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PODoes glBegin has any effect on lighting?
 

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  1. PODoes glBegin has any effect on lighting?
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    <p>I'm working on a project using opengl (I'm a beginner) and I'm having trouble with lighting.</p> <p>I got 2 drawing methods: one for rendering and an other for picking facets. The rendering method seems ok since it's working properly when I comment the picking one. I tried a few things and found that it's the glBegin() call (in the "picking method") which provokes the issue: Does glBegin has any kind of effect on ligthing ?</p> <p>I set the lights like this:</p> <pre><code>void GLView::createLight(int LightID, const Vector3 &amp;Position, const Vector3 &amp;Color, const float* ambient) { glLightfv(LightID,GL_AMBIENT, ambient); glLightfv(LightID,GL_POSITION,&amp;Position.v[0]); glLightfv(LightID,GL_DIFFUSE,&amp;Color.v[0]); glEnable(LightID); } void GLView::setLights() { float diffuse[]={1,1,1,1}; float lmodel_ambient[4] = {0.5f, 0.5f, 0.5f, 0.5f}; float ambient_0[] = {0.0f,0.0f,0.0f,1.0f}; glMaterialfv(GL_FRONT_AND_BACK,GL_DIFFUSE,&amp;diffuse[0]); glLightModeli(GL_LIGHT_MODEL_TWO_SIDE,1); createLight(GL_LIGHT0,Vector3(0,0.3,1),Vector3(0.7,0.7,0.7),&amp;ambient_0[0]); createLight(GL_LIGHT1,Vector3(-1,0,0.3),Vector3(0.4,0.2,0),&amp;ambient_0[0]); createLight(GL_LIGHT2,Vector3(1,-0.2,0.1),Vector3(0,0.05,0.15),&amp;ambient_0[0]); } </code></pre> <p>Drawing methods:</p> <pre><code>void GLView::draw(TRenderStyle RenderStyle) { int W=width(); int H=height(); float WW=W/2; float HH=H/2; float Zoom=camera-&gt;Zoom*std::min(width(),height()); float Lens=HH/tan(FieldOfView/360*acos(-1)); glEnable(GL_NORMALIZE); glEnable(GL_CULL_FACE); glDisable(GL_FOG); glDisable(GL_BLEND); glDisable(GL_LIGHTING); glColorMask(true,true,true,true); switch (RenderStyle) { case rsScene:{ //rendering } break; case rsMouseWindow: //for picking facets case rsMouseAction:{ glBegin(GL_TRIANGLES); //it's working fine if I comment these 2 lines glEnd(); } break; } } </code></pre> <p>I'm aware it's a vague question, but it really looks like glBegin is affecting lighting and I don't know what to do about it.</p> <p>Thanks for your help.</p> <p>***Edit: The problem is when glBegin() is called only the last initialized light is working.</p>
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    1. USKamouth
    1. USKamouth
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    1. COWhy do you glDisable(GL_LIGHTING); is you want lighting ?
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      1. PODoes glBegin has any effect on lighting?
      1. USneodelphi
    2. COI want lighting in the rendering method but not in the picking one. I commented this line but the result is the same (Disable/Enable lighting is done in the two methods).
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      1. PODoes glBegin has any effect on lighting?
      1. USKamouth
    3. CONot sure if this relates to your problem, but you should render at least one triangle between 'glBegin(GL_TRIANGLES)' and 'glEnd()'. Else those functions don't do anything at all, and might potentially break your code.
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      1. PODoes glBegin has any effect on lighting?
      1. USKevin
 

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