draw: increase far Z, separate path for space quads, fix billboard batching

apps/demos/scenery/scenes/ingame.c

@@ -12,7 +12,7 @@
 
 
 #define TERRAIN_FREQUENCY 0.15f
-#define TERRAIN_DISTANCE 64
+#define TERRAIN_DISTANCE 128
 #define HALF_TERRAIN_DISTANCE ((float)TERRAIN_DISTANCE / 2)
 #define PLAYER_HEIGHT 0.6f
 
@@ -161,6 +161,7 @@ static void draw_terrain(SceneIngame *scn) {
                             (Rect){ .w = 128, .h = 128 },
                             (Color){255, 255, 255, 255});
 
+            /* TODO: only draw upclose */
             draw_billboard("/assets/grasses/10.png",
                           (Vec3){ (float)x, d0 + 0.15f, (float)y },
                           (Vec2){0.3f, 0.3f},