Add some simple shading to the walls

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

raycaster.c

@@ -282,22 +282,28 @@ void drawRays3D()
 
     // * Compare shortest horizontal and vertical line, then use the shortest
     // This is what actually determines our ray that hits a wall!
+
+    // Vertical wall hit
     if (disV < disH)
     {
       rx = vx;
       ry = vy;
       disT = disV;
+      // Vertical walls are drawn a little brighter than horizontal walls
+      glColor3f(0.9, 0, 0);
     }
 
+    // Horizontal wall hit
     if (disH < disV)
     {
       rx = hx;
       ry = hy;
       disT = disH;
+      // Horizontal walls are drawn a little darker than vertical walls
+      glColor3f(0.7, 0, 0);
     }
 
-    // * Draw the shortest line
-    glColor3f(1, 0, 0);
+    // * Draw the ray
     glLineWidth(3);
     glBegin(GL_LINES);
     glVertex2i(px, py);
@@ -307,7 +313,6 @@ void drawRays3D()
     // * --- Draw 3D Walls ---
 
     // Correct the fish-eye effect
-
     float ca = pa - ra;
     if (ra < 0)
     {