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  [SOLVED] Draw Oval in OpenGL  (Read 3141 times)
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Offline paulo.carabuena

Senior Newbie





« Posted 2011-12-19 22:59:34 »

hi.. can you guys help me with this..

i want to implement a draw oval function for opengl.. i am using lwjgl btw.. here is my code so far..

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   public void drawOval(int x, int y, int width, int height) {
      float theta;
      float angle_increment;
      float x1;
      float y1;
     
      angle_increment = (float) Math.PI / 500;
      GL11.glPushMatrix();
     
      GL11.glTranslatef(x+(width/2), y+(height/2), 0);

      GL11.glColor4f(
            this.color.getRedComponent()/255,
            this.color.getGreenComponent()/255,
            this.color.getBlueComponent()/255,
            this.color.getAlpha()/255
            );
         
      GL11.glBegin(GL11.GL_LINE_LOOP);
      for(theta = 0.0f; theta < Math.PI; theta += angle_increment) {
         x1 = (float) (width/2 * Math.cos(theta));
         y1 = (float) (height/2 * Math.sin(theta));

         GL11.glVertex2f(x1, y1);
      }
      GL11.glEnd();
     
      GL11.glPopMatrix();
   }


this function draws only the lower half of the circle.. idk how to fix it, any help is appreciated.. thanks in advance Smiley
Offline Riven
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Hand over your head.


« Reply #1 - Posted 2011-12-19 23:04:12 »

1  
 for(theta = 0.0f; theta < Math.PI; theta += angle_increment) {

circle is 2 PI persecutioncomplex

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Offline paulo.carabuena

Senior Newbie





« Reply #2 - Posted 2011-12-19 23:05:39 »

ok i found out what's wrong.. i should have used 2*Math.PI instead of just one since the circle has a range of 2*PI radians..  Grin
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Offline paulo.carabuena

Senior Newbie





« Reply #3 - Posted 2011-12-19 23:06:41 »

yeah.. i am quite an idiot for not noticing that..  Grin thanks anyway..  Grin
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