cocos2d ccDrawPoly崩潰

Question

我試圖用ccDrawPoly來創建一些隨機看起來像小行星的多邊形。要做到這一點，我寫了一個簡單的函數，它在段中繪製一個圓圈（隨機化每次迭代的圓弧半徑）以創建一種「顛簸」的多邊形。頂點被存儲在一個NSMutableArray，然後提供給ccDrawPolygon（代碼如下）：

float maxRadiusVariation = self.radius * 0.2; // 20% of radius 
float cx = self.radius, cy = self.radius; 
int minSegmentAngle = 5; 
int maxSegmentAngle = 45; 
int angle = 0; 

while(angle < 360) 
{ 
    float newRadius = self.radius/2 + rand()%(int)maxRadiusVariation; 

    float x = cx + (cos(CC_DEGREES_TO_RADIANS(angle)) * newRadius); 
    float y = cy + (sin(CC_DEGREES_TO_RADIANS(angle)) * newRadius); 

    [vertices addObject:[NSArray arrayWithObjects:[NSNumber numberWithFloat:x], [NSNumber numberWithFloat:y], nil]]; 

    int angleIncrement = minSegmentAngle + rand()%maxSegmentAngle; 
    angle += angleIncrement; 
} 

的cocos2d上調用繪製內部崩潰。我相信我的問題可能是如何，我抓住了多邊形頂點了我的NSMutableArray緩存，並試圖繪製出來：

CGPoint cgVertices[[vertices count]]; 

    for(int i = 0; i < [vertices count]; i++) 
    { 
     NSArray *vertex = [vertices objectAtIndex:i]; 
     float x = [[vertex objectAtIndex:0] floatValue]; 
     float y = [[vertex objectAtIndex:1] floatValue]; 
     cgVertices[i] = ccp(x, y); 
    } 
    ccDrawPoly(cgVertices, [vertices count], YES); 

對於位的進一步的信息，我已經包含了頂點數組的例子cocos2d崩潰之前的內容。爲了使它更容易可視化，我添加了一個我創建的圖形（藍色像素代表圓心，白色像素是頂點，紅色線是連接它們的直線）。

http://nial.me/output.png

(
     (
     93, 
     60 
    ), 
     (
     "96.25231", 
     "76.90473" 
    ), 
     (
     "91.17692", 
     78 
    ), 
     (
     "83.78063", 
     "81.41218" 
    ), 
     (
     "78.77886", 
     "95.3179" 
    ), 
     (
     "68.77309", 
     "98.00043" 
    ), 
     (
     44, 
     "87.71281" 
    ), 
     (
     "34.08406", 
     "87.79144" 
    ), 
     (
     "26.45318", 
     "81.78556" 
    ), 
     (
     "22.51079", 
     "70.74986" 
    ), 
     (
     "23.02254", 
     "61.29128" 
    ), 
     (
     "27.64341", 
     "44.21864" 
    ), 
     (
     "30.8436", 
     "37.22053" 
    ), 
     (
     "52.57661", 
     "27.84579" 
    ), 
     (
     "62.44148", 
     "25.08526" 
    ), 
     (
     "73.42231", 
     "29.853" 
    ), 
     (
     "84.13467", 
     "37.49406" 
    ), 
     (
     "89.13047", 
     "49.39737" 
    ) 
) 

Answer 1

你繪製方法繪製之外？如果你是，下面的解釋可能會有所幫助。

您不能在CCNode繪圖函數外使用ccDrawPoly。 注意它在大寫狀態'不要在你的方法之外繪製你的東西'。在CCNode的繪製方法的以下定義中。在cocos2d-IOS ccDrawPoly的

// This is CCNode's draw method

-(void) draw 
{ 
     // override me 
     // Only use this function to draw your stuff. 
     // DON'T draw your stuff outside this method 
} 

實施例：ActionsTest.m

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

    float x = winSize.width*2 - 100; 
    float y = winSize.height; 

    CGPoint vertices[] = { ccp(5,5), ccp(x-5,5), ccp(x-5,y-5), ccp(5,y-5) }; 
    ccDrawPoly(vertices, 4, YES); 
} 

來源：Draw and Update Reference