1 // 生成顶点法线
2 bool YfCalculateVertexNormal
3 (
4 void* pNormalsBuffer,
5 Yuint normalStriding,
6 Yuint normalPos,
7 const void* pVerticesBuffer,
8 Yuint vertexNum,
9 Yuint vertexStriding,
10 Yuint vertexPos,
11 void* pIndicesBuffer,
12 Yuint trianglesNum,
13 YeIndexType indexType,
14 Yuint indexStriding,
15 Yuint indexPos
16 )
17 {
18 if (!pNormalsBuffer || !pVerticesBuffer || !pIndicesBuffer ||
19 vertexNum < 3 || trianglesNum < 1)
20 {
21 return false;
22 }
23
24 char* vertexPtr = (char*)pVerticesBuffer + vertexPos;
25 char* normalPtr = (char*)pNormalsBuffer + normalPos;
26 char* indexPtr = (char*)pIndicesBuffer + indexPos;
27
28 const YsVector* curVertexPtr[3];
29 YsVector* curNormalPtr[3];
30 Yuint nOffset = 0;
31 YsVector vSub_1;
32 YsVector vSub_2;
33 YsVector vCross;
34
35 for (Yuint i = 0; i < vertexNum; i++)
36 {
37 curNormalPtr[0] = (YsVector*)(normalPtr + i * normalStriding);
38 curNormalPtr[0]->SetZero();
39 }
40
41 if (indexType == YE_INDEX_16_BIT)
42 {
43 YsTriIndex16* triIndexPtr = NULL;
44 for (Yuint i = 0; i < trianglesNum; i++)
45 {
46 triIndexPtr = (YsTriIndex16*)(indexPtr + i * indexStriding);
47 curVertexPtr[0] = (YsVector*)(vertexPtr + triIndexPtr->index0 * vertexStriding);
48 curVertexPtr[1] = (YsVector*)(vertexPtr + triIndexPtr->index1 * vertexStriding);
49 curVertexPtr[2] = (YsVector*)(vertexPtr + triIndexPtr->index2 * vertexStriding);
50 curNormalPtr[0] = (YsVector*)(normalPtr + triIndexPtr->index0 * normalStriding);
51 curNormalPtr[1] = (YsVector*)(normalPtr + triIndexPtr->index1 * normalStriding);
52 curNormalPtr[2] = (YsVector*)(normalPtr + triIndexPtr->index2 * normalStriding);
53
54 vSub_1 = *curVertexPtr[1] - *curVertexPtr[0];
55 vSub_2 = *curVertexPtr[2] - *curVertexPtr[0];
56 YfVector3Cross(vCross, vSub_1, vSub_2);
57
58 for (Yuint j = 0; j < 3; j++)
59 {
60 curNormalPtr[j]->x += vCross.x;
61 curNormalPtr[j]->y += vCross.y;
62 curNormalPtr[j]->z += vCross.z;
63 }
64 }
65 }
66 else
67 {
68 YsTriIndex32* triIndexPtr = NULL;
69 for (Yuint i = 0; i < trianglesNum; i++)
70 {
71 triIndexPtr = (YsTriIndex32*)(indexPtr + i * indexStriding);
72 curVertexPtr[0] = (YsVector*)(vertexPtr + triIndexPtr->index0 * vertexStriding);
73 curVertexPtr[1] = (YsVector*)(vertexPtr + triIndexPtr->index1 * vertexStriding);
74 curVertexPtr[2] = (YsVector*)(vertexPtr + triIndexPtr->index2 * vertexStriding);
75 curNormalPtr[0] = (YsVector*)(normalPtr + triIndexPtr->index0 * normalStriding);
76 curNormalPtr[1] = (YsVector*)(normalPtr + triIndexPtr->index1 * normalStriding);
77 curNormalPtr[2] = (YsVector*)(normalPtr + triIndexPtr->index2 * normalStriding);
78
79 vSub_1 = *curVertexPtr[1] - *curVertexPtr[0];
80 vSub_2 = *curVertexPtr[2] - *curVertexPtr[0];
81 YfVector3Cross(vCross, vSub_1, vSub_2);
82
83 for (Yuint j = 0; j < 3; j++)
84 {
85 curNormalPtr[j]->x += vCross.x;
86 curNormalPtr[j]->y += vCross.y;
87 curNormalPtr[j]->z += vCross.z;
88 }
89 }
90 }
91
92 for (Yuint i = 0; i < vertexNum; i++)
93 {
94 curNormalPtr[0] = (YsVector*)(normalPtr + i * normalStriding);
95 curNormalPtr[0]->Normalize();
96 }
97
98 return true;
99 }
