Item entities

This commit is contained in:
2026-09-25 16:26:45 -03:00
parent 5fb23cf404
commit a254b96f65
18 changed files with 797 additions and 94 deletions
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@@ -0,0 +1,141 @@
import { TEXTURE_SIZE } from "$/common/constants.ts";
import { BlockRegistry, EverythingRegistry, ItemRegistry } from "$/common/everything_registry.ts";
import { AssetManager } from "$/client/assets.ts";
import { get_sprite_region } from "$/client/sprites.ts";
import type { ItemEntity } from "$/client/entity/item_entity.ts";
import { push_vertex, Texture } from "$/client/renderer/mod.ts";
// how big items on the ground are drawn, minecraft's ground transform
const BLOCK_SCALE = 0.25;
const ITEM_SCALE = 0.5;
// keeps texture lookups off the sprite's edge
const UV_PAD = 0.5;
// each face's corners in drawing order (counter clockwise from outside) on a unit cube, with its shade.
// top, bottom, front, back, left, right, like the chunk mesher
const CUBE_FACES = [
{ corners: [[0, 1, 1], [1, 1, 1], [1, 1, 0], [0, 1, 0]], shade: 1.0, texture: "top" },
{ corners: [[0, 0, 0], [1, 0, 0], [1, 0, 1], [0, 0, 1]], shade: 0.5, texture: "bottom" },
{ corners: [[0, 0, 1], [1, 0, 1], [1, 1, 1], [0, 1, 1]], shade: 0.8, texture: "front" },
{ corners: [[1, 0, 0], [0, 0, 0], [0, 1, 0], [1, 1, 0]], shade: 0.8, texture: "side" },
{ corners: [[0, 0, 0], [0, 0, 1], [0, 1, 1], [0, 1, 0]], shade: 0.6, texture: "side" },
{ corners: [[1, 0, 1], [1, 0, 0], [1, 1, 0], [1, 1, 1]], shade: 0.6, texture: "side" },
] as const;
// sprite end each corner gets, u then v
const CORNER_UVS = [[0, 1], [1, 1], [1, 0], [0, 0]] as const;
// where the extra copies of a bigger stack sit, as fractions of the model's size
const COPY_OFFSETS = [[0, 0, 0], [0.35, 0.2, -0.25], [-0.3, 0.4, 0.2], [0.15, 0.6, 0.35], [-0.2, 0.8, -0.3]];
// minecraft draws more copies of the model the bigger the stack is
function copies(amount: number) {
if (amount > 48) return 5;
if (amount > 32) return 4;
if (amount > 16) return 3;
if (amount > 1) return 2;
return 1;
}
// the atlas has to be the current texture
export function render_item_entity(entity: ItemEntity, partial_tick: number) {
const atlas = AssetManager.instance.get<Texture>("bworld:textures");
const item_info = EverythingRegistry.get<ItemRegistry>("items", entity.item.type_id);
const block_info = item_info?.block_id
? EverythingRegistry.get<BlockRegistry>("blocks", item_info.block_id)
: undefined;
// spinning and bobbing, like minecraft's ItemEntityRenderer
const time = entity.age + partial_tick;
const angle = time / 20 + entity.bob_offset;
const bob = Math.sin(time / 10 + entity.bob_offset) * 0.1 + 0.1;
const { x, y, z } = entity.render_position(partial_tick);
const scale = block_info ? BLOCK_SCALE : ITEM_SCALE;
for (let i = 0; i < copies(entity.item.amount); i++) {
const [ox, oy, oz] = COPY_OFFSETS[i];
const base = { x: x + ox * scale, y: y + bob + oy * scale * 0.5, z: z + oz * scale };
if (block_info) {
push_block(atlas, block_info, base, scale, angle);
} else {
push_sprite(atlas, item_texture(entity, item_info), base, scale, angle);
}
}
}
// a small cube turned around its middle
function push_block(
atlas: Texture,
block: BlockRegistry,
base: { x: number; y: number; z: number },
size: number,
angle: number,
) {
const sin = Math.sin(angle);
const cos = Math.cos(angle);
const corner = (cx: number, cy: number, cz: number) => {
const lx = (cx - 0.5) * size;
const lz = (cz - 0.5) * size;
return [base.x + lx * cos - lz * sin, base.y + cy * size, base.z + lx * sin + lz * cos];
};
for (const face of CUBE_FACES) {
const region = get_sprite_region(block_face_texture(block, face.texture));
push_textured_quad(atlas, region, face.corners.map(([cx, cy, cz]) => corner(cx, cy, cz)), face.shade);
}
}
// a flat sprite standing up and turning, drawn from both sides
function push_sprite(
atlas: Texture,
texture_id: string,
base: { x: number; y: number; z: number },
size: number,
angle: number,
) {
const region = get_sprite_region(texture_id);
const dx = Math.cos(angle) * size / 2;
const dz = Math.sin(angle) * size / 2;
const bottom = base.y;
const top = base.y + size;
const front = [
[base.x - dx, bottom, base.z - dz],
[base.x + dx, bottom, base.z + dz],
[base.x + dx, top, base.z + dz],
[base.x - dx, top, base.z - dz],
];
push_textured_quad(atlas, region, front, 1);
// the back is the same quad the other way round, mirrored so it isn't drawn backwards
push_textured_quad(atlas, region, [front[1], front[0], front[3], front[2]], 1);
}
function push_textured_quad(atlas: Texture, region: { x: number; y: number }, corners: number[][], shade: number) {
const u0 = (region.x * TEXTURE_SIZE + UV_PAD) / atlas.width;
const v0 = (region.y * TEXTURE_SIZE + UV_PAD) / atlas.height;
const u1 = ((region.x + 1) * TEXTURE_SIZE - UV_PAD) / atlas.width;
const v1 = ((region.y + 1) * TEXTURE_SIZE - UV_PAD) / atlas.height;
for (const i of [0, 1, 2, 0, 2, 3]) {
const [px, py, pz] = corners[i];
const [cu, cv] = CORNER_UVS[i];
push_vertex(px, py, pz, cu ? u1 : u0, cv ? v1 : v0, shade, shade, shade, 1);
}
}
function block_face_texture(block: BlockRegistry, face: "top" | "bottom" | "front" | "side") {
const textures = block.textures;
if (typeof textures === "string") {
return textures;
}
if ("top" in textures) {
return face === "top" ? textures.top : face === "bottom" ? textures.bottom : textures.side;
}
return face === "front" ? textures.front : textures.side;
}
function item_texture(entity: ItemEntity, item_info: ItemRegistry | undefined) {
const texture_id = item_info?.texture_id;
if (typeof texture_id === "function") {
return texture_id(entity.item);
}
return texture_id ?? "engine:missing";
}
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@@ -6,6 +6,8 @@ import { get_sprite_region } from "$/client/sprites.ts";
import type { MultiPlayerGameMode } from "$/client/game_mode.ts";
import type { Entity } from "$/client/entity/entity.ts";
import { RemotePlayer } from "$/client/entity/remote_player.ts";
import { ItemEntity } from "$/client/entity/item_entity.ts";
import { render_item_entity } from "./item_renderer.ts";
import {
draw_terrain,
flush_batch,
@@ -84,7 +86,14 @@ export class LevelRenderer {
render_player(entity, partial_tick);
}
}
flush_batch();
set_current_texture(level.image.tex);
for (const entity of level.entities.values()) {
if (entity instanceof ItemEntity) {
render_item_entity(entity, partial_tick);
}
}
flush_batch();
}