/godot-asset-generator

DALL-E 3 API Guide

Complete reference for using OpenAI's DALL-E 3 API for game asset generation.

Authentication

Set the OPENAI_API_KEY environment variable:

export OPENAI_API_KEY="sk-..."

Get your API key from: https://platform.openai.com/api-keys

API Endpoint

POST https://api.openai.com/v1/images/generations

Request Format

{
  "model": "dall-e-3",
  "prompt": "your prompt here",
  "n": 1,
  "size": "1024x1024",
  "quality": "standard",
  "style": "vivid",
  "response_format": "b64_json"
}

Parameters

model

• dall-e-3 - Latest model, best quality
• dall-e-2 - Older model, cheaper, less capable

size

quality

• standard - Default, good for most uses ($0.040/image)
• hd - Higher detail, sharper ($0.080/image)

style

• vivid - Default, dramatic and vibrant
• natural - More realistic, less stylized

response_format

• url - Returns temporary URL (expires in 1 hour)
• b64_json - Returns base64-encoded image data

Response Format

{
  "created": 1699000000,
  "data": [
    {
      "revised_prompt": "A detailed pixel art knight...",
      "b64_json": "iVBORw0KGgoAAAANSUhEUgAA..."
    }
  ]
}

Note: DALL-E 3 may revise your prompt. The revised_prompt field shows what was actually used.

Rate Limits

Pricing (as of 2024)

Error Handling

Common Errors

Content Policy

DALL-E 3 has content restrictions. Avoid:

• Violence or gore
• Adult content
• Real people's faces
• Copyrighted characters by name

If rejected, rephrase the prompt to be more abstract.

TypeScript Example

interface DalleRequest {
  model: "dall-e-3" | "dall-e-2";
  prompt: string;
  n: number;
  size: "1024x1024" | "1792x1024" | "1024x1792";
  quality?: "standard" | "hd";
  style?: "vivid" | "natural";
  response_format?: "url" | "b64_json";
}

async function generateWithDalle(prompt: string): Promise<string> {
  const apiKey = Deno.env.get("OPENAI_API_KEY");

  const response = await fetch("https://api.openai.com/v1/images/generations", {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "Authorization": `Bearer ${apiKey}`,
    },
    body: JSON.stringify({
      model: "dall-e-3",
      prompt,
      n: 1,
      size: "1024x1024",
      quality: "standard",
      response_format: "b64_json",
    }),
  });

  if (!response.ok) {
    throw new Error(`DALL-E API error: ${response.status}`);
  }

  const data = await response.json();
  return data.data[0].b64_json;
}

Game Asset Tips

Pixel Art

prompt: "pixel art [subject], 16-bit style, game sprite, clean pixels,
         no anti-aliasing, transparent background, limited color palette"
quality: "standard"  // HD adds unwanted detail
style: "vivid"       // More saturated colors

Backgrounds

prompt: "[scene description], game background art, painted style,
         horizontal composition, no characters"
size: "1792x1024"    // Landscape for backgrounds
quality: "hd"        // More detail for backgrounds

UI Elements

prompt: "game UI [element], flat design, clean edges, [color scheme],
         game interface style"
quality: "standard"
style: "vivid"

Consistency Tips

1. Use detailed prompts - DALL-E 3 follows prompts closely
2. Specify art style explicitly - "16-bit pixel art", "hand-painted"
3. Request transparent backgrounds - Add "transparent background" or "isolated on white"
4. Batch with same prompt structure - Keep base prompt consistent

Cost Optimization

1. Start with standard quality - Use HD only when needed
2. Use 1024x1024 for sprites - Smaller is cheaper
3. Test prompts on DALL-E 2 first - Much cheaper for iteration
4. Cache and reuse - Don't regenerate identical requests
5. Batch wisely - Generate variations only when needed

Integration with generate-image.ts

# Basic usage
deno run scripts/generate-image.ts --provider dalle \
  --prompt "pixel art knight" --output ./knight.png

# HD quality
deno run scripts/generate-image.ts --provider dalle \
  --prompt "game background forest" --output ./forest.png \
  --quality hd --size 1792x1024

# With style preset
deno run scripts/generate-image.ts --provider dalle \
  --prompt "knight character, front view" --output ./knight.png \
  --style pixel-art