compute_histogram()

std::array< uint32_t, 256 > MayaFlux::Yantra::VisionAnalyzer::compute_histogram ( const std::shared_ptr< Core::VKImage > &  image, uint32_t  w, uint32_t  h  )

private

Dispatch otsu_histogram.comp over image, zeroing the buffer first.

Definition at line 331 of file VisionAnalyzer.cpp.

{
    if (!m_histogram_ctx) {
        m_histogram_ctx = std::make_shared<TextureExecutionContext>(
            GpuComputeConfig {
                .shader_path = "otsu_histogram.comp.spv",
                .workgroup_size = { 8, 8, 1 },
                .push_constant_size = sizeof(HistogramPC) },
            Portal::Graphics::ImageFormat::RGBA8,
            TextureExecutionContext::OutputMode::SCALAR,
            1,
            std::vector<GpuBufferBinding> {
                { .set = 0, .binding = 3, .direction = GpuBufferBinding::Direction::INPUT_OUTPUT, .element_type = GpuBufferBinding::ElementType::UINT32 } },
            GpuBufferBinding::ElementType::IMAGE_STORAGE);
    }
 
    m_histogram_ctx->ensure_shared_buffer(0, 3, 768, GpuBufferBinding::ElementType::UINT32,
        Portal::Graphics::BufferUsageHint::COMPUTE);
 
    const std::array<uint32_t, 768> zero {};
    m_histogram_ctx->upload_shared_raw(0, 3, reinterpret_cast<const uint8_t*>(zero.data()), sizeof(zero));
 
    m_histogram_ctx->stage_image(image);
    m_histogram_ctx->set_push_constants(HistogramPC { .width = w, .height = h, .channels = 0 });
    m_histogram_ctx->set_output_dimensions(w, h);
 
    auto& foundry = Portal::Graphics::get_shader_foundry();
    const auto fence = m_histogram_ctx->dispatch_async({});
    m_histogram_ctx->clear_output_dimensions();
    foundry.wait_for_fence(fence);
    foundry.release_fence(fence);
 
    std::array<uint32_t, 256> histogram {};
    m_histogram_ctx->download_shared(0, 3, histogram.data(), sizeof(histogram));
    return histogram;
}

References MayaFlux::Portal::Graphics::COMPUTE, fence, MayaFlux::Portal::Graphics::get_shader_foundry(), h, image, MayaFlux::Portal::Graphics::GpuBufferBinding::IMAGE_STORAGE, MayaFlux::Portal::Graphics::GpuBufferBinding::INPUT_OUTPUT, m_histogram_ctx, MayaFlux::Yantra::TextureExecutionContext::SCALAR, MayaFlux::Portal::Graphics::GpuComputeConfig::shader_path, and MayaFlux::Portal::Graphics::GpuBufferBinding::UINT32.

Referenced by measure_appearance().

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