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# Copyright (c) 2021-2024, NVIDIA CORPORATION. All rights reserved.
#
# SPDX-License-Identifier: Apache-2.0
#
# Licensed under the Apache License, Version 2.0 the "License";
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
get_filename_component(FOLDER_NAME ${CMAKE_CURRENT_LIST_DIR} NAME)
get_filename_component(PARENT_DIR ${CMAKE_CURRENT_LIST_DIR} PATH)
get_filename_component(CATEGORY_NAME ${PARENT_DIR} NAME)
add_sample_with_tags(
ID ${FOLDER_NAME}
CATEGORY ${CATEGORY_NAME}
AUTHOR "Sascha Willems"
NAME "HPP Dynamic uniform buffers"
DESCRIPTION "Demonstrates the use of dynamic offsets into one single uniform buffers for rendering multiple objects, using vulkan.hpp"
SHADER_FILES_GLSL
"dynamic_uniform_buffers/glsl/base.vert"
"dynamic_uniform_buffers/glsl/base.frag"
SHADER_FILES_HLSL
"dynamic_uniform_buffers/hlsl/base.vert.hlsl"
"dynamic_uniform_buffers/hlsl/base.frag.hlsl")
@@ -0,0 +1,27 @@
////
- Copyright (c) 2019-2023, The Khronos Group
-
- SPDX-License-Identifier: Apache-2.0
-
- Licensed under the Apache License, Version 2.0 the "License";
- you may not use this file except in compliance with the License.
- You may obtain a copy of the License at
-
- http://www.apache.org/licenses/LICENSE-2.0
-
- Unless required by applicable law or agreed to in writing, software
- distributed under the License is distributed on an "AS IS" BASIS,
- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- See the License for the specific language governing permissions and
- limitations under the License.
-
////
:pp: {plus}{plus}
= HPP Dynamic Uniform Buffers
ifdef::site-gen-antora[]
TIP: The source for this sample can be found in the https://github.com/KhronosGroup/Vulkan-Samples/tree/main/samples/api/hpp_dynamic_uniform_buffers[Khronos Vulkan samples github repository].
endif::[]
NOTE: A transcoded version of the API sample https://github.com/KhronosGroup/Vulkan-Samples/tree/main/samples/api/dynamic_uniform_buffers[Dynamic Uniform buffers] that illustrates the usage of the C{pp} bindings of Vulkan provided by vulkan.hpp.
@@ -0,0 +1,414 @@
/* Copyright (c) 2021-2025, NVIDIA CORPORATION. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 the "License";
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Demonstrates the use of dynamic uniform buffers, using vulkan.hpp
*
* Instead of using one uniform buffer per-object, this example allocates one big uniform buffer
* with respect to the alignment reported by the device via minUniformBufferOffsetAlignment that
* contains all matrices for the objects in the scene.
*
* The used descriptor type vk::DescriptorType::eUniformBufferDynamic then allows to set a dynamic
* offset used to pass data from the single uniform buffer to the connected shader binding point.
*/
#include "hpp_dynamic_uniform_buffers.h"
#include <benchmark_mode/benchmark_mode.h>
#include <iostream>
#include <random>
HPPDynamicUniformBuffers::HPPDynamicUniformBuffers()
{
title = "HPP Dynamic uniform buffers";
}
HPPDynamicUniformBuffers ::~HPPDynamicUniformBuffers()
{
if (has_device() && get_device().get_handle())
{
if (ubo_data_dynamic.model)
{
aligned_free(ubo_data_dynamic.model);
}
vk::Device device = get_device().get_handle();
// Clean up used Vulkan resources
// Note : Inherited destructor cleans up resources stored in base class
device.destroyPipeline(pipeline);
device.destroyPipelineLayout(pipeline_layout);
device.destroyDescriptorSetLayout(descriptor_set_layout);
}
}
// Wrapper functions for aligned memory allocation
// There is currently no standard for this in C++ that works across all platforms and vendors, so we abstract this
void *HPPDynamicUniformBuffers::aligned_alloc(size_t size, size_t alignment)
{
void *data = nullptr;
#if defined(_MSC_VER) || defined(__MINGW32__)
data = _aligned_malloc(size, alignment);
#else
int res = posix_memalign(&data, alignment, size);
if (res != 0)
{
data = nullptr;
}
#endif
return data;
}
void HPPDynamicUniformBuffers::aligned_free(void *data)
{
#if defined(_MSC_VER) || defined(__MINGW32__)
_aligned_free(data);
#else
free(data);
#endif
}
bool HPPDynamicUniformBuffers::prepare(const vkb::ApplicationOptions &options)
{
assert(!prepared);
if (HPPApiVulkanSample::prepare(options))
{
prepare_camera();
generate_cube();
prepare_uniform_buffers();
descriptor_set_layout = create_descriptor_set_layout();
pipeline_layout = get_device().get_handle().createPipelineLayout({.setLayoutCount = 1, .pSetLayouts = &descriptor_set_layout});
pipeline = create_pipeline();
descriptor_pool = create_descriptor_pool();
descriptor_set = vkb::common::allocate_descriptor_set(get_device().get_handle(), descriptor_pool, descriptor_set_layout);
update_descriptor_set();
build_command_buffers();
prepared = true;
}
return prepared;
}
bool HPPDynamicUniformBuffers::resize(const uint32_t width, const uint32_t height)
{
HPPApiVulkanSample::resize(width, height);
update_uniform_buffers();
return true;
}
void HPPDynamicUniformBuffers::build_command_buffers()
{
vk::DeviceSize offset = 0;
std::array<vk::ClearValue, 2> clear_values = {default_clear_color, vk::ClearDepthStencilValue{0.0f, 0}};
vk::RenderPassBeginInfo render_pass_begin_info{.renderPass = render_pass,
.renderArea = {{0, 0}, extent},
.clearValueCount = static_cast<uint32_t>(clear_values.size()),
.pClearValues = clear_values.data()};
for (size_t i = 0; i < draw_cmd_buffers.size(); ++i)
{
render_pass_begin_info.framebuffer = framebuffers[i];
vk::CommandBuffer command_buffer = draw_cmd_buffers[i];
command_buffer.begin(vk::CommandBufferBeginInfo());
command_buffer.beginRenderPass(render_pass_begin_info, vk::SubpassContents::eInline);
command_buffer.setViewport(0, {{0.0f, 0.0f, static_cast<float>(extent.width), static_cast<float>(extent.height), 0.0f, 1.0f}});
command_buffer.setScissor(0, {{{0, 0}, extent}});
command_buffer.bindPipeline(vk::PipelineBindPoint::eGraphics, pipeline);
command_buffer.bindVertexBuffers(0, static_cast<vk::Buffer>(vertex_buffer->get_handle()), offset);
command_buffer.bindIndexBuffer(index_buffer->get_handle(), 0, vk::IndexType::eUint32);
// Render multiple objects using different model matrices by dynamically offsetting into one uniform buffer
for (uint32_t j = 0; j < OBJECT_INSTANCES; j++)
{
// One dynamic offset per dynamic descriptor to offset into the ubo containing all model matrices
uint32_t dynamic_offset = j * static_cast<uint32_t>(dynamic_alignment);
// Bind the descriptor set for rendering a mesh using the dynamic offset
command_buffer.bindDescriptorSets(vk::PipelineBindPoint::eGraphics, pipeline_layout, 0, descriptor_set, dynamic_offset);
command_buffer.drawIndexed(index_count, 1, 0, 0, 0);
}
draw_ui(command_buffer);
command_buffer.endRenderPass();
command_buffer.end();
}
}
void HPPDynamicUniformBuffers::render(float delta_time)
{
if (prepared)
{
draw();
if (!paused)
{
update_dynamic_uniform_buffer(delta_time);
}
if (camera.updated)
{
update_uniform_buffers();
}
}
}
vk::DescriptorPool HPPDynamicUniformBuffers::create_descriptor_pool()
{
// Example uses one ubo, on dynamic ubo, and one combined image sampler
std::array<vk::DescriptorPoolSize, 3> pool_sizes = {{{vk::DescriptorType::eUniformBuffer, 1},
{vk::DescriptorType::eUniformBufferDynamic, 1},
{vk::DescriptorType::eCombinedImageSampler, 1}}};
return get_device().get_handle().createDescriptorPool(
{.maxSets = 2, .poolSizeCount = static_cast<uint32_t>(pool_sizes.size()), .pPoolSizes = pool_sizes.data()});
}
vk::DescriptorSetLayout HPPDynamicUniformBuffers::create_descriptor_set_layout()
{
std::array<vk::DescriptorSetLayoutBinding, 3> bindings = {{{0, vk::DescriptorType::eUniformBuffer, 1, vk::ShaderStageFlagBits::eVertex},
{1, vk::DescriptorType::eUniformBufferDynamic, 1, vk::ShaderStageFlagBits::eVertex},
{2, vk::DescriptorType::eCombinedImageSampler, 1, vk::ShaderStageFlagBits::eFragment}}};
return get_device().get_handle().createDescriptorSetLayout({.bindingCount = static_cast<uint32_t>(bindings.size()), .pBindings = bindings.data()});
}
vk::Pipeline HPPDynamicUniformBuffers::create_pipeline()
{
// Load shaders
std::vector<vk::PipelineShaderStageCreateInfo> shader_stages = {load_shader("dynamic_uniform_buffers", "base.vert.spv", vk::ShaderStageFlagBits::eVertex),
load_shader("dynamic_uniform_buffers", "base.frag.spv", vk::ShaderStageFlagBits::eFragment)};
// Vertex bindings and attributes
vk::VertexInputBindingDescription vertex_input_binding{0, sizeof(Vertex), vk::VertexInputRate::eVertex};
std::array<vk::VertexInputAttributeDescription, 2> vertex_input_attributes = {
{{0, 0, vk::Format::eR32G32B32Sfloat, offsetof(Vertex, pos)}, // Location 0 : Position
{1, 0, vk::Format::eR32G32B32Sfloat, offsetof(Vertex, color)}}}; // Location 1 : Color
vk::PipelineVertexInputStateCreateInfo vertex_input_state{.vertexBindingDescriptionCount = 1,
.pVertexBindingDescriptions = &vertex_input_binding,
.vertexAttributeDescriptionCount = static_cast<uint32_t>(vertex_input_attributes.size()),
.pVertexAttributeDescriptions = vertex_input_attributes.data()};
vk::PipelineColorBlendAttachmentState blend_attachment_state{.colorWriteMask = vk::ColorComponentFlagBits::eR | vk::ColorComponentFlagBits::eG |
vk::ColorComponentFlagBits::eB | vk::ColorComponentFlagBits::eA};
// Note: Using reversed depth-buffer for increased precision, so Greater depth values are kept
vk::PipelineDepthStencilStateCreateInfo depth_stencil_state;
depth_stencil_state.depthTestEnable = true;
depth_stencil_state.depthWriteEnable = true;
depth_stencil_state.depthCompareOp = vk::CompareOp::eGreater;
depth_stencil_state.back.compareOp = vk::CompareOp::eGreater;
return vkb::common::create_graphics_pipeline(get_device().get_handle(),
pipeline_cache,
shader_stages,
vertex_input_state,
vk::PrimitiveTopology::eTriangleList,
0,
vk::PolygonMode::eFill,
vk::CullModeFlagBits::eNone,
vk::FrontFace::eCounterClockwise,
{blend_attachment_state},
depth_stencil_state,
pipeline_layout,
render_pass);
}
void HPPDynamicUniformBuffers::draw()
{
HPPApiVulkanSample::prepare_frame();
// Submit to queue
submit_info.setCommandBuffers(draw_cmd_buffers[current_buffer]);
queue.submit(submit_info);
HPPApiVulkanSample::submit_frame();
}
void HPPDynamicUniformBuffers::generate_cube()
{
// Setup vertices indices for a colored cube
std::vector<Vertex> vertices = {
{{-1.0f, -1.0f, 1.0f}, {1.0f, 0.0f, 0.0f}},
{{1.0f, -1.0f, 1.0f}, {0.0f, 1.0f, 0.0f}},
{{1.0f, 1.0f, 1.0f}, {0.0f, 0.0f, 1.0f}},
{{-1.0f, 1.0f, 1.0f}, {0.0f, 0.0f, 0.0f}},
{{-1.0f, -1.0f, -1.0f}, {1.0f, 0.0f, 0.0f}},
{{1.0f, -1.0f, -1.0f}, {0.0f, 1.0f, 0.0f}},
{{1.0f, 1.0f, -1.0f}, {0.0f, 0.0f, 1.0f}},
{{-1.0f, 1.0f, -1.0f}, {0.0f, 0.0f, 0.0f}},
};
// clang-format off
std::vector<uint32_t> indices = { 0, 1, 2, 2, 3, 0, 1, 5, 6, 6, 2, 1, 7, 6, 5, 5, 4, 7,
4, 0, 3, 3, 7, 4, 4, 5, 1, 1, 0, 4, 3, 2, 6, 6, 7, 3 };
// clang-format on
index_count = static_cast<uint32_t>(indices.size());
auto vertex_buffer_size = vertices.size() * sizeof(Vertex);
auto index_buffer_size = indices.size() * sizeof(uint32_t);
// Create buffers
// For the sake of simplicity we won't stage the vertex data to the gpu memory
// Vertex buffer
vertex_buffer =
std::make_unique<vkb::core::BufferCpp>(get_device(), vertex_buffer_size, vk::BufferUsageFlagBits::eVertexBuffer, VMA_MEMORY_USAGE_CPU_TO_GPU);
vertex_buffer->update(vertices.data(), vertex_buffer_size);
index_buffer = std::make_unique<vkb::core::BufferCpp>(get_device(), index_buffer_size, vk::BufferUsageFlagBits::eIndexBuffer, VMA_MEMORY_USAGE_CPU_TO_GPU);
index_buffer->update(indices.data(), index_buffer_size);
}
void HPPDynamicUniformBuffers::prepare_camera()
{
camera.type = vkb::CameraType::LookAt;
camera.set_position(glm::vec3(0.0f, 0.0f, -30.0f));
camera.set_rotation(glm::vec3(0.0f));
// Note: Using reversed depth-buffer for increased precision, so Znear and Zfar are flipped
camera.set_perspective(60.0f, static_cast<float>(extent.width) / static_cast<float>(extent.height), 256.0f, 0.1f);
}
// Prepare and initialize uniform buffer containing shader uniforms
void HPPDynamicUniformBuffers::prepare_uniform_buffers()
{
// Allocate data for the dynamic uniform buffer object
// We allocate this manually as the alignment of the offset differs between GPUs
// Calculate required alignment based on minimum device offset alignment
vk::DeviceSize min_ubo_alignment = get_device().get_gpu().get_handle().getProperties().limits.minUniformBufferOffsetAlignment;
dynamic_alignment = sizeof(glm::mat4);
if (min_ubo_alignment > 0)
{
dynamic_alignment = (dynamic_alignment + min_ubo_alignment - 1) & ~(min_ubo_alignment - 1);
}
size_t buffer_size = OBJECT_INSTANCES * dynamic_alignment;
ubo_data_dynamic.model = static_cast<glm::mat4 *>(aligned_alloc(buffer_size, dynamic_alignment));
assert(ubo_data_dynamic.model);
std::cout << "minUniformBufferOffsetAlignment = " << min_ubo_alignment << std::endl;
std::cout << "dynamicAlignment = " << dynamic_alignment << std::endl;
// Vertex shader uniform buffer block
// Static shared uniform buffer object with projection and view matrix
uniform_buffers.view =
std::make_unique<vkb::core::BufferCpp>(get_device(), sizeof(ubo_vs), vk::BufferUsageFlagBits::eUniformBuffer, VMA_MEMORY_USAGE_CPU_TO_GPU);
uniform_buffers.dynamic =
std::make_unique<vkb::core::BufferCpp>(get_device(), buffer_size, vk::BufferUsageFlagBits::eUniformBuffer, VMA_MEMORY_USAGE_CPU_TO_GPU);
// Prepare per-object matrices with offsets and random rotations
std::default_random_engine rnd_engine(lock_simulation_speed ? 0 : static_cast<unsigned>(time(nullptr)));
std::normal_distribution<float> rnd_dist(-1.0f, 1.0f);
for (uint32_t i = 0; i < OBJECT_INSTANCES; i++)
{
rotations[i] = glm::vec3(rnd_dist(rnd_engine), rnd_dist(rnd_engine), rnd_dist(rnd_engine)) * 2.0f * glm::pi<float>();
rotation_speeds[i] = glm::vec3(rnd_dist(rnd_engine), rnd_dist(rnd_engine), rnd_dist(rnd_engine));
}
update_uniform_buffers();
update_dynamic_uniform_buffer(0.0f, true);
}
void HPPDynamicUniformBuffers::update_descriptor_set()
{
vk::DescriptorBufferInfo view_buffer_descriptor{uniform_buffers.view->get_handle(), 0, vk::WholeSize};
vk::DescriptorBufferInfo dynamic_buffer_descriptor{uniform_buffers.dynamic->get_handle(), 0, dynamic_alignment};
std::array<vk::WriteDescriptorSet, 2> write_descriptor_sets = {{// Binding 0 : Projection/View matrix uniform buffer
{.dstSet = descriptor_set,
.dstBinding = 0,
.descriptorCount = 1,
.descriptorType = vk::DescriptorType::eUniformBuffer,
.pBufferInfo = &view_buffer_descriptor},
// Binding 1 : Instance matrix as dynamic uniform buffer
{.dstSet = descriptor_set,
.dstBinding = 1,
.descriptorCount = 1,
.descriptorType = vk::DescriptorType::eUniformBufferDynamic,
.pBufferInfo = &dynamic_buffer_descriptor}}};
get_device().get_handle().updateDescriptorSets(write_descriptor_sets, {});
}
void HPPDynamicUniformBuffers::update_dynamic_uniform_buffer(float delta_time, bool force)
{
// Update at max. 60 fps
animation_timer += delta_time;
if ((animation_timer + 0.0025 < (1.0f / 60.0f)) && (!force))
{
return;
}
// Dynamic ubo with per-object model matrices indexed by offsets in the command buffer
auto dim = static_cast<uint32_t>(pow(OBJECT_INSTANCES, (1.0f / 3.0f)));
auto fdim = static_cast<float>(dim);
glm::vec3 offset(5.0f);
for (uint32_t x = 0; x < dim; x++)
{
auto fx = static_cast<float>(x);
for (uint32_t y = 0; y < dim; y++)
{
auto fy = static_cast<float>(y);
for (uint32_t z = 0; z < dim; z++)
{
auto fz = static_cast<float>(z);
auto index = x * dim * dim + y * dim + z;
// Aligned offset
auto model_mat = reinterpret_cast<glm::mat4 *>((reinterpret_cast<uint64_t>(ubo_data_dynamic.model) + (index * dynamic_alignment)));
// Update rotations
rotations[index] += animation_timer * rotation_speeds[index];
// Update matrices
glm::vec3 pos(-((fdim * offset.x) / 2.0f) + offset.x / 2.0f + fx * offset.x,
-((fdim * offset.y) / 2.0f) + offset.y / 2.0f + fy * offset.y,
-((fdim * offset.z) / 2.0f) + offset.z / 2.0f + fz * offset.z);
*model_mat = glm::translate(glm::mat4(1.0f), pos);
*model_mat = glm::rotate(*model_mat, rotations[index].x, glm::vec3(1.0f, 1.0f, 0.0f));
*model_mat = glm::rotate(*model_mat, rotations[index].y, glm::vec3(0.0f, 1.0f, 0.0f));
*model_mat = glm::rotate(*model_mat, rotations[index].z, glm::vec3(0.0f, 0.0f, 1.0f));
}
}
}
animation_timer = 0.0f;
uniform_buffers.dynamic->update(ubo_data_dynamic.model, static_cast<size_t>(uniform_buffers.dynamic->get_size()));
// Flush to make changes visible to the device
uniform_buffers.dynamic->flush();
}
void HPPDynamicUniformBuffers::update_uniform_buffers()
{
// Fixed ubo with projection and view matrices
ubo_vs.projection = camera.matrices.perspective;
ubo_vs.view = camera.matrices.view;
uniform_buffers.view->convert_and_update(ubo_vs);
}
std::unique_ptr<vkb::Application> create_hpp_dynamic_uniform_buffers()
{
return std::make_unique<HPPDynamicUniformBuffers>();
}
@@ -0,0 +1,108 @@
/* Copyright (c) 2021-2024, NVIDIA CORPORATION. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 the "License";
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Demonstrates the use of dynamic uniform buffers, using vulkan.hpp
*
* Instead of using one uniform buffer per-object, this example allocates one big uniform buffer
* with respect to the alignment reported by the device via minUniformBufferOffsetAlignment that
* contains all matrices for the objects in the scene.
*
* The used descriptor type vk::DescriptorType::eUniformBufferDynamic then allows to set a dynamic
* offset used to pass data from the single uniform buffer to the connected shader binding point.
*/
#pragma once
#include <hpp_api_vulkan_sample.h>
#define OBJECT_INSTANCES 125
class HPPDynamicUniformBuffers : public HPPApiVulkanSample
{
public:
HPPDynamicUniformBuffers();
~HPPDynamicUniformBuffers();
private:
// One big uniform buffer that contains all matrices
// Note that we need to manually allocate the data to cope for GPU-specific uniform buffer offset alignments
struct UboDataDynamic
{
glm::mat4 *model = nullptr;
};
struct UboVS
{
glm::mat4 projection;
glm::mat4 view;
};
struct UniformBuffers
{
std::unique_ptr<vkb::core::BufferCpp> view;
std::unique_ptr<vkb::core::BufferCpp> dynamic;
};
struct Vertex
{
float pos[3];
float color[3];
};
private:
static void *aligned_alloc(size_t size, size_t alignment);
static void aligned_free(void *data);
private:
// from vkb::Application
bool prepare(const vkb::ApplicationOptions &options) override;
bool resize(const uint32_t width, const uint32_t height) override;
// from HPPApiVulkanSample
void render(float delta_time) override;
void build_command_buffers() override;
vk::DescriptorPool create_descriptor_pool();
vk::DescriptorSetLayout create_descriptor_set_layout();
vk::Pipeline create_pipeline();
void draw();
void generate_cube();
void prepare_camera();
void prepare_uniform_buffers();
void update_descriptor_set();
void update_dynamic_uniform_buffer(float delta_time, bool force = false);
void update_uniform_buffers();
private:
float animation_timer = 0.0f;
vk::DescriptorSet descriptor_set;
vk::DescriptorSetLayout descriptor_set_layout;
size_t dynamic_alignment = 0;
std::unique_ptr<vkb::core::BufferCpp> index_buffer;
uint32_t index_count = 0;
vk::Pipeline pipeline;
vk::PipelineLayout pipeline_layout;
glm::vec3 rotations[OBJECT_INSTANCES]; // Store random per-object rotations
glm::vec3 rotation_speeds[OBJECT_INSTANCES];
UboDataDynamic ubo_data_dynamic;
UboVS ubo_vs;
UniformBuffers uniform_buffers;
std::unique_ptr<vkb::core::BufferCpp> vertex_buffer;
};
std::unique_ptr<vkb::Application> create_hpp_dynamic_uniform_buffers();