/// This only needs to be done once for all the particles, because the view /// matrix does not change any between them. If you were to modify the view /// matrix at all, you would need to recalculate the camera pos and up vector. void BillboardMatrixBase::GetCameraPosAndUp(Vector3d& vCameraPos, Vector3d& vCameraUp) { Matrix4d mView; glGetDoublev(GL_MODELVIEW_MATRIX, mView.Data()); // The values in the view matrix for the camera are the negative values of // the camera. This is because of the way gluLookAt works; I'm don't fully // understand why gluLookAt does what it does, but I know doing this works:) // I know that gluLookAt creates a the look vector as (eye - center), the // resulting direction vector is a vector from center to eye (the oposite // of what are view direction really is). vCameraPos = -mView.Column(3); vCameraUp = mView.Row(1); // zero the translation in the matrix, so we can use the matrix to transform // camera postion to world coordinates using the view matrix mView.Column(3, Vector3d()); // the view matrix is how to get to the gluLookAt pos from what we gave as // input for the camera position, so to go the other way we need to reverse // the rotation. Transposing the matrix will do this. mView.TransposeRotation(); // get the correct position of the camera in world space vCameraPos = mView * vCameraPos; }
void ModelDisplayState::RenderStaticModels(RenderOptions& options) const { const std::vector<CompositeModel3d::StaticModelData>& vecStaticModels = m_spModel->StaticList(); ATLASSERT(m_vecStaticModelTextures.size() == vecStaticModels.size()); for (size_t i=0, iMax = vecStaticModels.size(); i<iMax; i++) { // enable model texture, if loaded if (m_vecStaticModelTextures[i] != NULL) m_vecStaticModelTextures[i]->Bind(); // find mount point and matrix const CompositeModel3d::StaticModelData& data = vecStaticModels[i]; ATLASSERT(data.m_iJointIndex >= 0); ATLASSERT(size_t(data.m_iJointIndex) < m_vecJointRenderData.size()); size_t uiMountIndex = static_cast<size_t>(data.m_iJointIndex); Matrix4d matGlobal = m_vecJointRenderData[uiMountIndex].GlobalMatrix(); matGlobal.Transpose(); // transform current modelview matrix glPushMatrix(); glMultMatrixd(matGlobal.Data()); // render model data.m_spStatic->Render(options); // render mount point if (options.Get(RenderOptions::optionModelJoints)) RenderMountPoint(); glPopMatrix(); } }