REFLECTION D'OBJ (OPENGL)

Finalement voila deux sources des deux effets :
constater vous meme :D 

Reflection : Methode Courant 
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);// Clears the screen.
   glLoadIdentity();                   //Reset modelview matrix for new frame.


   // Here we just set the camera's position.
   gluLookAt(0.0f, 1.5f, 2.5f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f, 0.0f);

   // Since our reflections uses the stencil buffer we must enable it.  Just like if we
   // are enabling depth testing.
   glEnable(GL_STENCIL_TEST);

   // Next we must disable depth testing and turn off color modifications on all colors.
   glDisable(GL_DEPTH_TEST);
   glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);

   // Next two functions will set up the stencil buffer and stencil test.
   glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
   glStencilFunc(GL_ALWAYS, 1, 1);  // Test all.

   // Now we will draw everything that can reflect the surroundings.  This will not
   // actually draw the ground just the "area" that makes up it.
   DrawGround();

   // Now we enable depth testing back and enable the color mask.
   glEnable(GL_DEPTH_TEST);
   glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);   

   // Next we will set the stencil test to pixels equal to 1.  What this means is that
   // every pixel on the object that reflects if it has a 1 set to it then we draw on it.
   // Above we set the stencil test to always 1 so when we rendered the ground every pixel
   // of the ground was given the ability to be drawn on.  Now we draw everything that we
   // want reflection onto the "ground stencil area".
   glStencilFunc(GL_EQUAL, 1, 1);
   glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);

   // Draw the reflection.
   glPushMatrix();

      // We scale to invert the object onto the ground.
      glScalef(1.0, -1.0, 1.0);

      // Draw the reflected cube.
      DrawCube();

   glPopMatrix();

   // Now we are done.  We can disable the stencil buffer so what we draw from here on out
   // is not drawn on the ground "area".
   glDisable(GL_STENCIL_TEST);

   // Now we can draw the ground.  We will blend the ground with the stencil "area"and give
   // it alpha so we can see the reflection.
   glEnable(GL_BLEND);
   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

   // Set the alpha to 50%.
   glColor4f(1.0f, 1.0f, 1.0f, 0.5f);

   // Draw the ground.
   DrawGround();

   // Stop the blending.
   glDisable(GL_BLEND);

   // Well we are done.  Now we draw the cube normally.
   DrawCube();


   // Increase the objects rotation.
   Rotation += 0.5;

   // Reset it if the rotation goes over 360.
   if(Rotation > 360.0f)
      Rotation = 0.0f;

 
   glFlush();
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Reflection propre algo
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    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	
    glLoadIdentity();								

//Place la camera

gluLookAt(0.0f, 2.8f, -4.0f, 0.0f, 0.8f, 0.0f, 0.0f, 1.0f, 0.0f);


glPushMatrix();

    // Inversé l'obj sur le sol
    glScalef(1.0, -1.0, 1.0);

    // Dessine le cube reflecté
    DrawCube();

glPopMatrix();
   
   glEnable(GL_BLEND);
   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

   glColor4f(1.0f, 1.0f, 1.0f, 0.7f);

   // Dessine le sol
   DrawGround();

   glDisable(GL_BLEND);
  //Le Cube Normal

	DrawCube();

// Rotation
   rot += 0.5;

   if(rot > 360.0f)
      rot = 0.0f;

   glFlush();
	return TRUE;

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