OpenGL 2D Text in 3D Space

Since this is your first post: try to post OpenGL specific questions in the OpenGL forum.

To your question: You could do it in a 3D viewport, but it''s not that trivial. The simplest way is to use orthographic projection, esp. if you already have it working there.

Here is some code snippet:

// assume, you are currently in perspective 3D projection.
// And that the current matrix mode is GL_MODELVIEW

// Draw your 3D scene here

// Save your projection matrix
glMatrixMode(GL_PROJECTION);
glPushMatrix();

// Switch to orthographic projection
glLoadIdentity();
glOrtho(...)

// Back to the modelview matrix mode, so that you can translate/scale your text
glMatrixMode(GL_MODELVIEW);

// Render your 2D text

// get back the old prespective projection matrix
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glMatrixMode(GL_MODELVIEW);

// And you are in perspective mode again.

/ Yann

Modify as necessary to suit your needs:

void print(int x, int y, const char *string)
{
        //Assume we are in MODEL_VIEW already
	glPushMatrix ();
	glLoadIdentity ();
	glMatrixMode(GL_PROJECTION);
	glPushMatrix ();
	glLoadIdentity();

	GLint viewport [4];
	glGetIntegerv (GL_VIEWPORT, viewport);
	gluOrtho2D (0,viewport[2], viewport[3], 0);
	
	glDepthFunc (GL_ALWAYS);
	glColor3f (1,1,1);
	glRasterPos2f(x, y);
	for (int i = 0; string!= '\0'; ++i)
		glutBitmapCharacter(GLUT_BITMAP_HELVETICA_18, string[i]);
	glDepthFunc (GL_LESS);
	glPopMatrix ();
	glMatrixMode(GL_MODELVIEW);
	glPopMatrix ();
}
  

[edited by - invective on May 25, 2002 1:03:53 PM]