Mouse Cursor Position in OpenGL coordinates

OpenGL OpenGL: Basic Coding
1

Is there an easy way to get the current mouse position in OpenGL coordinates without using GLUT?

I’m using an ortho projection and everyting is drawn at -1 so the Z coordinate doesn’t really matter to me, but if I could somehow read the mouse position in opengl coordinates that would be super helpful in moving forward.

2

“without using GLUT” -> and using what instead ? GL alone does not handle a mouse.

3

You can do this by math calc or by using the glReadPixels

Vector2 ScreenToGlobal(Integer X; Integer Y);
{
var
  viewport:   array [1..4]  of Integer;
  modelview:  array [1..16] of Double;
  projection: array [1..16] of Double;
  Point:      array [0..2]  of Double;
  winZ:       Double;
  glGetDoublev(GL_MODELVIEW_MATRIX, @modelview);
  glGetDoublev(GL_PROJECTION_MATRIX, @projection);
  glGetIntegerv(GL_VIEWPORT, @viewport);

  if (Y == 0) {Y := 1};

  glReadPixels(X, -Y, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, @winZ );
  gluUnProject(X, viewport[4]-Y, winZ, @modelview, @projection, @viewport, Point[0], Point[1], Point[2]);

  Result[0] = Point[0];
  Result[1] = Point[1];
}

using math, you need to know what’s your zoom value, your current camera position and your mouse position

4

hmmm…I for some reason thought gluUnProject was GLUT…apparently its not…I seem to have gluUnProject. I’ve found plenty of examples of gluUnproject…I guess I just need to know now how to get my mouse cursor position in screen coordinates.

5

Actually, I figured it out…thanks!