Struct StandardMaterial 

pub struct StandardMaterial {
    pub base_color: LinearRgba,
    pub metallic: f32,
    pub roughness: f32,
    pub emissive: LinearRgba,
    pub alpha_mode: AlphaMode,
    pub alpha_cutoff: f32,
    pub double_sided: bool,
}

A physically-based rendering (PBR) material using the metallic-roughness workflow.

This is the primary material type for realistic 3D objects in Khora. It implements the standard PBR metallic-roughness model, which is widely used in modern game engines and 3D content creation tools (e.g., glTF 2.0 standard).

PBR Properties

• Base Color: The surface’s base color (albedo). For metals, this represents the reflectance; for dielectrics, this is the diffuse color.
• Metallic: Controls whether the surface behaves like a metal (1.0) or a dielectric/non-metal (0.0). Intermediate values create unrealistic results.
• Roughness: Controls how smooth (0.0) or rough (1.0) the surface appears. This affects specular reflections.

Texture Maps

Supports all common PBR texture maps:

• Base color/albedo
• Metallic-roughness combined (metallic in B channel, roughness in G channel)
• Normal map for surface detail
• Ambient occlusion for subtle shadows
• Emissive for self-illuminating areas

Examples

use khora_core::asset::StandardMaterial;
use khora_core::math::LinearRgba;

// Create a rough, non-metallic surface (e.g., concrete)
let concrete = StandardMaterial {
    base_color: LinearRgba::new(0.5, 0.5, 0.5, 1.0),
    metallic: 0.0,
    roughness: 0.9,
    ..Default::default()
};

// Create a smooth, metallic surface (e.g., polished gold)
let gold = StandardMaterial {
    base_color: LinearRgba::new(1.0, 0.766, 0.336, 1.0),
    metallic: 1.0,
    roughness: 0.2,
    ..Default::default()
};

Fields

base_color: LinearRgba

The base color (albedo) of the material.

For metals, this is the reflectance color at normal incidence. For dielectrics, this is the diffuse color.

metallic: f32

Optional texture for the base color.

If present, this texture’s RGB values are multiplied with base_color. The alpha channel can be used for transparency when combined with appropriate alpha_mode.

Future work: Texture asset system integration pending. The metallic factor (0.0 = dielectric, 1.0 = metal).

This value should typically be either 0.0 or 1.0 for physically accurate results. Intermediate values can be used for artistic effects but are not physically based.

roughness: f32

The roughness factor (0.0 = smooth, 1.0 = rough).

Controls the microsurface detail of the material, affecting specular reflection. Lower values produce sharp, mirror-like reflections; higher values produce more diffuse reflections.

emissive: LinearRgba

Optional texture for metallic and roughness values.

glTF 2.0 convention: Blue channel = metallic, Green channel = roughness. If present, the texture values are multiplied with the metallic and roughness factors.

Future work: Texture asset system integration pending. Optional normal map for adding surface detail.

Normal maps perturb the surface normal to create the illusion of fine geometric detail without adding actual geometry. Stored in tangent space.

Future work: Texture asset system integration pending. Optional ambient occlusion map.

AO maps darken areas that should receive less ambient light, such as crevices and contact points. The red channel is typically used.

Future work: Texture asset system integration pending. The emissive color of the material.

Allows the material to emit light. This color is added to the final shaded result and is not affected by lighting. Useful for self-illuminating objects like screens, neon signs, or magical effects.

alpha_mode: AlphaMode

Optional texture for emissive color.

If present, this texture’s RGB values are multiplied with emissive.

Future work: Texture asset system integration pending. The alpha blending mode for this material.

Determines how transparency is handled. See AlphaMode for details.

alpha_cutoff: f32

The alpha cutoff threshold when using AlphaMode::Mask.

Fragments with alpha values below this threshold are discarded. Typically set to 0.5. Only used when alpha_mode is AlphaMode::Mask.

double_sided: bool

Whether the material should be rendered double-sided.

If false, back-facing triangles are culled for better performance. If true, both sides of the geometry are rendered.

Trait Implementations

impl Clone for StandardMaterial

fn clone(&self) -> StandardMaterial

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for StandardMaterial

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for StandardMaterial

fn default() -> StandardMaterial

Returns the “default value” for a type.

impl Material for StandardMaterial

fn base_color(&self) -> LinearRgba

Returns the base color (albedo or diffuse) of the material. Default implementation is White.

fn emissive_color(&self) -> LinearRgba

Returns the emissive color of the material. Default implementation is Black.

fn specular_power(&self) -> f32

Returns the specular power or roughness conversion for the material. Default implementation is 32.0.

fn ambient_color(&self) -> LinearRgba

Returns the ambient color modifier for the material. Default implementation is (0.1, 0.1, 0.1, 0.0).

impl Asset for StandardMaterial