Function main

examples/cpu/histogram.cpp:52–133

void populateBins(Bitmap& bmp, int *hist_array, const unsigned nbins, float *hist_cols);

int main(void)
{
    Bitmap bmp = createBitmap(IMGW, IMGH);
    /*
     * First Forge call should be a window creation call
     * so that necessary OpenGL context is created for any
     * other forge::* object to be created successfully
     */
    forge::Window wnd(DIMX, DIMY, "Histogram Demo");
    wnd.makeCurrent();

    forge::Image img(IMGW, IMGH, FG_RGBA, forge::u8);

    forge::Chart chart(FG_CHART_2D);

    /* set x axis limits to maximum and minimum values of data
     * and y axis limits to range [0, number of pixels ideally]
     * but practically total number of pixels as y range will skew
     * the histogram graph vertically. Therefore setting it to
     * 25% of total number of pixels */
    chart.setAxesLimits(0, 1, 0, IMGW*IMGH/(float)(NBINS/4.0));

    /*
     * Create histogram object specifying number of bins
     */
    forge::Histogram hist = chart.histogram(NBINS, forge::s32);
    /*
     * Set histogram colors
     */
    hist.setColor(FG_YELLOW);

    GfxHandle* handles[3];

    createGLBuffer(&handles[0], img.pixels(), FORGE_IMAGE_BUFFER);
    createGLBuffer(&handles[1], hist.vertices(), FORGE_VERTEX_BUFFER);
    createGLBuffer(&handles[2], hist.colors(), FORGE_VERTEX_BUFFER);

    do {
        /*
         * generate image, and prepare data to pass into
         * Histogram's underlying vertex buffer object
         */
        kernel(bmp);

        copyToGLBuffer(handles[0], (ComputeResourceHandle)bmp.ptr, img.size());

        //forge::copy(img, (const void*)bmp.ptr);

        /* copy your data into the vertex buffer object exposed by
         * forge::Histogram class and then proceed to rendering.
         * To help the users with copying the data from compute
         * memory to display memory, Forge provides copy headers
         * along with the library to help with this task
         */
        std::vector<int> histArray(NBINS, 0);
        std::vector<float> colArray(3*NBINS, 0.0f);
        populateBins(bmp, histArray.data(), NBINS, colArray.data());