heightfield.h

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/*
* Copyright 2016 Autodesk, Inc. All rights reserved.
* Use of this software is subject to the terms of the Autodesk license agreement and any attachments or Appendices thereto provided at the time of installation or download,
* or which otherwise accompanies this software in either electronic or hard copy form, or which is signed by you and accepted by Autodesk.
*/

#pragma once

#include "gwnavruntime/math/vec3f.h"
#include "gwnavruntime/math/triangle3f.h"
#include "gwnavruntime/collision/heightfieldblob.h"
#include "gwnavruntime/blob/blobaggregate.h"
#include "gwnavruntime/math/box2f.h"
#include "gwnavruntime/collision/collisiontypes.h"
#include "gwnavruntime/collision/heightfieldtile.h"

namespace Kaim
{

class DisplayListManager;
class FileOpenerBase;
class IndexedMesh;
class HeightFieldBlob;

typedef Vec2i HeightfieldTilePos;     
typedef Box2i HeightfieldTileBox;     

typedef Vec2i HeightfieldVertexPos;   
typedef Box2i HeightfieldVertexBox;   

struct HeightFieldConfig
{
    HeightFieldConfig() : m_xAltitudeCount(0), m_yAltitudeCount(0), m_tileSize(0.f) {}

    KyUInt32  m_xAltitudeCount;
    KyUInt32  m_yAltitudeCount;
    KyFloat32 m_tileSize;
    Vec2f     m_origin;
};


class HeightField : public RefCountBase<HeightField, MemStat_CollisionData>
{
    KY_CLASS_WITHOUT_COPY(HeightField)
public:
    HeightField() : m_blob(nullptr), m_altitudes(nullptr), m_tileSizeInv(1.f) {}
    ~HeightField() { Clear(); }

    KyResult Initialize(const HeightFieldConfig& config);
    KyResult InitFromBlob(HeightFieldBlob* blob);
    KyResult InitFromBlobHandler(Ptr<BlobHandler<HeightFieldBlob> > handler);
    void Clear();

    // RayCast on this heightfield.  Returns RayHit if any triangles are intersected.
    CollisionRayCastResult RayCast(const Vec3f& startPoint, const Vec3f& endPoint) const;

    KY_INLINE KyUInt32 GetXTileCount() const { return m_tileBox.CountX(); }
    KY_INLINE KyUInt32 GetYTileCount() const { return m_tileBox.CountY(); }
    KY_INLINE KyUInt32 GetTileCount()  const { return GetXTileCount() * GetYTileCount(); }

    KY_INLINE KyUInt32 GetXAltitudeCount() const { return m_vertexBox.CountX(); }
    KY_INLINE KyUInt32 GetYAltitudeCount() const { return m_vertexBox.CountY(); }
    KY_INLINE KyUInt32 GetAltitudeCount()  const { return GetXAltitudeCount() * GetYAltitudeCount(); }

    KY_INLINE KyFloat32 GetXExtents() const { return GetXTileCount() * m_blob->m_tileSize; }
    KY_INLINE KyFloat32 GetYExtents() const { return GetYTileCount() * m_blob->m_tileSize; }

    KY_INLINE void SetAltitude(const HeightfieldVertexPos& pixelPos, KyFloat32 altitude)
    {
        m_altitudes[m_vertexBox.GetRowMajorIndex(pixelPos)] = altitude;
    }

    KY_INLINE Vec3f GetVertex(const HeightfieldVertexPos& vertexPos) const
    {
        const KyFloat32 altitude = GetAltitude(vertexPos);
        return m_blob->m_origin + Vec3f((KyFloat32)vertexPos.x * m_blob->m_tileSize, (KyFloat32)vertexPos.y * m_blob->m_tileSize, altitude);
    }

    KY_INLINE KyResult GetTileAtPos(const Vec3f& pos, HeightFieldTile& tile) const
    {
        // Transform pos, snap it to grid.
        const Vec3f localPos = pos - m_blob->m_origin;
        const CellPos cellPos(SnapFloat(localPos.x), SnapFloat(localPos.y));
        return GetTileAtPos(cellPos, tile);
    }

    KY_INLINE KyResult GetTileAtPos(const HeightfieldTilePos& pixelPos, HeightFieldTile& tile) const
    {
        if (m_tileBox.DoesContain(pixelPos) == false)
            return KY_ERROR;

        const KyFloat32 southEastX = ((KyFloat32)pixelPos.x * m_blob->m_tileSize) + m_blob->m_origin.x + m_blob->m_tileSize;
        const KyFloat32 southEastY = ((KyFloat32)pixelPos.y * m_blob->m_tileSize) + m_blob->m_origin.y;

        tile.m_vertices[0].x = southEastX;
        tile.m_vertices[0].y = southEastY;
        tile.m_vertices[0].z = GetAltitude(pixelPos.NeighborEast());

        tile.m_vertices[1].x = southEastX;
        tile.m_vertices[1].y = southEastY + m_blob->m_tileSize;
        tile.m_vertices[1].z = GetAltitude(pixelPos.NeighborNorthEast());

        tile.m_vertices[2].x = southEastX - m_blob->m_tileSize;
        tile.m_vertices[2].y = southEastY + m_blob->m_tileSize;
        tile.m_vertices[2].z = GetAltitude(pixelPos.NeighborNorth());

        tile.m_vertices[3].x = southEastX - m_blob->m_tileSize;
        tile.m_vertices[3].y = southEastY;
        tile.m_vertices[3].z = GetAltitude(pixelPos);

        tile.m_cellPos = pixelPos;

        return KY_SUCCESS;
    }

    Box2f GetAABB2D() const
    {
        return Box2f(m_blob->m_origin.Get2d(), m_blob->m_origin.Get2d() +
            Vec2f(m_blob->m_xAltitudeCount * m_blob->m_tileSize, m_blob->m_yAltitudeCount * m_blob->m_tileSize));
    }

    void VisualDebug(DisplayListManager* displayListManager);

    KyResult ConvertToIndexedMesh(IndexedMesh& mesh) const;

    KyResult WriteToObj(File* file) const;

    BlobHandler<HeightFieldBlob>* GetBlobHandler() { return m_blobHandler; }

private:

    KY_INLINE KyFloat32 GetAltitude(const HeightfieldVertexPos& vertexPos) const
    {
        return m_altitudes[m_vertexBox.GetRowMajorIndex(vertexPos)];
    }

    KyResult GetStartTile(const Vec3f& startPoint, const Vec3f& endPoint, HeightFieldTile& tile) const;
    KyResult GetNextTile(const HeightFieldTile& tile, const Vec2f& rayA, const Vec2f& rayB, HeightFieldTile& outTile, const HeightFieldTile* destTile = nullptr) const;
    CollisionRayCastResult RayVsTriangle(const Triangle3f& tri, const Vec3f& from, const Vec3f& to) const;

    KY_INLINE KyUInt32 SnapFloat(KyFloat32 inputValue) const
    {
        return KyUInt32(inputValue * m_tileSizeInv);
    }

    KY_INLINE Vec3f Interpolate(const Vec3f& v0, const Vec3f& v1, KyFloat32 rt) const
    {
        const KyFloat32 s = 1.0f - rt;
        return Vec3f(s * v0[0] + rt * v1[0],
                     s * v0[1] + rt * v1[1],
                     s * v0[2] + rt * v1[2]);
    }

    void OnSetBlob();

    Ptr<BlobHandler<HeightFieldBlob> > m_blobHandler;
    HeightFieldBlob*                   m_blob;
    KyFloat32*                         m_altitudes; // Shortcut
    KyFloat32                          m_tileSizeInv;
    HeightfieldTileBox                 m_tileBox;
    HeightfieldVertexBox               m_vertexBox;
    Vec3f                              m_verts[4];
};

}