From b71e1268fa6e07877ec3e54bce43b0315466e369 Mon Sep 17 00:00:00 2001
From: parax0 <parax0@github.com>
Date: Thu, 14 Jan 2016 21:15:06 -0700
Subject: [PATCH] Added experimental code for re-splitting world meshes in
 MP2/3/DKCR

---
 src/Core/Resource/Factory/CAreaLoader.cpp  | 20 ++++++-
 src/Core/Resource/Factory/CModelLoader.cpp | 62 +++++++++++++++++++++-
 src/Core/Resource/Factory/CModelLoader.h   |  1 +
 src/Core/Resource/Model/SSurface.h         |  2 +
 4 files changed, 82 insertions(+), 3 deletions(-)

diff --git a/src/Core/Resource/Factory/CAreaLoader.cpp b/src/Core/Resource/Factory/CAreaLoader.cpp
index 65aa13a3..d91010da 100644
--- a/src/Core/Resource/Factory/CAreaLoader.cpp
+++ b/src/Core/Resource/Factory/CAreaLoader.cpp
@@ -74,17 +74,33 @@ void CAreaLoader::ReadGeometryPrime()
     mBlockMgr->ToNextBlock();
 
     // Geometry
+    std::vector<CModel*> FileModels;
+
     for (u32 m = 0; m < mNumMeshes; m++) {
         std::cout << "\rLoading mesh " << std::dec << m + 1 << "/" << mNumMeshes;
 
-        CModel *pTerrainModel = CModelLoader::LoadWorldModel(*mpMREA, *mBlockMgr, *mpArea->mMaterialSet, mVersion);
-        mpArea->AddWorldModel(pTerrainModel);
+        CModel *pModel = CModelLoader::LoadWorldModel(*mpMREA, *mBlockMgr, *mpArea->mMaterialSet, mVersion);
+        FileModels.push_back(pModel);
+
+        if (mVersion <= ePrime)
+            mpArea->AddWorldModel(pModel);
 
         if (mVersion >= eEchoes) {
             mBlockMgr->ToNextBlock();
             mBlockMgr->ToNextBlock();
         }
     }
+
+    // Split meshes
+    if (mVersion >= eEchoesDemo)
+    {
+        std::vector<CModel*> SplitModels;
+        CModelLoader::BuildWorldMeshes(FileModels, SplitModels, true);
+
+        for (u32 iMdl = 0; iMdl < SplitModels.size(); iMdl++)
+            mpArea->AddWorldModel(SplitModels[iMdl]);
+    }
+
     mpArea->MergeTerrain();
     std::cout << "\n";
 }
diff --git a/src/Core/Resource/Factory/CModelLoader.cpp b/src/Core/Resource/Factory/CModelLoader.cpp
index 47131771..9f4969e0 100644
--- a/src/Core/Resource/Factory/CModelLoader.cpp
+++ b/src/Core/Resource/Factory/CModelLoader.cpp
@@ -1,6 +1,7 @@
 #include "CModelLoader.h"
 #include "CMaterialLoader.h"
 #include "Core/Log.h"
+#include <map>
 
 CModelLoader::CModelLoader()
 {
@@ -236,7 +237,15 @@ void CModelLoader::LoadSurfaceHeaderPrime(IInputStream& Model, SSurface *pSurf)
     Model.Seek(0xC, SEEK_CUR);
     u32 ExtraSize = Model.ReadLong();
     pSurf->ReflectionDirection = CVector3f(Model);
-    if (mVersion >= eEchoesDemo) Model.Seek(0x4, SEEK_CUR); // Extra values in Echoes. Not sure what they are.
+
+    if (mVersion >= eEchoesDemo)
+    {
+        Model.Seek(0x2, SEEK_CUR); // Skipping unknown value
+        pSurf->MeshID = Model.ReadShort();
+    }
+    else
+        pSurf->MeshID = -1;
+
     bool HasAABox = (ExtraSize >= 0x18); // MREAs have a set of bounding box coordinates here.
 
     // If this surface has a bounding box, we can just read it here. Otherwise we'll fill it in manually.
@@ -555,6 +564,57 @@ CModel* CModelLoader::LoadCorruptionWorldModel(IInputStream &MREA, CBlockMgrIn &
     return pModel;
 }
 
+void CModelLoader::BuildWorldMeshes(const std::vector<CModel*>& rkIn, std::vector<CModel*>& rOut, bool DeleteInputModels)
+{
+    // This function takes the gigantic models with all surfaces combined from MP2/3/DKCR and splits the surfaces to reform the original uncombined meshes.
+    std::map<u32, CModel*> OutputMap;
+
+    for (u32 iMdl = 0; iMdl < rkIn.size(); iMdl++)
+    {
+        CModel *pModel = rkIn[iMdl];
+        pModel->mHasOwnSurfaces = false;
+        pModel->mHasOwnMaterials = false;
+
+        for (u32 iSurf = 0; iSurf < pModel->mSurfaces.size(); iSurf++)
+        {
+            SSurface *pSurf = pModel->mSurfaces[iSurf];
+            u32 ID = (u32) pSurf->MeshID;
+            auto Iter = OutputMap.find(ID);
+
+            // No model for this ID; create one!
+            if (Iter == OutputMap.end())
+            {
+                CModel *pOutMdl = new CModel();
+                pOutMdl->mMaterialSets.resize(1);
+                pOutMdl->mMaterialSets[0] = pModel->mMaterialSets[0];
+                pOutMdl->mHasOwnMaterials = false;
+                pOutMdl->mSurfaces.push_back(pSurf);
+                pOutMdl->mHasOwnSurfaces = true;
+                pOutMdl->mVertexCount = pSurf->VertexCount;
+                pOutMdl->mTriangleCount = pSurf->TriangleCount;
+                pOutMdl->mAABox.ExpandBounds(pSurf->AABox);
+
+                OutputMap[ID] = pOutMdl;
+                rOut.push_back(pOutMdl);
+            }
+
+            // Existing model; add this surface to it
+            else
+            {
+                CModel *pOutMdl = Iter->second;
+                pOutMdl->mSurfaces.push_back(pSurf);
+                pOutMdl->mVertexCount += pSurf->VertexCount;
+                pOutMdl->mTriangleCount += pSurf->TriangleCount;
+                pOutMdl->mAABox.ExpandBounds(pSurf->AABox);
+            }
+        }
+
+        // Done with this model, should we delete it?
+        if (DeleteInputModels)
+            delete pModel;
+    }
+}
+
 CModel* CModelLoader::ImportAssimpNode(const aiNode *pNode, const aiScene *pScene, CMaterialSet& matSet)
 {
     CModelLoader loader;
diff --git a/src/Core/Resource/Factory/CModelLoader.h b/src/Core/Resource/Factory/CModelLoader.h
index 0810fcf8..f5ee132a 100644
--- a/src/Core/Resource/Factory/CModelLoader.h
+++ b/src/Core/Resource/Factory/CModelLoader.h
@@ -59,6 +59,7 @@ public:
     static CModel* LoadCMDL(IInputStream& CMDL);
     static CModel* LoadWorldModel(IInputStream& MREA, CBlockMgrIn& BlockMgr, CMaterialSet& MatSet, EGame Version);
     static CModel* LoadCorruptionWorldModel(IInputStream& MREA, CBlockMgrIn& BlockMgr, CMaterialSet& MatSet, u32 HeaderSecNum, u32 GPUSecNum, EGame Version);
+    static void BuildWorldMeshes(const std::vector<CModel*>& rkIn, std::vector<CModel*>& rOut, bool DeleteInputModels);
     static CModel* ImportAssimpNode(const aiNode *pNode, const aiScene *pScene, CMaterialSet& matSet);
     static EGame GetFormatVersion(u32 Version);
 };
diff --git a/src/Core/Resource/Model/SSurface.h b/src/Core/Resource/Model/SSurface.h
index d3770a8f..232027ba 100644
--- a/src/Core/Resource/Model/SSurface.h
+++ b/src/Core/Resource/Model/SSurface.h
@@ -12,6 +12,7 @@
 #include <Math/CVector3f.h>
 #include <vector>
 
+// Should prolly be a class
 struct SSurface
 {
     u32 VertexCount;
@@ -20,6 +21,7 @@ struct SSurface
     CVector3f CenterPoint;
     u32 MaterialID;
     CVector3f ReflectionDirection;
+    u16 MeshID;
 
     struct SPrimitive
     {