CCSprite 上的白色叠加

问题描述

我想在我的 CCSprite 上应用某种颜色叠加".基本上，将其完全染成白色.

I'd like to apply some kind of "color overlay" over a CCSprite of mine. Basically, tint it completely white.

我可以使用

mySprite.color = ccc3(0,0,0);

我的精灵得到了黑色覆盖.然而，

And my sprite gets a black color overlay. However,

mySprite.color = ccc3(255,255,255);

自然不会影响我的精灵.相反，我的精灵保持原来的颜色.

Will, naturally, not affect my sprite. Instead, my sprite keeps its original color.

那么，还有其他方法可以实现吗?我真的负担不起为我所有的动画/精灵等制作白色版本.

So, is there another method to achieve such? I really can't afford to make a white version of all my animations/sprites etc.

推荐答案

您可以将此灰度代码转换为白色或任何颜色http://www.cocos2d-iphone.org/forum/topic/10227#post-58662

you can convert this grayscale code to do white or any color http://www.cocos2d-iphone.org/forum/topic/10227#post-58662

UIImage *convertToColor(UIImage *source, ccColor3B color)
{
    CGSize size = [source size];
    int width = size.width;
    int height = size.height;

    // the pixels will be painted to this array
    uint32_t *pixels = (uint32_t *) malloc(width * height * sizeof(uint32_t));

    // clear the pixels so any transparency is preserved
    memset(pixels, 0, width * height * sizeof(uint32_t));

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    // create a context with RGBA pixels
    CGContextRef context = CGBitmapContextCreate(pixels, width, height, 8, width * sizeof(uint32_t), colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedLast);

    // paint the bitmap to our context which will fill in the pixels array
    CGContextDrawImage(context, CGRectMake(0, 0, width, height), source.CGImage);

    for(int y = 0; y < height; y++) {
        for(int x = 0; x < width; x++) {
            uint8_t *rgbaPixel = (uint8_t *) &pixels[y * width + x];

            // convert to grayscale using recommended method: http://en.wikipedia.org/wiki/Grayscale#Converting_color_to_grayscale
            uint32_t gray = 0.3 * rgbaPixel[rgbaRED] + 0.59 * rgbaPixel[rgbaGREEN] + 0.11 * rgbaPixel[rgbaBLUE];

            // set the pixels to white
            if (gray > 0)
            {
                rgbaPixel[rgbaRED] = color.r;
                rgbaPixel[rgbaGREEN] = color.g;
                rgbaPixel[rgbaBLUE] = color.b;
            }
        }
    }

    // create a new CGImageRef from our context with the modified pixels
    CGImageRef image = CGBitmapContextCreateImage(context);

    // we're done with the context, color space, and pixels
    CGContextRelease(context);
    CGColorSpaceRelease(colorSpace);
    free(pixels);

    // make a new UIImage to return
    UIImage *resultUIImage = [UIImage imageWithCGImage:image];

    // we're done with image now too
    CGImageRelease(image);

    return resultUIImage;
}
CCSprite *colorSprite(CCSprite *sprite, ccColor3B color)
{
    UIImage *image = convertSpriteToImage(sprite);
    UIImage *white = convertToColor(image, color);
    CCTexture2D *texture = [[CCTexture2D alloc] initWithImage:white];
    CCSprite *newSprite = [CCSprite spriteWithTexture:texture];
    return newSprite;
}
UIImage *convertSpriteToImage(CCSprite *sprite)
{
    sprite.scale = 1.0f;
    sprite.position = ccp(sprite.contentSize.width / 2, sprite.contentSize.height / 2);

    CCRenderTexture *renderer = [CCRenderTexture renderTextureWithWidth:sprite.contentSize.width height:sprite.contentSize.height];
    [renderer begin];
    [sprite visit];
    [renderer end];

    return [UIImage imageWithData:[renderer getUIImageAsDataFromBuffer:kCCImageFormatPNG]];
}

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