SceneKit绘制模型与骨骼动画的实现
原创
#####研究目的
sceneKit里可以绘制几种几何模型，但那些不规律的形状如果不想使用模型，那么就要自己绘制了#####demo效果
1.gif
Untitled.gif
#####原理和步骤
1.定义 模型的 顶点坐标 纹理坐标 法线 骨骼顶点 骨骼动画 等数据
2.调用以下方法画出模型
根据顶点坐标和模型类型画出模型，模型类型可以是点、线、三角形
为什么是三角形呢？因为三角形是最小边几何图形
+ (instancetype)geometrySourceWithVertices:(const SCNVector3 \*)vertices count:(NSInteger)count;
3.调用以下方法设置纹理
+ (instancetype)geometrySourceWithNormals:(const SCNVector3 \*)normals count:(NSInteger)count;
用以下方法设置模型图片 就是设置node的纹理
SCNGeometry \*geo = [SCNGeometry geometryWithSources:sources elements:elements];
UIImage \* image = [UIImage imageNamed:@"xy.jpg"];
SCNMaterial \*mat = [SCNMaterial material];
mat.diffuse.contents = image;
geo.firstMaterial = mat;
geo.firstMaterial.doubleSided = YES;
4.调用以下方法画出法线
+ (instancetype)geometrySourceWithTextureCoordinates:(const CGPoint \*)texcoord count:(NSInteger)count;
5.调用以下方法画出骨骼顶点
+ (instancetype)geometrySourceWithData:(NSData \*)data semantic:(SCNGeometrySourceSemantic)semantic vectorCount:(NSInteger)vectorCount floatComponents:(BOOL)floatComponents componentsPerVector:(NSInteger)componentsPerVector bytesPerComponent:(NSInteger)bytesPerComponent dataOffset:(NSInteger)offset dataStride:(NSInteger)stride;
6.调用以下方法设置与骨骼顶点向连接的部分
+ (instancetype)geometrySourceWithData:(NSData \*)data semantic:(SCNGeometrySourceSemantic)semantic vectorCount:(NSInteger)vectorCount floatComponents:(BOOL)floatComponents componentsPerVector:(NSInteger)componentsPerVector bytesPerComponent:(NSInteger)bytesPerComponent dataOffset:(NSInteger)offset dataStride:(NSInteger)stride;
7.调用以下方法设置骨骼动画皮肤那方面的
+ (instancetype)geometrySourceWithData:(NSData \*)data semantic:(SCNGeometrySourceSemantic)semantic vectorCount:(NSInteger)vectorCount floatComponents:(BOOL)floatComponents componentsPerVector:(NSInteger)componentsPerVector bytesPerComponent:(NSInteger)bytesPerComponent dataOffset:(NSInteger)offset dataStride:(NSInteger)stride
8.调用以下方法设置把骨骼相信存放到一个SCNSkinner类
+ (instancetype)skinnerWithBaseGeometry:(nullable SCNGeometry \*)baseGeometry bones:(NSArray<SCNNode \*> \*)bones boneInverseBindTransforms:(nullable NSArray<NSValue \*> \*)boneInverseBindTransforms boneWeights:(SCNGeometrySource \*)boneWeights boneIndices:(SCNGeometrySource \*)boneIndices API\_AVAILABLE(macos(10.10));
9.调用以下方法设置骨骼动画的值和类型
+ (SCNAction \*)repeatActionForever:(SCNAction \*)action;
10.调用以下方法运行骨骼动画
- (void)runAction:(SCNAction \*)action API\_AVAILABLE(macos(10.10));#####关键性代码--模型本体和纹理
- (void)addNode1 {
typedef struct {
float x, y, z; // position
float nx, ny, nz; // normal
float s, t; // texture coordinates
} MyVertex;
MyVertex vertices[] = {
// Z轴0.5处的平面
-0.5, 0.5, 0.5, 0, 0, 1, 0, 0,
-0.5, -0.5, 0.5, 0, 0, 1, 0, 1,
0.5, -0.5, 0.5, 0, 0, 1, 1, 1,
0.5, -0.5, 0.5, 0, 0, 1, 1, 1,
0.5, 0.5, 0.5, 0, 0, 1, 1, 0,
-0.5, 0.5, 0.5, 0, 0, 1, 0, 0,
// X轴-0.5处的平面
-0.5, 0.5, -0.5, -1, 0, 0, 0, 0,
-0.5, -0.5, -0.5, -1, 0, 0, 0, 1,
-0.5, -0.5, 0.5, -1, 0, 0, 1, 1,
-0.5, -0.5, 0.5, -1, 0, 0, 1, 1,
-0.5, 0.5, 0.5, -1, 0, 0, 1, 0,
-0.5, 0.5, -0.5, -1, 0, 0, 0, 0,
// Z轴-0.5处的平面
0.5, -0.5, -0.5, 0, 0, -1, 0, 1,
-0.5, -0.5, -0.5, 0, 0, -1, 1, 1,
-0.5, 0.5, -0.5, 0, 0, -1, 1, 0,
-0.5, 0.5, -0.5, 0, 0, -1, 1, 0,
0.5, 0.5, -0.5, 0, 0, -1, 0, 0,
0.5, -0.5, -0.5, 0, 0, -1, 0, 1,
// X轴0.5处的平面
0.5, -0.5, 0.5, 1, 0, 0, 0, 1,
0.5, -0.5, -0.5, 1, 0, 0, 1, 1,
0.5, 0.5, -0.5, 1, 0, 0, 1, 0,
0.5, 0.5, -0.5, 1, 0, 0, 1, 0,
0.5, 0.5, 0.5, 1, 0, 0, 0, 0,
0.5, -0.5, 0.5, 1, 0, 0, 0, 1,
// Y轴0.5处的平面
0.5, 0.5, -0.5, 0, 1, 0, 1, 0,
-0.5, 0.5, -0.5, 0, 1, 0, 0, 0,
-0.5, 0.5, 0.5, 0, 1, 0, 0, 1,
-0.5, 0.5, 0.5, 0, 1, 0, 0, 1,
0.5, 0.5, 0.5, 0, 1, 0, 1, 1,
0.5, 0.5, -0.5, 0, 1, 0, 1, 0,
// Y轴-0.5处的平面
-0.5, -0.5, 0.5, 0, -1, 0, 0, 0,
-0.5, -0.5, -0.5, 0, -1, 0, 0, 1,
0.5, -0.5, -0.5, 0, -1, 0, 1, 1,
0.5, -0.5, -0.5, 0, -1, 0, 1, 1,
0.5, -0.5, 0.5, 0, -1, 0, 1, 0,
-0.5, -0.5, 0.5, 0, -1, 0, 0, 0,
};
NSData \*data = [NSData dataWithBytes:vertices length:sizeof(vertices)];
SCNGeometrySource \*vertexSource, \*normalSource, \*tcoordSource;
vertexSource = [SCNGeometrySource geometrySourceWithData:data
semantic:SCNGeometrySourceSemanticVertex
vectorCount:6
floatComponents:YES
componentsPerVector:3 // x, y, z
bytesPerComponent:sizeof(float)
dataOffset:offsetof(MyVertex, x)
dataStride:sizeof(MyVertex)];
normalSource = [SCNGeometrySource geometrySourceWithData:data
semantic:SCNGeometrySourceSemanticNormal
vectorCount:6
floatComponents:YES
componentsPerVector:3 // nx, ny, nz
bytesPerComponent:sizeof(float)
dataOffset:offsetof(MyVertex, nx)
dataStride:sizeof(MyVertex)];
tcoordSource = [SCNGeometrySource geometrySourceWithData:data
semantic:SCNGeometrySourceSemanticTexcoord
vectorCount:6
floatComponents:YES
componentsPerVector:2 // s, t
bytesPerComponent:sizeof(float)
dataOffset:offsetof(MyVertex, s)
dataStride:sizeof(MyVertex)];
int indices[] = {
0,1,2,3,4,5,
6,7,8,9,10,11,
12,13,14,15,16,17,
18,19,20,21,22,23,
24,25,26,27,28,29,
30,31,32,33,34,35
};
NSMutableArray \* elements = [[NSMutableArray alloc]init];
for (int i = 0; i<36; i+=6) {
int indiceChild[] = {indices[i],indices[i+1],indices[i+2], indices[i+3],indices[i+4],indices[i+5]};
NSData \* indexData = [NSData dataWithBytes:indiceChild length:sizeof(indiceChild)];
SCNGeometryElement \* element = [SCNGeometryElement geometryElementWithData:indexData
primitiveType:SCNGeometryPrimitiveTypeTriangles
primitiveCount:2
bytesPerIndex:sizeof(int)];
[elements addObject:element];
}
SCNGeometry \* geometry = [SCNGeometry geometryWithSources:@[vertexSource,normalSource,tcoordSource]
elements:elements];
UIImage \* image = [UIImage imageNamed:@"xy.jpg"];
SCNMaterial \* material = [[SCNMaterial alloc]init];
material.diffuse.contents = image;
geometry.materials = @[material];
SCNNode \* node = [SCNNode nodeWithGeometry:geometry];
node.position = SCNVector3Make(0, 0, -1);
[self.scnView.scene.rootNode addChildNode:node];
}#####关键性代码--骨骼动画
-(SCNNode \*)createCustomRigBlock {
// baseGeometry
SCNVector3 positions[] = {
SCNVector3Make(0, 0, 0),
SCNVector3Make(0, 0, 1),
SCNVector3Make(1, 0, 1),
SCNVector3Make(1, 0, 0),
SCNVector3Make(0, 1, 0),
SCNVector3Make(0, 1, 1),
SCNVector3Make(1, 1, 1),
SCNVector3Make(1, 1, 0),
SCNVector3Make(0, 2, 0),
SCNVector3Make(0, 2, 1),
SCNVector3Make(1, 2, 1),
SCNVector3Make(1, 2, 0)
};
SCNGeometrySource \* baseGeometrySource = [SCNGeometrySource geometrySourceWithVertices:positions count:12];
typedef struct {
uint16\_t a, b, c;
} Triangles;
Triangles tVectors[20] = {
0,1,2,
0,2,3,
0,1,5,
0,4,5,
4,5,9,
4,8,9,
1,2,6,
1,5,6,
5,6,10,
5,9,10,
2,3,7,
2,6,7,
6,7,11,
6,10,11,
3,0,4,
3,4,7,
7,4,8,
7,8,11,
8,9,10,
8,10,11,
};
NSData \*triangleData = [NSData dataWithBytes:tVectors length:sizeof(tVectors)];
SCNGeometryElement \* baseGeometryElement = [SCNGeometryElement geometryElementWithData:triangleData primitiveType:SCNGeometryPrimitiveTypeTriangles primitiveCount:20 bytesPerIndex:sizeof(uint16\_t)];
SCNGeometry \* baseGeometry = [SCNGeometry geometryWithSources:[NSArray arrayWithObject:baseGeometrySource] elements:[NSArray arrayWithObject:baseGeometryElement]];
baseGeometry.firstMaterial.emission.contents = [UIColor redColor];
baseGeometry.firstMaterial.doubleSided = YES;
baseGeometry.firstMaterial.transparency = 0.6;
SCNNode \* mNode = [SCNNode nodeWithGeometry:baseGeometry];
mNode.position = SCNVector3Make(15, 0, 9);
int vectorCount = (int)[(SCNGeometrySource \*)[mNode.geometry geometrySourcesForSemantic:SCNGeometrySourceSemanticVertex].firstObject vectorCount];
//bones ... the bones of the rig
NSMutableArray \* bonesArray = [NSMutableArray new];
for (int i = 0; i < 3; i++) {
SCNNode \* boneNode = [SCNNode new];
boneNode.name = [NSString stringWithFormat:@"bone\_%i",I];
if (bonesArray.count > 0) {
[bonesArray.lastObject addChildNode:boneNode];
}
boneNode.position = SCNVector3Make(0, 0.75, 0);
//add a sphere to each bone, to visually check its position etc.
SCNSphere \*boneSphereGeom = [SCNSphere sphereWithRadius:0.1];
boneSphereGeom.firstMaterial.emission.contents = [UIColor redColor];
boneNode.geometry = boneSphereGeom;
[bonesArray addObject:boneNode];
}
[mNode addChildNode:bonesArray[0]];
//boneInverseBindTransforms ... this defines the geometries transformation in the default pose!
//决定骨骼的位置
NSMutableArray \* bibtArray = [NSMutableArray new];
for (int i = 0; i < 3; i++) {
SCNMatrix4 initialPositionMatrix = SCNMatrix4MakeTranslation(0.5, (i\*0.5)+0.25, 0.5);
SCNMatrix4 inverseFinalMatrix = SCNMatrix4Invert(initialPositionMatrix);
NSValue \* bibtValue = [NSValue valueWithSCNMatrix4:inverseFinalMatrix];
[bibtArray addObject:bibtValue];
}
//boneWeights ... the weights, at which each vertex is influenced by certain bones (which bones is defined by "boneIndices")
typedef struct {
float a, b, c;
} WeightVectors;
WeightVectors vectors[vectorCount];
for (int i = 0; i < vectorCount; i++) {
// set the same boneWeights for every vertex
vectors[i].a = 1;
vectors[i].b = 0;
vectors[i].c = 0;
}
NSData \*weightData = [NSData dataWithBytes:vectors length:sizeof(vectors)];
SCNGeometrySource \* boneWeightsGeometrySource = [SCNGeometrySource geometrySourceWithData:weightData
semantic:SCNGeometrySourceSemanticBoneWeights
vectorCount:vectorCount
floatComponents:YES
componentsPerVector:3
bytesPerComponent:sizeof(float)
dataOffset:offsetof(WeightVectors, a)
dataStride:sizeof(WeightVectors)];
//boneIndices
typedef struct {
short k, l, m; // boneWeight
} IndexVectors;
IndexVectors iVectors[vectorCount];
for (int i = 0; i < vectorCount; i++) {
if (i > 7) {
iVectors[i].k = 1;
iVectors[i].l = 0;
iVectors[i].m = 0;
} else {
iVectors[i].k = 0;
iVectors[i].l = 0;
iVectors[i].m = 0;
}
}
NSData \*indexData = [NSData dataWithBytes:iVectors length:sizeof(iVectors)];
SCNGeometrySource \* boneIndicesGeometrySource = [SCNGeometrySource geometrySourceWithData:indexData
semantic:SCNGeometrySourceSemanticBoneIndices
vectorCount:vectorCount
floatComponents:YES
componentsPerVector:3
bytesPerComponent:sizeof(short)
dataOffset:offsetof(IndexVectors, k)
dataStride:sizeof(IndexVectors)];
SCNSkinner \* mNodeSkinner = [SCNSkinner skinnerWithBaseGeometry:baseGeometry
bones:bonesArray
boneInverseBindTransforms:bibtArray
boneWeights:boneWeightsGeometrySource
boneIndices:boneIndicesGeometrySource];
mNode.skinner = mNodeSkinner;
[[bonesArray objectAtIndex:1] runAction:[SCNAction repeatActionForever:[SCNAction rotateByX:0 y:0 z:2 duration:2]]];
return mNode;
}原创声明：本文系作者授权腾讯云开发者社区发表，未经许可，不得转载。
如有侵权，请联系 cloudcommunity@tencent.com 删除。
原创声明：本文系作者授权腾讯云开发者社区发表，未经许可，不得转载。
如有侵权，请联系 cloudcommunity@tencent.com 删除。
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