转换纹理中的UIImage

问题描述

在我的opengl项目中，我需要在纹理中转换UIImage;这样做的方法是什么？
你能帮助我吗？

In my opengl project I need to convert an UIImage in texture; what's the way to do it?Can you help me?

推荐答案

我没有测试以下但我将分3步拆分转换：

I haven't test the following but i will decompose the conversion in 3 steps:

1. 提取图片信息：

1. Extract info for your image:

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

分配 textureData 以上属性：

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);

设置纹理：

Set-up your texture:

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：

阅读这个啧啧;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。

Read this tut; everything is explained from the conversion of one image to a texture and applying a texture in an iOS environment.

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