autohero/docs/sprites_instruction.md

🎮 Sprite & Tileset Implementation Guide (Vertical Slice)

1. Scope

This document defines technical requirements and pipeline rules for using generated sprites, tilesets, and VFX in the project.

Goal: enable a developer to import, slice, and assemble a fully playable vertical slice without ambiguity.

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2. Global Standards

Camera: Top-down (3/4)
Tile Size: 64x64 px
Internal Grid: 16x16 px
Padding: 2 px
Format: PNG (RGBA)
Filter Mode: Point (no filtering)
Compression: None
Pixels Per Unit: 64

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3. Project Structure

/assets
  /tiles
  /props
  /buildings
  /characters
  /enemies
  /items
  /vfx
  /ui

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4. Tileset Implementation

4.1 Import Settings

• Sprite Mode: Multiple
• Mesh Type: Full Rect
• Filter: Point
• Compression: None

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4.2 Grid Slicing

Cell Size: 64x64
Offset: 0,0
Padding: 2px (if present in atlas)
Pivot: Center (0.5, 0.5)

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4.3 Tile Categories

Ground Layer (collision + navigation)

road_center
road_variation_01..03
road_edge_N/E/S/W
road_corner_outer
road_corner_inner

Overlay Layer (no collision)

overlay_corruption
overlay_cracks
overlay_grass

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4.4 Tilemap Layers

Layer 0: Ground
Layer 1: Overlay
Layer 2: Props (optional tile-based)

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4.5 Autotile Requirements

Each terrain type must include:

1 center
4 edges
4 outer corners
4 inner corners
3+ variations

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5. Props Implementation

5.1 Import

• Sprite Mode: Single
• Pivot: Bottom-Center (0.5, 0.0)

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5.2 Rules

Height: 0.5–1.5 tile
Scale: consistent with tile grid
Collider: BoxCollider (manual)

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6. Character (Hero)

6.1 Import Settings

Sprite Mode: Multiple
Cell Size: 64x64
Pivot: Bottom-Center (0.5, 0.0)

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6.2 Animation Layout

Row = animation
Column = frame
Direction = left → right

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6.3 Required Animations

idle: 6 frames
walk: 8 frames
attack: 6–8 frames
hit: 4 frames
death: 6 frames

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6.4 Runtime Setup

• Animator Controller required

• State machine:

  • Idle ↔ Walk
  • Walk → Attack
  • Any → Hit
  • Any → Death

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6.5 Collision

Collider: Capsule
Hitbox: smaller than sprite
Weapon hitbox: separate trigger collider

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7. Enemies

7.1 Parameters

Size: 96–128 px
Pivot: Bottom-Center

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7.2 Animations

idle
move
attack
hit
death

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7.3 Gameplay Rules

• Weak points must be visually highlighted
• Hitbox must NOT match full sprite size

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8. Items (Loot)

8.1 Import

Size: 32x32
Pivot: Center (0.5, 0.5)

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8.2 Categories

consumables
currency
equipment
keys

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8.3 Visual Encoding

common = neutral
rare = blue
epic = purple

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9. VFX

9.1 Import

Size: 64–128 px
Pivot: Center
Material: Additive / Alpha Blend

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9.2 Types

slash
impact
portal
particles
electricity

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9.3 Rules

• VFX must be separate from characters
• Use flipbook animation where applicable
• Do NOT bake effects into base sprites

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10. UI

10.1 Sizes

Icons: 32x32
Slots: 64x64
Panels: flexible

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10.2 Rules

• Icons must be readable without text
• Glow indicates interactivity

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11. Lighting Model

11.1 Separation

Base sprite = no heavy lighting
Emissive = separate (windows, crystals)
Lighting = runtime (engine)

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11.2 Restrictions

DO NOT bake global lighting into tiles
DO NOT mix emissive with base diffuse

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12. Naming Convention

tiles/road_center_01.png
tiles/road_edge_n_01.png

props/lamp_01.png

characters/hero_idle_01.png
characters/hero_attack_03.png

enemies/corrupt_beast_idle_01.png

items/potion_red.png

vfx/slash_01.png

ui/icon_attack.png

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13. Engine Setup (Unity / Godot)

13.1 Import Settings

Filter Mode = Point
Compression = None
Pixels Per Unit = 64

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13.2 Sprite Mode

Tilesets → Multiple
Props/Items → Single
Characters → Multiple

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14. Collision System

Tilemap Collider → Ground
Box Collider → Props
Capsule Collider → Characters
Trigger Collider → Attacks / Loot

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15. Render Order

1 Ground
2 Overlay
3 Props
4 Characters
5 VFX
6 UI

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16. Gameplay Loop (Vertical Slice)

1. Player movement (tilemap navigation)
2. Enter corruption zone
3. Enemy aggro
4. Combat (melee + VFX)
5. Loot drop
6. Loot collection
7. Exit via portal

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17. Critical Constraints

All assets must align to 64x64 grid
All sprites must have correct pivot
No mixed pixel density
No baked lighting abuse
Tiles ≠ Props (strict separation)
Minimum 3 variations per tile type

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18. Acceptance Criteria

Implementation is valid if:

• Tilemap builds without seams
• Character animations play correctly
• Combat loop is functional
• Loot is collectible and readable
• Portal completes loop
• No visual scale inconsistencies

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End of document