spacemolt image generator

generate-post-image.sh

#!/usr/bin/env bash
# Generate a SpaceMolt-style image with Gemini nano-banana-pro.
#
# Usage:
#   GEMINI_API_KEY=... ./generate-post-image.sh "a lobster captain inspecting a cargo manifest"
#   GEMINI_API_KEY=... ./generate-post-image.sh -o out.jpg "prompt..."
#
# Style is loaded from patreon-post-style.json next to this script.

set -euo pipefail

MODEL="gemini-3-pro-image-preview"
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
STYLE_FILE="${STYLE_FILE:-$SCRIPT_DIR/patreon-post-style.json}"
OUT=""

usage() {
  echo "usage: $0 [-o output.jpg] [-s style.json] \"prompt text\"" >&2
  exit 1
}

while getopts ":o:s:m:h" opt; do
  case "$opt" in
    o) OUT="$OPTARG" ;;
    s) STYLE_FILE="$OPTARG" ;;
    m) MODEL="$OPTARG" ;;
    h|*) usage ;;
  esac
done
shift $((OPTIND - 1))

[[ $# -ge 1 ]] || usage
PROMPT="$*"

: "${GEMINI_API_KEY:?GEMINI_API_KEY must be set in env}"
[[ -f "$STYLE_FILE" ]] || { echo "style file not found: $STYLE_FILE" >&2; exit 1; }

if [[ -z "$OUT" ]]; then
  OUT="$SCRIPT_DIR/generated-$(date +%Y%m%d-%H%M%S).jpg"
fi

STYLE_JSON="$(cat "$STYLE_FILE")"
FULL_PROMPT=$(cat <<EOF
Generate an image in the following house style. The style is defined as JSON; follow every constraint (palette, lighting, composition, do/dont). Render the SUBJECT below using this style.

STYLE:
$STYLE_JSON

SUBJECT:
$PROMPT
EOF
)

REQUEST=$(jq -n --arg p "$FULL_PROMPT" '{
  contents: [ { parts: [ { text: $p } ] } ]
}')

TMP_RESPONSE="$(mktemp)"
trap 'rm -f "$TMP_RESPONSE"' EXIT

HTTP_CODE=$(curl -sS -o "$TMP_RESPONSE" -w "%{http_code}" \
  -X POST \
  -H "Content-Type: application/json" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  "https://generativelanguage.googleapis.com/v1beta/models/${MODEL}:generateContent" \
  -d "$REQUEST")

if [[ "$HTTP_CODE" != "200" ]]; then
  echo "API request failed (HTTP $HTTP_CODE):" >&2
  cat "$TMP_RESPONSE" >&2
  exit 1
fi

IMAGE_B64=$(jq -r '
  .candidates[0].content.parts[]
  | select(.inlineData != null or .inline_data != null)
  | (.inlineData.data // .inline_data.data)
' "$TMP_RESPONSE" | head -n1)

if [[ -z "$IMAGE_B64" || "$IMAGE_B64" == "null" ]]; then
  echo "no image returned. response:" >&2
  cat "$TMP_RESPONSE" >&2
  exit 1
fi

echo "$IMAGE_B64" | base64 -d > "$OUT"
echo "wrote $OUT"

patreon-post-style.json

{
  "style_name": "spacemolt_cinematic_illustration",
  "medium": {
    "type": "digital painted illustration",
    "rendering": "semi-realistic concept art with painterly brushwork",
    "finish": "glossy, high-contrast, cinematic",
    "reference_lineage": "Pixar-meets-concept-art with EVE Online sci-fi HUDs"
  },
  "lighting": {
    "primary": "cool cyan key light from screens and holograms",
    "secondary": "warm orange rim light on organic subjects",
    "ambient": "deep space backlight from nebulae",
    "contrast": "high",
    "color_temperature_kelvin": 6500,
    "highlights": "soft bloom on glowing UI elements and chest panels"
  },
  "camera": {
    "lens_equivalent_mm": 35,
    "aperture": "f/4",
    "angle": "slight low-angle, wide cinematic framing",
    "depth_of_field": "shallow-to-moderate, foreground subject sharp, midground softened",
    "aspect_ratio": "16:9 cinematic"
  },
  "color_palette": {
    "primary": {
      "plasma_cyan": "#22D3EE",
      "deep_space_navy": "#0B1A2E",
      "nebula_violet": "#3B1E5E"
    },
    "accent": {
      "claw_orange": "#D9601F",
      "shell_crimson": "#A6321A",
      "alert_red": "#EF4444",
      "hologram_mint": "#5EEAD4"
    },
    "neutral": {
      "console_charcoal": "#1F2937",
      "metal_steel": "#6B7280",
      "ui_white": "#E5F2FF"
    },
    "harmony_rule": "complementary cyan/orange split with violet support"
  },
  "composition": {
    "layout": "wide horizontal triptych, subjects framed by foreground console and background space",
    "rule": "off-center hero subject left, environmental detail right, asymmetric balance",
    "depth_layers": [
      "foreground hero + console",
      "midground floating subjects + HUD panels",
      "background nebula + asteroids"
    ],
    "negative_space": "moderate; busy but legible"
  },
  "subjects_treatment": {
    "characters": "anthropomorphic creatures with expressive, slightly cartoonish faces but realistic textures",
    "tech": "chunky retro-futurist with embedded glowing panels and rivets",
    "scale_play": "exaggerated proportions for comedic effect"
  },
  "textures": [
    "chitinous shell with subsurface scattering",
    "brushed metal with scratches",
    "frosted holographic glass",
    "matte spacesuit fabric",
    "rocky pitted asteroid surface"
  ],
  "ui_overlays": {
    "style": "floating semi-transparent HUD panels",
    "borders": "1-2px cyan glow with corner brackets",
    "typography": "uppercase monospaced sans-serif, slight letter-spacing",
    "fill": "rgba(11, 26, 46, 0.75)",
    "accents": "red highlight tokens for ALERT/ERROR words",
    "placement": "callouts arranged around but not covering character faces"
  },
  "atmosphere": {
    "effects": [
      "lens bloom",
      "subtle chromatic aberration on highlights",
      "volumetric dust",
      "distant starfield"
    ],
    "particles": "floating debris and asteroid fragments"
  },
  "mood": {
    "primary": "satirical, chaotic, energetic",
    "secondary": "sci-fi adventurous with comedic self-awareness",
    "tone_keywords": ["irreverent", "tactical", "absurd", "cinematic"]
  },
  "do": [
    "lean into cyan/orange complementary contrast",
    "keep one expressive hero subject anchoring the frame",
    "use HUD overlays to add narrative without cluttering faces",
    "render shells, metal, and glass with distinct material response"
  ],
  "dont": [
    "no flat vector or cel-shaded looks",
    "no photorealism — keep painterly brushwork visible",
    "no emoji; HUD text only in monospaced uppercase",
    "avoid centered symmetrical compositions"
  ]
}