Made detail mesh optional, create dummy mesh if no data is provided.

Detour/Include/DetourNavMeshBuilder.h

@@ -35,7 +35,7 @@ struct dtNavMeshCreateParams
 	const unsigned char* polyAreas;			// Array of area ids per polygon.
 	int polyCount;							// Number of polygons
 	int nvp;								// Number of verts per polygon.
-	// Navmesh Detail
+	// Navmesh Detail (optional)
 	const unsigned int* detailMeshes;		// Detail meshes, uses same format as rcPolyMeshDetail.
 	const float* detailVerts;				// Detail mesh vertices, uses same format as rcPolyMeshDetail (wu).
 	int detailVertsCount;					// Total number of detail vertices

Detour/Source/DetourNavMeshBuilder.cpp

@@ -252,8 +252,8 @@ bool dtCreateNavMeshData(dtNavMeshCreateParams* params, unsigned char** outData,
 		return false;
 	if (!params->polyCount || !params->polys)
 		return false;
-	if (!params->detailMeshes || !params->detailVerts || !params->detailTris)
+//	if (!params->detailMeshes || !params->detailVerts || !params->detailTris)
-		return false;
+//		return false;
 
 	const int nvp = params->nvp;
 	
@@ -323,6 +323,11 @@ bool dtCreateNavMeshData(dtNavMeshCreateParams* params, unsigned char** outData,
 	
 	// Find unique detail vertices.
 	int uniqueDetailVertCount = 0;
+	int detailTriCount = 0;
+	if (params->detailMeshes)
+	{
+		// Has detail mesh, count unique detail vertex count and use input detail tri count.
+		detailTriCount = params->detailTriCount;
 		for (int i = 0; i < params->polyCount; ++i)
 		{
 			const unsigned short* p = &params->polys[i*nvp*2];
@@ -336,6 +341,24 @@ bool dtCreateNavMeshData(dtNavMeshCreateParams* params, unsigned char** outData,
 			ndv -= nv;
 			uniqueDetailVertCount += ndv;
 		}
+	}
+	else
+	{
+		// No input detail mesh, build detail mesh from nav polys.
+		uniqueDetailVertCount = 0; // No extra detail verts.
+		detailTriCount = 0;
+		for (int i = 0; i < params->polyCount; ++i)
+		{
+			const unsigned short* p = &params->polys[i*nvp*2];
+			int nv = 0;
+			for (int j = 0; j < nvp; ++j)
+			{
+				if (p[j] == MESH_NULL_IDX) break;
+				nv++;
+			}
+			detailTriCount += nv-2;
+		}
+	}
 	
 	// Calculate data size
 	const int headerSize = dtAlign4(sizeof(dtMeshHeader));
@@ -344,7 +367,7 @@ bool dtCreateNavMeshData(dtNavMeshCreateParams* params, unsigned char** outData,
 	const int linksSize = dtAlign4(sizeof(dtLink)*maxLinkCount);
 	const int detailMeshesSize = dtAlign4(sizeof(dtPolyDetail)*params->polyCount);
 	const int detailVertsSize = dtAlign4(sizeof(float)*3*uniqueDetailVertCount);
-	const int detailTrisSize = dtAlign4(sizeof(unsigned char)*4*params->detailTriCount);
+	const int detailTrisSize = dtAlign4(sizeof(unsigned char)*4*detailTriCount);
 	const int bvTreeSize = dtAlign4(sizeof(dtBVNode)*params->polyCount*2);
 	const int offMeshConsSize = dtAlign4(sizeof(dtOffMeshConnection)*storedOffMeshConCount);
 	
@@ -385,7 +408,7 @@ bool dtCreateNavMeshData(dtNavMeshCreateParams* params, unsigned char** outData,
 	dtVcopy(header->bmax, params->bmax);
 	header->detailMeshCount = params->polyCount;
 	header->detailVertCount = uniqueDetailVertCount;
-	header->detailTriCount = params->detailTriCount;
+	header->detailTriCount = detailTriCount;
 	header->bvQuantFactor = 1.0f / params->cs;
 	header->offMeshBase = params->polyCount;
 	header->walkableHeight = params->walkableHeight;
@@ -488,6 +511,8 @@ bool dtCreateNavMeshData(dtNavMeshCreateParams* params, unsigned char** outData,
 	// Store detail meshes and vertices.
 	// The nav polygon vertices are stored as the first vertices on each mesh.
 	// We compress the mesh data by skipping them and using the navmesh coordinates.
+	if (params->detailMeshes)
+	{
 		unsigned short vbase = 0;
 		for (int i = 0; i < params->polyCount; ++i)
 		{
@@ -508,6 +533,34 @@ bool dtCreateNavMeshData(dtNavMeshCreateParams* params, unsigned char** outData,
 		}
 		// Store triangles.
 		memcpy(navDTris, params->detailTris, sizeof(unsigned char)*4*params->detailTriCount);
+	}
+	else
+	{
+		// Create dummy detail mesh by triangulating polys.
+		int tbase = 0;
+		for (int i = 0; i < params->polyCount; ++i)
+		{
+			dtPolyDetail& dtl = navDMeshes[i];
+			const int nv = navPolys[i].vertCount;
+			dtl.vertBase = 0;
+			dtl.vertCount = 0;
+			dtl.triBase = (unsigned int)tbase;
+			dtl.triCount = (unsigned char)(nv-2);
+			// Triangulate polygon (local indices).
+			for (int j = 2; j < nv; ++j)
+			{
+				unsigned char* t = &navDTris[tbase*4];
+				t[0] = 0;
+				t[1] = (unsigned char)(j-1);
+				t[2] = (unsigned char)j;
+				// Bit for each edge that belongs to poly boundary.
+				t[3] = (1<<2);
+				if (j == 2) t[3] |= (1<<0);
+				if (j == nv-1) t[3] |= (1<<4);
+				tbase++;
+			}
+		}
+	}
 
 	// Store and create BVtree.
 	// TODO: take detail mesh into account! use byte per bbox extent?