InstancedMesh3d.h

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#pragma once
 
#include "Nodes/3D/StaticMesh3d.h"
 
struct MeshInstanceData
{
    glm::vec3 mPosition = {0.0f, 0.0f, 0.0f};
    glm::vec3 mRotation = {0.0f, 0.0f, 0.0f};
    glm::vec3 mScale = {1.0f, 1.0f, 1.0f};
};
 
// POLYPHASE_API: exported for native addons (e.g. the Houdini HDA addon bakes
// instance point clouds into InstancedMesh3D nodes). Note that per-instance
// scale is uniform — CalculateInstanceTransform uses MeshInstanceData::mScale.x
// for all three axes.
class POLYPHASE_API InstancedMesh3D : public StaticMesh3D
{
public:
 
    DECLARE_NODE(InstancedMesh3D, StaticMesh3D);
 
    InstancedMesh3D();
    ~InstancedMesh3D();
 
    virtual const char* GetTypeName() const override;
    virtual void GatherProperties(std::vector<Property>& outProps) override;
 
    virtual void Create() override;
    virtual void Destroy() override;
    virtual void Render() override;
    virtual void Tick(float deltaTime) override;
    virtual void EditorTick(float deltaTime) override;
 
    virtual void SaveStream(Stream& stream, Platform platform) override;
    virtual void LoadStream(Stream& stream, Platform platform, uint32_t version) override;
 
    virtual bool IsInstancedMesh3D() const override;
 
    virtual void SetStaticMesh(StaticMesh* staticMesh);
 
    virtual Bounds GetLocalBounds() const override;
    virtual AABB GetLocalAABB() const override;
 
    virtual void GatherProxyDraws(std::vector<DebugDraw>& inoutDraws) override;
 
    uint32_t GetNumInstances() const;
    const MeshInstanceData& GetInstanceData(int32_t index) const;
    const std::vector<MeshInstanceData>& GetInstanceData() const;
    void SetInstanceData(int32_t index, const MeshInstanceData& data);
    void SetInstanceData(const std::vector<MeshInstanceData>& data);
    void AddInstanceData(const MeshInstanceData& data, int32_t index = -1);
    void RemoveInstanceData(int32_t index);
 
    uint32_t GetTotalVertexCount() const;
 
    bool IsInstanceDataDirty() const;
    void MarkInstanceDataDirty();
    void UpdateInstanceData();
    bool WasInstanceDataUpdatedThisFrame() const;
 
    bool ShouldUnroll() const;
 
    InstancedMeshCompResource* GetInstancedMeshResource();
 
    btTransform CalculateInstanceBulletTransform(int32_t instanceIndex);
    glm::mat4 CalculateInstanceTransform(int32_t instanceIndex);
    Bounds CalculateInstanceBounds(int32_t instanceIndex);
 
    btCompoundShape* GeneratePaintCollisionShape();
    btCompoundShape* GenerateTriangleCollisionShape();
 
protected:
 
    virtual void RecreateCollisionShape() override;
    void CalculateLocalBounds();
 
    void Unroll();
 
    std::vector<MeshInstanceData> mInstanceData;
    float mUnrolledCullDistance = 0.0f;
    float mUnrolledCellSize = 25.0f;
    bool mAlwaysUnroll = false;
 
    bool mInstanceDataDirty = true;
    bool mInstanceDataUpdatedThisFrame = false;
    bool mUnrolled = false;
    Bounds mBounds;
    AABB mAABB;
 
    InstancedMeshCompResource mInstancedMeshResource;
};