func uploadGeometry(mesh *geometry) {
gl.GenVertexArrays(1, &mesh.glVao)
gl.BindVertexArray(mesh.glVao)
gl.GenBuffers(1, &mesh.glVertBuf)
gl.BindBuffer(gl.ARRAY_BUFFER, mesh.glVertBuf)
gl.EnableVertexAttribArray(progPosAttrLoc)
gl.VertexAttribPointer(progPosAttrLoc, 3, gl.FLOAT, gl.FALSE, 0, gl.Pointer(nil))
gl.BufferData(gl.ARRAY_BUFFER, gl.Sizeiptr(4*len(mesh.glVerts)), gl.Pointer(&mesh.glVerts[0]), gl.STATIC_DRAW)
gl.BindBuffer(gl.ARRAY_BUFFER, 0)
gl.BindVertexArray(0)
}
func renderGeometry(mesh *geometry) {
gl.BindVertexArray(mesh.glVao)
gl.DrawArrays(mesh.glMode, 0, mesh.glNumVerts)
gl.BindVertexArray(0)
}