DXSDK Mesh loader: computing bounding boxes programmatically when loading the model

2 files changed, 90 insertions, 7 deletions

diff --git a/AssetLoader/interface/DXSDKMeshLoader.h b/AssetLoader/interface/DXSDKMeshLoader.h
index 18ecf93..c79d0dd 100644
--- a/AssetLoader/interface/DXSDKMeshLoader.h
+++ b/AssetLoader/interface/DXSDKMeshLoader.h
@@ -50,9 +50,7 @@ namespace Diligent
 #define INVALID_SAMPLER_SLOT    ((Uint32)-1)
 #define ERROR_RESOURCE_VALUE    1
 
-//--------------------------------------------------------------------------------------
 // Enumerated Types.
-//--------------------------------------------------------------------------------------
 enum DXSDKMESH_PRIMITIVE_TYPE
 {
     PT_TRIANGLE_LIST = 0,
@@ -80,9 +78,7 @@ enum FRAME_TRANSFORM_TYPE
     FTT_ABSOLUTE,    //This is not currently used but is here to support absolute transformations in the future
 };
 
-//--------------------------------------------------------------------------------------
 // Structures.  Unions with pointers are forced to 64bit.
-//--------------------------------------------------------------------------------------
 struct DXSDKMESH_HEADER
 {
     //Basic Info and sizes
@@ -109,6 +105,48 @@ struct DXSDKMESH_HEADER
     Uint64 MaterialDataOffset;
 };
 
+enum DXSDKMESH_VERTEX_SEMANTIC
+{
+    DXSDKMESH_VERTEX_SEMANTIC_POSITION = 0,
+    DXSDKMESH_VERTEX_SEMANTIC_BLENDWEIGHT,   // 1
+    DXSDKMESH_VERTEX_SEMANTIC_BLENDINDICES,  // 2
+    DXSDKMESH_VERTEX_SEMANTIC_NORMAL,        // 3
+    DXSDKMESH_VERTEX_SEMANTIC_PSIZE,         // 4
+    DXSDKMESH_VERTEX_SEMANTIC_TEXCOORD,      // 5
+    DXSDKMESH_VERTEX_SEMANTIC_TANGENT,       // 6
+    DXSDKMESH_VERTEX_SEMANTIC_BINORMAL,      // 7
+    DXSDKMESH_VERTEX_SEMANTIC_TESSFACTOR,    // 8
+    DXSDKMESH_VERTEX_SEMANTIC_POSITIONT,     // 9
+    DXSDKMESH_VERTEX_SEMANTIC_COLOR,         // 10
+    DXSDKMESH_VERTEX_SEMANTIC_FOG,           // 11
+    DXSDKMESH_VERTEX_SEMANTIC_DEPTH,         // 12
+    DXSDKMESH_VERTEX_SEMANTIC_SAMPLE         // 13
+};
+
+enum DXSDKMESH_VERTEX_DATA_TYPE
+{
+    DXSDKMESH_VERTEX_DATA_TYPE_FLOAT1    =  0,  // 1D float expanded to (value, 0., 0., 1.)
+    DXSDKMESH_VERTEX_DATA_TYPE_FLOAT2    =  1,  // 2D float expanded to (value, value, 0., 1.)
+    DXSDKMESH_VERTEX_DATA_TYPE_FLOAT3    =  2,  // 3D float expanded to (value, value, value, 1.)
+    DXSDKMESH_VERTEX_DATA_TYPE_FLOAT4    =  3,  // 4D float
+    DXSDKMESH_VERTEX_DATA_TYPE_D3DCOLOR  =  4,  // 4D packed unsigned bytes mapped to 0. to 1. range
+                                                // Input is in D3DCOLOR format (ARGB) expanded to (R, G, B, A)
+    DXSDKMESH_VERTEX_DATA_TYPE_UBYTE4    =  5,  // 4D unsigned byte
+    DXSDKMESH_VERTEX_DATA_TYPE_SHORT2    =  6,  // 2D signed short expanded to (value, value, 0., 1.)
+    DXSDKMESH_VERTEX_DATA_TYPE_SHORT4    =  7,  // 4D signed short
+
+    DXSDKMESH_VERTEX_DATA_TYPE_UBYTE4N   =  8,  // Each of 4 bytes is normalized by dividing to 255.0
+    DXSDKMESH_VERTEX_DATA_TYPE_SHORT2N   =  9,  // 2D signed short normalized (v[0]/32767.0,v[1]/32767.0,0,1)
+    DXSDKMESH_VERTEX_DATA_TYPE_SHORT4N   = 10,  // 4D signed short normalized (v[0]/32767.0,v[1]/32767.0,v[2]/32767.0,v[3]/32767.0)
+    DXSDKMESH_VERTEX_DATA_TYPE_USHORT2N  = 11,  // 2D unsigned short normalized (v[0]/65535.0,v[1]/65535.0,0,1)
+    DXSDKMESH_VERTEX_DATA_TYPE_USHORT4N  = 12,  // 4D unsigned short normalized (v[0]/65535.0,v[1]/65535.0,v[2]/65535.0,v[3]/65535.0)
+    DXSDKMESH_VERTEX_DATA_TYPE_UDEC3     = 13,  // 3D unsigned 10 10 10 format expanded to (value, value, value, 1)
+    DXSDKMESH_VERTEX_DATA_TYPE_DEC3N     = 14,  // 3D signed 10 10 10 format normalized and expanded to (v[0]/511.0, v[1]/511.0, v[2]/511.0, 1)
+    DXSDKMESH_VERTEX_DATA_TYPE_FLOAT16_2 = 15,  // Two 16-bit floating point values, expanded to (value, value, 0, 1)
+    DXSDKMESH_VERTEX_DATA_TYPE_FLOAT16_4 = 16,  // Four 16-bit floating point values
+    DXSDKMESH_VERTEX_DATA_TYPE_UNUSED    = 17,  // When the type field in a decl is unused.
+};
+
 struct DXSDKMESH_VERTEX_ELEMENT
 {
     Uint16    Stream;     // Stream index
@@ -119,6 +157,7 @@ struct DXSDKMESH_VERTEX_ELEMENT
     Uint8     UsageIndex; // Semantic index
 };
 
+
 struct DXSDKMESH_VERTEX_BUFFER_HEADER
 {
     Uint64 NumVertices;
@@ -281,9 +320,7 @@ struct SDKANIMATION_FRAME_DATA
 };
 
 
-//--------------------------------------------------------------------------------------
-// CDXUTDXSDKMesh class.  This class reads the DXSDKMesh file format for use by the samples
-//--------------------------------------------------------------------------------------
+// This class reads the DXSDKMesh file formats
 class DXSDKMesh
 {
 public:
@@ -323,6 +360,11 @@ public:
         return ( Uint32 )m_pVertexBufferArray[ m_pMeshArray[ iMesh ].VertexBuffers[iVB] ].StrideUint8s;
     }
 
+    Uint32  GetVertexStride( Uint32 iVB ) const
+    {
+        return ( Uint32 )m_pVertexBufferArray[ iVB ].StrideUint8s;
+    }
+
     Uint64  GetNumMeshVertices( Uint32 iMesh, Uint32 iVB ) const
     {
         return m_pVertexBufferArray[ m_pMeshArray[ iMesh ].VertexBuffers[iVB] ].NumVertices;
@@ -355,6 +397,8 @@ protected:
     bool                            CreateFromMemory( Uint8* pData,
                                                       Uint32 DataUint8s );
 
+    void                            ComputeBoundingBoxes();
+
     //These are the pointers to the two chunks of data loaded in from the mesh file
     std::vector<Uint8>      m_StaticMeshData;
     //Uint8*  m_pAnimationData    = nullptr;
diff --git a/AssetLoader/src/DXSDKMeshLoader.cpp b/AssetLoader/src/DXSDKMeshLoader.cpp
index bc4b521..97c61c9 100644
--- a/AssetLoader/src/DXSDKMeshLoader.cpp
+++ b/AssetLoader/src/DXSDKMeshLoader.cpp
@@ -57,6 +57,43 @@ bool DXSDKMesh::CreateFromFile( const char* szFileName )
     return res;
 }
 
+void DXSDKMesh::ComputeBoundingBoxes()
+{
+    for( Uint32 i = 0; i < m_pMeshHeader->NumMeshes; i++ )
+    {
+        auto& Mesh = m_pMeshArray[i];
+        float3 Min(+FLT_MAX, +FLT_MAX, +FLT_MAX);
+        float3 Max(-FLT_MAX, -FLT_MAX, -FLT_MAX);
+        const auto& VertexData = m_pVertexBufferArray[ Mesh.VertexBuffers[0] ];
+        auto* PosDecl = VertexData.Decl;
+        while (PosDecl->Stream != 0xFF && PosDecl->Usage != DXSDKMESH_VERTEX_SEMANTIC_POSITION)
+            ++PosDecl;
+        VERIFY(PosDecl->Stream != 0xFF, "Position semantic not found in this buffer");
+        VERIFY(PosDecl->Type == DXSDKMESH_VERTEX_DATA_TYPE_FLOAT3, "Vertex is expected to be a 3-component float vector");
+        
+        auto IndexType = GetIndexType(i);
+        const auto* Vertices = GetRawVerticesAt(Mesh.VertexBuffers[0]);
+        const auto* Indices = GetRawIndicesAt(Mesh.IndexBuffer);
+        auto Stride = GetVertexStride(Mesh.VertexBuffers[0]);
+        for(Uint32 subsetIdx = 0; subsetIdx < Mesh.NumSubsets; ++subsetIdx)
+        {
+            auto& Subset = m_pSubsetArray[ Mesh.pSubsets[subsetIdx] ];
+            
+            for(Uint32 v = 0; v < Subset.IndexCount; ++v)
+            {
+                Uint32 Index = IndexType == IT_16BIT ?
+                    reinterpret_cast<const Uint16*>(Indices)[Subset.IndexStart + v] : 
+                    reinterpret_cast<const Uint32*>(Indices)[Subset.IndexStart + v];
+                const float3& Vertex = 
+                    reinterpret_cast<const float3&>(Vertices[Index * Stride + PosDecl->Offset]);
+                Min = std::min(Min, Vertex);
+                Max = std::max(Max, Vertex);
+            }
+        }
+        Mesh.BoundingBoxCenter  = (Max + Min) * 0.5;
+        Mesh.BoundingBoxExtents = (Max - Min);
+    }
+}
 
 bool DXSDKMesh::CreateFromMemory( Uint8* pData,
                                   Uint32 DataUint8s )
@@ -119,6 +156,8 @@ bool DXSDKMesh::CreateFromMemory( Uint8* pData,
         m_ppIndices[i] = reinterpret_cast<Uint8*>( pBufferData + ( m_pIndexBufferArray[i].DataOffset - BufferDataStart ) );
     }
 
+    ComputeBoundingBoxes();
+
     return true;
 }