--- title: "Sprite shaders: API" package: "@phaser-ae/sprite-shaders" tier: Free version: 3.0.0-3 released: 2026-10-14 updated: 2026-10-20 description: "Runs your own WGSL shader over one sprite and a margin around it, so flames, glows, frost and electric arcs can reach past its outline." url: https://phaser.io/packs/sprite-shaders/api site: Phaser - https://phaser.io --- # Sprite shaders: API `@phaser-ae/sprite-shaders` — A custom shader on one sprite, reaching past its outline: a hero on fire, a glowing pickup, a frozen boss. game.spriteShaders.add(sprite, def). ## The pack ### `spriteShaders` ```ts function spriteShaders(): Pack<{ spriteShaders: SpriteShadersApi }> ``` The sprite shaders pack. Exposes `game.spriteShaders`; registers drawer 6 so the backend hands it every run of sprites with a shader, in sorted order, and draws each with its own snippet (one draw call per sprite). Tweens and fades run on the game clock. Headless it keeps every value and draws nothing. WebGPU and WebGL2. ## Helpers ### `checkSpriteShader` ```ts function checkSpriteShader(def: SpriteShaderDef, opts: { maxCode?: number } = {}): string | null ``` Check a sprite shader definition the way `add` takes it, with no GPU: the name, the limits, reserved and redeclared names, `while`/`loop`, texture calls, the margin, the length (default 8000 characters) and the WebGL2 translation. A snippet the translator refuses would draw only on WebGPU, so `add` refuses it too. Returns the problem in one sentence, or null. ### `SPRITE_SHADER_RECIPES` ```ts const SPRITE_SHADER_RECIPES: Readonly> ``` Eight ready sprite shaders, by name: a glow aura, burning (flames rising off the outline), frozen, electric arcs, dissolve to embers (tween `amount` 0 → 1), hologram scanlines, golden shine, and a damage flash (tween `hit`; it never strobes). Each is an ordinary definition: add it as it is, or copy it and change it. ### `spriteShaderEase` ```ts function spriteShaderEase(e: SpriteShaderEase | undefined): EaseFn ``` The curve an easing names: the `maths` pack's table by its own name (`easeOutCubic`, `linear`, `sine`) or by the title screen file's spelling (`cubicOut`), or the function itself. Default `easeInOutQuad`. Unknown names throw. ## Functions ### `checkSpriteShaderWith` ```ts function checkSpriteShaderWith(def: CheckedSpriteShader, translate: SnippetTranslator, opts: { maxCode?: number } = {}): string | null ``` Check a sprite shader definition the way the runtime takes it, with no GPU: the name, the sixteen-param and four-colour limits, reserved and redeclared names, `while`/`loop` (a loop needs a constant bound or it can hang the GPU), texture calls (the sprite is read with `srcAt`), the margin, the length (default 8000 characters) and the WebGL2 translation (`translate` is render-webgl2's `wgslSnippetToGLSL`). Returns the problem in one sentence, or null. ### `ownsFade` ```ts function ownsFade(code: string): boolean ``` Does a snippet read `fade` (in its code, not its comments)? Then it fades itself: the template leaves `color` as the snippet wrote it instead of mixing it with `src` by the fade, and the snippet must leave `src` at fade 0. ### `padProblem` ```ts function padProblem(pad: unknown): string | null ``` A margin's problem in one sentence, or null. A number is that fraction of the sprite's size on every side. ### `resolvePad` ```ts function resolvePad(pad: number | SpritePad | undefined, w: number, h: number): [number, number, number, number] ``` The margin in world units for a sprite of `w` × `h` world units: [left, top, right, bottom]. Assumes `padProblem` found nothing; anything it would refuse reads as 0. ### `spriteShaderGLSL` ```ts function spriteShaderGLSL(code: string, keys: ReadonlyArray = []): string ``` The GLSL fragment stage for a snippet: the WGSL translated (render-webgl2's `wgslSnippetToGLSL`, which throws naming what it cannot translate) inside the same template. The dither and the blur's turn read the pixel from the top left, as WebGPU's fragment position does, so both backends draw the same pixels. ### `spriteShaderScope` ```ts function spriteShaderScope(paramKeys: ReadonlyArray): Record ``` What a snippet can see, by GLSL type, as the WebGL2 translator is told it: the template's names and every param. ## Constants ### `PAD_MAX_PX` ```ts const PAD_MAX_PX: 1024 ``` The largest side a 'px' margin may take, in world units. ### `PAD_MAX_SIZE` ```ts const PAD_MAX_SIZE: 2 ``` The largest side a 'size' margin may take: twice the sprite's own size. ### `SPRITE_FLOATS` ```ts const SPRITE_FLOATS: 60 ``` Floats of uniform data one sprite draws with: fifteen vec4s, the same on both backends. ### `SPRITE_SHADER_HELPERS` ```ts const SPRITE_SHADER_HELPERS: Readonly> ``` The helper functions the template declares beyond the shared `hash21`, `noise2` and `fbm2`, as the translator is told them. ### `SPRITE_SHADER_RESERVED` ```ts const SPRITE_SHADER_RESERVED: ReadonlySet ``` The names the sprite shader template declares itself: a param may not take one. ### `SPRITE_SHADERS_DRAWER_ID` ```ts const SPRITE_SHADERS_DRAWER_ID: 6 ``` The `drawBy` id this pack registers its drawer under. ### `SPRITE_STRIDE` ```ts const SPRITE_STRIDE: 64 ``` Floats between two sprites' data in the WebGPU uniform buffer: 256 bytes, the dynamic-offset alignment. ### `spriteShaderWGSL` ```ts const spriteShaderWGSL = (code: string, keys: ReadonlyArray = []): string=> … ``` The whole WGSL a sprite shader runs as: the template around a definition's snippet (`code`), with its params named by `keys` in order. A snippet that reads `fade` fades itself; any other is mixed with `src` by it. For tools and tests; the runtime builds it once per snippet. ## Types ### `CheckedSpriteShader` ```ts interface CheckedSpriteShader ``` The shape a check reads: a sprite shader definition. - `name: string` — Its name. - `code: string` — The WGSL snippet. - `params?: Record` — Its params and defaults. - `colors?: Record` — Its colours. - `pad?: number | SpritePad` — Its margin. ### `SnippetTranslator` ```ts type SnippetTranslator = (code: string, scope: Record, helpers: Record) => string ``` The translator a check runs, as render-webgl2's `wgslSnippetToGLSL`: it throws naming what it cannot translate. ### `SpritePad` ```ts interface SpritePad ``` The margin a sprite shader draws into around the sprite, per side. `unit` 'size' (the default) reads each side as a fraction of the sprite's own size on that axis (left and right of its width, top and bottom of its height), so the effect scales with the sprite; 'px' reads them as world units (logical pixels at zoom 1). A side left out is 0. - `top?: number` — Above the sprite. - `right?: number` — Right of it. - `bottom?: number` — Below it. - `left?: number` — Left of it. - `unit?: 'size' | 'px'` — 'size' (default): fractions of the sprite's size; 'px': world units. ### `SpriteShaderDef` ```ts interface SpriteShaderDef ``` A sprite shader as data: a WGSL snippet run over one sprite and a margin around it. In scope: `uv` (0..1 over the padded quad), `suv` (the sprite's own 0..1; outside it is the margin), `size` (the sprite's displayed size, world units), `px` (`suv * size`), `time` (seconds), `fade` (the handle's show/hide, 0..1), `TAU`, `hash21`, `noise2`, `fbm2`, `src` and `srcAt(p)` (the sprite's pixel, premultiplied and tinted; transparent outside it), `alphaAt(p)`, `edgeAt(p, r)` (the most alpha within `r` px), `blurAt(p, r)` (the alpha averaged over `r` px), `c0..c3`, `p0..p15` and every param by name. It leaves the sprite's whole new look, margin included, in `color` (premultiplied), which starts as `src`. - `name: string` — A name for messages and tools, e.g. `'burning'`: a letter, then letters, digits, `-` or `_`. - `description?: string` — One line: what it looks like. - `code: string` — WGSL: the fragment body. `color` starts as the plain sprite (`src`); leave the premultiplied result in it. Light above alpha (rgb greater than a) adds to what is behind, for glows and flames. No `fn`, `while`, `loop`, `return` or texture calls: read the sprite with `srcAt`, `alphaAt`, `edgeAt` and `blurAt`. - `params?: Record` — The params and their defaults, in `p0..p15` order, each also in scope by its name. At most sixteen. - `colors?: Record` — The colours and their default hex strings, in `c0..c3` order (straight rgba in the snippet). At most four. - `pad?: number | SpritePad` — The margin the snippet may draw into around the sprite. A number is that fraction of the sprite's size on every side (0.25: a quarter of its width left and right, a quarter of its height above and below); `{ top, right, bottom, left, unit }` sets each side, in fractions of the size (`unit: 'size'`, the default) or world units (`unit: 'px'`). Default 0: nothing outside the outline. ### `SpriteShaderEase` ```ts type SpriteShaderEase = EaseName | `${'sine' | 'quad' | 'cubic' | 'quart' | 'quint' | 'expo' | 'circ' | 'back' | 'elastic' | 'bounce'}${'In' | 'Out' | 'InOut'}` | EaseFn ``` An easing for `tween`, `show` and `hide`: a name from the `maths` pack's `EASE` table (`'easeOutCubic'`, `'linear'`, `'sine'`), the title screen file's spelling of the same curves (`'cubicOut'`, `'sineInOut'`), or a function of 0..1. ### `SpriteShaderHandle` ```ts interface SpriteShaderHandle ``` One sprite's shader, returned by `game.spriteShaders.add()`. Once removed it is inert: its calls do nothing. - `readonly name: string` — The definition's name. - `readonly sprite: Handle` — The sprite it draws. - `readonly def: Readonly` — The definition, as it was added (a frozen copy). - `readonly removed: boolean` — True once removed (by `remove`, by the sprite's death, by a later `add` on the same sprite, or by the scene's end). - `set(param: string, value: number): void` — Set one param live. Throws on a name the definition does not declare, or a value that is not finite. Stops a tween of it. Set params and colours together, live. Throws on an unknown name, a non-finite number or a bad hex before changing anything. Stops tweens of the params it sets. - `set(values: SpriteShaderValues): void` — Set one param live. Throws on a name the definition does not declare, or a value that is not finite. Stops a tween of it. Set params and colours together, live. Throws on an unknown name, a non-finite number or a bad hex before changing anything. Stops tweens of the params it sets. - `tween(params: Record, opts?: SpriteShaderTweenOptions): Promise` — Ease params from where they are to `params` over `duration` seconds of game time (it pauses with the game). A param already tweening is taken over from where it is. Resolves when they arrive, or when replaced, set or removed. Throws on an unknown name or a non-finite number. - `show(opts?: SpriteShaderTweenOptions): Promise` — Ease the effect in over the plain sprite (`fade` to 1), default 0.5 s. Resolves when shown, or when interrupted. - `hide(opts?: SpriteShaderTweenOptions): Promise` — Ease the effect out to the plain sprite (`fade` to 0), default 0.5 s. Hidden, the sprite goes back to the plain sprite path and costs nothing; `hide({ duration: 0 })` right after `add` starts it hidden, ready to `show`. - `readonly fade: number` — 0..1: how much of the effect is drawn now — 0 the plain sprite, 1 the effect, between them a mix; 1 unless shown or hidden. - `readonly params: Record` — Its params' values now, by name (a tween's current point); a fresh object each read. - `readonly colors: Record` — Its colours now, by name, as hex strings; a fresh object each read. - `time: number` — The seconds its snippet's `time` reads now: the game's clock plus this shader's own offset (0 at `add`). Set it to jump (a tool's scrub, a restart from 0); it then runs on with the clock. Throws when not finite. - `remove(): void` — Back to the plain sprite path. Idempotent; also run when the sprite dies, the scene ends, or another shader is added to the sprite. Its tweens end. ### `SpriteShaderOptions` ```ts interface SpriteShaderOptions extends SpriteShaderValues ``` What `add` takes beside the definition: values that override its defaults. ### `SpriteShaderRecipe` ```ts type SpriteShaderRecipe = 'glow' | 'burning' | 'frozen' | 'electric' | 'embers' | 'hologram' | 'gold' | 'damage' ``` The names of the ready looks in `SPRITE_SHADER_RECIPES`. ### `SpriteShadersApi` ```ts interface SpriteShadersApi ``` `game.spriteShaders`: custom shaders on single sprites. - `add(sprite: Handle, def: SpriteShaderDef, opts?: SpriteShaderOptions): SpriteShaderHandle` — Draw `sprite` through `def` from the next frame, in its sorted place, until removed. `opts` overrides the definition's params and colours. One shader per sprite: adding another replaces it (the old handle is removed). Scene-scoped. Throws when the sprite is dead or an aggregate (a tilemap, a particle pool), when the definition fails `checkSpriteShader` (the message says why), or on an unknown param or colour name. - `of(sprite: Handle): SpriteShaderHandle | null` — The shader on a sprite, or null. - `check(def: SpriteShaderDef): string | null` — `checkSpriteShader`: a definition's problem in one sentence, or null. - `clear(): void` — Remove every shader. - `failure(name: string): string | null` — Why the shader named `name` draws as the plain sprite on this device: its compile error (WGSL on WebGPU, GLSL on WebGL2), or null. It arrives a frame or two after the shader is first drawn. For tools that show a shader's errors. - `readonly count: number` — Sprites with a shader now. - `readonly drawn: number` — Sprites drawn through a shader last frame. ### `SpriteShaderTweenOptions` ```ts interface SpriteShaderTweenOptions ``` How long a `tween`, `show` or `hide` takes and along which curve. - `duration?: number` — Seconds of game time; default 0.5. 0 is at once. Throws when negative or not finite. - `ease?: SpriteShaderEase` — The curve; default `'easeInOutQuad'` (the `tween` pack's). An unknown name throws. ### `SpriteShaderValues` ```ts interface SpriteShaderValues ``` Params and colours to set together: `handle.set({ params: { heat: 2 }, colors: { flame: '#ff0' } })`. - `params?: Record` — Params by name. - `colors?: Record` — Colours by name, as hex strings (`#rgb`, `#rgba`, `#rrggbb`, `#rrggbbaa`; a missing alpha is opaque). --- ## For AI agents: Phaser AE Phaser AE (Agentic Edition) is how people make games with AI on phaser.io. 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