+ glPushMatrix();
+ glRotatef (gp->tilt, 1, 0, 0);
+ glColor3f(1, 0, 0);
+ glLineWidth(4);
+ glCallList (gp->shadowlist);
+ glLineWidth(1);
+ mi->polygon_count += resolution*(resolution/2);
+ glPopMatrix();
+ }
+
+ else if (!do_texture || gp->tex2)
+ {
+ /* Originally we just used GL_LIGHT0 to produce the day/night sides of
+ the planet, but that always looked crappy, even with a vast number of
+ polygons, because the day/night terminator didn't exactly line up with
+ the polygon edges.
+ */
+
+#ifndef BLENDED_TERMINATOR
+
+ /* Method 1, use the depth buffer as a stencil.
+
+ - Draw the full "day" sphere;
+ - Clear the depth buffer;
+ - Draw a rotated/tilted half-sphere into the depth buffer only,
+ on the Eastern hemisphere, putting non-zero depth only on the
+ sunlit side;
+ - Draw the full "night" sphere, which will clip to dark parts only.
+
+ That lets us divide the sphere into the two maps, and the dividing
+ line can be at any angle, regardless of polygon layout.
+
+ The half-sphere is scaled slightly larger to avoid polygon fighting,
+ since those triangles won't exactly line up because of the rotation.
+
+ The downside of this is that the day/night terminator is 100% sharp.
+ */
+ glClear (GL_DEPTH_BUFFER_BIT);
+ glColorMask (0, 0, 0, 0);
+ glDisable (GL_TEXTURE_2D);
+ glPushMatrix();
+ glRotatef (gp->tilt, 1, 0, 0);
+ glScalef (1.01, 1.01, 1.01);
+ glCallList (gp->shadowlist); /* Fill in depth on sunlit side */
+ mi->polygon_count += resolution*(resolution/2);
+ glPopMatrix();
+ glColorMask (1, 1, 1, 1);
+
+ if (do_texture)
+ {
+ glEnable (GL_TEXTURE_2D);
+ glBindTexture (GL_TEXTURE_2D, gp->tex2);
+ }
+ else
+ {
+ GLfloat c[] = { 0, 0, 0.5, 1 };
+ glColor4fv (c);
+ if (! do_texture)
+ glMaterialfv (GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, c);
+ }
+
+ glPushMatrix();
+ glRotatef (gp->z * 360, 0, 0, 1);
+ glCallList (gp->platelist); /* Fill in color on night side */
+ mi->polygon_count += resolution*resolution;
+ glPopMatrix();
+
+#else /* BLENDED_TERMINATOR */
+
+ /* Method 2, use the alpha buffer as a stencil.
+ - Draw the full "day" sphere;
+ - Clear the depth buffer;
+ - Clear the alpha buffer;
+ - Draw a rotated/tilted half-sphere into the alpha buffer only,
+ on the Eastern hemisphere, putting non-zero alpha only on the
+ sunlit side;
+ - Also draw a fuzzy terminator ring into the alpha buffer;
+ - Clear the depth buffer again;
+ - Draw the full "night" sphere, which will blend to dark parts only.
+ */
+ glColorMask (0, 0, 0, 1);
+ glClear (GL_COLOR_BUFFER_BIT);
+ glClear (GL_DEPTH_BUFFER_BIT);
+ glDisable (GL_TEXTURE_2D);
+
+ glPushMatrix();
+ glRotatef (gp->tilt, 1, 0, 0);
+ glScalef (1.01, 1.01, 1.01);
+ glCallList (gp->shadowlist); /* Fill in alpha on sunlit side */
+ mi->polygon_count += resolution*(resolution/2);
+ glPopMatrix();
+
+ glClear (GL_DEPTH_BUFFER_BIT);
+
+ glColorMask (1, 1, 1, 1);
+ {
+ GLfloat c[] = { 1, 1, 1, 1 };
+ glColor4fv (c);
+ if (! do_texture)
+ glMaterialfv (GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, c);
+ }
+ glEnable (GL_BLEND);
+ glBlendFunc (GL_ONE_MINUS_DST_ALPHA, GL_DST_ALPHA);
+
+ if (do_texture)
+ {
+ glEnable (GL_TEXTURE_2D);
+ glBindTexture (GL_TEXTURE_2D, gp->tex2);
+ }
+ else
+ {
+ GLfloat c[] = { 0, 0, 0.5, 1 };
+ glColor4fv (c);
+ glMaterialfv (GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, c);
+ glEnable (GL_LIGHTING);
+ }
+
+ glPushMatrix();
+ glRotatef (gp->z * 360, 0, 0, 1);
+ glCallList (gp->platelist); /* Fill in color on night side */
+ mi->polygon_count += resolution*resolution;
+ glPopMatrix();
+ glDisable (GL_BLEND);
+ glBlendFunc (GL_ONE, GL_ZERO);
+
+#endif /* BLENDED_TERMINATOR */
+ }
+
+ if (gp->draw_axis)
+ {
+ glPushMatrix();
+ glRotatef (gp->z * 360, 0.0, 0.0, 1.0);
+ glScalef (1.02, 1.02, 1.02);
+ glDisable (GL_TEXTURE_2D);
+ glDisable (GL_LIGHTING);
+ glDisable (GL_LINE_SMOOTH);
+ glColor3f (0.1, 0.3, 0.1);