bool                        YfBuildSpiralStairsVertices

 (

     Yreal                   radius,

     Yreal                   assistRadius,

     Yreal                   height,

     Yuint                   slices,

     Yuint                   stacks,

     YeOriginPose            originPose,

     Yuint                   vertexStriding,

     Yuint                   vertexPos,

     void*                   pVerticesBuffer

 )

 {

     if (stacks <  || slices <  || !pVerticesBuffer)

     {

         return false;

     }

     Yuint numVertices  =  + stacks * ;

     //Yuint numTriangles = stacks * 8;

     char* vertexPtr = (char*)pVerticesBuffer + vertexPos;

     YsVector3* curVertexPtr = NULL;

     Yuint nOffset = ;

     Yreal originOffsetY = 0.0f;

     if (originPose == YE_ORIGIN_POSE_TOP)

     {

         originOffsetY = -height;

     }

     else if (originPose == YE_ORIGIN_POSE_CENTER)

     {

         originOffsetY = -height * 0.5f;

     }

     Yreal fStepTexcoord = 1.0f / (stacks - );

     Yreal fStepHeight = height / stacks;

     Yreal fStepAngle = YD_REAL_TWAIN_PI / slices;

     Yreal angleXZ;

     Yreal posX, posZ;

     for (Yuint i = ; i <= stacks; i++)

     {

         angleXZ = i * fStepAngle;

         posX = yf_sin(angleXZ);

         posZ = yf_cos(angleXZ);

         nOffset = i *  * vertexStriding;

         curVertexPtr = (YsVector3*)(vertexPtr + nOffset);

         curVertexPtr->x = radius * posX;

         curVertexPtr->y = i * fStepHeight + originOffsetY;

         curVertexPtr->z = radius * posZ;

         nOffset += vertexStriding;

         curVertexPtr = (YsVector3*)(vertexPtr + nOffset);

         curVertexPtr->x = assistRadius * posX;

         curVertexPtr->y = i * fStepHeight + originOffsetY;

         curVertexPtr->z = assistRadius * posZ;

         if (i == stacks)

         {

             continue;

         }

         nOffset += vertexStriding;

         curVertexPtr = (YsVector3*)(vertexPtr + nOffset);

         curVertexPtr->x = radius * posX;

         curVertexPtr->y = (i+) * fStepHeight + originOffsetY;

         curVertexPtr->z = radius * posZ;

         nOffset += vertexStriding;

         curVertexPtr = (YsVector3*)(vertexPtr + nOffset);

         curVertexPtr->x = assistRadius * posX;

         curVertexPtr->y = (i+) * fStepHeight + originOffsetY;

         curVertexPtr->z = assistRadius * posZ;

     }

     return true;

 } 

 bool                        YfBuildSpiralStairsTriIndices

 (

     Yuint                   stacks,

     YeIndexType             indexType,

     Yuint                   indexStriding,

     Yuint                   indexPos,

     void*                   pTriIndicesBuffer

 )

 {

     return YfBuildStairsTriIndices(

                 stacks,

                 indexType,

                 indexStriding,

                 indexPos,

                 pTriIndicesBuffer

                 );

 }  

 bool                        YfBuildSpiralStairsWireIndices

 (

     Yuint                   stacks,

     YeIndexType             indexType,

     Yuint                   indexStriding,

     Yuint                   indexPos,

     void*                   pWireIndicesBuffer

 )

 {

     return YfBuildStairsWireIndices(

                 stacks,

                 indexType,

                 indexStriding,

                 indexPos,

                 pWireIndicesBuffer

                 );

 }