DGLE_RESULT DGLE_API CMesh::RecalculateTangentSpace()
{
if (!_pBuffer)
return S_FALSE;
TDrawDataDesc desc;
_pBuffer->GetBufferDrawDataDesc(desc);
if (desc.uiTextureVertexOffset == -1 ||
(desc.uiTangentOffset == -1 && desc.uiBinormalOffset != -1) || (desc.uiTangentOffset != -1 && desc.uiBinormalOffset == -1)) // confusing situation should never happen
return E_ABORT;
if (desc.uiNormalOffset == -1)
RecalculateNormals(false);
uint stride, verts_data_size, verts_count, idxs_data_size, idxs_count;
_CopyMeshData(desc, stride, verts_data_size, verts_count, idxs_data_size, idxs_count);
TDrawDataDesc desc_new(desc);
bool do_delete_new = false;
if (desc.uiTangentOffset == -1 && desc.uiBinormalOffset == -1)
{
do_delete_new = true;
const uint new_verts_data_size = verts_data_size + verts_count * 6 * sizeof(float);
desc_new.pData = new uint8[new_verts_data_size + idxs_data_size];
memcpy(desc_new.pData, desc.pData, verts_data_size);
desc_new.uiTangentOffset = verts_data_size;
desc_new.uiTangentStride = 0;
desc_new.uiBinormalOffset = verts_data_size + verts_count * 3 * sizeof(float);
desc_new.uiBinormalStride = 0;
if (idxs_count != 0)
{
desc_new.pIndexBuffer = &desc_new.pData[new_verts_data_size];
memcpy(&desc_new.pData[new_verts_data_size], &desc.pData[verts_data_size], idxs_data_size);
}
memset(&desc_new.pData[verts_data_size], 0, new_verts_data_size - verts_data_size);
}
else
{
const uint t_stride = desc_new.uiTangentStride == 0 ? 3 * sizeof(float) : desc_new.uiTangentStride,
b_stride = desc_new.uiBinormalStride == 0 ? 3 * sizeof(float) : desc_new.uiBinormalStride;
for (uint i = 0; i < verts_count; ++i)
{
*(reinterpret_cast<TVector3 *>(&desc_new.pData[desc_new.uiTangentOffset + i * t_stride])) = TVector3();
*(reinterpret_cast<TVector3 *>(&desc_new.pData[desc_new.uiBinormalOffset + i * b_stride])) = TVector3();
}
}
const uint t_stride = desc_new.uiTangentStride == 0 ? 3 * sizeof(float) : desc_new.uiTangentStride,
b_stride = desc_new.uiBinormalStride == 0 ? 3 * sizeof(float) : desc_new.uiBinormalStride,
tex_stride = desc_new.uiTextureVertexStride == 0 ? 2 * sizeof(float) : desc_new.uiTextureVertexStride,
v_stride = desc_new.uiVertexStride == 0 ? 3 * sizeof(float) : desc_new.uiVertexStride,
n_stride = desc_new.uiNormalStride == 0 ? 3 * sizeof(float) : desc_new.uiNormalStride,
count = idxs_count == 0 ? verts_count / 3 : idxs_count / 3;
for(uint i = 0; i < count; ++i)
{
uint face[3];
if (idxs_count == 0)
{
face[0] = i * 3;
face[1] = i * 3 + 1;
face[2] = i * 3 + 2;
}
else
if (desc_new.bIndexBuffer32)
{
face[0] = reinterpret_cast<uint *>(&desc_new.pIndexBuffer[i * 3 * sizeof(uint)])[0];
face[1] = reinterpret_cast<uint *>(&desc_new.pIndexBuffer[i * 3 * sizeof(uint)])[1];
face[2] = reinterpret_cast<uint *>(&desc_new.pIndexBuffer[i * 3 * sizeof(uint)])[2];
}
else
{
face[0] = reinterpret_cast<uint16 *>(&desc_new.pIndexBuffer[i * 3 * sizeof(uint16)])[0];
face[1] = reinterpret_cast<uint16 *>(&desc_new.pIndexBuffer[i * 3 * sizeof(uint16)])[1];
face[2] = reinterpret_cast<uint16 *>(&desc_new.pIndexBuffer[i * 3 * sizeof(uint16)])[2];
}
const TPoint3 * const v[3] = {
reinterpret_cast<TPoint3 *>(&desc_new.pData[face[0] * v_stride]),
reinterpret_cast<TPoint3 *>(&desc_new.pData[face[1] * v_stride]),
reinterpret_cast<TPoint3 *>(&desc_new.pData[face[2] * v_stride])};
const TPoint2 * const t[3] = {
reinterpret_cast<TPoint2 *>(&desc_new.pData[desc_new.uiTextureVertexOffset + face[0] * tex_stride]),
reinterpret_cast<TPoint2 *>(&desc_new.pData[desc_new.uiTextureVertexOffset + face[1] * tex_stride]),
reinterpret_cast<TPoint2 *>(&desc_new.pData[desc_new.uiTextureVertexOffset + face[2] * tex_stride])};
const TVector3 v1 = *v[1] - *v[0], v2 = *v[2] - *v[0];
const TVector2 v3 = *t[1] - *t[0], v4 = *t[2] - *t[0];
const float d = v3.Cross(v4);
if (d == 0.f) continue;
const float r = 1.f / d;
const TVector3 sdir = TVector3(v4.y * v1.x - v4.x * v2.x, v4.y * v1.y - v4.x * v2.y, v4.y * v1.z - v4.x * v2.z) * r,
tdir = TVector3(v3.x * v2.x - v3.y * v1.x, v3.x * v2.y - v3.y * v1.y, v3.x * v2.z - v3.y * v1.z) * r;
*(reinterpret_cast<TVector3 *>(&desc_new.pData[desc_new.uiTangentOffset + face[0] * t_stride])) += sdir;
*(reinterpret_cast<TVector3 *>(&desc_new.pData[desc_new.uiTangentOffset + face[1] * t_stride])) += sdir;
*(reinterpret_cast<TVector3 *>(&desc_new.pData[desc_new.uiTangentOffset + face[2] * t_stride])) += sdir;
*(reinterpret_cast<TVector3 *>(&desc_new.pData[desc_new.uiBinormalOffset + face[0] * b_stride])) += tdir;
*(reinterpret_cast<TVector3 *>(&desc_new.pData[desc_new.uiBinormalOffset + face[1] * b_stride])) += tdir;
*(reinterpret_cast<TVector3 *>(&desc_new.pData[desc_new.uiBinormalOffset + face[2] * b_stride])) += tdir;
}
for (uint i = 0; i < verts_count; ++i)
{
const TVector3 * const normal = reinterpret_cast<TVector3 *>(&desc_new.pData[desc_new.uiNormalOffset + i * n_stride]);
TVector3 *tangent = reinterpret_cast<TVector3 *>(&desc_new.pData[desc_new.uiTangentOffset + i * t_stride]),
*binormal = reinterpret_cast<TVector3 *>(&desc_new.pData[desc_new.uiBinormalOffset + i * b_stride]);
float dot_1 = normal->Dot(*tangent), dot_2;
*tangent = (*tangent - *normal * dot_1).Normalize();
dot_1 = normal->Dot(*tangent);
dot_2 = tangent->Dot(*binormal);
*binormal = (*binormal - *normal * dot_1 + *tangent * dot_2).Normalize();
}
PARANOIC_CHECK_RES(_pBuffer->Reallocate(desc_new, verts_count, idxs_count, CRDM_TRIANGLES));
if (do_delete_new)
delete[] desc_new.pData;
delete[] desc.pData;
return S_OK;
}
