//

#import "cocos2d.h"

@interface XLDashedLine : CCNode {
    CGPoint _pStart, _pEnd;
    CGPoint _pStartScaled, _pEndScaled;
    
    float _width, _scaledWidth;
    float _dashLength, _dashLengthScaled;
    
    ccColor4F _color;
}

@property (nonatomic, assign) CGPoint pStart, pEnd;
@property (nonatomic, assign) float width;
@property (nonatomic, assign) ccColor4F color;
@property (nonatomic, assign) float dashLength;

+(id) lineWithPStart:(CGPoint)pStart 
                pEnd:(CGPoint)pEnd 
               width:(float)width 
               color:(ccColor4F)color 
          dashLength:(float)dashLength;

-(id) initWithPStart:(CGPoint)pStart 
                pEnd:(CGPoint)pEnd 
               width:(float)width 
               color:(ccColor4F)color 
          dashLength:(float)dashLength;

@end

//
//  XLDashedLine.m
//  XLDashedLine
//
//  Created by Richard Wei on 11-8-31.
//  Copyright 2011 Xinranmsn Labs. All rights reserved.
//

#import "XLDashedLine.h"


#define ccp2ccpr(__point__) ccp(__point__.x * CC_CONTENT_SCALE_FACTOR(), __point__.y * CC_CONTENT_SCALE_FACTOR())
#define ccpr2ccp(__point__) ccp(__point__.x / CC_CONTENT_SCALE_FACTOR(), __point__.y / CC_CONTENT_SCALE_FACTOR())
#define ccpr(__x__, __y__) ccp(__x__ * CC_CONTENT_SCALE_FACTOR(), __y__ * CC_CONTENT_SCALE_FACTOR())
#define sclr2sclrr(__scl__) ((__scl__) * CC_CONTENT_SCALE_FACTOR())


static ccColor4F ccc4F(float _r, float _g, float _b, float _a) {
    ccColor4F retColor = {_r, _g, _b, _a};
    return retColor;
}


/** 核心逻辑~ */
static inline void drawDashedLine(CGPoint origin, CGPoint destination, float dashLength) {
	float dx = destination.x - origin.x;
    float dy = destination.y - origin.y;
    float dist = sqrtf(dx * dx + dy * dy);
    
    float x = dx / dist * dashLength;
    float y = dy / dist * dashLength;
    
    CGPoint p2;
    
	glDisable(GL_TEXTURE_2D);
	glDisableClientState(GL_TEXTURE_COORD_ARRAY);
	glDisableClientState(GL_COLOR_ARRAY);
    glEnable(GL_LINE_SMOOTH);
    
    for (float i = 0.0f; i <= dist / dashLength * .5; i++) {
        p2.x = origin.x + x;
        p2.y = origin.y + y;
        ccVertex2F vertices[2] = {{origin.x, origin.y}, {p2.x, p2.y}};
        
        glVertexPointer(2, GL_FLOAT, 0, vertices);
        glDrawArrays(GL_LINES, 0, 2);
        
        origin.x += x * 2;
        origin.y += y * 2;
    }
    
    glDisable(GL_LINE_SMOOTH);
    glEnableClientState(GL_COLOR_ARRAY);
	glEnableClientState(GL_TEXTURE_COORD_ARRAY);
	glEnable(GL_TEXTURE_2D);
}

@implementation XLDashedLine

@synthesize pStart = _pStart;
@synthesize pEnd = _pEnd;
@synthesize width = _width;
@synthesize color = _color;
@synthesize dashLength = _dashLength;


+(id) lineWithPStart:(CGPoint)pStart 
                pEnd:(CGPoint)pEnd 
               width:(float)width 
               color:(ccColor4F)color 
          dashLength:(float)dashLength {
    return [[[self alloc] initWithPStart:pStart pEnd:pEnd width:width color:color dashLength:dashLength] autorelease];
}

-(id) init {
    if ((self = [super init])) {
        self.pStart = CGPointZero;
        self.pEnd = CGPointZero;
        self.width = .0f;
        self.color = ccc4F(.0f, .0f, .0f, .0f);
        self.dashLength = .0f;
    }
    return self;
}

-(id) initWithPStart:(CGPoint)pStart 
                pEnd:(CGPoint)pEnd 
               width:(float)width 
               color:(ccColor4F)color 
          dashLength:(float)dashLength {
    if ((self = [super init])) {
        self.pStart = pStart;
        self.pEnd = pEnd;
        self.width = width;
        self.color = color;
        self.dashLength = dashLength;
    }
    return self;
}

-(void) draw {
    glLineWidth(_scaledWidth);
    glColor4f(_color.r, _color.g, _color.b, _color.a);
    drawDashedLine(_pStartScaled, _pEndScaled, _dashLengthScaled);
    glLineWidth(1.0f);
    [super draw];
}

-(void) setPStart:(CGPoint)pStart {
    _pStart = pStart;
    _pStartScaled = ccp2ccpr(pStart);
}
-(void) setPEnd:(CGPoint)pEnd {
    _pEnd = pEnd;
    _pEndScaled = ccp2ccpr(pEnd);
}
-(void) setWidth:(float)width {
    _width = width;
    _scaledWidth = sclr2sclrr(width);
}
-(void) setDashLength:(float)dashLength {
    _dashLength = dashLength;
    _dashLengthScaled = sclr2sclrr(dashLength);
}

@end