图1.凹凸贴图开启的效果
图2.不使用凹凸贴图
要想使用凹凸贴图，必须计算切线空间（纹理空间）的切线和副法线，否则不能正确的得到光照值，计算切线空间我使用的计算代码如下：
Vector3f vCurVertexPosi( pVBBump[nCurVertexIndex].fPositionX, pVBBump[nCurVertexIndex].fPositionY, pVBBump[nCurVertexIndex].fPositionZ );
Vector3f vCampVertexPosi( pVBBump[nCampVertexIndex].fPositionX, pVBBump[nCampVertexIndex].fPositionY, pVBBump[nCampVertexIndex].fPositionZ );
Vector3f vCurVertexNormal( pVBBump[nCurVertexIndex].fNormalX, pVBBump[nCurVertexIndex].fNormalY, pVBBump[nCurVertexIndex].fNormalZ );
Vector3f vTangent = (vCampVertexPosi-vCurVertexPosi).UNIT();
Vector3f vTangentTemp = (vTangent^vCurVertexNormal).UNIT();
vTangent = vCurVertexNormal^vTangentTemp;
float fDifferU = pVBBump[nCampVertexIndex].fTextureU - pVBBump[nCurVertexIndex].fTextureU;
float fDifferV = pVBBump[nCampVertexIndex].fTextureV - pVBBump[nCurVertexIndex].fTextureV;
Vector3f vNormalU = ( vTangent*fDifferU + vTangentTemp*fDifferV ).UNIT();
Vector3f vNormalV = vCurVertexNormal^vNormalU;
pVBBump[nCurVertexIndex].fNormalUX = vNormalU.X;
pVBBump[nCurVertexIndex].fNormalUY = vNormalU.Y;
pVBBump[nCurVertexIndex].fNormalUZ = vNormalU.Z;
pVBBump[nCurVertexIndex].fNormalVX = vNormalV.X;
pVBBump[nCurVertexIndex].fNormalVY = vNormalV.Y;
pVBBump[nCurVertexIndex].fNormalVZ = vNormalV.Z;
其中vCurVertexPosi是当前需要计算切线空间的顶点vCampVertexPosi是相邻的顶点，用来比较相对纹理坐标“^”表示向量积UINT方法是将向量单位化，实现后的效果如图1，图2显示的是没有使用凹凸纹理的效果