Method BuildSbt

tests/framework/ray_tracing_objects.cpp:2323–2593

}

void Pipeline::BuildSbt() {
    // As of now, no function support if not using any ray generation shader
    assert(GetRayGenShaderGroupsCount() > 0);

    // Gather shader indices
    // ---
    // Used this as reference:
    // https://github.com/nvpro-samples/nvpro_core/blob/ba24b73e3a918adfe6ca932a6bf749a1d874d9b0/nvvk/sbtwrapper_vk.cpp#L81
    std::vector<uint32_t> ray_gen_group_handle_indices;
    std::vector<uint32_t> miss_group_handle_indices;
    std::vector<uint32_t> hit_group_handle_indices;

    uint32_t shader_i = 0;
    for (uint32_t ray_gen_i = 0; ray_gen_i < size32(ray_gen_shaders_); ++ray_gen_i) {
        ray_gen_group_handle_indices.emplace_back(shader_i++);
    }
    for (uint32_t miss_i = 0; miss_i < size32(miss_shaders_); ++miss_i) {
        miss_group_handle_indices.emplace_back(shader_i++);
    }
    for (uint32_t hit_i = 0; hit_i < (size32(hit_shaders_)); ++hit_i) {
        hit_group_handle_indices.emplace_back(shader_i++);
    }

    for (const Pipeline* lib : libraries_) {
        for (uint32_t ray_gen_i = 0; ray_gen_i < size32(lib->ray_gen_shaders_); ++ray_gen_i) {
            ray_gen_group_handle_indices.emplace_back(shader_i++);
        }
        for (uint32_t miss_i = 0; miss_i < size32(lib->miss_shaders_); ++miss_i) {
            miss_group_handle_indices.emplace_back(shader_i++);
        }
        for (uint32_t hit_i = 0; hit_i < (size32(lib->hit_shaders_)); ++hit_i) {
            hit_group_handle_indices.emplace_back(shader_i++);
        }
    }

    VkPhysicalDeviceRayTracingPipelinePropertiesKHR rt_pipeline_props = vku::InitStructHelper();
    test_.GetPhysicalDeviceProperties2(rt_pipeline_props);
    const uint32_t sbt_shader_size = rt_pipeline_props.shaderGroupHandleSize + shader_record_size_;
    const uint32_t sbt_shader_size_aligned = Align(sbt_shader_size, rt_pipeline_props.shaderGroupHandleAlignment);

    // Since every ray generation entry in the ray tracing shader headers buffer can be the start of the ray gen SBT,
    // they all have to be aligned to shaderGroupBaseAlignment (which may be smaller than the handle size)
    const VkDeviceSize ray_gen_shaders_sbt_entry_byte_size =
        GetRayGenShaderGroupsCount() * Align(sbt_shader_size, rt_pipeline_props.shaderGroupBaseAlignment);
    // For miss and closest hit shaders, we consider that the corresponding SBTs always start at the first miss/closest hit entry
    // => only it needs to be aligned to shaderGroupBaseAlignment,
    // and within miss/closes hit entries alignment is shaderGroupHandleAlignment
    const VkDeviceSize miss_shaders_sbt_entry_byte_size = GetMissShaderGroupsCount() * sbt_shader_size_aligned;
    const VkDeviceSize hit_shaders_sbt_entry_byte_size = GetHitShaderGroupsCount() * sbt_shader_size_aligned;
    VkDeviceSize sbt_buffer_size = ray_gen_shaders_sbt_entry_byte_size;
    sbt_buffer_size = Align<VkDeviceSize>(sbt_buffer_size, rt_pipeline_props.shaderGroupBaseAlignment);
    sbt_buffer_size += miss_shaders_sbt_entry_byte_size;
    sbt_buffer_size = Align<VkDeviceSize>(sbt_buffer_size, rt_pipeline_props.shaderGroupBaseAlignment);
    sbt_buffer_size += hit_shaders_sbt_entry_byte_size;

    // Allocate buffer to store SBT, and fill it with sbt_host_storage
    VkBufferCreateInfo sbt_buffer_info = vku::InitStructHelper();