source/renderer/MikktspaceWrap.h

   1 /* Copyright (C) 2021 Wildfire Games.
   2  * This file is part of 0 A.D.
   3  *
   4  * 0 A.D. is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * 0 A.D. is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #ifndef INCLUDED_MIKKWRAP
  19 #define INCLUDED_MIKKWRAP
  20
  21 #include "graphics/MeshManager.h"
  22 #include "graphics/ModelDef.h"
  23 #include "third_party/mikktspace/mikktspace.h"
  24
  25 #include <vector>
  26
  27 class MikkTSpace
  28 {
  29
  30 public:
  31
  32         MikkTSpace(const CModelDefPtr& m, std::vector<float>& v, bool gpuSkinning);
  33
  34         void Generate();
  35
  36 private:
  37
  38         SMikkTSpaceInterface m_Interface;
  39         SMikkTSpaceContext m_Context;
  40
  41         const CModelDefPtr& m_Model;
  42
  43         std::vector<float>& m_NewVertices;
  44
  45         bool m_GpuSkinning;
  46
  47         /**
  48          * @param[in] pContext - Pointer to the MikkTSpace context.
  49          * @returns - the number of faces (triangles/quads) on the mesh to be processed.
  50          */
  51         static int GetNumFaces(const SMikkTSpaceContext* pContext);
  52
  53         /**
  54          * @param[in] pContext - Pointer to the MikkTSpace context.
  55          * @param[in] iFace - Number in the range { 0, 1, ..., getNumFaces() - 1 }.
  56          * @returns - the number of faces (triangles/quads) on the mesh to be processed.
  57          */
  58         static int GetNumVerticesOfFace(const SMikkTSpaceContext* pContext, const int iFace);
  59
  60         /**
  61          * @param[in] pContext - Pointer to the MikkTSpace context.
  62          * @returns - The MikkTSpace.
  63          */
  64         static MikkTSpace* GetUserDataFromContext(const SMikkTSpaceContext* pContext);
  65
  66         /**
  67          * @param[in] pContext - Pointer to the MikkTSpace context.
  68          * @param[in] iFace - Number in the range { 0, 1, ..., getNumFaces() - 1 }.
  69          * @param[in] iVert - Number in the range { 0, 1, 2 } for triangles and { 0, 1, 2, 3 } for quads.
  70          * @returns - The MikkTSpace.
  71          */
  72         static SModelVertex GetVertex(const SMikkTSpaceContext* pContext, const int iFace, const int iVert);
  73
  74         /**
  75          * @param[in] pContext - Pointer to the MikkTSpace context.
  76          * @param[out] fvPosOut - The array containing the face.
  77          * @param[in] iFace - Number in the range { 0, 1, ..., getNumFaces() - 1 }.
  78          * @param[in] iVert - Number in the range { 0, 1, 2 } for triangles and { 0, 1, 2, 3 } for quads.
  79          */
  80         static void GetPosition(const SMikkTSpaceContext* pContext,
  81                         float* fvPosOut, const int iFace, const int iVert);
  82
  83         /**
  84          * @param[in] pContext - Pointer to the MikkTSpace context.
  85          * @param[out] fvNormOut iVert - The array containing the normal.
  86          * @param[in] iFace - Number in the range { 0, 1, ..., getNumFaces() - 1 }.
  87          * @param[in] iVert - Number in the range { 0, 1, 2 } for triangles and { 0, 1, 2, 3 } for quads.
  88          */
  89         static void GetNormal(const SMikkTSpaceContext* pContext,
  90                         float* fvNormOut, const int iFace, const int iVert);
  91
  92         /**
  93          * @param[in] pContext - Pointer to the MikkTSpace context.
  94          * @param[out] fvTexcOut iVert - Array containing the UV.
  95          * @param[in] iFace - Number in the range { 0, 1, ..., getNumFaces() - 1 }.
  96          * @param[in] iVert - Number in the range { 0, 1, 2 } for triangles and { 0, 1, 2, 3 } for quads.
  97          */
  98         static void GetTexCoord(const SMikkTSpaceContext* pContext,
  99                         float* fvTexcOut, const int iFace, const int iVert);
 100
 101         /**
 102          * @brief This function is used to return tangent space results to the application.
 103          * For normal maps it is sufficient to use the following simplified version of the bitangent which is generated at pixel/vertex level.
 104          * fSign = bIsOrientationPreserving ? 1.0f : (-1.0f);
 105          * bitangent = fSign * cross(vN, tangent);
 106          * @param[in] pContext - Pointer to the MikkTSpace context.
 107          * @param[in] fvTangent - fvTangent - The tangent vector.
 108          * @param[in] fvBiTangent - The "real" bitangent vector. Not be perpendicular to fvTangent. However, both are perpendicular to the vertex normal.
 109          * @param[in] fMagS - magniture of the fvTangent vector.
 110          * @param[in] fMagT - magniture of the fvBiTangent vector.
 111          * @param[in] bIsOrientationPreserving - Whether the orientation should be preserved.
 112          * @param[in] iFace - Number in the range {0,1,2} for triangles and {0,1,2,3} for quads.
 113          * @param[in] iVert - Array containing the position vector of the face.
 114          */
 115         static void SetTSpace(const SMikkTSpaceContext* pContext, const float* fvTangent,
 116                         const float* UNUSED(fvBiTangent), const float UNUSED(fMagS), const float UNUSED(fMagT),
 117                         const tbool bIsOrientationPreserving, const int iFace, const int iVert);
 118
 119 };
 120
 121
 122 #endif // INCLUDED_MIKKWRAP