我正在尝试使用 OpenGL ES 和 ffmpeg 从图像创建视频,但是在 iPad(4.3) 上我在 glReadPixels
-(NSData *) glToUIImage {
int numberOfComponents = NUMBER_OF_COMPONENTS; //4
int width = PICTURE_WIDTH;
int height = PICTURE_HEIGHT;
NSInteger myDataLength = width * height * numberOfComponents;
NSMutableData * buffer= [NSMutableData dataWithLength :myDataLength];
[self checkForGLError];
GLenum type = NUMBER_OF_COMPONENTS == 3 ? GL_RGB : GL_RGBA; //RGBA
glReadPixels(0, 0, width, height, type, GL_UNSIGNED_BYTE, [buffer mutableBytes]); //EXC_BAD_ACCESS here
return buffer;
}
它在 iPhone 4 (4.3) 和 iPod Touch 上工作,但在 iPhone 3G(3.0) 和 iPad(4.3) 上有问题。你能帮我解决这个问题吗?
同样在 iPhone 3G(3.0) 和 iPad(4.3) 上,我遇到了视频问题 - 前 5-20 个视频帧有垃圾。也许优化问题?还是架构?
已编辑 堆栈:
#0 0x33be3964 in void BlockNxN<64ul, 16ul, 1, BLOCK_CONVERTER_NULL_32>(unsigned long, int, int, unsigned long, int, int, unsigned int, unsigned int, unsigned int, unsigned int) ()
#1 0x33be1c76 in glrBIFDetile ()
#2 0x33b586b2 in sgxGetImage(SGXImageReadParams const*) ()
#3 0x33b50d38 in gldReadPixels ()
#4 0x31813e16 in glReadPixels_Exec ()
#5 0x31e3c518 in glReadPixels ()
最佳答案
我想通了!!!
我已经解决这个问题大约两周了。
您必须在 [(EAGLView *)eagleView presentFramebuffer];
之前调用 glReadPixels()
因此在读取像素之前必须绑定(bind) colorRenderbuffer。 final方法列表:
int numberOfComponents = NUMBER_OF_COMPONENTS;
int width = PICTURE_WIDTH;
int height = PICTURE_HEIGHT;
NSInteger myDataLength = width * height * numberOfComponents;
NSMutableData * buffer= [NSMutableData dataWithLength :myDataLength];
glBindRenderbuffer(GL_RENDERBUFFER_OES, [((EAGLView *)eagleView) colorRenderbuffer]);
[self checkForGLError];
glPixelStorei(GL_PACK_ALIGNMENT, 4); // force 4 byte alignment
glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, [buffer mutableBytes]);
return buffer;
关于iphone - OpenGL ES glReadPixels exc_bad_access,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/8308993/