+byte shadebubble(float dx, float dy, vec3_t light)
+{
+ float dz, f, dot;
+ vec3_t normal;
+ if ((dx*dx+dy*dy) < 1) // it does hit the sphere
+ {
+ dz = 1 - (dx*dx+dy*dy);
+ f = 0;
+ // back side
+ normal[0] = dx;normal[1] = dy;normal[2] = dz;
+ VectorNormalize(normal);
+ dot = DotProduct(normal, light);
+ if (dot > 0.5) // interior reflection
+ f += ((dot * 2) - 1);
+ else if (dot < -0.5) // exterior reflection
+ f += ((dot * -2) - 1);
+ // front side
+ normal[0] = dx;normal[1] = dy;normal[2] = -dz;
+ VectorNormalize(normal);
+ dot = DotProduct(normal, light);
+ if (dot > 0.5) // interior reflection
+ f += ((dot * 2) - 1);
+ else if (dot < -0.5) // exterior reflection
+ f += ((dot * -2) - 1);
+ f *= 128;
+ f += 16; // just to give it a haze so you can see the outline
+ f = bound(0, f, 255);
+ return (byte) f;
+ }
+ else
+ return 0;
+}
+