fix renderglitches when changing render distance ingame

Author: Pannoniae

src/ui/GameScreen.cs

@@ -181,7 +181,7 @@ public override void onKeyDown(IKeyboard keyboard, Key key, int scancode) {
 
         // reload chunks
         if (key == Key.A && keyboard.IsKeyPressed(Key.F3)) {
-            remeshWorld();
+            remeshWorld(Settings.instance.renderDistance);
         }
 
         if (key == Key.F) {
@@ -229,12 +229,18 @@ public override void onKeyDown(IKeyboard keyboard, Key key, int scancode) {
         }
     }
 
-    public void remeshWorld() {
+    public void remeshWorld(int oldRenderDist) {
         setUniforms();
         foreach (var chunk in world.chunks.Values) {
             // don't set chunk if not loaded yet, else we will have broken chunkgen/lighting errors
             if (chunk.status >= ChunkStatus.MESHED) {
-                chunk.meshChunk();
+                if (oldRenderDist < Settings.instance.renderDistance) {
+                    // just unload everything
+                    chunk.status = ChunkStatus.MESHED - 1;
+                }
+                else {
+                    chunk.meshChunk();
+                }
             }
         }
         world.player.loadChunksAroundThePlayer(Settings.instance.renderDistance);

src/ui/SettingsMenu.cs

@@ -44,7 +44,7 @@ public SettingsMenu() {
         AO.topCentre();
         AO.clicked += () => {
             settings.AO = AO.getIndex() == 1;
-            remeshIfRequired();
+            remeshIfRequired(settings.renderDistance);
         };
         AO.tooltip = "Ambient Occlusion makes block corners darker to simulate shadows.";
         settingElements.Add(AO);
@@ -55,7 +55,7 @@ public SettingsMenu() {
         smoothLighting.topCentre();
         smoothLighting.clicked += () => {
             settings.smoothLighting = smoothLighting.getIndex() == 1;
-            remeshIfRequired();
+            remeshIfRequired(settings.renderDistance);
         };
         smoothLighting.tooltip = "Smooth Lighting improves the game's look by smoothing the lighting between blocks.";
         settingElements.Add(smoothLighting);
@@ -92,7 +92,7 @@ public SettingsMenu() {
         renderDistance.tooltip = "The maximum distance at which blocks are rendered.\nHigher values may reduce performance.";
         renderDistance.applied += () => {
             settings.renderDistance = (int)renderDistance.value;
-            remeshIfRequired();
+            remeshIfRequired((int)renderDistance.value);
         };
         renderDistance.getText = value => "Render Distance: " + value;
         settingElements.Add(renderDistance);
@@ -127,9 +127,9 @@ public SettingsMenu() {
         layoutSettingsTwoCols(settingElements, new Vector2D<int>(0, 16), vsync.GUIbounds.Width);
     }
 
-    private void remeshIfRequired() {
+    private void remeshIfRequired(int oldRenderDist) {
         if (Game.instance.currentScreen == Screen.GAME_SCREEN) {
-            Screen.GAME_SCREEN.remeshWorld();
+            Screen.GAME_SCREEN.remeshWorld(oldRenderDist);
         }
     }