iPhone OpenGLES视频纹理

Question

i know that apple offers a sample called GLCameraRipple which is using CVOpenGLESTextureCacheCreateTextureFromImage to achieve this. But when i changed to glTexImage2D, it displays nothing, what's wrong with my code?

if (format == kCVPixelFormatType_32BGRA) {
CVPixelBufferRef pixelBuf = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(pixelBuf, 0);
void *baseaddress = CVPixelBufferGetBaseAddress(pixelBuf);

glGenTextures(1, &textureID);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, textureID);

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, baseaddress);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );

CVPixelBufferUnlockBaseAddress(pixelBuf, 0);
}

thank you very much for any help!

Answer 1

There are a couple of problems here. First, the GLCameraRipple example was built to take in YUV camera data, not BGRA. Your above code is only uploading one texture of BGRA data, rather than the separate Y and UV planes expected by the application. It uses a colorspace conversion shader to merge these planes as a first stage, and that needs the YUV data to work.

Second, you are allocating a new texture for each uploaded frame, which is a really bad idea. This is particularly bad if you don't delete that texture when done, because you will chew up resources this way. You should allocate a texture once for each plane you'll upload, then keep that texture around as you upload each video frame, deleting it only when you're done processing video.

You'll either need to rework the above to upload the separate Y and UV planes, or remove / rewrite their color processing shader. If you go the BGRA route, you'll also need to be sure that the camera is now giving you BGRA frames instead of YUV ones.