使用C ++和目标C从原始图像复制数据

Question

I'm getting a callback from a library that gives me a raw image which is 640*480*4 R8G8B8A8

I did copying it into another buffer then I try to skip the 4th buffer because my framework works only with R8G8B8

I tried to debug and see the bytes in the variable d, but the bytes are all garbage.

-(void)onRawImageBuffer:(NSData * _Nonnull)data withWidth:(int)width andHeight:(int)height andBytesPerPixel:(int)bytesPerPixel;
{
    NSUInteger len = [data length];



    memcpy(m_CopyData, [data bytes], len);


    for(int i =0; i < 640*480*3;i++)
    {
        if ( i%4 == 3 )
            continue;
        else{
            m_FrameData[i] = m_CopyData[i];

        }
    }

    NSData* d = [NSData dataWithBytes:(const void *)m_FrameData length:640*480*3];


    Input::SensorInput::getSingleton()->setVideoData( m_FrameData );



}

Answer 1

1. You are hard coding width and height;
2. Your loop must still go to width * height * 4 ;
3. You have not allocated m_FrameData ;
4. You are not considering bytesPerPixel ;
5. continue; still advance i by one, you must use two indices;
6. It's very inefficient, better copy RGB together, skip A, advance src pointer by 4 and dst pointer by 3.