less than half finished block states

common/constants.ts

@@ -12,3 +12,9 @@ export interface SpriteRegion {
 
 export const faces = ["west", "east", "bottom", "top", "north", "south"] as const;
 export type Faces = typeof faces[number];
+
+export const AIR = 0;
+export const VOID = 0xFFFFFFFF;
+
+export const ID_MASK = 0xFFFF;
+export const STATE_SHIFT = 16;

common/everything_registry.ts

@@ -62,6 +62,23 @@ interface TextureFront {
 	side: string;
 }
 
+export interface BlockStateDefinition {
+	name: string;
+	bits: number;
+	default: number;
+}
+
+interface CompiledStateDefinition {
+	name: string;
+	mask: number;
+	shift: number;
+}
+
+interface BlockStateVariant {
+	model: string;
+	y: number;
+}
+
 export interface BlockRegistry {
 	id: string;
 	textures: string | TextureSideTopBottom | TextureFront;
@@ -74,12 +91,17 @@ export interface BlockRegistry {
 	tool_to_break?: string;
 	drop_table?: string;
 
+	states?: BlockStateDefinition[];
+	variants?: Record<string, BlockStateVariant>;
+
 	on_create?(dimension: Dimension, block: Block): void;
 	on_break?(dimension: Dimension, block: Block): void;
 	on_click?(dimension: Dimension, block: Block): void;
 	on_interact?(dimension: Dimension, block: Block): boolean;
 	on_tick?(dimension: Dimension, block: Block, tick_delta: number): void;
 	on_second?(dimension: Dimension, block: Block, second_delta: number): void;
+
+	compiled_states?: CompiledStateDefinition[];
 }
 
 export interface ItemRegistry<T = unknown | undefined> {

common/utils.ts

@@ -1,5 +1,5 @@
 import { AssetManager } from "../client/assets.ts";
-import { SpriteRegion } from "./constants.ts";
+import { ID_MASK, SpriteRegion, STATE_SHIFT } from "./constants.ts";
 import { BlockRegistry, EverythingRegistry, ItemRegistry } from "./everything_registry.ts";
 
 export function point_inside_rec(
@@ -56,3 +56,53 @@ export function register_block_item(block: BlockRegistry) {
 		block_id: block.id,
 	});
 }
+
+export function get_state_value(value: number, block_info: BlockRegistry, name: string) {
+	if (!block_info.states) {
+		return undefined;
+	}
+
+	if (!block_info.compiled_states) {
+		compile_block_states(block_info);
+	}
+
+	const state_bits = value >>> STATE_SHIFT;
+
+	const s = block_info.compiled_states!.find((s) => s.name === name)!;
+	return (state_bits & s.mask) >>> s.shift;
+}
+
+export function set_state_value(value: number, block_info: BlockRegistry, name: string, new_value: number) {
+	if (!block_info.states) {
+		return undefined;
+	}
+
+	if (!block_info.compiled_states) {
+		compile_block_states(block_info);
+	}
+	const id = value & ID_MASK;
+	let state_bits = value >>> 16;
+
+	const s = block_info.compiled_states!.find((s) => s.name === name)!;
+
+	state_bits = (state_bits & ~s.mask) | (new_value << s.shift);
+
+	return (state_bits << 16) | id;
+}
+
+function compile_block_states(block_info: BlockRegistry) {
+	if (!block_info.states) {
+		return;
+	}
+
+	let offset = 0;
+
+	block_info.compiled_states = block_info.states.map((s) => {
+		const shift = offset;
+		const mask = ((1 << s.bits) - 1) << shift;
+
+		offset += s.bits;
+
+		return { name: s.name, mask, shift };
+	});
+}