Merge branch '87-mesh-shader-implementation' into 'develop'

Resolve "Mesh Shader Implementation"

Closes #87

See merge request !74

include/vkcv/Context.hpp

@@ -4,6 +4,7 @@
 #include <vk_mem_alloc.hpp>
 
 #include "QueueManager.hpp"
+#include "DrawcallRecording.hpp"
 
 namespace vkcv
 {

include/vkcv/Core.hpp

@@ -249,13 +249,21 @@ namespace vkcv
 		bool beginFrame(uint32_t& width, uint32_t& height);
 
 		void recordDrawcallsToCmdStream(
-            const CommandStreamHandle       cmdStreamHandle,
+			const CommandStreamHandle       cmdStreamHandle,
 			const PassHandle                renderpassHandle, 
 			const PipelineHandle            pipelineHandle,
 			const PushConstants             &pushConstants,
 			const std::vector<DrawcallInfo> &drawcalls,
 			const std::vector<ImageHandle>  &renderTargets);
 
+		void recordMeshShaderDrawcalls(
+			const CommandStreamHandle               cmdStreamHandle,
+			const PassHandle                        renderpassHandle,
+			const PipelineHandle                    pipelineHandle,
+			const PushConstants&                    pushConstantData,
+            const std::vector<MeshShaderDrawcall>&  drawcalls,
+			const std::vector<ImageHandle>&         renderTargets);
+
 		void recordComputeDispatchToCmdStream(
 			CommandStreamHandle cmdStream,
 			PipelineHandle computePipeline,

include/vkcv/DrawcallRecording.hpp

@@ -13,6 +13,11 @@ namespace vkcv {
         vk::Buffer      buffer;
     };
 
+    enum class IndexBitCount{
+        Bit16,
+        Bit32
+    };
+
     struct DescriptorSetUsage {
         inline DescriptorSetUsage(uint32_t setLocation, vk::DescriptorSet vulkanHandle,
 								  const std::vector<uint32_t>& dynamicOffsets = {}) noexcept
@@ -24,12 +29,14 @@ namespace vkcv {
     };
 
     struct Mesh {
-        inline Mesh(std::vector<VertexBufferBinding> vertexBufferBindings, vk::Buffer indexBuffer, size_t indexCount) noexcept
-            : vertexBufferBindings(vertexBufferBindings), indexBuffer(indexBuffer), indexCount(indexCount){}
+        inline Mesh(std::vector<VertexBufferBinding> vertexBufferBindings, vk::Buffer indexBuffer, size_t indexCount, IndexBitCount indexBitCount = IndexBitCount::Bit16) noexcept
+            : vertexBufferBindings(vertexBufferBindings), indexBuffer(indexBuffer), indexCount(indexCount), indexBitCount(indexBitCount){}
 
         std::vector<VertexBufferBinding>    vertexBufferBindings;
         vk::Buffer                          indexBuffer;
         size_t                              indexCount;
+        IndexBitCount                       indexBitCount;
+
     };
 
     struct DrawcallInfo {
@@ -48,4 +55,21 @@ namespace vkcv {
         const PushConstants     &pushConstants,
         const size_t            drawcallIndex);
 
-}
+    void InitMeshShaderDrawFunctions(vk::Device device);
\ No newline at end of file
+
+    struct MeshShaderDrawcall {
+        inline MeshShaderDrawcall(const std::vector<DescriptorSetUsage> descriptorSets, uint32_t taskCount)
+            : descriptorSets(descriptorSets), taskCount(taskCount) {}
+
+        std::vector<DescriptorSetUsage> descriptorSets;
+        uint32_t                        taskCount;
+    };
+
+    void recordMeshShaderDrawcall(
+        vk::CommandBuffer                       cmdBuffer,
+        vk::PipelineLayout                      pipelineLayout,
+        const PushConstants&                 pushConstantData,
+        const uint32_t                          pushConstantOffset,
+        const MeshShaderDrawcall&               drawcall,
+        const uint32_t                          firstTask);
+}

include/vkcv/ShaderStage.hpp

@@ -9,7 +9,11 @@ namespace vkcv {
 		TESS_EVAL,
 		GEOMETRY,
 		FRAGMENT,
-		COMPUTE
+		COMPUTE,
+		TASK,
+		MESH
 	};
 
+
+
 }

modules/CMakeLists.txt

@@ -4,6 +4,7 @@ add_subdirectory(asset_loader)
 add_subdirectory(camera)
 add_subdirectory(gui)
 add_subdirectory(material)
+add_subdirectory(meshlet)
 add_subdirectory(scene)
 add_subdirectory(shader_compiler)
 add_subdirectory(testing)

modules/meshlet/CMakeLists.txt

+cmake_minimum_required(VERSION 3.16)
+project(vkcv_meshlet)
+
+# setting c++ standard for the module
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+set(vkcv_meshlet_source ${PROJECT_SOURCE_DIR}/src)
+set(vkcv_meshlet_include ${PROJECT_SOURCE_DIR}/include)
+
+# Add source and header files to the module
+set(vkcv_meshlet_sources
+		${vkcv_meshlet_include}/vkcv/meshlet/Meshlet.hpp
+		${vkcv_meshlet_source}/vkcv/meshlet/Meshlet.cpp
+
+		${vkcv_meshlet_include}/vkcv/meshlet/Tipsify.hpp
+		${vkcv_meshlet_source}/vkcv/meshlet/Tipsify.cpp
+
+		${vkcv_meshlet_include}/vkcv/meshlet/Forsyth.hpp
+		${vkcv_meshlet_source}/vkcv/meshlet/Forsyth.cpp)
+
+# adding source files to the module
+add_library(vkcv_meshlet STATIC ${vkcv_meshlet_sources})
+
+
+# link the required libraries to the module
+target_link_libraries(vkcv_meshlet vkcv ${vkcv_libraries})
+
+# including headers of dependencies and the VkCV framework
+target_include_directories(vkcv_meshlet SYSTEM BEFORE PRIVATE ${vkcv_include} ${vkcv_includes} ${vkcv_asset_loader_include} ${vkcv_camera_include})
+
+# add the own include directory for public headers
+target_include_directories(vkcv_meshlet BEFORE PUBLIC ${vkcv_meshlet_include})
+
+# linking with libraries from all dependencies and the VkCV framework
+target_link_libraries(vkcv_meshlet vkcv vkcv_asset_loader vkcv_camera)

modules/meshlet/include/vkcv/meshlet/Forsyth.hpp

+#pragma once
+
+#include "Meshlet.hpp"
+
+namespace vkcv::meshlet
+{
+ /**
+  * Reorders the index buffer, simulating a LRU cache, so that vertices are grouped together in close triangle patches
+  * @param idxBuf current IndexBuffer
+  * @param vertexCount of the mesh
+  * @return new reordered index buffer to replace the input index buffer
+  * References:
+  * https://tomforsyth1000.github.io/papers/fast_vert_cache_opt.html
+  * https://www.martin.st/thesis/efficient_triangle_reordering.pdf
+  * https://github.com/vivkin/forsyth/blob/master/forsyth.h
+  */
+ VertexCacheReorderResult forsythReorder(const std::vector<uint32_t> &idxBuf, const size_t vertexCount);
+}

modules/meshlet/include/vkcv/meshlet/Meshlet.hpp

+#pragma once
+
+#include <vector>
+#include <map>
+#include <glm/glm.hpp>
+#include <vkcv/asset/asset_loader.hpp>
+
+namespace vkcv::meshlet {
+
+    struct Vertex {
+        glm::vec3   position;
+        float       padding0;
+        glm::vec3   normal;
+        float       padding1;
+    };
+
+    struct Meshlet {
+        uint32_t    vertexOffset;
+        uint32_t    vertexCount;
+        uint32_t    indexOffset;
+        uint32_t    indexCount;
+        glm::vec3   meanPosition;
+        float       boundingSphereRadius;
+    };
+
+    struct VertexCacheReorderResult {
+        /**
+         * @param indexBuffer new indexBuffer
+         * @param skippedIndices indices that have a spacial break
+         */
+        VertexCacheReorderResult(const std::vector<uint32_t> indexBuffer, const std::vector<uint32_t> skippedIndices)
+                :indexBuffer(indexBuffer), skippedIndices(skippedIndices) {}
+
+        std::vector<uint32_t> indexBuffer;
+        std::vector<uint32_t>  skippedIndices;
+    };
+
+    struct MeshShaderModelData {
+        std::vector<Vertex>     vertices;
+        std::vector<uint32_t>   localIndices;
+        std::vector<Meshlet>    meshlets;
+    };
+
+    std::vector<Vertex> convertToVertices(
+            const std::vector<uint8_t>&         vertexData,
+            const uint64_t                      vertexCount,
+            const vkcv::asset::VertexAttribute& positionAttribute,
+            const vkcv::asset::VertexAttribute& normalAttribute);
+
+    MeshShaderModelData createMeshShaderModelData(
+            const std::vector<Vertex>&      inVertices,
+            const std::vector<uint32_t>&    inIndices,
+            const std::vector<uint32_t>& deadEndIndices = {});
+
+    std::vector<uint32_t> assetLoaderIndicesTo32BitIndices(
+            const std::vector<uint8_t>& indexData,
+            vkcv::asset::IndexType indexType);
+
+}
\ No newline at end of file

modules/meshlet/include/vkcv/meshlet/Tipsify.hpp

+#pragma once
+
+#include "Meshlet.hpp"
+#include <algorithm>
+#include <iostream>
+
+namespace vkcv::meshlet {
+    /**
+     * reorders the IndexBuffer, so all usages of vertices to triangle are as close as possible
+     * @param indexBuffer32Bit current IndexBuffer
+     * @param vertexCount of the mesh
+     * @param cacheSize of the priority cache <br>
+     * Recommended: 20. Keep the value between 5 and 50 <br>
+     * low:         more random and patchy<br>
+     * high:        closer vertices have higher chance -> leads to sinuous lines
+     * @return new IndexBuffer that replaces the input IndexBuffer, and the indices that are skipped
+     *
+     * https://gfx.cs.princeton.edu/pubs/Sander_2007_%3ETR/tipsy.pdf
+     * https://www.martin.st/thesis/efficient_triangle_reordering.pdf
+     */
+    VertexCacheReorderResult tipsifyMesh(const std::vector<uint32_t> &indexBuffer32Bit,
+                                         const int vertexCount, const unsigned int cacheSize = 20);
+}
\ No newline at end of file

modules/meshlet/src/vkcv/meshlet/Forsyth.cpp

+#include "vkcv/meshlet/Forsyth.hpp"
+#include <vkcv/Logger.hpp>
+#include <array>
+#include <cmath>
+
+namespace vkcv::meshlet
+{
+    /*
+     * CACHE AND VALENCE
+     * SIZE AND SCORE CONSTANTS
+     * CHANGE AS NEEDED
+     */
+
+    // set these to adjust performance and result quality
+    const size_t VERTEX_CACHE_SIZE = 8;
+    const size_t CACHE_FUNCTION_LENGTH = 32;
+
+    // score function constants
+    const float CACHE_DECAY_POWER = 1.5f;
+    const float LAST_TRI_SCORE = 0.75f;
+
+    const float VALENCE_BOOST_SCALE = 2.0f;
+    const float VALENCE_BOOST_POWER = 0.5f;
+
+    // sizes for precalculated tables
+    // make sure that cache score is always >= vertex_cache_size
+    const size_t CACHE_SCORE_TABLE_SIZE = 32;
+    const size_t VALENCE_SCORE_TABLE_SIZE = 32;
+
+    // precalculated tables
+    std::array<float, CACHE_SCORE_TABLE_SIZE> cachePositionScore = {};
+    std::array<float, VALENCE_SCORE_TABLE_SIZE> valenceScore = {};
+
+    // function to populate the cache position and valence score tables
+    void initScoreTables()
+    {
+        for(size_t i = 0; i < CACHE_SCORE_TABLE_SIZE; i++)
+        {
+            float score = 0.0f;
+            if (i < 3)
+            {
+                score = LAST_TRI_SCORE;
+            }
+            else
+            {
+                const float scaler = 1.0f / static_cast<float>(CACHE_FUNCTION_LENGTH - 3);
+                score = 1.0f - (i - 3) * scaler;
+                score = std::pow(score, CACHE_DECAY_POWER);
+            }
+            cachePositionScore[i] = score;
+        }
+
+        for(size_t i = 0; i < VALENCE_SCORE_TABLE_SIZE; i++)
+        {
+            const float valenceBoost = std::pow(i, -VALENCE_BOOST_POWER);
+            const float score = VALENCE_BOOST_SCALE * valenceBoost;
+
+            valenceScore[i] = score;
+        }
+    }
+
+    /**
+     * Return the vertex' score, depending on its current active triangle count and cache position
+     * Add a valence boost to score, if active triangles are below VALENCE_SCORE_TABLE_SIZE
+     * @param numActiveTris the active triangles on this vertex
+     * @param cachePos the vertex' position in the cache
+     * @return vertex' score
+     */
+    float findVertexScore(uint32_t numActiveTris, int32_t cachePos)
+    {
+        if(numActiveTris == 0)
+            return 0.0f;
+
+        float score = 0.0f;
+
+        if (cachePos >= 0)
+            score = cachePositionScore[cachePos];
+
+        if (numActiveTris < VALENCE_SCORE_TABLE_SIZE)
+            score += valenceScore[numActiveTris];
+
+        return score;
+    }
+
+    VertexCacheReorderResult forsythReorder(const std::vector<uint32_t> &idxBuf, const size_t vertexCount)
+    {
+        std::vector<uint32_t> skippedIndices;
+
+        initScoreTables();
+
+        // get the total triangle count from the index buffer
+        const size_t triangleCount = idxBuf.size() / 3;
+
+        // per-vertex active triangle count
+        std::vector<uint8_t> numActiveTris(vertexCount, 0);
+        // iterate over indices, count total occurrences of each vertex
+        for(const auto index : idxBuf)
+        {
+            if(numActiveTris[index] == UINT8_MAX)
+            {
+                vkcv_log(LogLevel::ERROR, "Unsupported mesh.");
+                vkcv_log(LogLevel::ERROR, "Vertex shared by too many triangles.");
+                return VertexCacheReorderResult({}, {});
+            }
+
+            numActiveTris[index]++;
+        }
+
+
+        // allocate remaining vectors
+        /**
+         * offsets: contains the vertices' offset into the triangleIndices vector
+         * Offset itself is the sum of triangles required by the previous vertices
+         *
+         * lastScore: the vertices' most recent calculated score
+         *
+         * cacheTag: the vertices' most recent cache score
+         *
+         * triangleAdded: boolean flags to denote whether a triangle has been processed or not
+         *
+         * triangleScore: total score of the three vertices making up the triangle
+         *
+         * triangleIndices: indices for the triangles
+         */
+        std::vector<uint32_t> offsets(vertexCount, 0);
+        std::vector<float> lastScore(vertexCount, 0.0f);
+        std::vector<int8_t> cacheTag(vertexCount, -1);
+
+        std::vector<bool> triangleAdded(triangleCount, false);
+        std::vector<float> triangleScore(triangleCount, 0.0f);
+
+        std::vector<int32_t> triangleIndices(idxBuf.size(), 0);
+
+
+        // sum the number of active triangles for all previous vertices
+        // null the number of active triangles afterwards for recalculation in second loop
+        uint32_t sum = 0;
+        for(size_t i = 0; i < vertexCount; i++)
+        {
+            offsets[i] = sum;
+            sum += numActiveTris[i];
+            numActiveTris[i] = 0;
+        }
+        // create the triangle indices, using the newly calculated offsets, and increment numActiveTris
+        // every vertex should be referenced by a triangle index now
+        for(size_t i = 0; i < triangleCount; i++)
+        {
+            for(size_t j = 0; j < 3; j++)
+            {
+                uint32_t v = idxBuf[3 * i + j];
+                triangleIndices[offsets[v] + numActiveTris[v]] = static_cast<int32_t>(i);
+                numActiveTris[v]++;
+            }
+        }
+
+        // calculate and initialize the triangle score, by summing the vertices' score
+        for (size_t i = 0; i < vertexCount; i++)
+        {
+            lastScore[i] = findVertexScore(numActiveTris[i], static_cast<int32_t>(cacheTag[i]));
+
+            for(size_t j = 0; j < numActiveTris[i]; j++)
+            {
+                triangleScore[triangleIndices[offsets[i] + j]] += lastScore[i];
+            }
+        }
+
+        // find best triangle to start reordering with
+        int32_t bestTriangle = -1;
+        float   bestScore    = -1.0f;
+        for(size_t i = 0; i < triangleCount; i++)
+        {
+            if(triangleScore[i] > bestScore)
+            {
+                bestScore = triangleScore[i];
+                bestTriangle = static_cast<int32_t>(i);
+            }
+        }
+
+        // allocate output triangles
+        std::vector<int32_t> outTriangles(triangleCount, 0);
+        uint32_t outPos = 0;
+
+        // initialize cache (with -1)
+        std::array<int32_t, VERTEX_CACHE_SIZE + 3> cache = {};
+        for(auto &element : cache)
+        {
+            element = -1;
+        }
+
+        uint32_t scanPos = 0;
+
+        // begin reordering routine
+        // output the currently best triangle, as long as there are triangles left to output
+        while(bestTriangle >= 0)
+        {
+            // mark best triangle as added
+            triangleAdded[bestTriangle] = true;
+            // output this triangle
+            outTriangles[outPos++] = bestTriangle;
+
+            // push best triangle's vertices into the cache
+            for(size_t i = 0; i < 3; i++)
+            {
+                uint32_t v = idxBuf[3 * bestTriangle + i];
+
+                // get vertex' cache position, if its -1, set its position to the end
+                int8_t endPos = cacheTag[v];
+                if(endPos < 0)
+                    endPos = static_cast<int8_t>(VERTEX_CACHE_SIZE + i);
+
+                // shift vertices' cache entries forward by one
+                for(int8_t j = endPos; j > i; j--)
+                {
+                    cache[j] = cache[j - 1];
+
+                    // if cache slot is valid vertex,
+                    // update the vertex cache tag accordingly
+                    if (cache[j] >= 0)
+                        cacheTag[cache[j]]++;
+                }
+
+                // insert current vertex into its new target slot
+                cache[i] = static_cast<int32_t>(v);
+                cacheTag[v] = static_cast<int8_t>(i);
+
+                // find current triangle in the list of active triangles
+                // remove it by moving the last triangle into the slot the current triangle is holding.
+                for (size_t j = 0; j < numActiveTris[v]; j++)
+                {
+                    if(triangleIndices[offsets[v] + j] == bestTriangle)
+                    {
+                        triangleIndices[offsets[v] + j] = triangleIndices[offsets[v] + numActiveTris[v] - 1];
+                        break;
+                    }
+                }
+                // shorten the list
+                numActiveTris[v]--;
+            }
+
+            // update scores of all triangles in cache
+            for (size_t i = 0; i < cache.size(); i++)
+            {
+                int32_t v = cache[i];
+                if (v < 0)
+                    break;
+
+                // this vertex has been pushed outside of the actual cache
+                if(i >= VERTEX_CACHE_SIZE)
+                {
+                    cacheTag[v] = -1;
+                    cache[i] = -1;
+                }
+
+                float newScore = findVertexScore(numActiveTris[v], cacheTag[v]);
+                float diff = newScore - lastScore[v];
+
+                for(size_t j = 0; j < numActiveTris[v]; j++)
+                {
+                    triangleScore[triangleIndices[offsets[v] + j]] += diff;
+                }
+                lastScore[v] = newScore;
+            }
+
+            // find best triangle reference by vertices in cache
+            bestTriangle = -1;
+            bestScore = -1.0f;
+            for(size_t i = 0; i < VERTEX_CACHE_SIZE; i++)
+            {
+                if (cache[i] < 0)
+                    break;
+
+                int32_t v = cache[i];
+                for(size_t j = 0; j < numActiveTris[v]; j++)
+                {
+                    int32_t t = triangleIndices[offsets[v] + j];
+                    if(triangleScore[t] > bestScore)
+                    {
+                        bestTriangle = t;
+                        bestScore = triangleScore[t];
+                    }
+                }
+            }
+
+            // if no triangle was found at all, continue scanning whole list of triangles
+            if (bestTriangle < 0)
+            {
+                for(; scanPos < triangleCount; scanPos++)
+                {
+                    if(!triangleAdded[scanPos])
+                    {
+                        bestTriangle = scanPos;
+
+                        skippedIndices.push_back(3 * outPos);
+
+                        break;
+                    }
+                }
+            }
+        }
+
+
+        // convert triangle index array into full triangle list
+        std::vector<uint32_t> outIndices(idxBuf.size(), 0);
+        outPos = 0;
+        for(size_t i = 0; i < triangleCount; i++)
+        {
+            int32_t t = outTriangles[i];
+            for(size_t j = 0; j < 3; j++)
+            {
+                int32_t v = idxBuf[3 * t + j];
+                outIndices[outPos++] = static_cast<uint32_t>(v);
+            }
+        }
+
+        return VertexCacheReorderResult(outIndices, skippedIndices);
+    }
+}
\ No newline at end of file

modules/meshlet/src/vkcv/meshlet/Meshlet.cpp

+
+#include "vkcv/meshlet/Meshlet.hpp"
+#include <vkcv/Logger.hpp>
+#include <cassert>
+#include <iostream>
+
+namespace vkcv::meshlet {
+
+std::vector<vkcv::meshlet::Vertex> convertToVertices(
+        const std::vector<uint8_t>&         vertexData,
+        const uint64_t                      vertexCount,
+        const vkcv::asset::VertexAttribute& positionAttribute,
+        const vkcv::asset::VertexAttribute& normalAttribute) {
+
+    assert(positionAttribute.type   == vkcv::asset::PrimitiveType::POSITION);
+    assert(normalAttribute.type     == vkcv::asset::PrimitiveType::NORMAL);
+
+    std::vector<vkcv::meshlet::Vertex> vertices;
+    vertices.reserve(vertexCount);
+
+    const size_t positionStepSize   = positionAttribute.stride == 0 ? sizeof(glm::vec3) : positionAttribute.stride;
+    const size_t normalStepSize     = normalAttribute.stride   == 0 ? sizeof(glm::vec3) : normalAttribute.stride;
+
+    for (int i = 0; i < vertexCount; i++) {
+        Vertex v;
+
+        const size_t positionOffset = positionAttribute.offset  + positionStepSize  * i;
+        const size_t normalOffset   = normalAttribute.offset    + normalStepSize    * i;
+
+        v.position  = *reinterpret_cast<const glm::vec3*>(&(vertexData[positionOffset]));
+        v.normal    = *reinterpret_cast<const glm::vec3*>(&(vertexData[normalOffset]));
+        vertices.push_back(v);
+    }
+    return vertices;
+}
+
+MeshShaderModelData createMeshShaderModelData(
+        const std::vector<Vertex>&      inVertices,
+        const std::vector<uint32_t>&    inIndices,
+        const std::vector<uint32_t>&    deadEndIndices) {
+
+    MeshShaderModelData data;
+    size_t currentIndex = 0;
+
+    const size_t maxVerticesPerMeshlet = 64;
+    const size_t maxIndicesPerMeshlet  = 126 * 3;
+
+    bool indicesAreLeft = true;
+
+    size_t deadEndIndicesIndex = 0;
+
+    while (indicesAreLeft) {
+        Meshlet meshlet;
+
+        meshlet.indexCount  = 0;
+        meshlet.vertexCount = 0;
+
+        meshlet.indexOffset  = data.localIndices.size();
+        meshlet.vertexOffset = data.vertices.size();
+
+        std::map<uint32_t, uint32_t> globalToLocalIndexMap;
+        std::vector<uint32_t> globalIndicesOrdered;
+
+        while (true) {
+
+            if (deadEndIndicesIndex < deadEndIndices.size()) {
+                const uint32_t deadEndIndex = deadEndIndices[deadEndIndicesIndex];
+                if (deadEndIndex == currentIndex) {
+                    deadEndIndicesIndex++;
+                    break;
+                }
+            }
+
+            indicesAreLeft = currentIndex + 1 <= inIndices.size();
+            if (!indicesAreLeft) {
+                break;
+            }
+
+            bool enoughSpaceForIndices = meshlet.indexCount + 3 < maxIndicesPerMeshlet;
+            if (!enoughSpaceForIndices) {
+                break;
+            }
+
+            size_t vertexCountToAdd = 0;
+            for (int i = 0; i < 3; i++) {
+                const uint32_t globalIndex = inIndices[currentIndex + i];
+                const bool containsVertex  = globalToLocalIndexMap.find(globalIndex) != globalToLocalIndexMap.end();
+                if (!containsVertex) {
+                    vertexCountToAdd++;
+                }
+            }
+
+            bool enoughSpaceForVertices = meshlet.vertexCount + vertexCountToAdd < maxVerticesPerMeshlet;
+            if (!enoughSpaceForVertices) {
+                break;
+            }
+
+            for (int i = 0; i < 3; i++) {
+                const uint32_t globalIndex = inIndices[currentIndex + i];
+
+                uint32_t localIndex;
+                const bool indexAlreadyExists = globalToLocalIndexMap.find(globalIndex) != globalToLocalIndexMap.end();
+                if (indexAlreadyExists) {
+                    localIndex = globalToLocalIndexMap[globalIndex];
+                }
+                else {
+                    localIndex = globalToLocalIndexMap.size();
+                    globalToLocalIndexMap[globalIndex] = localIndex;
+                    globalIndicesOrdered.push_back(globalIndex);
+                }
+
+                data.localIndices.push_back(localIndex);
+            }
+
+            meshlet.indexCount  += 3;
+            currentIndex        += 3;
+            meshlet.vertexCount += vertexCountToAdd;
+        }
+
+        for (const uint32_t globalIndex : globalIndicesOrdered) {
+            const Vertex v = inVertices[globalIndex];
+            data.vertices.push_back(v);
+        }
+
+        // compute mean position
+        meshlet.meanPosition = glm::vec3(0);
+        const uint32_t meshletLastVertexIndex = meshlet.vertexOffset + meshlet.vertexCount;
+
+        for (uint32_t vertexIndex = meshlet.vertexOffset; vertexIndex < meshletLastVertexIndex; vertexIndex++) {
+            const Vertex& v         = data.vertices[vertexIndex];
+            meshlet.meanPosition    += v.position;
+        }
+        meshlet.meanPosition /= meshlet.vertexCount;
+
+        // compute bounding sphere radius
+        meshlet.boundingSphereRadius = 0.f;
+        for (uint32_t vertexIndex = meshlet.vertexOffset; vertexIndex < meshletLastVertexIndex; vertexIndex++) {
+            const Vertex& v = data.vertices[vertexIndex];
+            const float d                   = glm::distance(v.position, meshlet.meanPosition);
+            meshlet.boundingSphereRadius    = glm::max(meshlet.boundingSphereRadius, d);
+        }
+
+        data.meshlets.push_back(meshlet);
+    }
+
+    return data;
+}
+
+std::vector<uint32_t> assetLoaderIndicesTo32BitIndices(const std::vector<uint8_t>& indexData, vkcv::asset::IndexType indexType) {
+    std::vector<uint32_t> indices;
+    if (indexType == vkcv::asset::IndexType::UINT16) {
+        for (int i = 0; i < indexData.size(); i += 2) {
+            const uint16_t index16Bit = *reinterpret_cast<const uint16_t *>(&(indexData[i]));
+            const uint32_t index32Bit = static_cast<uint32_t>(index16Bit);
+            indices.push_back(index32Bit);
+        }
+    } else if (indexType == vkcv::asset::IndexType::UINT32) {
+        for (int i = 0; i < indexData.size(); i += 4) {
+            const uint32_t index32Bit = *reinterpret_cast<const uint32_t *>(&(indexData[i]));
+            indices.push_back(index32Bit);
+        }
+    } else {
+        vkcv_log(vkcv::LogLevel::ERROR, "Unsupported index type");
+    }
+    return indices;
+}
+}
\ No newline at end of file

modules/meshlet/src/vkcv/meshlet/Tipsify.cpp

+
+#include <vkcv/Logger.hpp>
+#include "vkcv/meshlet/Tipsify.hpp"
+#include <iostream>
+
+namespace vkcv::meshlet {
+
+    const int maxUsedVertices           = 128;
+
+    /**
+     * modulo operation with maxUsedVertices
+     * @param number for modulo operation
+     * @return number between 0 and maxUsedVertices - 1
+     */
+    int mod( int number ){
+        return (number + maxUsedVertices) % maxUsedVertices;
+    }
+
+    /**
+     * searches for the next VertexIndex that was used before or returns any vertexIndex if no used was found
+     * @param livingTriangles
+     * @param usedVerticeStack
+     * @param usedVerticeCount
+     * @param usedVerticeOffset
+     * @param vertexCount
+     * @param lowestLivingVertexIndex
+     * @param currentTriangleIndex
+     * @param skippedIndices
+     * @return a VertexIndex to be used as fanningVertexIndex
+     */
+    int skipDeadEnd(
+            const std::vector<uint8_t> &livingTriangles,
+            const std::vector<uint32_t> &usedVerticeStack,
+            int &usedVerticeCount,
+            int &usedVerticeOffset,
+            int vertexCount,
+            int &lowestLivingVertexIndex,
+            int &currentTriangleIndex,
+            std::vector<uint32_t> &skippedIndices) {
+
+        // returns the latest vertex used that has a living triangle
+        while (mod(usedVerticeCount) != usedVerticeOffset) {
+            // iterate from the latest to the oldest. + maxUsedVertices to always make it a positive number in the range 0 to maxUsedVertices -1
+            int nextVertex = usedVerticeStack[mod(--usedVerticeCount)];
+
+            if (livingTriangles[nextVertex] > 0) {
+                return nextVertex;
+            }
+        }
+        // returns any vertexIndex since no last used has a living triangle
+        while (lowestLivingVertexIndex + 1 < vertexCount) {
+            lowestLivingVertexIndex++;
+            if (livingTriangles[lowestLivingVertexIndex] > 0) {
+                // add index of the vertex to skippedIndices
+                skippedIndices.push_back(static_cast<uint32_t>(currentTriangleIndex * 3));
+                return lowestLivingVertexIndex;
+            }
+        }
+        return -1;
+    }
+
+    /**
+     * searches for the best next candidate as a fanningVertexIndex
+     * @param vertexCount
+     * @param lowestLivingVertexIndex
+     * @param cacheSize
+     * @param possibleCandidates
+     * @param numPossibleCandidates
+     * @param lastTimestampCache
+     * @param currentTimeStamp
+     * @param livingTriangles
+     * @param usedVerticeStack
+     * @param usedVerticeCount
+     * @param usedVerticeOffset
+     * @param currentTriangleIndex
+     * @param skippedIndices
+     * @return a VertexIndex to be used as fanningVertexIndex
+     */
+    int getNextVertexIndex(int vertexCount,
+                           int &lowestLivingVertexIndex,
+                           int cacheSize,
+                           const std::vector<uint32_t> &possibleCandidates,
+                           int numPossibleCandidates,
+                           const std::vector<uint32_t> &lastTimestampCache,
+                           int currentTimeStamp,
+                           const std::vector<uint8_t> &livingTriangles,
+                           const std::vector<uint32_t> &usedVerticeStack,
+                           int &usedVerticeCount,
+                           int &usedVerticeOffset,
+                           int &currentTriangleIndex,
+                           std::vector<uint32_t> &skippedIndices) {
+        int nextVertexIndex = -1;
+        int maxPriority     = -1;
+        // calculates the next possibleCandidates that is recently used
+        for (int j = 0; j < numPossibleCandidates; j++) {
+            int vertexIndex = possibleCandidates[j];
+
+            // the candidate needs to be not fanned out yet
+            if (livingTriangles[vertexIndex] > 0) {
+                int priority = -1;
+
+                // prioritizes recent used vertices, but tries not to pick one that has many triangles -> fills holes better
+                if ( currentTimeStamp - lastTimestampCache[vertexIndex] + 2 * livingTriangles[vertexIndex] <=
+                    cacheSize) {
+                    priority = currentTimeStamp - lastTimestampCache[vertexIndex];
+                }
+                // select the vertexIndex with the highest priority
+                if (priority > maxPriority) {
+                    maxPriority     = priority;
+                    nextVertexIndex = vertexIndex;
+                }
+            }
+        }
+
+        // if no candidate is alive, try and find another one
+        if (nextVertexIndex == -1) {
+            nextVertexIndex = skipDeadEnd(
+                    livingTriangles,
+                    usedVerticeStack,
+                    usedVerticeCount,
+                    usedVerticeOffset,
+                    vertexCount,
+                    lowestLivingVertexIndex,
+                    currentTriangleIndex,
+                    skippedIndices);
+        }
+        return nextVertexIndex;
+    }
+
+    VertexCacheReorderResult tipsifyMesh(
+            const std::vector<uint32_t> &indexBuffer32Bit,
+            const int vertexCount,
+            const unsigned int cacheSize) {
+
+        if (indexBuffer32Bit.empty() || vertexCount <= 0) {
+            vkcv_log(LogLevel::ERROR, "Invalid Input.");
+            return VertexCacheReorderResult(indexBuffer32Bit , {});
+        }
+        int triangleCount = indexBuffer32Bit.size() / 3;
+
+       // dynamic array for vertexOccurrence
+        std::vector<uint8_t> vertexOccurrence(vertexCount, 0);
+        // count the occurrence of a vertex in all among all triangles
+        for (size_t i = 0; i < triangleCount * 3; i++) {
+            vertexOccurrence[indexBuffer32Bit[i]]++;
+        }
+
+        int sum = 0;
+        std::vector<uint32_t> offsetVertexOccurrence(vertexCount + 1, 0);
+        // highest offset for later iteration
+        int maxOffset = 0;
+        // calculate the offset of each vertex from the start
+        for (int i = 0; i < vertexCount; i++) {
+            offsetVertexOccurrence[i]   = sum;
+            sum                         += vertexOccurrence[i];
+
+            if (vertexOccurrence[i] > maxOffset) {
+                maxOffset = vertexOccurrence[i];
+            }
+            // reset for reuse
+            vertexOccurrence[i] = 0;
+        }
+        offsetVertexOccurrence[vertexCount] = sum;
+
+        // vertexIndexToTriangle = which vertex belongs to which triangle
+        std::vector<uint32_t> vertexIndexToTriangle(3 * triangleCount, 0);
+        // vertexOccurrence functions as number of usages in all triangles
+        // lowestLivingVertexIndex = number of a triangle
+        for (int i = 0; i < triangleCount; i++) {
+            // get the pointer to the first vertex of the triangle
+            // this allows us to iterate over the indexBuffer with the first vertex of the triangle as start
+            const uint32_t *vertexIndexOfTriangle = &indexBuffer32Bit[i * 3];
+
+            vertexIndexToTriangle[offsetVertexOccurrence[vertexIndexOfTriangle[0]] + vertexOccurrence[vertexIndexOfTriangle[0]]] = i;
+            vertexOccurrence[vertexIndexOfTriangle[0]]++;
+
+            vertexIndexToTriangle[offsetVertexOccurrence[vertexIndexOfTriangle[1]] + vertexOccurrence[vertexIndexOfTriangle[1]]] = i;
+            vertexOccurrence[vertexIndexOfTriangle[1]]++;
+
+            vertexIndexToTriangle[offsetVertexOccurrence[vertexIndexOfTriangle[2]] + vertexOccurrence[vertexIndexOfTriangle[2]]] = i;
+            vertexOccurrence[vertexIndexOfTriangle[2]]++;
+        }
+
+        // counts if a triangle still uses this vertex
+        std::vector<uint8_t>  livingVertices = vertexOccurrence;
+        std::vector<uint32_t> lastTimestampCache(vertexCount, 0);
+
+        // stack of already used vertices, if it'currentTimeStamp full it will write to 0 again
+        std::vector<uint32_t> usedVerticeStack(maxUsedVertices, 0);
+
+        //currently used vertices
+        int usedVerticeCount     = 0;
+        // offset if maxUsedVertices was reached and it loops back to 0
+        int usedVerticeOffset    = 0;
+
+        // saves if a triangle was emitted (used in the IndexBuffer)
+        std::vector<bool> isEmittedTriangles(triangleCount, false);
+
+        // reordered Triangles that get rewritten to the new IndexBuffer
+        std::vector<uint32_t> reorderedTriangleIndexBuffer(triangleCount, 0);
+
+        // offset to the latest not used triangleIndex
+        int triangleOutputOffset    = 0;
+        // vertexIndex to fan out from (fanning VertexIndex)
+        int currentVertexIndex      = 0;
+        int currentTimeStamp        = cacheSize + 1;
+        int lowestLivingVertexIndex = 0;
+
+        std::vector<uint32_t> possibleCandidates(3 * maxOffset);
+
+        int currentTriangleIndex = 0;
+        // list of vertex indices where a deadEnd was reached
+        // useful to know where the mesh is potentially not contiguous
+        std::vector<uint32_t> skippedIndices;
+
+        // run while not all indices are fanned out, -1 equals all are fanned out
+        while (currentVertexIndex >= 0) {
+            // number of possible candidates for a fanning VertexIndex
+            int numPossibleCandidates   = 0;
+            // offset of currentVertexIndex and the next VertexIndex
+            int startOffset             = offsetVertexOccurrence[currentVertexIndex];
+            int endOffset               = offsetVertexOccurrence[currentVertexIndex + 1];
+            // iterates over every triangle of currentVertexIndex
+            for (int offset = startOffset; offset < endOffset; offset++) {
+                int triangleIndex = vertexIndexToTriangle[offset];
+
+                // checks if the triangle is already emitted
+                if (!isEmittedTriangles[triangleIndex]) {
+
+                    // get the pointer to the first vertex of the triangle
+                    // this allows us to iterate over the indexBuffer with the first vertex of the triangle as start
+                    const uint32_t *vertexIndexOfTriangle        = &indexBuffer32Bit[3 * triangleIndex];
+
+                    currentTriangleIndex++;
+
+                    // save emitted vertexIndexOfTriangle to reorderedTriangleIndexBuffer and set it to emitted
+                    reorderedTriangleIndexBuffer[triangleOutputOffset++]    = triangleIndex;
+                    isEmittedTriangles[triangleIndex]                       = true;
+
+                    // save all vertexIndices of the triangle to reuse as soon as possible
+                    for (int j = 0; j < 3; j++) {
+                        int vertexIndex = vertexIndexOfTriangle[j];
+
+                        //save vertexIndex to reuseStack
+                        usedVerticeStack[mod(usedVerticeCount++)] = vertexIndex;
+
+                        // after looping back increase the start, so it only overrides the oldest vertexIndex
+                        if ((mod(usedVerticeCount)) ==
+                            (mod(usedVerticeOffset))) {
+                            usedVerticeOffset = mod(usedVerticeOffset + 1);
+                        }
+                        // add vertex to next possibleCandidates as fanning vertex
+                        possibleCandidates[numPossibleCandidates++] = vertexIndex;
+
+                        // remove one occurrence of the vertex, since the triangle is used
+                        livingVertices[vertexIndex]--;
+
+                        // writes the timestamp (number of iteration) of the last usage, if it wasn't used within the last cacheSize iterations
+                        if (currentTimeStamp - lastTimestampCache[vertexIndex] > cacheSize) {
+                            lastTimestampCache[vertexIndex] = currentTimeStamp;
+                            currentTimeStamp++;
+                        }
+                    }
+                }
+            }
+
+            // search for the next vertexIndex to fan out
+            currentVertexIndex = getNextVertexIndex(
+                    vertexCount, lowestLivingVertexIndex, cacheSize, possibleCandidates, numPossibleCandidates, lastTimestampCache, currentTimeStamp,
+                    livingVertices, usedVerticeStack, usedVerticeCount, usedVerticeOffset, currentTriangleIndex, skippedIndices);
+        }
+
+        std::vector<uint32_t> reorderedIndexBuffer(3 * triangleCount);
+
+        triangleOutputOffset = 0;
+        // rewriting the TriangleIndexBuffer to the new IndexBuffer
+        for (int i = 0; i < triangleCount; i++) {
+            int triangleIndex = reorderedTriangleIndexBuffer[i];
+            // rewriting the triangle index to vertices
+            for (int j = 0; j < 3; j++) {
+                int vertexIndex = indexBuffer32Bit[(3 * triangleIndex) + j];
+                reorderedIndexBuffer[triangleOutputOffset++] = vertexIndex;
+            }
+        }
+
+        return VertexCacheReorderResult(reorderedIndexBuffer, skippedIndices);
+    }
+}
\ No newline at end of file

modules/scene/CMakeLists.txt

@@ -13,7 +13,7 @@ set(vkcv_scene_sources
 		${vkcv_scene_include}/vkcv/scene/Bounds.hpp
 		${vkcv_scene_source}/vkcv/scene/Bounds.cpp
 		
-		${vkcv_scene_source}/vkcv/scene/Frustum.hpp
+		${vkcv_scene_include}/vkcv/scene/Frustum.hpp
 		${vkcv_scene_source}/vkcv/scene/Frustum.cpp
 		
 		${vkcv_scene_include}/vkcv/scene/MeshPart.hpp
@@ -21,7 +21,7 @@ set(vkcv_scene_sources
 		
 		${vkcv_scene_include}/vkcv/scene/Mesh.hpp
 		${vkcv_scene_source}/vkcv/scene/Mesh.cpp
-		
+
 		${vkcv_scene_include}/vkcv/scene/Node.hpp
 		${vkcv_scene_source}/vkcv/scene/Node.cpp
 		
@@ -42,4 +42,4 @@ target_include_directories(vkcv_scene SYSTEM BEFORE PRIVATE ${vkcv_include} ${vk
 target_include_directories(vkcv_scene BEFORE PUBLIC ${vkcv_scene_include})
 
 # linking with libraries from all dependencies and the VkCV framework
-target_link_libraries(vkcv_scene vkcv vkcv_asset_loader vkcv_material vkcv_camera)
+target_link_libraries(vkcv_scene vkcv vkcv_asset_loader vkcv_material vkcv_camera)
\ No newline at end of file

modules/scene/src/vkcv/scene/Frustum.cpp

 
-#include "Frustum.hpp"
+#include "vkcv/scene/Frustum.hpp"
 
 namespace vkcv::scene {
 	

modules/scene/src/vkcv/scene/Mesh.cpp

 
 #include "vkcv/scene/Mesh.hpp"
 #include "vkcv/scene/Scene.hpp"
-#include "Frustum.hpp"
+#include "vkcv/scene/Frustum.hpp"
 
 namespace vkcv::scene {
 	

modules/scene/src/vkcv/scene/Node.cpp

 
 #include "vkcv/scene/Node.hpp"
 #include "vkcv/scene/Scene.hpp"
-#include "Frustum.hpp"
+#include "vkcv/scene/Frustum.hpp"
 
 #include <algorithm>
 

modules/shader_compiler/src/vkcv/shader/GLSLCompiler.cpp

@@ -52,6 +52,10 @@ namespace vkcv::shader {
 				return EShLangFragment;
 			case ShaderStage::COMPUTE:
 				return EShLangCompute;
+			case ShaderStage::TASK:
+				return EShLangTaskNV;
+			case ShaderStage::MESH:
+				return EShLangMeshNV;
 			default:
 				return EShLangCount;
 		}

projects/CMakeLists.txt

@@ -5,3 +5,4 @@ add_subdirectory(first_mesh)
 add_subdirectory(first_scene)
 add_subdirectory(particle_simulation)
 add_subdirectory(voxelization)
+add_subdirectory(mesh_shader)

projects/mesh_shader/.gitignore

+first_triangle
\ No newline at end of file