Change standard material defaults and update docs (#7664)

# Objective

Standard material defaults are currently strange, and the docs are wrong re: metallic.

## Solution

Change the defaults to be similar to [Godot](https://github.com/godotengine/godot/pull/62756).

---

## Changelog

#### Changed

- `StandardMaterial` now defaults to a dielectric material (0.0 `metallic`) with 0.5 `perceptual_roughness`.

## Migration Guide

`StandardMaterial`'s default have now changed to be a fully dielectric material with medium roughness. If you want to use the old defaults, you can set  `perceptual_roughness = 0.089` and `metallic = 0.01` (though metallic should generally only be set to 0.0 or 1.0).
This commit is contained in:
Elabajaba 2023-02-14 07:43:19 +00:00
parent 2efc0293ed
commit 01043bf83a

View file

@ -78,22 +78,27 @@ pub struct StandardMaterial {
/// Linear perceptual roughness, clamped to `[0.089, 1.0]` in the shader.
///
/// Defaults to minimum of `0.089`.
/// Defaults to `0.5`.
///
/// Low values result in a "glossy" material with specular highlights,
/// while values close to `1` result in rough materials.
///
/// If used together with a roughness/metallic texture, this is factored into the final base
/// color as `roughness * roughness_texture_value`.
///
/// 0.089 is the minimum floating point value that won't be rounded down to 0 in the
/// calculations used.
//
// Technically for 32-bit floats, 0.045 could be used.
// See <https://google.github.io/filament/Filament.html#materialsystem/parameterization/>
pub perceptual_roughness: f32,
/// How "metallic" the material appears, within `[0.0, 1.0]`,
/// going from dielectric to pure metallic.
/// How "metallic" the material appears, within `[0.0, 1.0]`.
///
/// Defaults to `0.01`.
/// This should be set to 0.0 for dielectric materials or 1.0 for metallic materials.
/// For a hybrid surface such as corroded metal, you may need to use in-between values.
///
/// The closer to `1` the value, the more the material will
/// reflect light like a metal such as steel or gold.
/// Defaults to `0.00`, for dielectric.
///
/// If used together with a roughness/metallic texture, this is factored into the final base
/// color as `metallic * metallic_texture_value`.
@ -236,19 +241,16 @@ pub struct StandardMaterial {
impl Default for StandardMaterial {
fn default() -> Self {
StandardMaterial {
// White because it gets multiplied with texture values if someone uses
// a texture.
base_color: Color::rgb(1.0, 1.0, 1.0),
base_color_texture: None,
emissive: Color::BLACK,
emissive_texture: None,
// This is the minimum the roughness is clamped to in shader code
// See <https://google.github.io/filament/Filament.html#materialsystem/parameterization/>
// It's the minimum floating point value that won't be rounded down to 0 in the
// calculations used. Although technically for 32-bit floats, 0.045 could be
// used.
perceptual_roughness: 0.089,
// Few materials are purely dielectric or metallic
// This is just a default for mostly-dielectric
metallic: 0.01,
// Matches Blender's default roughness.
perceptual_roughness: 0.5,
// Metallic should generally be set to 0.0 or 1.0.
metallic: 0.0,
metallic_roughness_texture: None,
// Minimum real-world reflectance is 2%, most materials between 2-5%
// Expressed in a linear scale and equivalent to 4% reflectance see