remix-add-sprite

Add Sprite to Game Workflow

Overview

This skill guides you through generating sprite sheets for canvas-based games on the Remix platform.

Prerequisites

• The game HTML file must already exist (follow the game-creation workflow first if starting from scratch).
• A game must be created on the Remix platform (you need a game ID).
• The REMIX_API_KEY environment variable must be set.

Steps

1. Check for Existing Game ID

Use gameId from task context or prior tool results when available.

Otherwise, read the nearest .remix-cli.json. Older projects may still use .remix-mcp.json. If either contains a gameId, reuse it.

Only if none of those sources contain a gameId should you follow the upload-game workflow to create one.

2. Generate the Sprite Sheet

Prefer MCP generateSpriteSheet:

generateSpriteSheet({
  gameId: "<your-game-id>",
  prompt: "a pixel-art knight walking, side view, 2D game character",
  gridSize: 4
})

The response includes hosted spriteUrl, transparentSpriteUrl, grid metadata, and any warnings. If you need to write REST calls instead, confirm the exact schema from the OpenAPI spec first.

3. Integrate the Sprite Sheet into the Game

Use the returned URL with canvas drawImage to render individual frames:

const sprite = new Image();
sprite.src = "https://returned-sprite-url.png";

const frameWidth = 64;  // width of a single frame
const frameHeight = 64; // height of a single frame
const totalFrames = 4;
let currentFrame = 0;

sprite.onload = () => {
  function animate() {
    ctx.clearRect(0, 0, canvas.width, canvas.height);

    // Draw the current frame from the sprite sheet
    ctx.drawImage(
      sprite,
      currentFrame * frameWidth, 0,  // source x, y in the sprite sheet
      frameWidth, frameHeight,        // source width, height
      player.x, player.y,            // destination x, y on canvas
      frameWidth, frameHeight         // destination width, height
    );

    currentFrame = (currentFrame + 1) % totalFrames;
    requestAnimationFrame(animate);
  }
  animate();
};

Use transparentSpriteUrl when you need the sprite rendered over other game elements without a background.

Tips

• Be specific about frame count and action. "4-frame walk cycle" is better than "walking character".
• Specify art style. Include "pixel-art", "hand-drawn", "flat vector", etc. in your prompt.
• Frame layout follows the returned grid metadata. Do not assume a single horizontal strip; compute frame width and height from the generated sheet and requested gridSize.
• Use transparentSpriteUrl for in-game sprites that need to overlay backgrounds or other elements.
• Preload before gameplay. Wait for onload before starting the game loop.