🔒 Locked

Stupid question

Started by Marty666 Jan 9, 2004 at 5:19 AM 4 replies 450+ views

Original Post

Jan 9, 2004 at 5:19 AM

Hi all, I started programming again. I''m trying to make a simple 3D game using glut. I use the glutBitmapCharacter function to put text on screen. This works, but the text seems to stay in one place when i move the camera, while i want it to stay in the same place on the screen. I use glRasterPos to prevent this, but the text is now invisible. I tried pushing the matrix then setting it to projection then using gluOrtho2D before drawing the text and then setting the matrix back to modelview and popping the matrix, but this seems to have strange effects. (All is rendered on bottom row of pixels only, rest is black) How can i switch between 2D and 3D easilly and fast to write fonts to the screen and render 3D? Thanx, Marty

Tree Penguin

Jan 9, 2004 at 5:26 AM

This:


glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0f, (GLfloat)scrw/(GLfloat)scrh, 0.1f, 500.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
// Draw 3D

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0,scrw,scrh,0.0,-1.0,1.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
// Draw 2D

This works fine for me, if it''s fast, i don''t know, it is fast enough not noticing horrible fps decreasing.

Marty666

Jan 9, 2004 at 5:43 AM


void Print(float x, float y, char *string)
{
	glMatrixMode(GL_PROJECTION); //This is the matrix to set before gluOrtho2D, right?
	glPushMatrix(); //Keep the matrix before I glLoadIdentity
	glLoadIdentity(); //Reset it
	gluOrtho2D(800, 0, 600, 0); //Make the Ortho Raster
	glDisable(GL_DEPTH_TEST); //Do I need this?
	
	int length;
    length = strlen(string); //This many chars to draw
	glRasterPos2i(x,y); //Start at this RasterPos
	for (int i = 0; i < length; i++)
		glutBitmapCharacter(GLUT_BITMAP_9_BY_15, string); //Do ''m all
	
	glEnable(GL_DEPTH_TEST); //Do I need this?
	glPopMatrix(); //Restore my old matrix
	glMatrixMode(GL_MODELVIEW); //Go on in 3D	
}

Marty666

Jan 9, 2004 at 5:44 AM

This should work, right?
So why don''t i see any fonts on screen?

Thanx, Marty

Tree Penguin

Jan 9, 2004 at 6:03 AM

Try translating one unit away, the character might be at the same depth as the camera''s origin (0).

Marty666

Jan 9, 2004 at 6:04 AM

Ok, it works, thanx for helping!

For anyone that''s looking for glut fonts:


void Print(float x, float y, char *string)
{
    glMatrixMode(GL_PROJECTION);
	glPushMatrix();				// save projection matrix
	glLoadIdentity();			// reset projection matrix
	glOrtho(0.0,800,600,0.0,-1.0,1.0); //set up 2D
	glMatrixMode(GL_MODELVIEW);
	glPushMatrix();				// save modelview matrix
	glLoadIdentity();			// reset modelview matrix
	int length;
    length = strlen(string);	// This many chars to draw
	glRasterPos2i(x,y);			// Start at this RasterPos
	for (int i = 0; i < length; i++)
		glutBitmapCharacter(GLUT_BITMAP_9_BY_15, string); //Do ''m all
	glMatrixMode(GL_PROJECTION);
	glPopMatrix();				// Restore projection matrix
	glMatrixMode(GL_MODELVIEW);
	glPopMatrix();				// Restore modelview matrix
}

Topic Locked

This topic has been locked by a moderator. New replies are not allowed.