RacingEngine/src/VulkanAcceleration.h at d0c4d0b10cd34d1ff7040f9572906d3cfe5ada62 · TECHNICANGEL/RacingEngine · GitHub

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#pragma once

#include <vulkan/vulkan.h>
#include <glm/glm.hpp>
#include <vector>

// Forward declaration
struct Transform;

struct Vertex {
    glm::vec3 pos;
    glm::vec3 normal;
};

struct AccelerationStructure {
    VkAccelerationStructureKHR handle = VK_NULL_HANDLE;
    VkBuffer buffer = VK_NULL_HANDLE;
    VkDeviceMemory memory = VK_NULL_HANDLE;
    VkDeviceAddress deviceAddress = 0;
};

struct GeometryObject {
    VkBuffer vertexBuffer = VK_NULL_HANDLE;
    VkDeviceMemory vertexBufferMemory = VK_NULL_HANDLE;
    VkBuffer indexBuffer = VK_NULL_HANDLE;
    VkDeviceMemory indexBufferMemory = VK_NULL_HANDLE;
    uint32_t vertexCount = 0;
    uint32_t indexCount = 0;
    AccelerationStructure blas;

    // CPU copies for deformation/destruction
    std::vector<Vertex> cpuVertices;
    std::vector<uint32_t> cpuIndices;
};

class VulkanAcceleration {
public:
    // Multiple geometry objects
    std::vector<GeometryObject> objects;

    // Top Level Acceleration Structure
    AccelerationStructure tlas;

    // Instance buffer (for dynamic TLAS updates)
    VkBuffer instanceBuffer = VK_NULL_HANDLE;
    VkDeviceMemory instanceBufferMemory = VK_NULL_HANDLE;
    uint32_t instanceCount = 0;

    // Pre-allocated scratch buffer for TLAS updates (avoids per-frame allocation)
    VkBuffer tlasScratchBuffer = VK_NULL_HANDLE;
    VkDeviceMemory tlasScratchMemory = VK_NULL_HANDLE;
    VkDeviceSize tlasScratchSize = 0;
    VkDeviceAddress tlasScratchAddress = 0;
    VkDeviceAddress instanceBufferAddress = 0;

    // Function pointers for ray tracing
    PFN_vkGetBufferDeviceAddressKHR vkGetBufferDeviceAddressKHR;
    PFN_vkCreateAccelerationStructureKHR vkCreateAccelerationStructureKHR;
    PFN_vkDestroyAccelerationStructureKHR vkDestroyAccelerationStructureKHR;
    PFN_vkGetAccelerationStructureBuildSizesKHR vkGetAccelerationStructureBuildSizesKHR;
    PFN_vkGetAccelerationStructureDeviceAddressKHR vkGetAccelerationStructureDeviceAddressKHR;
    PFN_vkCmdBuildAccelerationStructuresKHR vkCmdBuildAccelerationStructuresKHR;

    void loadRayTracingFunctions(VkDevice device);

    // Create different geometry types
    void createScene(VkPhysicalDevice physicalDevice, VkDevice device,
                    VkQueue graphicsQueue, VkCommandPool commandPool);

    void createGroundPlane(VkPhysicalDevice physicalDevice, VkDevice device,
                          VkQueue graphicsQueue, VkCommandPool commandPool);

    void createCube(VkPhysicalDevice physicalDevice, VkDevice device,
                   VkQueue graphicsQueue, VkCommandPool commandPool,
                   glm::vec3 position, glm::vec3 scale);

    void createBottomLevelAS(VkPhysicalDevice physicalDevice, VkDevice device,
                            VkQueue graphicsQueue, VkCommandPool commandPool,
                            GeometryObject& object);

    // Refit/Update BLAS after geometry modification
    void updateBottomLevelAS(VkPhysicalDevice physicalDevice, VkDevice device,
                            VkQueue graphicsQueue, VkCommandPool commandPool,
                            GeometryObject& object);

    // Helper to upload modified vertices to GPU
    void updateGeometry(VkPhysicalDevice physicalDevice, VkDevice device,
                       VkQueue graphicsQueue, VkCommandPool commandPool,
                       uint32_t objectIndex);

    void createTopLevelAS(VkPhysicalDevice physicalDevice, VkDevice device,
                         VkQueue graphicsQueue, VkCommandPool commandPool);

    // Update TLAS with new transforms (for dynamic objects) - OLD synchronous version
    void updateTopLevelAS(VkPhysicalDevice physicalDevice, VkDevice device,
                         VkQueue graphicsQueue, VkCommandPool commandPool,
                         const std::vector<Transform>& transforms);

    // NEW: Prepare instance data for TLAS update (CPU side, call before recording)
    void prepareInstanceData(VkDevice device, const std::vector<Transform>& transforms);

    // NEW: Record TLAS update commands into existing command buffer (no submit)
    void recordTLASUpdate(VkCommandBuffer commandBuffer);

    // NEW: Allocate scratch buffer for TLAS updates (call once after createTopLevelAS)
    void allocateTLASScratchBuffer(VkPhysicalDevice physicalDevice, VkDevice device);

    void cleanup(VkDevice device);

private:
    uint32_t findMemoryType(VkPhysicalDevice physicalDevice, uint32_t typeFilter,
                           VkMemoryPropertyFlags properties);

    void createBuffer(VkPhysicalDevice physicalDevice, VkDevice device, VkDeviceSize size,
                     VkBufferUsageFlags usage, VkMemoryPropertyFlags properties,
                     VkBuffer& buffer, VkDeviceMemory& bufferMemory);

    VkDeviceAddress getBufferDeviceAddress(VkDevice device, VkBuffer buffer);
};