Game VFX: Mesh + Texture + Engine Math

Core Philosophy

> 3D 软件造壳，AI/贴图画皮，引擎赋魂。

VFX ≈ 简单 Mesh（塑料外壳）× 滚动贴图（活涂装）× 引擎数学（缩放/旋转/淡出/错开）

Do not render finished FX in DCC or rely on TyFlow/Houdini for indie iteration.

Do not replace textures with pure procedural noise2d() unless prototyping.

Standard Pipeline

AI Texture Prompt Hints

Generate seamless, high-contrast masks suitable for UV scroll:

• seamless jade ink wash noise, high contrast alpha, tileable, 512x512, no background
• seamless magic energy noise, soft core bright edges dark, tileable
• Avoid illustrative single-frame art; need tileable mask/energy maps.

Drop into assets/textures/vfx/ and assign to albedo_texture in shader.

Composition: 点 · 线 · 面

Layer with staggered delays (0.05–0.18s). Never spawn everything at t=0.

Color: 631 Rule + Contrast

Ink black (墨痕) is not part of 631 area — use as contrast edge (like bubble black rims): small coverage, high opacity.

Extended formula (fluid/magic):

主色冷色大面积 + 辅色邻近/弱对比 + 微面积色散高光 + 极小面积点缀色

For ink-wash projects: main = jade/teal; secondary = blue-purple mist; accent = warm gold; ink = near-black.

2.5D / Fixed Camera Rules (Critical)

Orthographic oblique camera (e.g. offset (20, 22.5, 20)) breaks many free-3D assumptions.

Billboard facing (Godot 4):

node.look_at(camera.global_position, Vector3.UP)
node.rotate_object_local(Vector3.RIGHT, -PI * 0.5)
node.rotate_object_local(Vector3.FORWARD, yaw_offset)

Godot Implementation Pattern

Shader Split (3 materials max)

Key uniforms: albedo_texture, scroll_speed, effect_time, intensity, expand_progress, tone_dark/mid/bright/accent.

Script Structure (heal_mesh_effect.gd reference)

HealEffect (Node3D, y=1.0 on Player)
├── Ground: pool + rings (horizontal planes)
├── Body: twirl billboards ×2 crossed yaw
├── Mist: secondary billboard (30%)
├── Ink: splashes, strokes, traces, rising flecks
└── Accent: core add + star billboards (10%)

API: trigger_heal() with cooldown; _process updates effect_time + billboard facing.

Tween Rules

# CORRECT — lambda passes float to intensity
_tween.tween_method(func(v): mat.set_shader_parameter("intensity", v), 0.0, 2.0, 0.3)

# WRONG — bind appends args; float hits wrong parameter
_tween.tween_method(_set_intensity.bind(mat), 0.0, 2.0, 0.3)  # breaks in GDScript 4

Return type for tween_method: MethodTweener, not Tween.

Typed arrays for texture pick:

const SPARK_TEX: Array[Texture2D] = [TEX_A, TEX_B, TEX_C]
var tex: Texture2D = SPARK_TEX[i % 3]

New Skill Checklist

Before shipping a VFX, verify:

• [ ] Texture visible in isolation (not hidden by procedural mask / fresnel kill)
• [ ] Body elements face camera in 2.5D
• [ ] 631 color balance readable on project background
• [ ] Ink/contrast layer present if style is ink-wash
• [ ] Staggered layer timing
• [ ] preload() textures; sync effect_time on all materials
• [ ] No dependency on sky/SDFGI/volumetric fog for this project style
• [ ] Headless load / in-game Q test passes

Anti-Patterns (Learned in game02)

Reference Implementation (game02)

Kenney mapping for heal: smoke_06 pool, circle_05 ring, twirl_02 body, light_03 halo, magic_02 mist, magic_04 core, star/spark accent, scratch/scorch/slash/trace ink.

For extended pitfalls and environment constraints, see reference.md.