Function regions

src/backend/opencl/kernel/regions.hpp:77–193

template<typename T>
void regions(Param out, Param in, const bool full_conn,
             const int n_per_thread) {
    using cl::Buffer;
    using cl::EnqueueArgs;
    using cl::NDRange;

    constexpr int THREADS_X = 16;
    constexpr int THREADS_Y = 16;

    auto kernels = getRegionsKernels<T>(full_conn, n_per_thread);

    const NDRange local(THREADS_X, THREADS_Y);

    const int blk_x = divup(in.info.dims[0], THREADS_X * 2);
    const int blk_y = divup(in.info.dims[1], THREADS_Y * 2);

    const NDRange global(blk_x * THREADS_X, blk_y * THREADS_Y);

    auto ilOp = kernels[0];
    auto ueOp = kernels[2];
    auto frOp = kernels[1];

    ilOp(EnqueueArgs(getQueue(), global, local), *out.data, out.info, *in.data,
         in.info);
    CL_DEBUG_FINISH(getQueue());

    int h_continue     = 1;
    Buffer* d_continue = bufferAlloc(sizeof(int));

    while (h_continue) {
        h_continue = 0;
        getQueue().enqueueFillBuffer(*d_continue, h_continue, 0, sizeof(int));
        ueOp(EnqueueArgs(getQueue(), global, local), *out.data, out.info,
             *d_continue);
        CL_DEBUG_FINISH(getQueue());
        getQueue().enqueueReadBuffer(*d_continue, CL_TRUE, 0, sizeof(int),
                                     &h_continue);
    }
    bufferFree(d_continue);

    // Now, perform the final relabeling.  This converts the equivalency
    // map from having unique labels based on the lowest pixel in the
    // component to being sequentially numbered components starting at
    // 1.
    int size = in.info.dims[0] * in.info.dims[1];

    compute::command_queue c_queue(getQueue()());

    // Wrap raw device ptr
    compute::context context(getContext()());
    compute::vector<T> tmp(size, context);
    clEnqueueCopyBuffer(getQueue()(), (*out.data)(), tmp.get_buffer().get(), 0,
                        0, size * sizeof(T), 0, NULL, NULL);

    // Sort the copy
    compute::sort(tmp.begin(), tmp.end(), c_queue);

    // Take the max element which is the number