Skip to content

xiaoiver/renderer

BranchesTags

Repository files navigation

renderer

Just another toy renderer. Inspired by bevy.

Features

Getting Started

import {
  App,
  System,
  StartUp,
  DefaultPlugins,
  Commands,
  Camera3dBundle,
  PbrBundle,
} from 'renderer';

class StartUpSystem extends System {
  commands = new Commands(this);

  constructor() {
    this.query(
      (q) =>
        q.using(
          Mesh,
          Material,
          Transform,
          GlobalTransform,
          Parent,
          Children,
          Camera,
          Perspective,
          Fxaa,
        ).write,
    );
  }

  initialize(): void {
    this.commands.spawn(
      new Camera3dBundle({
        camera: new Camera(),
        projection: new Perspective(),
        transform: Transform.from_xyz(-2.5, 4.5, 5.0).look_at(
          Vec3.ZERO,
          Vec3.Y,
        ),
      }),
      new Fxaa(),
    );

    this.commands.spawn(
      new PbrBundle({
        mesh: Mesh.from(new Cube(1)),
        material: new Material(),
        transform: Transform.from_xyz(0, 0.5, 0),
      }),
    );

    this.commands.execute();
  }
}

new App({
  canvas: $canvas,
})
  .addPlugins(...DefaultPlugins)
  .addSystems(StartUp, StartUpSystem)
  .run();

ECS

Bevy ECS makes Bevy’s API so elegant.

There're so many ECS architectural implementations for JS/TS. I found becsy is the most special one even if its multi-threading feature is not yet implemented.

ecs

Systems can be splitted into several stages, for now we support:

  • PreStartUp
  • StartUp - The schedule that runs once when the app starts.
  • PostStartUp
  • PreUpdate
  • Update - The schedule that contains app logic, get called on every frame.
  • PostUpdate

Shader combining and manipulating

Shader chunks can be combined at compiling time or runtime. glslify and its rollup plugin use the former way. But most web rendering engines choose the latter one such as:

Bevy use naga_oil. I try to compile it to WASM with wasm-pack so that features like preprocessing and imports will come in handy.

#import render::view::View
#import pbr::utils::coords_to_viewport_uv

@group(0) @binding(1) var<uniform> view: View;
@group(1) @binding(0) var skybox: texture_cube<f32>;
@group(1) @binding(1) var skybox_sampler: sampler;

It helps me a lot during the process of learning the structures in bevy shader system.

Note The order of uniforms and texture/sampler pairs is fixed.

Clustered Forward Shading

Clustered shading expands on the idea of tiled rendering but adds a segmentation on the 3rd axis. The “clustering” is done in view space, by splitting the frustum into a 3D grid.

Standart Material

name type description
base_color Color 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].
base_color_texture TexImageSource The texture component of the material's color before lighting. The actual pre-lighting color is base_color * this_texture. 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.
emissive Color 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.
emissive_texture TexImageSource The emissive map, multiplies pixels with [emissive] to get the final "emitting" color of a surface.
perceptual_roughness number 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.
metallic number 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.
metallic_roughness_texture TexImageSource 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.
reflectance number 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.

Light

Ambient Light

An ambient light, which lights the entire scene equally.

Online DEMO

this.commands.spawn(
  new AmbientLight({
    color: Color.RED,
    brightness: 0.2,
  }),
);
  • color Color
  • brightness number - A direct scale factor multiplied with color before being passed to the shader. Default to 0.05.

Directional Light

A Directional light. Directional lights don't exist in reality but they are a good approximation for light sources VERY far away, like the sun or the moon.

Online DEMO

this.commands.spawn(
  new DirectionalLightBundle({
    directional_light: new DirectionalLight({
      color: Color.rgb(0.98, 0.95, 0.82),
      shadows_enabled: true,
    }),
    transform: Transform.from_xyz(0.0, 0.0, 0.0).look_at(
      new Vec3(-1, -1, -1),
      Vec3.Y,
    ),
    cascade_shadow_config: new CascadeShadowConfigBuilder({
      first_cascade_far_bound: 4.0,
      maximum_distance: 10.0,
    }).build(),
  }),
);
  • color Color
  • illuminance number Illuminance in lux
  • shadows_enabled boolean

Point Light

Spot Light

Skybox

Create a cubemap and upload images in the following order:

Online DEMO

// The order of the array layers is [+X, -X, +Y, -Y, +Z, -Z]
const imageBitmaps = await Promise.all(
  [posx, negx, posy, negy, posz, negz].map(async (src) => loadImage(src)),
);
camera = this.commands.spawn(
  //... Omit other components
  new Skybox({
    image_handle: imageBitmaps,
  }),
);

skybox

Post Processing

FXAA

Anti-aliasing with FXAA.

fxaa

The parameters are as follows:

  • enabled boolean Defaults to true
  • edge_threshold Sensitivity Defaults to Sensitivity.High
  • edge_threshold_min Sensitivity Defaults to Sensitivity.High

Online DEMO

camera = this.commands.spawn(
  //... Omit other components
  new Fxaa({
    enabled: true,
    edge_threshold: Sensitivity.High,
    edge_threshold_min: Sensitivity.High,
  }),
);

Fog

Configures the “classic” computer graphics distance fog effect, in which objects appear progressively more covered in atmospheric haze the further away they are from the camera.

Online DEMO

camera = this.commands.spawn(
  //... Omit other components
  new FogSettings({
    color: Color.BLUE,
    falloff: new FogFalloff.Linear({
      start: 0,
      end: 100,
    }),
  }),
);

The parameters are as follows:

  • color Color The color of the fog effect.
  • directional_light_color Color Color used to modulate the influence of directional light colors on the fog, where the view direction aligns with each directional light direction, producing a “glow” or light dispersion effect.
  • directional_light_exponent number The exponent applied to the directional light alignment calculation. A higher value means a more concentrated “glow”.
  • falloff FogFalloff The rate at which fog intensity increases with distance is controlled by the falloff mode. Determines which falloff mode to use, and its parameters.

The falloff modes are as follows:

  • FogFalloff.Linear - A linear fog falloff that grows in intensity between start and end distances. This falloff mode is simpler to control than other modes, however it can produce results that look “artificial”, depending on the scene.
    • start number Distance from the camera where fog is completely transparent, in world units.
    • end number Distance from the camera where fog is completely opaque, in world units.

linear fogexponential fogatmospheric fog

  • FogFalloff.Exponential - An exponential fog falloff with a given density.
    • density number Multiplier applied to the world distance (within the exponential fog falloff calculation).
  • FogFalloff.ExponentialSquared - A squared exponential fog falloff with a given density.
    • density number Multiplier applied to the world distance (within the exponential squared fog falloff calculation).
  • FogFalloff.Atmospheric - A more general form of the Exponential mode.
    • extinction Vec3 Controls how much light is removed due to atmospheric “extinction”, i.e. loss of light due to photons being absorbed by atmospheric particles.
    • inscattering Vec3 Controls how much light is added due to light scattering from the sun through the atmosphere.

Tonemapping

HDR (High Dynamic Range) refers to the ability of the game engine to handle very bright lights or colors. The internal HDR image has to be converted down to SDR (Standard Dynamic Range) before it can be displayed on the screen. This process is called Tonemapping.

Tonemapping is the step of the rendering process where the colors of pixels are converted from their in-engine intermediate repesentation into the final values as they should be displayed on-screen.

This is very important with HDR applications, as in that case the image can contain very bright pixels (above 1.0) which need to be remapped into a range that can be displayed.

Online DEMO

camera = this.commands.spawn(
  new Camera3dBundle({
    //... Omit other components
    tonemapping: new Tonemapping(TonemmapingMethod.Reinhard),
  }),
);

The following tonemapping algorithms DO NOT require the special data from tonemapping_luts:

  • Reinhard
  • ReinhardLuminance
  • AcesFitted
  • SomewhatBoringDisplayTransform

The following tonemapping algorithms require the special data from tonemapping_luts:

  • AgX
  • TonyMcMapface
  • BlenderFilmic

Color Grading

Color Grading is a manipulation of the overall look of the image. Together with tonemapping, this affects the "tone"/"mood" of the final image.

Online DEMO

camera = this.commands.spawn(
  new Camera3dBundle({
    //... Omit other components
    color_grading: new ColorGrading({
      exposure: 0.0,
      gamma: 1.0,
      pre_saturation: 1.0,
      post_saturation: 1.0,
    }),
  }),
);
  • exposure number Exposure value (EV) offset, measured in stops.
  • gamma number Non-linear luminance adjustment applied before tonemapping. y = pow(x, gamma)
  • pre_saturation number Saturation adjustment applied before tonemapping. Values below 1.0 desaturate, with a value of 0.0 resulting in a grayscale image with luminance defined by ITU-R BT.709. Values above 1.0 increase saturation.
  • post_saturation number Saturation adjustment applied after tonemapping.
color = saturation(color, color_grading.pre_saturation);

Deband Dithering

Deband dithering helps color gradients or other areas with subtle changes in color to appear higher-quality, without a "color banding" effect. It is enabled by default, and can be disabled per-camera.

camera = this.commands.spawn(
  new Camera3dBundle({
    //... Omit other components
    dither: new DebandDither({
      enabled: true,
    }),
  }),
);

Controllers

Add plugin like FpsCameraPlugin first, it will enhance the capability of default camera. smooth-bevy-cameras

new App({
  canvas: $canvas,
})
  .add_plugins(...DefaultPlugins)
  .add_plugins(FpsCameraPlugin)
  // .add_plugins(OrbitCameraPlugin)
  .add_systems(StartUp, StartUpSystem)
  .run();

Then create FpsCameraBundle:

camera = this.commands.spawn(
  new Camera3dBundle({
    camera: new Camera(),
    projection: new Perspective(),
  }),
  new FpsCameraBundle({
    controller: new FpsCameraController(),
    eye: new Vec3(-2.5, 5.0, 5.0),
    target: Vec3.ZERO,
    up: Vec3.Y,
  }),
);

Now we support the following pairs which support different interaction with keyboard and mouse:

  • FpsCameraPlugin + FpsCameraBundle Online DEMO

    • WASD: Translate on the XZ plane
    • Shift/Space: Translate along the Y axis
    • Mouse: Rotate camera

  • OrbitCameraPlugin + OrbitCameraBundle Online DEMO

    • CTRL + mouse drag: Rotate camera
    • Right mouse drag: Pan camera
    • Mouse wheel: Zoom

Appendix

3D Gaussian Splatting

Using @loaders.gl loading PLY.

Marching cubes

Raytracing

GUI

About

Just another toy renderer. Inspired by bevy.

xiaoiver.github.io/renderer/

Topics

renderer webgpu bevy

Resources

Readme
Activity

Stars

3 stars

Watchers

1 watching

Forks

1 fork
Report repository

Releases

No releases published

Packages

No packages published

Languages