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En the following code, I create and export a triangle to USDC using the MDLAsset export function. The exported USDC file is correct, but I don't see the material component. It seems like the material is not being exported. Did I miss something? //new asset MDLAsset *asset = [[MDLAsset alloc] initWithBufferAllocator:nil]; //------------------ vertex descriptor ------------------------------------------------------------------------- MDLVertexAttribute *atrPos = [[MDLVertexAttribute alloc] initWithName:@"position" format:MDLVertexFormatFloat3 offset:0 bufferIndex:0]; MDLVertexAttribute *atrNor = [[MDLVertexAttribute alloc] initWithName:@"normal" format:MDLVertexFormatFloat3 offset:12 bufferIndex:0]; MDLVertexAttribute *atrCol = [[MDLVertexAttribute alloc] initWithName:@"color" format:MDLVertexFormatFloat4 offset:24 bufferIndex:0]; //layout (12 + 12 + 16) MDLVertexBufferLayout *lay = [[MDLVertexBufferLayout alloc] initWithStride:40]; //add descriptor and layaut MDLVertexDescriptor *vdc = [[MDLVertexDescriptor alloc] init]; vdc.attributes = [NSMutableArray arrayWithObjects:atrPos, atrNor, atrCol, nil]; vdc.layouts = [NSMutableArray arrayWithObjects:lay, nil]; //-------------- material --------------------------------------------------------------------------------------------------- MDLScatteringFunction *scatteringFunction = [MDLPhysicallyPlausibleScatteringFunction new]; MDLMaterial *material = [[MDLMaterial alloc] initWithName:@"matTest" scatteringFunction:scatteringFunction]; //--------------------- mesh ------------------------------------------------------------------------------------------------ //vertex (position, normal, and color RGBA) static const float triangleVertexData[] = { 0.0, 0.5, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0, 1.0, -0.5, -0.5, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.5, -0.5, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0, 1.0 }; //vertex buffer int numVertices = 3; int lenBufferForVertices = sizeof(triangleVertexData); MTKMeshBuffer *mtkMeshBufferForVertices = (MTKMeshBuffer *)[[asset bufferAllocator] newBuffer:lenBufferForVertices type:MDLMeshBufferTypeVertex]; NSData *nsData_vertex = [NSData dataWithBytes:triangleVertexData length:lenBufferForVertices]; [mtkMeshBufferForVertices fillData:nsData_vertex offset:0]; //index static uint16_t indices[] = {0, 1, 2}; //index buffer int numIndices = 3; int lenBufferForIndices = numIndices * sizeof(uint16_t); MTKMeshBuffer *mtkMeshBufferForIndices = (MTKMeshBuffer *)[[asset bufferAllocator] newBuffer:lenBufferForIndices type:MDLMeshBufferTypeIndex]; NSData *nsData_indices = [NSData dataWithBytes:indices length:lenBufferForIndices]; [mtkMeshBufferForIndices fillData:nsData_indices offset:0]; //submesh MDLSubmesh *submesh = [[MDLSubmesh alloc] initWithName:@"triangle" indexBuffer:mtkMeshBufferForIndices indexCount:numIndices indexType:MDLIndexBitDepthUInt16 geometryType:MDLGeometryTypeTriangles material:material]; //mesh MDLMesh *mdlMesh = [[MDLMesh alloc] initWithVertexBuffer:mtkMeshBufferForVertices vertexCount:numVertices descriptor:vdc submeshes:[NSArray arrayWithObjects:submesh, nil]]; //add mesh object to asset [asset addObject:mdlMesh]; //export to usdc BOOL res = [asset exportAssetToURL:[NSURL fileURLWithPath:filePath]];

I am developing a fully immersive application in Metal for Apple Vision Pro. I would like to know how I can access tap and double-tap events from Objective-C.

Hello. When I make a call to this function, ar_skeleton_create_neutral_pose_hand_skeleton, it is supposed to create a hand skeleton in a neutral pose. However, when I obtain the matrix for each of the joints using the function ar_skeleton_get_anchor_from_joint_transform_for_joint, it returns the identity matrix for all the joints. Is there something I'm missing? Thanks in advance.

Hello. I'm working with Metal in the AVP simulator. I want to perform tests with the hand tracking system, but it's generating the following error: "<ar_hand_tracking_provider_t: 0x60000296c1c0> is not supported on this device." The question is: Is it possible to simulate any type of hand tracking interaction in the AVP simulator? Thanks in advance.