起床方向上SCNNode的一侧

Based on Toyos answer, I have come up with the following code, which doesn't work. Hopefully this will help with coming closer to the end goal. I also used code found at Extracting vertices from scenekit to get the vertices of my SCNBoxNode.- (NSNumber *)valueForRotation:(SCNVector4)rotation andGeometry:(SCNGeometry*)geometry { SCNVector4 inverse = SCNVector4Make(rotation.x, rotation.y, rotation.z, -rotation.w); CATransform3D transform = CATransform3DMakeRotation(inverse.w, inverse.x, inverse.y, inverse.z); GLKMatrix4 matrix = GLKMatrix4Make(transform.m11, transform.m12, transform.m13, transform.m14, transform.m21, transform.m22, transform.m23, transform.m24, transform.m31, transform.m32, transform.m33, transform.m34, transform.m41, transform.m42, transform.m43, transform.m44); GLKVector4 vector = GLKVector4Make(rotation.x, rotation.y, rotation.z, rotation.w); GLKVector4 finalVector = GLKMatrix4MultiplyVector4(matrix, vector); NSArray *vertexSources = [geometry geometrySourcesForSemantic:SCNGeometrySourceSemanticVertex]; SCNGeometrySource *vertexSource = vertexSources[0]; // TODO: Parse all the sources NSInteger stride = vertexSource.dataStride; // in bytes NSInteger offset = vertexSource.dataOffset; // in bytes NSInteger componentsPerVector = vertexSource.componentsPerVector; NSInteger bytesPerVector = componentsPerVector * vertexSource.bytesPerComponent; NSInteger vectorCount = vertexSource.vectorCount; SCNVector3 vertices[vectorCount]; // A new array for vertices // for each vector, read the bytes NSLog(@"vetor count %i",vectorCount); float highestProduct = 0; int highestVector = -1; NSMutableArray *highVectors; for (NSInteger i=0; i<vectorCount; i++) { // Assuming that bytes per component is 4 (a float) // If it was 8 then it would be a double (aka CGFloat) float vectorData[componentsPerVector]; // The range of bytes for this vector NSRange byteRange = NSMakeRange(i*stride + offset, // Start at current stride + offset bytesPerVector); // and read the lenght of one vector // Read into the vector data buffer [vertexSource.data getBytes:&vectorData range:byteRange]; // At this point you can read the data from the float array float x = vectorData[0]; float y = vectorData[1]; float z = vectorData[2]; // ... Maybe even save it as an SCNVector3 for later use ... vertices[i] = SCNVector3Make(x, y, z); // ... or just log it NSLog(@"x:%f, y:%f, z:%f", x, y, z); float product = (x * finalVector.x) + (y * finalVector.y) + (z * finalVector.z); if (product > highestProduct) { highestProduct = product; highestVector = i; } } NSLog(@"highestProduct = %f",highestProduct); NSLog(@"highestVector = %i",highestVector); NSLog(@"top verticy = %f, %f, %f",vertices[highestVector].x,vertices[highestVector].y,vertices[highestVector].z); return [NSNumber numberWithInt:highestVector];}推荐答案这里是一种返回朝上的脸部索引的方法.假定"boxNode"是一个由6个面组成的框，其顺序如下(任意):前/右/后/左/上/下.它返回面朝上的索引.别忘了导入.对于任意网格，您将不得不使用面法线而不是"boxNormals"(这并不明显，因为SceneKit网格的每个顶点有一个法线，而不是每个面有一个法线，因此您必须计算每个面的法线你自己).Here is a method that returns the index of the face that's facing up. It assumes that "boxNode" is a box made of 6 faces with the following (arbitrary) order: front / right / back / left / up / bottom. It returns the index of the face that is facing up.Don't forget to import then .For an arbitrary mesh, you would have to use the face normals instead of "boxNormals" (which is not obvious to compute since SceneKit meshes have one normal per vertex, not one normal per face, so you would have to compute the normals per face yourself).- (NSUInteger) boxUpIndex:(SCNNode *)boxNode{ SCNVector4 rotation = boxNode.rotation; SCNVector4 invRotation = rotation; invRotation.w = -invRotation.w; SCNVector3 up = SCNVector3Make(0,1,0); //rotate up by invRotation SCNMatrix4 transform = SCNMatrix4MakeRotation(invRotation.w, invRotation.x, invRotation.y, invRotation.z); GLKMatrix4 glkTransform = SCNMatrix4ToGLKMatrix4(transform); GLKVector3 glkUp = SCNVector3ToGLKVector3(up); GLKVector3 rotatedUp = GLKMatrix4MultiplyVector3(glkTransform, glkUp); //build box normals (arbitrary order here) GLKVector3 boxNormals[6] = {{{0,0,1}}, {{1,0,0}}, {{0,0,-1}}, {{-1,0,0}}, {{0,1,0}}, {{0,-1,0}}, }; int bestIndex = 0; float maxDot = -1; for(int i=0; i<6; i++){ float dot = GLKVector3DotProduct(boxNormals[i], rotatedUp); if(dot > maxDot){ maxDot = dot; bestIndex = i; } } return bestIndex;} 这篇关于起床方向上SCNNode的一侧的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！