Environment Reflection

OpenGL OpenGL: Advanced Coding
1

How can I configure two texture units, one with the object’s texture, and the other with the environment map , to display properly? I tried a lot o combinations but I didnt get the correct effect

2

reflection is additive; color maps typically are modulating. Thus, you want texture environment 0 to modulate the base color texture, and texture environment 1 to add the result of the environment map.

3

Hi

I do it the following way.(not that lighting is used and that texture unit 0 is set to modulate) I interpolate between lit base texture and the env map by the texture environemnts constat alpha value;

  glActiveTexture(GL_TEXTURE1);
  glBindTexture(GL_TEXTURE_CUBE_MAP,cube_id);
  
  glTexGenf(GL_S,GL_TEXTURE_GEN_MODE,GL_REFLECTION_MAP);
  glTexGenf(GL_T,GL_TEXTURE_GEN_MODE,GL_REFLECTION_MAP);
  glTexGenf(GL_R,GL_TEXTURE_GEN_MODE,GL_REFLECTION_MAP);

  glEnable(GL_TEXTURE_CUBE_MAP);
  glEnable(GL_TEXTURE_GEN_S);
  glEnable(GL_TEXTURE_GEN_T);
  glEnable(GL_TEXTURE_GEN_R);

  
  glMatrixMode(GL_TEXTURE);
  glPushMatrix();

  matrix4f m;
  m.set_value(live_srotation);
    m=m.inverse();
  
  glMultMatrixf(m.m);
  
  

  glMatrixMode(GL_MODELVIEW);

  glTexEnvi (GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_COMBINE);

  GLfloat env_color1[4] = {0.0f,00.0f,0.0f,live_env_factor};

  glTexEnvfv(GL_TEXTURE_ENV,GL_TEXTURE_ENV_COLOR,env_color1);
  glTexEnvi (GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_COMBINE);

  // RGB combiner setup
  glTexEnvi (GL_TEXTURE_ENV,GL_COMBINE_RGB,GL_INTERPOLATE);

  // arg 0
  glTexEnvi (GL_TEXTURE_ENV,GL_SOURCE0_RGB,GL_PREVIOUS);
  glTexEnvi (GL_TEXTURE_ENV,GL_OPERAND0_RGB,GL_SRC_COLOR);
  // arg 1
  glTexEnvi (GL_TEXTURE_ENV,GL_SOURCE1_RGB,GL_TEXTURE);
  glTexEnvi (GL_TEXTURE_ENV,GL_OPERAND1_RGB,GL_SRC_COLOR);
  // arg 2
  glTexEnvi (GL_TEXTURE_ENV,GL_SOURCE2_RGB,GL_CONSTANT);
  glTexEnvi (GL_TEXTURE_ENV,GL_OPERAND2_RGB,GL_ONE_MINUS_SRC_ALPHA);
  glActiveTexture(GL_TEXTURE0);

Bye
ScottManDeath