collider.h

#pragma once
 
#include <cstdint>
#include <vector>
 
#include <glm/glm.hpp>
 
#include "core/reflect.h"
#include "resource/asset/mesh_asset.h"
 
namespace Vkm::Engine {

enum class ColliderShape : uint8_t {
    Box     = 0,   
    Capsule = 1,   
    Mesh    = 2,   
    Count          
};

struct ColliderPart {
    ColliderShape shape       = ColliderShape::Box;   
    glm::vec3     center      = {0.0f, 0.0f, 0.0f};   
    glm::vec3     halfExtents = {0.5f, 0.5f, 0.5f};   
    float         radius      = 0.5f;                 
    float         halfHeight  = 0.5f;                 
    MeshHandle    mesh        = {};                   
    glm::vec3     meshScale   = {1.0f, 1.0f, 1.0f};
};

struct MeshNode {
    glm::vec3 min = {0.0f, 0.0f, 0.0f};
    glm::vec3 max = {0.0f, 0.0f, 0.0f};
 
    uint32_t firstTriangle = 0;  
    uint32_t triangleCount = 0;  
    uint32_t rightChild    = 0;  
};

struct MeshColliderSource {
    uint64_t  uid     = 0;                    
    uint64_t  version = 0;                    
    glm::vec3 scale   = {0.0f, 0.0f, 0.0f};   
};

struct Collider {
    std::vector<ColliderPart> parts = { ColliderPart{} };

    std::vector<glm::vec3> meshPoints;
 
    std::vector<MeshNode> meshNodes;      
    MeshColliderSource    meshBuiltFrom;  
 
    bool isTrigger = false;  
    bool enabled   = true;
};
 
} // namespace Vkm::Engine
 
VKM_ENUM_NAMES(::Vkm::Engine::ColliderShape, "Box", "Capsule", "Mesh")
 
// Every shape's fields are reflected whatever the tag, so switching a part's shape and back keeps
// what it was authored with.
VKM_REFLECT_BEGIN(::Vkm::Engine::ColliderPart)
    VKM_F(shape)
    VKM_F(center)
    VKM_F(halfExtents)
    VKM_F(radius)
    VKM_F(halfHeight)
    VKM_F(mesh)
    VKM_F(meshScale)
VKM_REFLECT_END()
 
VKM_REFLECT_BEGIN(::Vkm::Engine::Collider)
    VKM_F(isTrigger)
    VKM_F(enabled)
    VKM_F(parts)
VKM_REFLECT_END()