Opengl ES 2.0-使用GLKit而不是Opengl API加载PNG

Question

我有一段代码，它使用glTexImage2D加载纹理，如下所示：

// to test texturing
CGImageRef imageRef = [[UIImage imageNamed:@"Blob.png"] CGImage];
int width = CGImageGetWidth(imageRef);
int height = CGImageGetHeight(imageRef);
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);
glActiveTexture(GL_TEXTURE0);
glGenTextures(1, &texId);
glBindTexture(GL_TEXTURE_2D, texId);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); 
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData);
glBindTexture(GL_TEXTURE_2D, 0);

我用这个替换了代码，代码没有抛出任何错误，而是显示了一个黑色图像。

NSError *error;
GLKTextureInfo *texture = [GLKTextureLoader textureWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"Blob.png" ofType:Nil]
                                                               options:Nil
                                                                 error:&error]; assert(!error);
//bind the texture to texture unit 0
glActiveTexture(GL_TEXTURE0 + 0);
glBindTexture(texture.target, texture.name);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glEnable(texture.target);
glBindTexture(GL_TEXTURE_2D, 0);

可能是什么问题？

我要移植的项目位于https://github.com/glman74/simpleFBO

Answer 1

pathForResource:@"Blob.png"类型：无

应该是pathForResource:@"Blob"类型：@"png"

大多数时候，如果nil

Answer 2

我就是这样解决的：

这是OpenGL初始化代码

NSError *error;
GLKTextureInfo *texture = [GLKTextureLoader
     textureWithContentsOfFile:
        [[NSBundle mainBundle] pathForResource:@"Blob.png" ofType:Nil]
     options:Nil
     error:&error];

这在渲染方法中进行，在本例中为glkView:drawInRect:

glBindTexture(GL_TEXTURE_2D, 0);