顶点数据的生成

 

1 bool                        YfBuildConeVertices 2 ( 3     Yreal                   radius,  4     Yreal                   height,  5     Yuint                   slices,  6     YeOriginPose            originPose, 7     Yuint                   vertexStriding,  8     Yuint                   vertexPos, 9     void*                   pVerticesBuffer10 )11 {12     if (slices < 2 || !pVerticesBuffer)13     {14         return false;15     }16 17     Yuint numVertices  = slices + 2;18 19     // 顶点赋值20     char* vertexPtr = (char*)pVerticesBuffer + vertexPos;21     YsVector3* curVertexPtr   = NULL;22     Yuint nOffset = 0;23 24     Yreal originOffsetY = 0.0f;25     if (originPose == YE_ORIGIN_POSE_TOP)26     {27         originOffsetY = -height;28     }29     else if (originPose == YE_ORIGIN_POSE_CENTER)30     {31         originOffsetY = -height * 0.5f;32     }33 34     // 锥尖顶点赋值35     {36         nOffset = 0;   37         curVertexPtr = (YsVector3*)(vertexPtr + nOffset);38         curVertexPtr->x = 0.0f;39         curVertexPtr->y = height + originOffsetY;40         curVertexPtr->z = 0.0f;41     }42 43     // 锥底顶点赋值44     {45         nOffset = (numVertices - 1) * vertexStriding;   46         curVertexPtr = (YsVector3*)(vertexPtr + nOffset);47         curVertexPtr->x = 0.0f;48         curVertexPtr->y = originOffsetY;49         curVertexPtr->z = 0.0f;50     }51 52     Yreal angleXZ;53     Yreal posX, posZ;        54     for (Yuint i = 0; i < slices; i++)55     {56         angleXZ = YD_REAL_TWAIN_PI * i / slices;57         posX = yf_sin(angleXZ);58         posZ = yf_cos(angleXZ);59         nOffset = (i + 1) * vertexStriding; 60 61         curVertexPtr = (YsVector3*)(vertexPtr + nOffset);62         curVertexPtr->x = radius * posX;63         curVertexPtr->y = originOffsetY;64         curVertexPtr->z = radius * posZ;65     }66 67     return true;68 }

 

三角形索引数据的生成

1 bool                        YfBuildConeTriIndices 2 ( 3     Yuint                   slices, 4     YeIndexType             indexType, 5     Yuint                   indexStriding,   6     Yuint                   indexPos, 7     void*                   pTriIndicesBuffer 8 )                            9 {10     if (slices < 2 || !pTriIndicesBuffer)11     {12         return false;13     }14 15     Yuint numVertices  = slices + 2;16     Yuint numTriangles = slices * 2;17     if (indexType == YE_INDEX_16_BIT && 18         numVertices > YD_MAX_UNSIGNED_INT16)19     {20         return false;21     }22 23     // 索引赋值24     char* indexPtr = (char*)pTriIndicesBuffer + indexPos;25     Yuint nOffset = 0;26     if (indexType == YE_INDEX_16_BIT)27     {28         YsTriIndex16* triIndexPtr = NULL;29         for (Yuint i= 0; i < slices; i++)30         {31             nOffset = (i * 2) * indexStriding;32             triIndexPtr = (YsTriIndex16*)(indexPtr + nOffset);33             triIndexPtr->index0 = 0;34             triIndexPtr->index1 = 1 + i;35             triIndexPtr->index2 = 1 + (i + 1)%slices;36 37             nOffset += indexStriding;38             triIndexPtr = (YsTriIndex16*)(indexPtr + nOffset);39             triIndexPtr->index0 = numVertices - 1;40             triIndexPtr->index1 = 1 + (i + 1)%slices;41             triIndexPtr->index2 = 1 + i;42         }43     }44     else45     {46         YsTriIndex32* triIndexPtr = NULL;47         for (Yuint i= 0; i < slices; i++)48         {49             nOffset = (i * 2) * indexStriding;50             triIndexPtr = (YsTriIndex32*)(indexPtr + nOffset);51             triIndexPtr->index0 = 0;52             triIndexPtr->index1 = 1 + i;53             triIndexPtr->index2 = 1 + (i + 1)%slices;54 55             nOffset += indexStriding;56             triIndexPtr = (YsTriIndex32*)(indexPtr + nOffset);57             triIndexPtr->index0 = numVertices - 1;58             triIndexPtr->index1 = 1 + (i + 1)%slices;59             triIndexPtr->index2 = 1 + i;60         }61     }62 63     return true;64 }

线框索引数据的生成

1 bool                        YfBuildConeWireIndices 2 ( 3     Yuint                   slices, 4     YeIndexType             indexType, 5     Yuint                   indexStriding,   6     Yuint                   indexPos, 7     void*                   pWireIndicesBuffer 8 ) 9 {10     if (slices < 2 || !pWireIndicesBuffer)11     {12         return false;13     }14 15     Yuint numVertices = slices + 2;16     Yuint numLines    = slices * 2;17     if (indexType == YE_INDEX_16_BIT && 18         numVertices > YD_MAX_UNSIGNED_INT16)19     {20         return false;21     }22 23     // 索引赋值24     char* indexPtr = (char*)pWireIndicesBuffer + indexPos;25     Yuint nOffset = 0;26     if (indexType == YE_INDEX_16_BIT)27     {28         YsLineIndex16* lineIndexPtr = NULL;29         for (Yuint i= 0; i < slices; i++)30         {31             nOffset = (i * 2) * indexStriding;32             lineIndexPtr = (YsLineIndex16*)(indexPtr + nOffset);33             lineIndexPtr->index0 = 0;34             lineIndexPtr->index1 = 1 + i;35 36             nOffset += indexStriding;37             lineIndexPtr = (YsLineIndex16*)(indexPtr + nOffset);38             lineIndexPtr->index0 = 1 + i;39             lineIndexPtr->index1 = 1 + (i + 1)%slices;40         }41     }42     else43     {44         YsLineIndex32* lineIndexPtr = NULL;45         for (Yuint i= 0; i < slices; i++)46         {47             nOffset = (i * 2) * indexStriding;48             lineIndexPtr = (YsLineIndex32*)(indexPtr + nOffset);49             lineIndexPtr->index0 = 0;50             lineIndexPtr->index1 = 1 + i;51 52             nOffset += indexStriding;53             lineIndexPtr = (YsLineIndex32*)(indexPtr + nOffset);54             lineIndexPtr->index0 = 1 + i;55             lineIndexPtr->index1 = 1 + (i + 1)%slices;56         }57     }58 59     return true;60 }