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Thread: Drawing a Square vs Loading a Square

  1. #1
    Junior Member
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    Oct 2008
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    Drawing a Square vs Loading a Square

    Hello.

    I was wondering what would be more efficient, loading a generic white square or drawing one instead. I intend on loading several dozens of these squares just to create a simple mosaic, and I'll be adjusting the opacity of each square individually.

    Thanks for your help.

    Cheers,
    Mark

  2. #2
    Senior Member
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    May 2008
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    104

    Re: Drawing a Square vs Loading a Square

    What do you mean by loading and drawing?

  3. #3
    Junior Member
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    Oct 2008
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    Re: Drawing a Square vs Loading a Square

    Quote Originally Posted by jpilon
    What do you mean by loading and drawing?
    Just a quick heads up, I'm working with the iPhone SDK. So when I use the word "load", I mean the following procedure (where myTexture is a simple white square):
    Code :
    [_myTexture drawAtPoint:CGPointMake(bounds.size.width / 2, bounds.size.height * 2)];
    And when I use the word "draw", I mean:
    Code :
    glPushMatrix();
    glTranslatef(10, 100, 0);
    GLshort vertArray[12] = {10,10,0, 10,20,0, 20,20,0, 20,10,0}; 
    GLubyte colArray[16] = {0,255,0,0, 255,0,0,0, 0,255,0,0, 0,255,0,0};
     
    //Enable vertices array
    glEnableClientState(GL_VERTEX_ARRAY);
    glVertexPointer(3, GL_SHORT, 0, vertArray);
     
    //Enable colour array
    glEnableClientState(GL_COLOR_ARRAY);
    glColorPointer(4, GL_UNSIGNED_BYTE, 0, colArray);
     
    //We want to draw triangles, 0=first element(vertices). 3=number of items (vertices) to draw from the array
    glColorPointer(4, GL_UNSIGNED_BYTE, 0, colArray);
    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
    glPopMatrix();
    I hope that clears up the ambiguity. And thanks for the help.

    --Mark

  4. #4
    Senior Member
    Join Date
    May 2008
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    104

    Re: Drawing a Square vs Loading a Square

    Oh I believe I understand. I'd be inclined to think that rendering your squares using 3d primitives ("drawing") would be much more efficient in this circumstance then rending a texture ("loading") which contains squares. But this can vary greatly depending on things such as hardware, and complexity of what your trying to render. The more polygons that would be required to render your model, the great chance that using a texture which has been pre-rendered would give you a boost in performance. So I believe it's quite situational, but I'm no expert on this topic, so others may have some suggestions.

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