Construction of Embree acceleration structure

Author: MrMagnifico

.vscode/settings.json

@@ -88,5 +88,9 @@
         "bitset": "cpp",
         "regex": "cpp",
         "typeindex": "cpp"
+    },
+    "cmake.buildEnvironment": {
+        "embree_DIR": "C:/embree-4.3.1.x64.windows/lib/cmake/embree-4.3.1/",
+        "TBB_DIR": "C:/Program Files (x86)/Intel/oneAPI/tbb/2021.12/lib/cmake/tbb/"
     }
 }

CMakeLists.txt

@@ -16,6 +16,8 @@ else()
 	set(REFERENCE_MODE ON)
 endif()
 
+set(embree_DIR "C:/embree-4.3.1/lib/cmake/embree-4.3.1/") # Replace with directory to local Embree installation
+find_package(embree REQUIRED)
 find_package(OpenGL REQUIRED)
 find_package(OpenMP REQUIRED)
 
@@ -24,7 +26,7 @@ enable_sanitizers(CGFinProjLib)
 set_project_warnings(CGFinProjLib)
 include(${CMAKE_CURRENT_LIST_DIR}/src/CMakeLists.txt)
 target_include_directories(CGFinProjLib INTERFACE "${CMAKE_CURRENT_LIST_DIR}/src/")
-target_link_libraries(CGFinProjLib INTERFACE CGFramework OpenGL::GLU OpenMP::OpenMP_CXX)
+target_link_libraries(CGFinProjLib INTERFACE CGFramework OpenGL::GLU OpenMP::OpenMP_CXX embree)
 target_compile_features(CGFinProjLib INTERFACE cxx_std_20)
 
 # Main executable config

framework/third_party/eigen-3.4.0/CMakeLists.txt

@@ -583,7 +583,7 @@ if(BUILD_TESTING)
   message(STATUS "         |   http://eigen.tuxfamily.org/index.php?title=Tests")
 endif()
 message(STATUS "blas     | Build BLAS library (not the same thing as Eigen)")
-message(STATUS "eigen_uninstall | Remove files installed by the install target")
+message(STATUS "uninstall| Remove files installed by the install target")
 message(STATUS "---------+--------------------------------------------------------------")
 message(STATUS "")
 

src/CMakeLists.txt

@@ -4,6 +4,7 @@ target_sources(CGFinProjLib
 
         "${CMAKE_CURRENT_LIST_DIR}/ray_tracing/bounding_volume_hierarchy.cpp"
         "${CMAKE_CURRENT_LIST_DIR}/ray_tracing/bvh_interface.cpp"
+        "${CMAKE_CURRENT_LIST_DIR}/ray_tracing/embree_interface.cpp"
         "${CMAKE_CURRENT_LIST_DIR}/ray_tracing/interpolate.cpp"
         "${CMAKE_CURRENT_LIST_DIR}/ray_tracing/intersect.cpp"
 

src/main.cpp

@@ -1,7 +1,8 @@
-#include <scene/light.h>
+#include <ray_tracing/embree_interface.h>
 #include <rendering/render.h>
 #include <rendering/reservoir.h>
 #include <rendering/screen.h>
+#include <scene/light.h>
 #include <ui/draw.h>
 #include <ui/ui.h>
 #include <utils/config.h>
@@ -60,6 +61,7 @@ int main(int argc, char** argv) {
         SceneType sceneType = SceneType::CornellNightClub;
         std::optional<Ray> optDebugRay;
         Scene scene         = loadScenePrebuilt(sceneType, config.dataPath);
+        EmbreeInterface embreeInterface(scene);
         BvhInterface bvh(&scene);
         std::shared_ptr<ReservoirGrid> previousFrameGrid;
 

src/ray_tracing/embree_interface.cpp

@@ -0,0 +1,52 @@
+#include "embree_interface.h"
+
+#include <utils/utils.h>
+
+#include <format>
+#include <stdexcept>
+
+EmbreeInterface::EmbreeInterface(const Scene& scene) {
+    // Create device
+    m_device = rtcNewDevice(NULL);
+    if (!m_device) { std::runtime_error(std::format("Error {}: Cannot create device ", magic_enum::enum_name(rtcGetDeviceError(NULL)))); }
+    rtcSetDeviceErrorFunction(m_device, errorFunction, NULL);
+
+    // Load all geometry to Embree scene
+    m_scene = rtcNewScene(m_device);
+    for (const Mesh& mesh : scene.meshes) {
+        // Create and populate buffers to house vertex and triangle data
+        RTCGeometry geom    = rtcNewGeometry(m_device, RTC_GEOMETRY_TYPE_TRIANGLE);
+        rtcSetGeometryVertexAttributeCount(geom, 1);
+        glm::vec3* positions    = (glm::vec3*)  rtcSetNewGeometryBuffer(geom,   RTC_BUFFER_TYPE_VERTEX,             0,  RTC_FORMAT_FLOAT3,  sizeof(glm::vec3),  mesh.vertices.size());
+        glm::vec2* texCoords    = (glm::vec2*)  rtcSetNewGeometryBuffer(geom,   RTC_BUFFER_TYPE_VERTEX_ATTRIBUTE,   0,  RTC_FORMAT_FLOAT2,  sizeof(glm::vec2),  mesh.vertices.size());
+        glm::uvec3* indices     = (glm::uvec3*) rtcSetNewGeometryBuffer(geom,   RTC_BUFFER_TYPE_INDEX,              0,  RTC_FORMAT_UINT3,   sizeof(glm::uvec3), mesh.triangles.size());
+        populateVertexDataBuffers(positions, texCoords, mesh.vertices);
+        populateIndexBuffer(indices, mesh.triangles);
+
+        // Commit geometry and store its ID for material info lookup
+        rtcCommitGeometry(geom);
+        uint32_t geomId             = rtcAttachGeometry(m_scene, geom);
+        m_meshToMaterial[geomId]    = mesh.material;
+        rtcReleaseGeometry(geom);
+    }
+    rtcCommitScene(m_scene);
+}
+
+EmbreeInterface::~EmbreeInterface() {
+    rtcReleaseScene(m_scene);
+    rtcReleaseDevice(m_device);
+}
+
+void EmbreeInterface::populateVertexDataBuffers(glm::vec3* positionBuffer, glm::vec2* texCoordBuffer,
+                                                const std::vector<Vertex>& vertices) {
+    for (size_t vertexIdx = 0ULL; vertexIdx < vertices.size(); vertexIdx++) {
+        positionBuffer[vertexIdx]   = vertices[vertexIdx].position;
+        texCoordBuffer[vertexIdx]   = vertices[vertexIdx].texCoord;
+    }
+}
+
+void EmbreeInterface::populateIndexBuffer(glm::uvec3* indexBuffer, const std::vector<glm::uvec3>& indices) {
+    for (size_t triangleIdx = 0ULL; triangleIdx < indices.size(); triangleIdx++) {
+        indexBuffer[triangleIdx] = indices[triangleIdx];
+    }
+}

src/ray_tracing/embree_interface.h

@@ -0,0 +1,28 @@
+#pragma once
+#ifndef _EMBREE_INTERFACE_H_
+#define _EMBREE_INTERFACE_H_
+
+#include <embree4/rtcore.h>
+
+#include <scene/scene.h>
+
+#include <unordered_map>
+
+
+class EmbreeInterface {
+public:
+    EmbreeInterface(const Scene& scene);
+    ~EmbreeInterface();
+
+private:
+    void populateVertexDataBuffers(glm::vec3* positionBuffer, glm::vec2* texCoordBuffer,
+                                   const std::vector<Vertex>& vertices);
+    void populateIndexBuffer(glm::uvec3* indexBuffer, const std::vector<glm::uvec3>& indices);
+
+    RTCDevice m_device;
+    RTCScene m_scene;
+    std::unordered_map<uint32_t, Material> m_meshToMaterial;
+};
+
+
+#endif // _EMBREE_INTERFACE_H_

src/utils/utils.cpp

@@ -3,6 +3,8 @@ DISABLE_WARNINGS_PUSH()
 #include <glm/gtc/type_ptr.hpp>
 DISABLE_WARNINGS_POP()
 
+#include <embree4/rtcore.h>
+
 #include <framework/opengl_includes.h>
 
 #include <scene/texture.h>
@@ -54,6 +56,10 @@ bool testVisibilityLightSample(const glm::vec3& samplePos, const BvhInterface& b
     return false;
 }
 
+void errorFunction(void* userPtr, enum RTCError error, const char* str) {
+    std::cout << std::format("[EMBREE] {}: {}", magic_enum::enum_name(error), str) << std::endl;
+}
+
 void setOpenGLMatrices(const Trackball& camera) {
     // Load view matrix.
     glMatrixMode(GL_MODELVIEW);

src/utils/utils.h

@@ -29,6 +29,9 @@ inline bool inRangeInclusive(T val, T low, T high) { return low <= val && val <=
 glm::vec3 diffuseAlbedo(const HitInfo& hitInfo, const Features& features);
 bool testVisibilityLightSample(const glm::vec3& samplePos, const BvhInterface& bvh, const Features& features, Ray ray, HitInfo hitInfo);
 
+// Embree
+void errorFunction(void* userPtr, enum RTCError error, const char* str);
+
 // Framework
 void setOpenGLMatrices(const Trackball& camera);