ovis: add loadMesh

Author: paroj

modules/ovis/include/opencv2/ovis.hpp

@@ -414,6 +414,23 @@ CV_EXPORTS_W void createGridMesh(const String& name, const Size2f& size, const S
  */
 CV_EXPORTS_W void createTriangleMesh(const String& name, InputArray vertices, InputArray normals = noArray(), InputArray indices = noArray());
 
+/**
+ * Loads a mesh from a known resource location.
+ *
+ * The file format is determined by the file extension. Supported formats are Ogre @c .mesh and everything that Assimp can load.
+ * @param meshname Name of the mesh file
+ * @param vertices vertex coordinates, each value contains 3 floats
+ * @param indices per-face list of vertices, each value contains 3 ints
+ * @param normals per-vertex normals, each value contains 3 floats
+ * @param colors per-vertex colors, each value contains 4 uchars
+ * @param texCoords per-vertex texture coordinates, each value contains 2 floats
+ *
+ * @see addResourceLocation()
+ */
+CV_EXPORTS_W void loadMesh(const String& meshname, OutputArray vertices, OutputArray indices,
+                           OutputArray normals = noArray(), OutputArray colors = noArray(),
+                           OutputArray texCoords = noArray());
+
 /// @deprecated use setMaterialProperty
 CV_EXPORTS_W void updateTexture(const String& name, InputArray image);
 //! @}

modules/ovis/src/ovis.cpp

@@ -1155,5 +1155,77 @@ void updateTexture(const String& name, InputArray image)
     CV_Assert(tex);
     _createTexture(name, image.getMat());
 }
+
+void loadMesh(const String& meshname, OutputArray vertices, OutputArray indices, OutputArray normals, OutputArray colors, OutputArray texCoords)
+{
+    CV_Assert(_app);
+
+    auto mesh = MeshManager::getSingleton().load(meshname, RESOURCEGROUP_NAME);
+    auto smeshes = mesh->getSubMeshes();
+    CV_Assert(smeshes.size() == 1);
+
+    auto smesh = smeshes.front();
+
+    CV_Assert(smesh->operationType == RenderOperation::OT_TRIANGLE_LIST);
+
+    if (auto ibuf = smesh->indexData->indexBuffer)
+    {
+        auto idtype = ibuf->getType() == HardwareIndexBuffer::IT_16BIT ? CV_16S : CV_32S;
+        auto imat = Mat(smesh->indexData->indexCount, 3, idtype);
+        ibuf->readData(0, ibuf->getSizeInBytes(), imat.ptr());
+        imat.copyTo(indices);
+    }
+
+    auto vertexData = smesh->useSharedVertices ? mesh->sharedVertexData : smesh->vertexData;
+    DefaultHardwareBufferManagerBase swhbm;
+
+    // download all buffers to CPU for reorganization
+    auto tmpVertexData = vertexData->clone(true, &swhbm);
+    auto tgtDecl = swhbm.createVertexDeclaration();
+    tgtDecl->addElement(0, 0, VET_FLOAT3, VES_POSITION); // separate position buffer
+
+    bool has_normals = vertexData->vertexDeclaration->findElementBySemantic(VES_NORMAL);
+    bool has_texcoords = vertexData->vertexDeclaration->findElementBySemantic(VES_TEXTURE_COORDINATES);
+    bool has_colors = vertexData->vertexDeclaration->findElementBySemantic(VES_DIFFUSE);
+    if (has_normals)
+        tgtDecl->addElement(1, 0, VET_FLOAT3, VES_NORMAL); // separate normal buffer
+    if (has_texcoords)
+        tgtDecl->addElement(2, 0, VET_FLOAT2, VES_TEXTURE_COORDINATES); // separate texcoord buffer
+    if (has_colors)
+        tgtDecl->addElement(3, 0, VET_UBYTE4_NORM, VES_DIFFUSE); // separate color buffer
+
+    tmpVertexData->reorganiseBuffers(tgtDecl);
+
+    // copy data
+    auto vertmat = Mat(vertexData->vertexCount, 3, CV_32F);
+    auto posbuf = tmpVertexData->vertexBufferBinding->getBuffer(0);
+    posbuf->readData(0, posbuf->getSizeInBytes(), vertmat.ptr());
+    vertmat.copyTo(vertices);
+
+    if(has_normals && normals.needed())
+    {
+        auto normmat = Mat(vertexData->vertexCount, 3, CV_32F);
+        auto nbuf = tmpVertexData->vertexBufferBinding->getBuffer(1);
+        nbuf->readData(0, nbuf->getSizeInBytes(), normmat.ptr());
+        normmat.copyTo(normals);
+    }
+
+    if(has_texcoords && texCoords.needed())
+    {
+        auto texmat = Mat(vertexData->vertexCount, 2, CV_32F);
+        auto tbuf = tmpVertexData->vertexBufferBinding->getBuffer(2);
+        tbuf->readData(0, tbuf->getSizeInBytes(), texmat.ptr());
+        texmat.copyTo(texCoords);
+    }
+
+    if(has_colors && colors.needed())
+    {
+        auto colmat = Mat(vertexData->vertexCount, 4, CV_8U);
+        auto cbuf = tmpVertexData->vertexBufferBinding->getBuffer(3);
+        cbuf->readData(0, cbuf->getSizeInBytes(), colmat.ptr());
+        colmat.copyTo(colors);
+    }
+}
+
 }
 }