std::array<Eigen::MatrixXi, 4> FillGroup(const Eigen::MatrixXi& m)
{
std::array<Eigen::MatrixXi, 4> patterns;
patterns[0] = m;
// Found in this awesome answer http://stackoverflow.com/a/3488737/505049
patterns[1] = m.transpose().colwise().reverse().eval(); // Rotate 90 CW
patterns[2] = m.transpose().colwise().reverse().transpose().colwise().reverse().eval(); // Rotate 180. Not in the S.O. post
patterns[3] = m.transpose().rowwise().reverse().eval(); // Rotate 270 CW
return patterns;
}
// http://www.songho.ca/opengl/gl_vbo.html#create
IGL_INLINE void igl::opengl::create_index_vbo(
const Eigen::MatrixXi & F,
GLuint & F_vbo_id)
{
// Generate Buffers
glGenBuffers(1,&F_vbo_id);
// Bind Buffers
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,F_vbo_id);
// Copy data to buffers
// We expect a matrix with each vertex position on a row, we then want to
// pass this data to OpenGL reading across rows (row-major)
if(F.Options & Eigen::RowMajor)
{
glBufferData(
GL_ELEMENT_ARRAY_BUFFER,
sizeof(int)*F.size(),
F.data(),
GL_STATIC_DRAW);
}else
{
// Create temporary copy of transpose
Eigen::MatrixXi FT = F.transpose();
// If its column major then we need to temporarily store a transpose
glBufferData(
GL_ELEMENT_ARRAY_BUFFER,
sizeof(int)*F.size(),
FT.data(),
GL_STATIC_DRAW);
}
// bind with 0, so, switch back to normal pointer operation
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}