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Vulkan-Samples/samples/api/terrain_tessellation/terrain_tessellation.cpp
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2025-09-04 10:54:47 +08:00

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/* Copyright (c) 2019-2025, Sascha Willems
*
* 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.
*/
/*
* Dynamic terrain tessellation
*/
#include "terrain_tessellation.h"
#include "heightmap.h"
TerrainTessellation::TerrainTessellation()
{
title = "Dynamic terrain tessellation";
}
TerrainTessellation::~TerrainTessellation()
{
if (has_device())
{
// Clean up used Vulkan resources
// Note : Inherited destructor cleans up resources stored in base class
vkDestroyPipeline(get_device().get_handle(), pipelines.terrain, nullptr);
if (pipelines.wireframe != VK_NULL_HANDLE)
{
vkDestroyPipeline(get_device().get_handle(), pipelines.wireframe, nullptr);
}
vkDestroyPipeline(get_device().get_handle(), pipelines.skysphere, nullptr);
vkDestroyPipelineLayout(get_device().get_handle(), pipeline_layouts.skysphere, nullptr);
vkDestroyPipelineLayout(get_device().get_handle(), pipeline_layouts.terrain, nullptr);
vkDestroyDescriptorSetLayout(get_device().get_handle(), descriptor_set_layouts.terrain, nullptr);
vkDestroyDescriptorSetLayout(get_device().get_handle(), descriptor_set_layouts.skysphere, nullptr);
uniform_buffers.skysphere_vertex.reset();
uniform_buffers.terrain_tessellation.reset();
textures.heightmap.image.reset();
vkDestroySampler(get_device().get_handle(), textures.heightmap.sampler, nullptr);
textures.skysphere.image.reset();
vkDestroySampler(get_device().get_handle(), textures.skysphere.sampler, nullptr);
textures.terrain_array.image.reset();
vkDestroySampler(get_device().get_handle(), textures.terrain_array.sampler, nullptr);
if (query_pool != VK_NULL_HANDLE)
{
vkDestroyQueryPool(get_device().get_handle(), query_pool, nullptr);
}
}
}
void TerrainTessellation::request_gpu_features(vkb::PhysicalDevice &gpu)
{
auto &requested_features = gpu.get_mutable_requested_features();
// Tessellation shader support is required for this example
if (gpu.get_features().tessellationShader)
{
requested_features.tessellationShader = VK_TRUE;
}
else
{
throw vkb::VulkanException(VK_ERROR_FEATURE_NOT_PRESENT, "Selected GPU does not support tessellation shaders!");
}
// Fill mode non solid is required for wireframe display
if (gpu.get_features().fillModeNonSolid)
{
requested_features.fillModeNonSolid = VK_TRUE;
}
// Pipeline statistics
if (gpu.get_features().pipelineStatisticsQuery)
{
requested_features.pipelineStatisticsQuery = VK_TRUE;
}
// Enable anisotropic filtering if supported
if (gpu.get_features().samplerAnisotropy)
{
requested_features.samplerAnisotropy = VK_TRUE;
}
}
// Setup pool and buffer for storing pipeline statistics results
void TerrainTessellation::setup_query_result_buffer()
{
// Create query pool
if (get_device().get_gpu().get_features().pipelineStatisticsQuery)
{
VkQueryPoolCreateInfo query_pool_info = {};
query_pool_info.sType = VK_STRUCTURE_TYPE_QUERY_POOL_CREATE_INFO;
query_pool_info.queryType = VK_QUERY_TYPE_PIPELINE_STATISTICS;
query_pool_info.pipelineStatistics =
VK_QUERY_PIPELINE_STATISTIC_VERTEX_SHADER_INVOCATIONS_BIT |
VK_QUERY_PIPELINE_STATISTIC_TESSELLATION_EVALUATION_SHADER_INVOCATIONS_BIT;
query_pool_info.queryCount = 2;
VK_CHECK(vkCreateQueryPool(get_device().get_handle(), &query_pool_info, NULL, &query_pool));
}
}
// Retrieves the results of the pipeline statistics query submitted to the command buffer
void TerrainTessellation::get_query_results()
{
// We use vkGetQueryResults to copy the results into a host visible buffer
vkGetQueryPoolResults(
get_device().get_handle(),
query_pool,
0,
1,
sizeof(pipeline_stats),
pipeline_stats,
sizeof(uint64_t),
VK_QUERY_RESULT_64_BIT);
}
void TerrainTessellation::load_assets()
{
skysphere = load_model("scenes/geosphere.gltf");
textures.skysphere = load_texture("textures/skysphere_rgba.ktx", vkb::sg::Image::Color);
// Terrain textures are stored in a texture array with layers corresponding to terrain height
textures.terrain_array = load_texture_array("textures/terrain_texturearray_rgba.ktx", vkb::sg::Image::Color);
// Height data is stored in a one-channel texture
textures.heightmap = load_texture("textures/terrain_heightmap_r16.ktx", vkb::sg::Image::Other);
VkSamplerCreateInfo sampler_create_info = vkb::initializers::sampler_create_info();
// Calculate valid filter and mipmap modes
VkFilter filter = VK_FILTER_LINEAR;
VkSamplerMipmapMode mipmap_mode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
vkb::make_filters_valid(get_device().get_gpu().get_handle(), textures.heightmap.image->get_format(), &filter, &mipmap_mode);
// Setup a mirroring sampler for the height map
vkDestroySampler(get_device().get_handle(), textures.heightmap.sampler, nullptr);
sampler_create_info.magFilter = filter;
sampler_create_info.minFilter = filter;
sampler_create_info.mipmapMode = mipmap_mode;
sampler_create_info.addressModeU = VK_SAMPLER_ADDRESS_MODE_MIRRORED_REPEAT;
sampler_create_info.addressModeV = sampler_create_info.addressModeU;
sampler_create_info.addressModeW = sampler_create_info.addressModeU;
sampler_create_info.compareOp = VK_COMPARE_OP_NEVER;
sampler_create_info.minLod = 0.0f;
sampler_create_info.maxLod = static_cast<float>(textures.heightmap.image->get_mipmaps().size());
sampler_create_info.borderColor = VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE;
VK_CHECK(vkCreateSampler(get_device().get_handle(), &sampler_create_info, nullptr, &textures.heightmap.sampler));
filter = VK_FILTER_LINEAR;
mipmap_mode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
vkb::make_filters_valid(get_device().get_gpu().get_handle(), textures.terrain_array.image->get_format(), &filter, &mipmap_mode);
// Setup a repeating sampler for the terrain texture layers
vkDestroySampler(get_device().get_handle(), textures.terrain_array.sampler, nullptr);
sampler_create_info = vkb::initializers::sampler_create_info();
sampler_create_info.magFilter = filter;
sampler_create_info.minFilter = filter;
sampler_create_info.mipmapMode = mipmap_mode;
sampler_create_info.addressModeU = VK_SAMPLER_ADDRESS_MODE_REPEAT;
sampler_create_info.addressModeV = sampler_create_info.addressModeU;
sampler_create_info.addressModeW = sampler_create_info.addressModeU;
sampler_create_info.compareOp = VK_COMPARE_OP_NEVER;
sampler_create_info.minLod = 0.0f;
sampler_create_info.maxLod = static_cast<float>(textures.terrain_array.image->get_mipmaps().size());
sampler_create_info.borderColor = VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE;
if (get_device().get_gpu().get_features().samplerAnisotropy)
{
sampler_create_info.maxAnisotropy = 4.0f;
sampler_create_info.anisotropyEnable = VK_TRUE;
}
VK_CHECK(vkCreateSampler(get_device().get_handle(), &sampler_create_info, nullptr, &textures.terrain_array.sampler));
}
void TerrainTessellation::build_command_buffers()
{
VkCommandBufferBeginInfo command_buffer_begin_info = vkb::initializers::command_buffer_begin_info();
VkClearValue clear_values[2];
clear_values[0].color = default_clear_color;
clear_values[1].depthStencil = {0.0f, 0};
VkRenderPassBeginInfo render_pass_begin_info = vkb::initializers::render_pass_begin_info();
render_pass_begin_info.renderPass = render_pass;
render_pass_begin_info.renderArea.offset.x = 0;
render_pass_begin_info.renderArea.offset.y = 0;
render_pass_begin_info.renderArea.extent.width = width;
render_pass_begin_info.renderArea.extent.height = height;
render_pass_begin_info.clearValueCount = 2;
render_pass_begin_info.pClearValues = clear_values;
for (int32_t i = 0; i < draw_cmd_buffers.size(); ++i)
{
render_pass_begin_info.framebuffer = framebuffers[i];
VK_CHECK(vkBeginCommandBuffer(draw_cmd_buffers[i], &command_buffer_begin_info));
if (get_device().get_gpu().get_features().pipelineStatisticsQuery)
{
vkCmdResetQueryPool(draw_cmd_buffers[i], query_pool, 0, 2);
}
vkCmdBeginRenderPass(draw_cmd_buffers[i], &render_pass_begin_info, VK_SUBPASS_CONTENTS_INLINE);
VkViewport viewport = vkb::initializers::viewport(static_cast<float>(width), static_cast<float>(height), 0.0f, 1.0f);
vkCmdSetViewport(draw_cmd_buffers[i], 0, 1, &viewport);
VkRect2D scissor = vkb::initializers::rect2D(width, height, 0, 0);
vkCmdSetScissor(draw_cmd_buffers[i], 0, 1, &scissor);
vkCmdSetLineWidth(draw_cmd_buffers[i], 1.0f);
VkDeviceSize offsets[1] = {0};
// Skysphere
vkCmdBindPipeline(draw_cmd_buffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.skysphere);
vkCmdBindDescriptorSets(draw_cmd_buffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline_layouts.skysphere, 0, 1, &descriptor_sets.skysphere, 0, NULL);
draw_model(skysphere, draw_cmd_buffers[i]);
// Terrain
if (get_device().get_gpu().get_features().pipelineStatisticsQuery)
{
// Begin pipeline statistics query
vkCmdBeginQuery(draw_cmd_buffers[i], query_pool, 0, 0);
}
// Render
vkCmdBindPipeline(draw_cmd_buffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, wireframe ? pipelines.wireframe : pipelines.terrain);
vkCmdBindDescriptorSets(draw_cmd_buffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline_layouts.terrain, 0, 1, &descriptor_sets.terrain, 0, NULL);
vkCmdBindVertexBuffers(draw_cmd_buffers[i], 0, 1, terrain.vertices->get(), offsets);
vkCmdBindIndexBuffer(draw_cmd_buffers[i], terrain.indices->get_handle(), 0, VK_INDEX_TYPE_UINT32);
vkCmdDrawIndexed(draw_cmd_buffers[i], terrain.index_count, 1, 0, 0, 0);
if (get_device().get_gpu().get_features().pipelineStatisticsQuery)
{
// End pipeline statistics query
vkCmdEndQuery(draw_cmd_buffers[i], query_pool, 0);
}
draw_ui(draw_cmd_buffers[i]);
vkCmdEndRenderPass(draw_cmd_buffers[i]);
VK_CHECK(vkEndCommandBuffer(draw_cmd_buffers[i]));
}
}
// Generate a terrain quad patch for feeding to the tessellation control shader
void TerrainTessellation::generate_terrain()
{
const uint32_t patch_size = 64;
const float uv_scale = 1.0f;
const uint32_t vertex_count = patch_size * patch_size;
std::vector<Vertex> vertices(vertex_count);
const float wx = 2.0f;
const float wy = 2.0f;
for (auto x = 0; x < patch_size; x++)
{
for (auto y = 0; y < patch_size; y++)
{
uint32_t index = (x + y * patch_size);
vertices[index].pos[0] = x * wx + wx / 2.0f - static_cast<float>(patch_size) * wx / 2.0f;
vertices[index].pos[1] = 0.0f;
vertices[index].pos[2] = y * wy + wy / 2.0f - static_cast<float>(patch_size) * wy / 2.0f;
vertices[index].uv = glm::vec2(static_cast<float>(x) / patch_size, static_cast<float>(y) / patch_size) * uv_scale;
}
}
// Calculate normals from height map using a sobel filter
vkb::HeightMap heightmap("textures/terrain_heightmap_r16.ktx", patch_size);
for (auto x = 0; x < patch_size; x++)
{
for (auto y = 0; y < patch_size; y++)
{
// Get height samples centered around current position
float heights[3][3];
for (auto hx = -1; hx <= 1; hx++)
{
for (auto hy = -1; hy <= 1; hy++)
{
heights[hx + 1][hy + 1] = heightmap.get_height(x + hx, y + hy);
}
}
// Calculate the normal
glm::vec3 normal;
// Gx sobel filter
normal.x = heights[0][0] - heights[2][0] + 2.0f * heights[0][1] - 2.0f * heights[2][1] + heights[0][2] - heights[2][2];
// Gy sobel filter
normal.z = heights[0][0] + 2.0f * heights[1][0] + heights[2][0] - heights[0][2] - 2.0f * heights[1][2] - heights[2][2];
// Calculate missing up component of the normal using the filtered x and y axis
// The first value controls the bump strength
normal.y = 0.25f * sqrt(1.0f - normal.x * normal.x - normal.z * normal.z);
vertices[x + y * patch_size].normal = glm::normalize(normal * glm::vec3(2.0f, 1.0f, 2.0f));
}
}
// Indices
const uint32_t w = (patch_size - 1);
const uint32_t index_count = w * w * 4;
std::vector<uint32_t> indices(index_count);
for (auto x = 0; x < w; x++)
{
for (auto y = 0; y < w; y++)
{
uint32_t index = (x + y * w) * 4;
indices[index] = (x + y * patch_size);
indices[index + 1] = indices[index] + patch_size;
indices[index + 2] = indices[index + 1] + 1;
indices[index + 3] = indices[index] + 1;
}
}
terrain.index_count = index_count;
uint32_t vertex_buffer_size = vertex_count * sizeof(Vertex);
uint32_t index_buffer_size = index_count * sizeof(uint32_t);
// Create staging buffers
vkb::core::BufferC vertex_staging = vkb::core::BufferC::create_staging_buffer(get_device(), vertices);
vkb::core::BufferC index_staging = vkb::core::BufferC::create_staging_buffer(get_device(), indices);
terrain.vertices = std::make_unique<vkb::core::BufferC>(get_device(),
vertex_buffer_size,
VK_BUFFER_USAGE_VERTEX_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT,
VMA_MEMORY_USAGE_GPU_ONLY);
terrain.indices = std::make_unique<vkb::core::BufferC>(get_device(),
index_buffer_size,
VK_BUFFER_USAGE_INDEX_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT,
VMA_MEMORY_USAGE_GPU_ONLY);
// Copy from staging buffers
VkCommandBuffer copy_command = get_device().create_command_buffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);
VkBufferCopy copy_region = {};
copy_region.size = vertex_buffer_size;
vkCmdCopyBuffer(
copy_command,
vertex_staging.get_handle(),
terrain.vertices->get_handle(),
1,
&copy_region);
copy_region.size = index_buffer_size;
vkCmdCopyBuffer(
copy_command,
index_staging.get_handle(),
terrain.indices->get_handle(),
1,
&copy_region);
get_device().flush_command_buffer(copy_command, queue, true);
}
void TerrainTessellation::setup_descriptor_pool()
{
std::vector<VkDescriptorPoolSize> pool_sizes =
{
vkb::initializers::descriptor_pool_size(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 3),
vkb::initializers::descriptor_pool_size(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 3)};
VkDescriptorPoolCreateInfo descriptor_pool_create_info =
vkb::initializers::descriptor_pool_create_info(
static_cast<uint32_t>(pool_sizes.size()),
pool_sizes.data(),
2);
VK_CHECK(vkCreateDescriptorPool(get_device().get_handle(), &descriptor_pool_create_info, nullptr, &descriptor_pool));
}
void TerrainTessellation::setup_descriptor_set_layouts()
{
VkDescriptorSetLayoutCreateInfo descriptor_layout;
VkPipelineLayoutCreateInfo pipeline_layout_create_info;
std::vector<VkDescriptorSetLayoutBinding> set_layout_bindings;
// Terrain
set_layout_bindings =
{
// Binding 0 : Shared Tessellation shader ubo
vkb::initializers::descriptor_set_layout_binding(
VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT | VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT,
0),
// Binding 1 : Height map
vkb::initializers::descriptor_set_layout_binding(
VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,
VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT | VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT | VK_SHADER_STAGE_FRAGMENT_BIT,
1),
// Binding 3 : Terrain texture array layers
vkb::initializers::descriptor_set_layout_binding(
VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,
VK_SHADER_STAGE_FRAGMENT_BIT,
2),
};
descriptor_layout = vkb::initializers::descriptor_set_layout_create_info(set_layout_bindings.data(), static_cast<uint32_t>(set_layout_bindings.size()));
VK_CHECK(vkCreateDescriptorSetLayout(get_device().get_handle(), &descriptor_layout, nullptr, &descriptor_set_layouts.terrain));
pipeline_layout_create_info = vkb::initializers::pipeline_layout_create_info(&descriptor_set_layouts.terrain, 1);
VK_CHECK(vkCreatePipelineLayout(get_device().get_handle(), &pipeline_layout_create_info, nullptr, &pipeline_layouts.terrain));
// Skysphere
set_layout_bindings =
{
// Binding 0 : Vertex shader ubo
vkb::initializers::descriptor_set_layout_binding(
VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
VK_SHADER_STAGE_VERTEX_BIT,
0),
// Binding 1 : Color map
vkb::initializers::descriptor_set_layout_binding(
VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,
VK_SHADER_STAGE_FRAGMENT_BIT,
1),
};
descriptor_layout = vkb::initializers::descriptor_set_layout_create_info(set_layout_bindings.data(), static_cast<uint32_t>(set_layout_bindings.size()));
VK_CHECK(vkCreateDescriptorSetLayout(get_device().get_handle(), &descriptor_layout, nullptr, &descriptor_set_layouts.skysphere));
pipeline_layout_create_info = vkb::initializers::pipeline_layout_create_info(&descriptor_set_layouts.skysphere, 1);
VK_CHECK(vkCreatePipelineLayout(get_device().get_handle(), &pipeline_layout_create_info, nullptr, &pipeline_layouts.skysphere));
}
void TerrainTessellation::setup_descriptor_sets()
{
VkDescriptorSetAllocateInfo alloc_info;
std::vector<VkWriteDescriptorSet> write_descriptor_sets;
// Terrain
alloc_info = vkb::initializers::descriptor_set_allocate_info(descriptor_pool, &descriptor_set_layouts.terrain, 1);
VK_CHECK(vkAllocateDescriptorSets(get_device().get_handle(), &alloc_info, &descriptor_sets.terrain));
VkDescriptorBufferInfo terrain_buffer_descriptor = create_descriptor(*uniform_buffers.terrain_tessellation);
VkDescriptorImageInfo heightmap_image_descriptor = create_descriptor(textures.heightmap);
VkDescriptorImageInfo terrainmap_image_descriptor = create_descriptor(textures.terrain_array);
write_descriptor_sets =
{
// Binding 0 : Shared tessellation shader ubo
vkb::initializers::write_descriptor_set(
descriptor_sets.terrain,
VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
0,
&terrain_buffer_descriptor),
// Binding 1 : Displacement map
vkb::initializers::write_descriptor_set(
descriptor_sets.terrain,
VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,
1,
&heightmap_image_descriptor),
// Binding 2 : Color map (alpha channel)
vkb::initializers::write_descriptor_set(
descriptor_sets.terrain,
VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,
2,
&terrainmap_image_descriptor),
};
vkUpdateDescriptorSets(get_device().get_handle(), static_cast<uint32_t>(write_descriptor_sets.size()), write_descriptor_sets.data(), 0, NULL);
// Skysphere
alloc_info = vkb::initializers::descriptor_set_allocate_info(descriptor_pool, &descriptor_set_layouts.skysphere, 1);
VK_CHECK(vkAllocateDescriptorSets(get_device().get_handle(), &alloc_info, &descriptor_sets.skysphere));
VkDescriptorBufferInfo skysphere_buffer_descriptor = create_descriptor(*uniform_buffers.skysphere_vertex);
VkDescriptorImageInfo skysphere_image_descriptor = create_descriptor(textures.skysphere);
write_descriptor_sets =
{
// Binding 0 : Vertex shader ubo
vkb::initializers::write_descriptor_set(
descriptor_sets.skysphere,
VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
0,
&skysphere_buffer_descriptor),
// Binding 1 : Fragment shader color map
vkb::initializers::write_descriptor_set(
descriptor_sets.skysphere,
VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,
1,
&skysphere_image_descriptor),
};
vkUpdateDescriptorSets(get_device().get_handle(), static_cast<uint32_t>(write_descriptor_sets.size()), write_descriptor_sets.data(), 0, NULL);
}
void TerrainTessellation::prepare_pipelines()
{
VkPipelineInputAssemblyStateCreateInfo input_assembly_state_create_info =
vkb::initializers::pipeline_input_assembly_state_create_info(
VK_PRIMITIVE_TOPOLOGY_PATCH_LIST,
0,
VK_FALSE);
VkPipelineRasterizationStateCreateInfo rasterization_state =
vkb::initializers::pipeline_rasterization_state_create_info(
VK_POLYGON_MODE_FILL,
VK_CULL_MODE_BACK_BIT,
VK_FRONT_FACE_COUNTER_CLOCKWISE,
0);
VkPipelineColorBlendAttachmentState blend_attachment_state =
vkb::initializers::pipeline_color_blend_attachment_state(
0xf,
VK_FALSE);
VkPipelineColorBlendStateCreateInfo color_blend_state =
vkb::initializers::pipeline_color_blend_state_create_info(
1,
&blend_attachment_state);
// Note: Using reversed depth-buffer for increased precision, so Greater depth values are kept
VkPipelineDepthStencilStateCreateInfo depth_stencil_state =
vkb::initializers::pipeline_depth_stencil_state_create_info(
VK_TRUE,
VK_TRUE,
VK_COMPARE_OP_GREATER);
VkPipelineViewportStateCreateInfo viewport_state =
vkb::initializers::pipeline_viewport_state_create_info(1, 1, 0);
VkPipelineMultisampleStateCreateInfo multisample_state =
vkb::initializers::pipeline_multisample_state_create_info(
VK_SAMPLE_COUNT_1_BIT,
0);
std::vector<VkDynamicState> dynamic_state_enables = {
VK_DYNAMIC_STATE_VIEWPORT,
VK_DYNAMIC_STATE_SCISSOR,
VK_DYNAMIC_STATE_LINE_WIDTH};
VkPipelineDynamicStateCreateInfo dynamic_state =
vkb::initializers::pipeline_dynamic_state_create_info(
dynamic_state_enables.data(),
static_cast<uint32_t>(dynamic_state_enables.size()),
0);
// We render the terrain as a grid of quad patches
VkPipelineTessellationStateCreateInfo tessellation_state =
vkb::initializers::pipeline_tessellation_state_create_info(4);
// Vertex bindings an attributes
// Binding description
std::vector<VkVertexInputBindingDescription> vertex_input_bindings = {
vkb::initializers::vertex_input_binding_description(0, sizeof(TerrainTessellation::Vertex), VK_VERTEX_INPUT_RATE_VERTEX),
};
// Attribute descriptions
std::vector<VkVertexInputAttributeDescription> vertex_input_attributes = {
vkb::initializers::vertex_input_attribute_description(0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0), // Position
vkb::initializers::vertex_input_attribute_description(0, 1, VK_FORMAT_R32G32B32_SFLOAT, sizeof(float) * 3), // Normal
vkb::initializers::vertex_input_attribute_description(0, 2, VK_FORMAT_R32G32_SFLOAT, sizeof(float) * 6), // UV
};
VkPipelineVertexInputStateCreateInfo vertex_input_state = vkb::initializers::pipeline_vertex_input_state_create_info();
vertex_input_state.vertexBindingDescriptionCount = static_cast<uint32_t>(vertex_input_bindings.size());
vertex_input_state.pVertexBindingDescriptions = vertex_input_bindings.data();
vertex_input_state.vertexAttributeDescriptionCount = static_cast<uint32_t>(vertex_input_attributes.size());
vertex_input_state.pVertexAttributeDescriptions = vertex_input_attributes.data();
std::array<VkPipelineShaderStageCreateInfo, 4> shader_stages;
// Terrain tessellation pipeline
shader_stages[0] = load_shader("terrain_tessellation", "terrain.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
shader_stages[1] = load_shader("terrain_tessellation", "terrain.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
shader_stages[2] = load_shader("terrain_tessellation", "terrain.tesc.spv", VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT);
shader_stages[3] = load_shader("terrain_tessellation", "terrain.tese.spv", VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT);
VkGraphicsPipelineCreateInfo pipeline_create_info =
vkb::initializers::pipeline_create_info(pipeline_layouts.terrain, render_pass, 0);
pipeline_create_info.pVertexInputState = &vertex_input_state;
pipeline_create_info.pInputAssemblyState = &input_assembly_state_create_info;
pipeline_create_info.pRasterizationState = &rasterization_state;
pipeline_create_info.pColorBlendState = &color_blend_state;
pipeline_create_info.pMultisampleState = &multisample_state;
pipeline_create_info.pViewportState = &viewport_state;
pipeline_create_info.pDepthStencilState = &depth_stencil_state;
pipeline_create_info.pDynamicState = &dynamic_state;
pipeline_create_info.pTessellationState = &tessellation_state;
pipeline_create_info.stageCount = static_cast<uint32_t>(shader_stages.size());
pipeline_create_info.pStages = shader_stages.data();
pipeline_create_info.renderPass = render_pass;
VK_CHECK(vkCreateGraphicsPipelines(get_device().get_handle(), pipeline_cache, 1, &pipeline_create_info, nullptr, &pipelines.terrain));
// Terrain wireframe pipeline
if (get_device().get_gpu().get_features().fillModeNonSolid)
{
rasterization_state.polygonMode = VK_POLYGON_MODE_LINE;
VK_CHECK(vkCreateGraphicsPipelines(get_device().get_handle(), pipeline_cache, 1, &pipeline_create_info, nullptr, &pipelines.wireframe));
};
// Skysphere pipeline
// Stride from glTF model vertex layout
vertex_input_bindings[0].stride = sizeof(::Vertex);
rasterization_state.polygonMode = VK_POLYGON_MODE_FILL;
// Revert to triangle list topology
input_assembly_state_create_info.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
// Reset tessellation state
pipeline_create_info.pTessellationState = nullptr;
// Don't write to depth buffer
depth_stencil_state.depthWriteEnable = VK_FALSE;
pipeline_create_info.stageCount = 2;
pipeline_create_info.layout = pipeline_layouts.skysphere;
shader_stages[0] = load_shader("terrain_tessellation", "skysphere.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
shader_stages[1] = load_shader("terrain_tessellation", "skysphere.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
VK_CHECK(vkCreateGraphicsPipelines(get_device().get_handle(), pipeline_cache, 1, &pipeline_create_info, nullptr, &pipelines.skysphere));
}
// Prepare and initialize uniform buffer containing shader uniforms
void TerrainTessellation::prepare_uniform_buffers()
{
// Shared tessellation shader stages uniform buffer
uniform_buffers.terrain_tessellation = std::make_unique<vkb::core::BufferC>(get_device(),
sizeof(ubo_tess),
VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
VMA_MEMORY_USAGE_CPU_TO_GPU);
// Skysphere vertex shader uniform buffer
uniform_buffers.skysphere_vertex = std::make_unique<vkb::core::BufferC>(get_device(),
sizeof(ubo_vs),
VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
VMA_MEMORY_USAGE_CPU_TO_GPU);
update_uniform_buffers();
}
void TerrainTessellation::update_uniform_buffers()
{
// Tessellation
ubo_tess.projection = camera.matrices.perspective;
ubo_tess.modelview = camera.matrices.view * glm::mat4(1.0f);
ubo_tess.light_pos.y = -0.5f - ubo_tess.displacement_factor; // todo: Not used yet
ubo_tess.viewport_dim = glm::vec2(static_cast<float>(width), static_cast<float>(height));
frustum.update(ubo_tess.projection * ubo_tess.modelview);
memcpy(ubo_tess.frustum_planes, frustum.get_planes().data(), sizeof(glm::vec4) * 6);
float saved_factor = ubo_tess.tessellation_factor;
if (!tessellation)
{
// Setting this to zero sets all tessellation factors to 1.0 in the shader
ubo_tess.tessellation_factor = 0.0f;
}
uniform_buffers.terrain_tessellation->convert_and_update(ubo_tess);
if (!tessellation)
{
ubo_tess.tessellation_factor = saved_factor;
}
// Skysphere vertex shader
ubo_vs.mvp = camera.matrices.perspective * glm::mat4(glm::mat3(camera.matrices.view));
uniform_buffers.skysphere_vertex->convert_and_update(ubo_vs.mvp);
}
void TerrainTessellation::draw()
{
ApiVulkanSample::prepare_frame();
// Command buffer to be submitted to the queue
submit_info.commandBufferCount = 1;
submit_info.pCommandBuffers = &draw_cmd_buffers[current_buffer];
// Submit to queue
VK_CHECK(vkQueueSubmit(queue, 1, &submit_info, VK_NULL_HANDLE));
if (get_device().get_gpu().get_features().pipelineStatisticsQuery)
{
// Read query results for displaying in next frame
get_query_results();
}
ApiVulkanSample::submit_frame();
}
bool TerrainTessellation::prepare(const vkb::ApplicationOptions &options)
{
if (!ApiVulkanSample::prepare(options))
{
return false;
}
// Note: Using reversed depth-buffer for increased precision, so Znear and Zfar are flipped
camera.type = vkb::CameraType::FirstPerson;
camera.set_perspective(60.0f, static_cast<float>(width) / static_cast<float>(height), 512.0f, 0.1f);
camera.set_rotation(glm::vec3(-12.0f, 159.0f, 0.0f));
camera.set_translation(glm::vec3(18.0f, 22.5f, 57.5f));
camera.translation_speed = 7.5f;
load_assets();
generate_terrain();
if (get_device().get_gpu().get_features().pipelineStatisticsQuery)
{
setup_query_result_buffer();
}
prepare_uniform_buffers();
setup_descriptor_set_layouts();
prepare_pipelines();
setup_descriptor_pool();
setup_descriptor_sets();
build_command_buffers();
prepared = true;
return true;
}
void TerrainTessellation::render(float delta_time)
{
if (!prepared)
{
return;
}
draw();
}
void TerrainTessellation::view_changed()
{
update_uniform_buffers();
}
void TerrainTessellation::on_update_ui_overlay(vkb::Drawer &drawer)
{
if (drawer.header("Settings"))
{
if (drawer.checkbox("Tessellation", &tessellation))
{
update_uniform_buffers();
}
if (drawer.input_float("Factor", &ubo_tess.tessellation_factor, 0.05f, "%.2f"))
{
update_uniform_buffers();
}
if (get_device().get_gpu().get_features().fillModeNonSolid)
{
if (drawer.checkbox("Wireframe", &wireframe))
{
rebuild_command_buffers();
}
}
}
if (get_device().get_gpu().get_features().pipelineStatisticsQuery)
{
if (drawer.header("Pipeline statistics"))
{
drawer.text("VS invocations: %d", pipeline_stats[0]);
drawer.text("TE invocations: %d", pipeline_stats[1]);
}
}
}
std::unique_ptr<vkb::Application> create_terrain_tessellation()
{
return std::make_unique<TerrainTessellation>();
}