colorType type = RGB; // support GRAY, RGB or RGBA
    glImageDevice glh(imageWidth,imageHeight,type, windowWidth, windowHeight,windowName);
    // ::::::::::::::
    // cudaMalloc( and cudaMemcpy )
    // ::::::::::::::
    // Set device memory ptr. of showed image
    glh.setGlobalMemoryPtr((void *)gmem_RGBA);
    while (!glh.isClosed()) {
        // ::::::::::::::
        // GPU computing
        // ::::::::::::::
        // RGB to RGBA (CUDA does not support 3 components/pixel)
        // If you show RGB image, you must call RGB2RGBA func. or write CUDA code for RGBA image
        glImageDevice::RGB2RGBA(gmem_RGBA, gmem_RGB, imageWidth, imageHeight); 
        glh.show();
    }