CODEWITHSUNDEEP
iosobjective-csprite-kit
DivideByZer0
DivideByZer0

Reputation: 737

Drawing sprites programatically for sprite kit with alpha channel?

I'm trying to prototype an app for sprite kit, and it would be advantageous to me to be able to draw the sprites I need programatically for now, and then make actual sprites later. I've made a rough circle, and when I convert to a UIImage (or CGImage) using renderInContext, it shows up on the sprite view with a black background, ignoring the alpha channel, apparently. If I add the UIImage to a regular view as a UIImageView, the alpha channel is rendered properly. I was wondering what I'm doing wrong, or if theres' a workaround for this.

float rockSize = 100;

UIView* drawingView = [[UIView alloc] initWithFrame:CGRectMake(0,0,100,100)];
drawingView.backgroundColor = [UIColor clearColor];

CALayer* circleLayer = [CALayer layer];
circleLayer.frame = CGRectMake(0,0,rockSize,rockSize);
circleLayer.backgroundColor = [Utils getTiledColorFromColor:[UIColor purpleColor]].CGColor;
circleLayer.cornerRadius = rockSize/2.0;
circleLayer.masksToBounds = YES;

[drawingView.layer addSublayer:circleLayer];

UIGraphicsBeginImageContextWithOptions(CGSizeMake(rockSize, rockSize), NO, [UIScreen mainScreen].scale);
CGContextSetFillColorWithColor(UIGraphicsGetCurrentContext(), [UIColor clearColor].CGColor);
CGContextFillRect(UIGraphicsGetCurrentContext(), CGRectMake(0,0,rockSize,rockSize));
[drawingView.layer renderInContext: UIGraphicsGetCurrentContext()];

UIImage *layerImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

SKSpriteNode *rockNode = [SKSpriteNode spriteNodeWithTexture:[SKTexture textureWithImage:layerImage]];
CGPoint position = CGPointMake(200,100);
rockNode.position = position;

[self addChild:rockNode];

Upvotes: 1

Views: 1727

Answers (1)

yurish
yurish

Reputation: 1535

Such an affect when you see black view background frequently happens when the view has opaque property incorrectly set to YES without actually being opaque (usually this happens when the view is created programmatically, opaque = YES is default).

You can fix this for example by setting opaque to NO.

Upvotes: 3

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