如何在cocos2d中基于alpha进行纹理轮廓?我有一个纹理,我希望无处不在的alpha从0到非零或类似的东西画一条线,所以它只是勾勒出一切.
解决方法
我通过将图像复制到内存然后使用它来解决它:
我使用了渲染纹理,但是如果你不想使用它,我添加了关于要改变的内容的注释
我使用了渲染纹理,但是如果你不想使用它,我添加了关于要改变的内容的注释
// Get the size of the render texture,change to size of screen if you don't // use render texture CGSize s = RenderedWall.sprite.texture.contentSizeInPixels; int tx = s.width; int ty = s.height; int bitsPerComponent = 8; int bytesPerPixel = (bitsPerComponent * 4)/8; int bytesPerRow = bytesPerPixel * tx; NSInteger myDataLength = bytesPerRow * ty; NSMutableData *buffer = [[NSMutableData alloc] initWithCapacity:myDataLength]; Byte *bytes = (Byte *)[buffer mutableBytes]; glReadPixels(0,tx,ty,GL_RGBA,GL_UNSIGNED_BYTE,bytes); NSMutableData *newBuffer = [[NSMutableData alloc] initWithBytes:bytes length:myDataLength]; Byte *newBytes = (Byte *)[newBuffer mutableBytes]; // free the render texture,remove this if you don't use one [RenderedWall end]; for(int x = 0; x < tx; x++) { for(int y = 0; y < ty; y++) { int idx = y * bytesPerRow + x * bytesPerPixel + 3; int w = 1; if(bytes[idx] <= 254) { bool ok = false; for(int nx = -w; nx <= w; nx++) { for(int ny = -w; ny <= w; ny++) { if(x + nx < 0 || y + ny < 0 || x + nx >= tx || y + ny >= ty) continue; if(bytes[idx + nx * bytesPerPixel + ny * bytesPerRow] == 255) { ok = true; break; } } } if(ok) { newBytes[idx - 3] = 0; newBytes[idx - 2] = 0; newBytes[idx - 1] = 0; newBytes[idx] = 255; } } } } CCTexture2D *texture = [[CCTexture2D alloc] initWithData:newBytes pixelFormat:kCCTexture2DPixelFormat_RGBA8888 pixelsWide:tx pixelsHigh:ty contentSize:RenderedWall.sprite.texture.contentSize]; // The outlined sprite comes here. If you don't use render texture,you need to add clear here. CCSprite *RenderedWallSprite = [CCSprite spriteWithTexture:texture];
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