转换纹理中的UIImage

Question

在我的opengl项目中,我需要在纹理中转换UIImage; 这是怎么做的？你能帮助我吗？

Answer 1

我没有测试以下但我将分3步拆分转换:

1. 提取图片信息:

   UIImage* image = [UIImage imageNamed:@"imageToApplyAsATexture.png"];
   CGImageRef imageRef = [image CGImage];
   int width = CGImageGetWidth(imageRef);
   int height = CGImageGetHeight(imageRef);
   

2. textureData使用以上属性分配a :

   GLubyte* textureData = (GLubyte *)malloc(width * height * 4); // if 4 components per pixel (RGBA)
   
   CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
   NSUInteger bytesPerPixel = 4;
   NSUInteger bytesPerRow = bytesPerPixel * width;
   NSUInteger bitsPerComponent = 8;  
   CGContextRef context = CGBitmapContextCreate(textureData, width, height,
                                                bitsPerComponent, bytesPerRow, colorSpace,
                                                kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
   
   CGColorSpaceRelease(colorSpace);
   
   CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
   CGContextRelease(context);
   

3. 设置你的纹理:

   GLuint textureID;    
   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
   glGenTextures(1, &textureID);
   
   glBindTexture(GL_TEXTURE_2D, textureID);
   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData);
   

编辑:

读这个啧啧 ; 一切都是从一个图像转换为纹理并在iOS环境中应用纹理来解释的.