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Text Won't Overlap 2D Quad


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#1 ajm113   Members   -  Reputation: 311

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Posted 19 August 2012 - 08:53 PM

Hello everyone, I seem to be having a small problem with my font system not overlapping the quad I'm trying to draw that shows the background image for my menu system. I've tried moving around the glDisable GL_DEPTH_TEST and disabled DepthMask and a few other things and even rearranged the order of how the 2D stuff gets displayed, but I'm getting no effect from anything.

Here is my code

void Render()
{
	 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

	 glMatrixMode( GL_MODELVIEW );
	 glLoadIdentity();
	 glEnable(GL_BLEND);
     glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );

     //Draw 3D here....

    //Draw 2D here...

	 glEnable(GL_TEXTURE_2D);
	 glEnable(GL_BLEND);
    glDisable(GL_DEPTH_TEST);

     glColor3f(1, 1, 1);
	 glMatrixMode(GL_PROJECTION);	  // Select The Projection Matrix
	 glPushMatrix();		  // Store The Projection Matrix
	 glLoadIdentity();		 // Reset The Projection Matrix
	 glOrtho(0,640,0,480,-1,1);    // Set Up An Ortho Screen
	 glMatrixMode(GL_MODELVIEW);	   // Select The Modelview Matrix
	 glPushMatrix();		  // Store The Modelview Matrix
	 glLoadIdentity();		 // Reset The Modelview Matrix
	 glTranslated(0,0,0);	    // Position The Text (0,0 - Bottom Left)
     glBindTexture(GL_TEXTURE_2D, 1);

     glBegin(GL_QUADS);

       glTexCoord2f(0, 1.0);
       glVertex2i(0, 0);

      glTexCoord2f(1,1.0);
     glVertex2i(30, 0);

     glTexCoord2f(1.0, 0.0);
     glVertex2i(30, 30);

  glTexCoord2f(0.0, 0.0);
  glVertex2i(0, 30);

  glEnd();
}
	 glMatrixMode(GL_PROJECTION);	  // Select The Projection Matrix
	 glPopMatrix();		  // Restore The Old Projection Matrix
	 glMatrixMode(GL_MODELVIEW);	   // Select The Modelview Matrix
	 glPopMatrix();		  // Restore The Old Projection Matrix
	 glDisable(GL_TEXTURE_2D);
	 glDisable(GL_BLEND);
 
  glColor3f(1, 0, 1);
m_FontEngine.glPrint(20, 20, "Hello Menu!", 0);
glEnable(GL_DEPTH_TEST);	   // Enables Depth Testing     

}


Code of glPrint:
if (set>1)
{
  set=1;
}
     glEnable(GL_TEXTURE_2D);
     glEnable(GL_BLEND);

     glBlendFunc(GL_SRC_ALPHA,GL_ONE);	 // Select The Type Of Blending

     glBindTexture(GL_TEXTURE_2D, FontTextureId);  // Select Our Font Texture
     glMatrixMode(GL_PROJECTION);	  // Select The Projection Matrix
     glPushMatrix();		  // Store The Projection Matrix
     glLoadIdentity();		 // Reset The Projection Matrix
     glOrtho(0,640,0,480,-1,1);	   // Set Up An Ortho Screen
     glMatrixMode(GL_MODELVIEW);	   // Select The Modelview Matrix
     glPushMatrix();		  // Store The Modelview Matrix
    glLoadIdentity();		 // Reset The Modelview Matrix

glTranslated(x,y,0);	    // Position The Text (0,0 - Bottom Left)

     glListBase(base-32+(128*set));	  // Choose The Font Set (0 or 1)

     glCallLists(strlen(string),GL_UNSIGNED_BYTE,string);// Write The Text To The Screen

     glMatrixMode(GL_PROJECTION);	  // Select The Projection Matrix
     glPopMatrix();		  // Restore The Old Projection Matrix
     glMatrixMode(GL_MODELVIEW);	   // Select The Modelview Matrix
     glPopMatrix();		  // Restore The Old Projection Matrix


     glDisable(GL_TEXTURE_2D);
     glDisable(GL_BLEND);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

I think it may have something to do with how I'm setting up the projects on both of them, but I don't know what else it could be.

Thank you.

Attached Thumbnails

  • problem.png

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#2 Lazy Foo   Members   -  Reputation: 1105

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Posted 19 August 2012 - 09:10 PM

Have you tried changing this line:
glBlendFunc(GL_SRC_ALPHA,GL_ONE);   // Select The Type Of Blending

to

glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);   // Select The Type Of Blending

Because IIRC, the way you have it will make it so the color components add together. Since you're rendering on white, everything will be white because white = 1,1,1 and color values get truncated at 1.

Also, you seem to have a lot of extraneous state changes in your code. You should generally avoid making more state changes than you have to.

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#3 ajm113   Members   -  Reputation: 311

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Posted 20 August 2012 - 08:57 AM

I tried changing, it appears to fix this problem, but then it created another one where the alpha wasn't working anymore since I was using a .bmp file with a black background. So just to fix everything and even get a better looking font, I just went ahead and changed the bmp to a png file with a transparent background for the text and that pretty much toke care of it. I even tried turning on alpha test and it didn't do anything, but anyways I'll clean up the code.

Thanks for your help once again! Posted Image

Edited by ajm113, 20 August 2012 - 09:05 AM.

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