// Returns x, y in window co-ordinates at 0 in the z direction
func ProjToWindow(x, y float64) (float64, float64) {
var projmat, modelmat [16]float64
var viewport [4]int32
gl.GetDoublev(gl.PROJECTION_MATRIX, projmat[:])
gl.GetDoublev(gl.MODELVIEW_MATRIX, modelmat[:])
gl.GetIntegerv(gl.VIEWPORT, viewport[:])
px, py, _ := glu.Project(float64(x), float64(y), 0,
&modelmat, &projmat, &viewport)
//return int(px), int(viewport[3]) - int(py)
return px, float64(viewport[3]) - py
}
// Returns x, y in window co-ordinates at 0 in the z direction
func WindowToProj(x, y int) (float64, float64) {
var projmat, modelmat [16]float64
var viewport [4]int32
gl.GetDoublev(gl.PROJECTION_MATRIX, projmat[:])
gl.GetDoublev(gl.MODELVIEW_MATRIX, modelmat[:])
gl.GetIntegerv(gl.VIEWPORT, viewport[:])
// Need to convert so that y is at lower left
y = int(viewport[3]) - y
px, py, _ := glu.UnProject(float64(x), float64(y), 0,
&modelmat, &projmat, &viewport)
return px, py
}