bevy/crates/bevy_pbr/src/pbr_material.rs
2023-04-10 01:01:40 -03:00

539 lines
22 KiB
Rust
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

use crate::{
AlphaMode, Material, MaterialPipeline, MaterialPipelineKey, PBR_PREPASS_SHADER_HANDLE,
PBR_SHADER_HANDLE,
};
use bevy_asset::Handle;
use bevy_math::Vec4;
use bevy_reflect::{std_traits::ReflectDefault, FromReflect, Reflect, TypeUuid};
use bevy_render::{
color::Color, mesh::MeshVertexBufferLayout, render_asset::RenderAssets, render_resource::*,
texture::Image,
};
/// A material with "standard" properties used in PBR lighting
/// Standard property values with pictures here
/// <https://google.github.io/filament/Material%20Properties.pdf>.
///
/// May be created directly from a [`Color`] or an [`Image`].
#[derive(AsBindGroup, Reflect, FromReflect, Debug, Clone, TypeUuid)]
#[uuid = "7494888b-c082-457b-aacf-517228cc0c22"]
#[bind_group_data(StandardMaterialKey)]
#[uniform(0, StandardMaterialUniform)]
#[reflect(Default, Debug)]
pub struct StandardMaterial {
/// The color of the surface of the material before lighting.
///
/// Doubles as diffuse albedo for non-metallic, specular for metallic and a mix for everything
/// in between. If used together with a `base_color_texture`, this is factored into the final
/// base color as `base_color * base_color_texture_value`
///
/// Defaults to [`Color::WHITE`].
pub base_color: Color,
/// The texture component of the material's color before lighting.
/// The actual pre-lighting color is `base_color * this_texture`.
///
/// See [`base_color`] for details.
///
/// You should set `base_color` to [`Color::WHITE`] (the default)
/// if you want the texture to show as-is.
///
/// Setting `base_color` to something else than white will tint
/// the texture. For example, setting `base_color` to pure red will
/// tint the texture red.
///
/// [`base_color`]: StandardMaterial::base_color
#[texture(1)]
#[sampler(2)]
pub base_color_texture: Option<Handle<Image>>,
// Use a color for user friendliness even though we technically don't use the alpha channel
// Might be used in the future for exposure correction in HDR
/// Color the material "emits" to the camera.
///
/// This is typically used for monitor screens or LED lights.
/// Anything that can be visible even in darkness.
///
/// The emissive color is added to what would otherwise be the material's visible color.
/// This means that for a light emissive value, in darkness,
/// you will mostly see the emissive component.
///
/// The default emissive color is black, which doesn't add anything to the material color.
///
/// Note that **an emissive material won't light up surrounding areas like a light source**,
/// it just adds a value to the color seen on screen.
pub emissive: Color,
/// The emissive map, multiplies pixels with [`emissive`]
/// to get the final "emitting" color of a surface.
///
/// This color is multiplied by [`emissive`] to get the final emitted color.
/// Meaning that you should set [`emissive`] to [`Color::WHITE`]
/// if you want to use the full range of color of the emissive texture.
///
/// [`emissive`]: StandardMaterial::emissive
#[texture(3)]
#[sampler(4)]
pub emissive_texture: Option<Handle<Image>>,
/// Linear perceptual roughness, clamped to `[0.089, 1.0]` in the shader.
///
/// 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]`.
///
/// 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.
///
/// 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`.
pub metallic: f32,
/// Metallic and roughness maps, stored as a single texture.
///
/// The blue channel contains metallic values,
/// and the green channel contains the roughness values.
/// Other channels are unused.
///
/// Those values are multiplied by the scalar ones of the material,
/// see [`metallic`] and [`perceptual_roughness`] for details.
///
/// Note that with the default values of [`metallic`] and [`perceptual_roughness`],
/// setting this texture has no effect. If you want to exclusively use the
/// `metallic_roughness_texture` values for your material, make sure to set [`metallic`]
/// and [`perceptual_roughness`] to `1.0`.
///
/// [`metallic`]: StandardMaterial::metallic
/// [`perceptual_roughness`]: StandardMaterial::perceptual_roughness
#[texture(5)]
#[sampler(6)]
pub metallic_roughness_texture: Option<Handle<Image>>,
/// Specular intensity for non-metals on a linear scale of `[0.0, 1.0]`.
///
/// Use the value as a way to control the intensity of the
/// specular highlight of the material, i.e. how reflective is the material,
/// rather than the physical property "reflectance."
///
/// Set to `0.0`, no specular highlight is visible, the highlight is strongest
/// when `reflectance` is set to `1.0`.
///
/// Defaults to `0.5` which is mapped to 4% reflectance in the shader.
#[doc(alias = "specular_intensity")]
pub reflectance: f32,
/// The amount of light transmitted through the material (via refraction)
///
/// - When set to `0.0` (the default) no light is transmitted.
/// - When set to `1.0` all light is transmitted through the material.
///
/// The material's [`StandardMaterial::base_color`] also modulates the transmitted light.
///
/// **Important:** For transmission to have any effect, you must also set `alpha_mode` to [`AlphaMode::Blend`].
/// **Note:** Typically used in conjunction with [`StandardMaterial::thickness`] and [`StandardMaterial::ior`].
pub transmission: f32,
/// Thickness of the volume beneath the material surface.
///
/// When set to `0.0` (the default) the material appears as an infinitely-thin film,
/// transmitting light without distorting it.
///
/// When set to any other value, the material distorts light like a volumetric lens.
///
/// **Note:** Typically used in conjunction with [`StandardMaterial::transmission`] and [`StandardMaterial::ior`].
pub thickness: f32,
/// The index of refraction of the material
///
/// | Material | Index of Refraction |
/// |:----------------|:---------------------|
/// | Vacuum | 1 |
/// | Air | 1.00 |
/// | Ice | 1.31 |
/// | Water | 1.33 |
/// | Eyes | 1.38 |
/// | Quartz | 1.46 |
/// | Olive Oil | 1.47 |
/// | Honey | 1.49 |
/// | Acrylic | 1.49 |
/// | Window Glass | 1.52 |
/// | Polycarbonate | 1.58 |
/// | Flint Glass | 1.69 |
/// | Ruby | 1.71 |
/// | Glycerine | 1.74 |
/// | Saphire | 1.77 |
/// | Cubic Zirconia | 2.15 |
/// | Diamond | 2.42 |
/// | Moissanite | 2.65 |
///
/// **Note:** Typically used in conjunction with [`StandardMaterial::transmission`] and [`StandardMaterial::thickness`].
#[doc(alias = "index_of_refraction")]
#[doc(alias = "refraction_index")]
pub ior: f32,
/// Used to fake the lighting of bumps and dents on a material.
///
/// A typical usage would be faking cobblestones on a flat plane mesh in 3D.
///
/// # Notes
///
/// Normal mapping with `StandardMaterial` and the core bevy PBR shaders requires:
/// - A normal map texture
/// - Vertex UVs
/// - Vertex tangents
/// - Vertex normals
///
/// Tangents do not have to be stored in your model,
/// they can be generated using the [`Mesh::generate_tangents`] method.
/// If your material has a normal map, but still renders as a flat surface,
/// make sure your meshes have their tangents set.
///
/// [`Mesh::generate_tangents`]: bevy_render::mesh::Mesh::generate_tangents
#[texture(9)]
#[sampler(10)]
pub normal_map_texture: Option<Handle<Image>>,
/// Normal map textures authored for DirectX have their y-component flipped. Set this to flip
/// it to right-handed conventions.
pub flip_normal_map_y: bool,
/// Specifies the level of exposure to ambient light.
///
/// This is usually generated and stored automatically ("baked") by 3D-modelling software.
///
/// Typically, steep concave parts of a model (such as the armpit of a shirt) are darker,
/// because they have little exposure to light.
/// An occlusion map specifies those parts of the model that light doesn't reach well.
///
/// The material will be less lit in places where this texture is dark.
/// This is similar to ambient occlusion, but built into the model.
#[texture(7)]
#[sampler(8)]
pub occlusion_texture: Option<Handle<Image>>,
/// Support two-sided lighting by automatically flipping the normals for "back" faces
/// within the PBR lighting shader.
///
/// Defaults to `false`.
/// This does not automatically configure backface culling,
/// which can be done via `cull_mode`.
pub double_sided: bool,
/// Whether to cull the "front", "back" or neither side of a mesh.
/// If set to `None`, the two sides of the mesh are visible.
///
/// Defaults to `Some(Face::Back)`.
/// In bevy, the order of declaration of a triangle's vertices
/// in [`Mesh`] defines the triangle's front face.
///
/// When a triangle is in a viewport,
/// if its vertices appear counter-clockwise from the viewport's perspective,
/// then the viewport is seeing the triangle's front face.
/// Conversely, if the vertices appear clockwise, you are seeing the back face.
///
/// In short, in bevy, front faces winds counter-clockwise.
///
/// Your 3D editing software should manage all of that.
///
/// [`Mesh`]: bevy_render::mesh::Mesh
// TODO: include this in reflection somehow (maybe via remote types like serde https://serde.rs/remote-derive.html)
#[reflect(ignore)]
pub cull_mode: Option<Face>,
/// Whether to apply only the base color to this material.
///
/// Normals, occlusion textures, roughness, metallic, reflectance, emissive,
/// shadows, alpha mode and ambient light are ignored if this is set to `true`.
pub unlit: bool,
/// Whether to enable fog for this material.
pub fog_enabled: bool,
/// How to apply the alpha channel of the `base_color_texture`.
///
/// See [`AlphaMode`] for details. Defaults to [`AlphaMode::Opaque`].
pub alpha_mode: AlphaMode,
/// Adjust rendered depth.
///
/// A material with a positive depth bias will render closer to the
/// camera while negative values cause the material to render behind
/// other objects. This is independent of the viewport.
///
/// `depth_bias` affects render ordering and depth write operations
/// using the `wgpu::DepthBiasState::Constant` field.
///
/// [z-fighting]: https://en.wikipedia.org/wiki/Z-fighting
pub depth_bias: f32,
}
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,
// 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
// <https://google.github.io/filament/Material%20Properties.pdf>
reflectance: 0.5,
transmission: 0.0,
thickness: 0.0,
ior: 1.5,
occlusion_texture: None,
normal_map_texture: None,
flip_normal_map_y: false,
double_sided: false,
cull_mode: Some(Face::Back),
unlit: false,
fog_enabled: true,
alpha_mode: AlphaMode::Opaque,
depth_bias: 0.0,
}
}
}
impl From<Color> for StandardMaterial {
fn from(color: Color) -> Self {
StandardMaterial {
base_color: color,
alpha_mode: if color.a() < 1.0 {
AlphaMode::Blend
} else {
AlphaMode::Opaque
},
..Default::default()
}
}
}
impl From<Handle<Image>> for StandardMaterial {
fn from(texture: Handle<Image>) -> Self {
StandardMaterial {
base_color_texture: Some(texture),
..Default::default()
}
}
}
// NOTE: These must match the bit flags in bevy_pbr/src/render/pbr_types.wgsl!
bitflags::bitflags! {
/// Bitflags info about the material a shader is currently rendering.
/// This is accessible in the shader in the [`StandardMaterialUniform`]
#[repr(transparent)]
pub struct StandardMaterialFlags: u32 {
const BASE_COLOR_TEXTURE = (1 << 0);
const EMISSIVE_TEXTURE = (1 << 1);
const METALLIC_ROUGHNESS_TEXTURE = (1 << 2);
const OCCLUSION_TEXTURE = (1 << 3);
const DOUBLE_SIDED = (1 << 4);
const UNLIT = (1 << 5);
const TWO_COMPONENT_NORMAL_MAP = (1 << 6);
const FLIP_NORMAL_MAP_Y = (1 << 7);
const FOG_ENABLED = (1 << 8);
const ALPHA_MODE_RESERVED_BITS = (Self::ALPHA_MODE_MASK_BITS << Self::ALPHA_MODE_SHIFT_BITS); // ← Bitmask reserving bits for the `AlphaMode`
const ALPHA_MODE_OPAQUE = (0 << Self::ALPHA_MODE_SHIFT_BITS); // ← Values are just sequential values bitshifted into
const ALPHA_MODE_MASK = (1 << Self::ALPHA_MODE_SHIFT_BITS); // the bitmask, and can range from 0 to 7.
const ALPHA_MODE_BLEND = (2 << Self::ALPHA_MODE_SHIFT_BITS); //
const ALPHA_MODE_PREMULTIPLIED = (3 << Self::ALPHA_MODE_SHIFT_BITS); //
const ALPHA_MODE_ADD = (4 << Self::ALPHA_MODE_SHIFT_BITS); // Right now only values 05 are used, which still gives
const ALPHA_MODE_MULTIPLY = (5 << Self::ALPHA_MODE_SHIFT_BITS); // ← us "room" for two more modes without adding more bits
const NONE = 0;
const UNINITIALIZED = 0xFFFF;
}
}
impl StandardMaterialFlags {
const ALPHA_MODE_MASK_BITS: u32 = 0b111;
const ALPHA_MODE_SHIFT_BITS: u32 = 32 - Self::ALPHA_MODE_MASK_BITS.count_ones();
}
/// The GPU representation of the uniform data of a [`StandardMaterial`].
#[derive(Clone, Default, ShaderType)]
pub struct StandardMaterialUniform {
/// Doubles as diffuse albedo for non-metallic, specular for metallic and a mix for everything
/// in between.
pub base_color: Vec4,
// Use a color for user friendliness even though we technically don't use the alpha channel
// Might be used in the future for exposure correction in HDR
pub emissive: Vec4,
/// Linear perceptual roughness, clamped to [0.089, 1.0] in the shader
/// Defaults to minimum of 0.089
pub roughness: f32,
/// From [0.0, 1.0], dielectric to pure metallic
pub metallic: f32,
/// Specular intensity for non-metals on a linear scale of [0.0, 1.0]
/// defaults to 0.5 which is mapped to 4% reflectance in the shader
pub reflectance: f32,
/// Amount of light transmitted through the material
pub transmission: f32,
/// Thickness of the volume underneath the material surface
pub thickness: f32,
/// Index of Refraction
pub ior: f32,
/// The [`StandardMaterialFlags`] accessible in the `wgsl` shader.
pub flags: u32,
/// When the alpha mode mask flag is set, any base color alpha above this cutoff means fully opaque,
/// and any below means fully transparent.
pub alpha_cutoff: f32,
}
impl AsBindGroupShaderType<StandardMaterialUniform> for StandardMaterial {
fn as_bind_group_shader_type(&self, images: &RenderAssets<Image>) -> StandardMaterialUniform {
let mut flags = StandardMaterialFlags::NONE;
if self.base_color_texture.is_some() {
flags |= StandardMaterialFlags::BASE_COLOR_TEXTURE;
}
if self.emissive_texture.is_some() {
flags |= StandardMaterialFlags::EMISSIVE_TEXTURE;
}
if self.metallic_roughness_texture.is_some() {
flags |= StandardMaterialFlags::METALLIC_ROUGHNESS_TEXTURE;
}
if self.occlusion_texture.is_some() {
flags |= StandardMaterialFlags::OCCLUSION_TEXTURE;
}
if self.double_sided {
flags |= StandardMaterialFlags::DOUBLE_SIDED;
}
if self.unlit {
flags |= StandardMaterialFlags::UNLIT;
}
if self.fog_enabled {
flags |= StandardMaterialFlags::FOG_ENABLED;
}
let has_normal_map = self.normal_map_texture.is_some();
if has_normal_map {
if let Some(texture) = images.get(self.normal_map_texture.as_ref().unwrap()) {
match texture.texture_format {
// All 2-component unorm formats
TextureFormat::Rg8Unorm
| TextureFormat::Rg16Unorm
| TextureFormat::Bc5RgUnorm
| TextureFormat::EacRg11Unorm => {
flags |= StandardMaterialFlags::TWO_COMPONENT_NORMAL_MAP;
}
_ => {}
}
}
if self.flip_normal_map_y {
flags |= StandardMaterialFlags::FLIP_NORMAL_MAP_Y;
}
}
// NOTE: 0.5 is from the glTF default - do we want this?
let mut alpha_cutoff = 0.5;
match self.alpha_mode {
AlphaMode::Opaque => flags |= StandardMaterialFlags::ALPHA_MODE_OPAQUE,
AlphaMode::Mask(c) => {
alpha_cutoff = c;
flags |= StandardMaterialFlags::ALPHA_MODE_MASK;
}
AlphaMode::Blend => flags |= StandardMaterialFlags::ALPHA_MODE_BLEND,
AlphaMode::Premultiplied => flags |= StandardMaterialFlags::ALPHA_MODE_PREMULTIPLIED,
AlphaMode::Add => flags |= StandardMaterialFlags::ALPHA_MODE_ADD,
AlphaMode::Multiply => flags |= StandardMaterialFlags::ALPHA_MODE_MULTIPLY,
};
StandardMaterialUniform {
base_color: self.base_color.as_linear_rgba_f32().into(),
emissive: self.emissive.as_linear_rgba_f32().into(),
roughness: self.perceptual_roughness,
metallic: self.metallic,
reflectance: self.reflectance,
transmission: self.transmission,
thickness: self.thickness,
ior: self.ior,
flags: flags.bits(),
alpha_cutoff,
}
}
}
#[derive(Clone, PartialEq, Eq, Hash)]
pub struct StandardMaterialKey {
normal_map: bool,
cull_mode: Option<Face>,
depth_bias: i32,
}
impl From<&StandardMaterial> for StandardMaterialKey {
fn from(material: &StandardMaterial) -> Self {
StandardMaterialKey {
normal_map: material.normal_map_texture.is_some(),
cull_mode: material.cull_mode,
depth_bias: material.depth_bias as i32,
}
}
}
impl Material for StandardMaterial {
fn specialize(
_pipeline: &MaterialPipeline<Self>,
descriptor: &mut RenderPipelineDescriptor,
_layout: &MeshVertexBufferLayout,
key: MaterialPipelineKey<Self>,
) -> Result<(), SpecializedMeshPipelineError> {
if key.bind_group_data.normal_map {
if let Some(fragment) = descriptor.fragment.as_mut() {
fragment
.shader_defs
.push("STANDARDMATERIAL_NORMAL_MAP".into());
}
}
descriptor.primitive.cull_mode = key.bind_group_data.cull_mode;
if let Some(label) = &mut descriptor.label {
*label = format!("pbr_{}", *label).into();
}
if let Some(depth_stencil) = descriptor.depth_stencil.as_mut() {
depth_stencil.bias.constant = key.bind_group_data.depth_bias;
}
Ok(())
}
fn prepass_fragment_shader() -> ShaderRef {
PBR_PREPASS_SHADER_HANDLE.typed().into()
}
fn fragment_shader() -> ShaderRef {
PBR_SHADER_HANDLE.typed().into()
}
#[inline]
fn alpha_mode(&self) -> AlphaMode {
self.alpha_mode
}
#[inline]
fn depth_bias(&self) -> f32 {
self.depth_bias
}
#[inline]
fn transmissive(&self) -> bool {
self.transmission > 0.0
}
}