I can get a decent “glow” effect by drawing slightly larger, slightly more translucent copies of an object at the same position as the actual object.
glScalef(1,1,1);
glColor4f(1.0f, 0.0f, 0.0f, 1);
DrawSphere();
glScalef(1.1, 1.1, 1.1);
glColor4f(1.0f, 0.0f, 0.0f, .5);
DrawSphere();
glScalef(1.2, 1.2, 1.2);
glColor4f(1.0f, 0.0f, 0.0f, .2);
DrawSphere();
where DrawSphere() is
GLUquadricObj *quadratic;
quadratic = gluNewQuadric();
gluQuadricNormals(quadratic, GLU_SMOOTH);
gluSphere(quadratic, 1.0f, 32, 32);
However, if I want to do this with a textured object
glBindTexture(GL_TEXTURE_2D, ColorId_);
glEnable(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
gluQuadricTexture(quadratic, GL_TRUE);
Then where can I set the alpha parameter??
Thanks,
Dave