Hide gameplay features behind a flag

Gameplay features, such as an inventory and the need to collect
resources, can unnecessarily restrict creative freedom, so while
gameplay features are being developed, it would be good to keep them
behind a flag to avoid interrupting people who just want to build.

client/src/graphics/gui.rs

@@ -32,10 +32,16 @@ impl GuiState {
         align(Alignment::TOP_LEFT, || {
             pad(Pad::all(8.0), || {
                 colored_box_container(Color::BLACK.with_alpha(0.7), || {
+                    let material_count_string = if sim.cfg.gameplay_enabled {
+                        sim.count_inventory_entities_matching_material(sim.selected_material())
+                            .to_string()
+                    } else {
+                        "∞".to_string()
+                    };
                     label(format!(
                         "Selected material: {:?} (×{})",
                         sim.selected_material(),
-                        sim.count_inventory_entities_matching_material(sim.selected_material())
+                        material_count_string
                     ));
                 });
             });

client/src/sim.rs

@@ -578,7 +578,7 @@ impl Sim {
             Material::Void
         };
 
-        let consumed_entity = if placing {
+        let consumed_entity = if placing && self.cfg.gameplay_enabled {
             Some(self.get_any_inventory_entity_matching_material(material)?)
         } else {
             None

common/src/sim_config.rs

@@ -13,6 +13,8 @@ pub struct SimConfigRaw {
     /// Maximum distance at which anything can be seen in meters
     pub view_distance: Option<f32>,
     pub input_queue_size_ms: Option<u16>,
+    /// Whether gameplay-like restrictions exist, such as limited inventory
+    pub gameplay_enabled: Option<bool>,
     /// Number of voxels along the edge of a chunk
     pub chunk_size: Option<u8>,
     /// Approximate length of the edge of a voxel in meters
@@ -36,6 +38,7 @@ pub struct SimConfig {
     pub step_interval: Duration,
     pub view_distance: f32,
     pub input_queue_size: Duration,
+    pub gameplay_enabled: bool,
     pub chunk_size: u8,
     pub character: CharacterConfig,
     /// Scaling factor converting meters to absolute units
@@ -51,6 +54,7 @@ impl SimConfig {
             step_interval: Duration::from_secs(1) / x.rate.unwrap_or(30) as u32,
             view_distance: x.view_distance.unwrap_or(90.0) * meters_to_absolute,
             input_queue_size: Duration::from_millis(x.input_queue_size_ms.unwrap_or(50).into()),
+            gameplay_enabled: x.gameplay_enabled.unwrap_or(false),
             chunk_size,
             character: CharacterConfig::from_raw(&x.character, meters_to_absolute),
             meters_to_absolute,

server/src/sim.rs

@@ -451,32 +451,34 @@ impl Sim {
             tracing::warn!("Block update received from ungenerated chunk");
             return;
         };
-        if block_update.new_material != Material::Void {
-            let Some(consumed_entity_id) = block_update.consumed_entity else {
-                tracing::warn!("Tried to place block without consuming any entities");
-                return;
-            };
-            let Some(&consumed_entity) = self.entity_ids.get(&consumed_entity_id) else {
-                tracing::warn!("Tried to consume an unknown entity ID");
-                return;
-            };
-            if !self
-                .world
-                .get::<&Material>(consumed_entity)
-                .is_ok_and(|m| *m == block_update.new_material)
-            {
-                tracing::warn!("Tried to consume wrong material");
-                return;
+        if self.cfg.gameplay_enabled {
+            if block_update.new_material != Material::Void {
+                let Some(consumed_entity_id) = block_update.consumed_entity else {
+                    tracing::warn!("Tried to place block without consuming any entities");
+                    return;
+                };
+                let Some(&consumed_entity) = self.entity_ids.get(&consumed_entity_id) else {
+                    tracing::warn!("Tried to consume an unknown entity ID");
+                    return;
+                };
+                if !self
+                    .world
+                    .get::<&Material>(consumed_entity)
+                    .is_ok_and(|m| *m == block_update.new_material)
+                {
+                    tracing::warn!("Tried to consume wrong material");
+                    return;
+                }
+                if !self.remove_from_inventory(subject, consumed_entity_id) {
+                    tracing::warn!("Tried to consume entity not in player inventory");
+                    return;
+                }
+                self.destroy(consumed_entity);
             }
-            if !self.remove_from_inventory(subject, consumed_entity_id) {
-                tracing::warn!("Tried to consume entity not in player inventory");
-                return;
+            if old_material != Material::Void {
+                let (produced_entity, _) = self.spawn((old_material,));
+                self.add_to_inventory(subject, produced_entity);
             }
-            self.destroy(consumed_entity);
-        }
-        if old_material != Material::Void {
-            let (produced_entity, _) = self.spawn((old_material,));
-            self.add_to_inventory(subject, produced_entity);
         }
         assert!(self.graph.update_block(&block_update));
         self.modified_chunks.insert(block_update.chunk_id);