bevy/assets/shaders/animate_shader.wgsl
Robert Swain b333386271 Add reusable shader functions for transforming position/normal/tangent (#4901)
# Objective

- Add reusable shader functions for transforming positions / normals / tangents between local and world / clip space for 2D and 3D so that they are done in a simple and correct way
- The next step in #3969 so check there for more details.

## Solution

- Add `bevy_pbr::mesh_functions` and `bevy_sprite::mesh2d_functions` shader imports
  - These contain `mesh_` and `mesh2d_` versions of the following functions:
    - `mesh_position_local_to_world`
    - `mesh_position_world_to_clip`
    - `mesh_position_local_to_clip`
    - `mesh_normal_local_to_world`
    - `mesh_tangent_local_to_world`
- Use them everywhere where it is appropriate
  - Notably not in the sprite and UI shaders where `mesh2d_position_world_to_clip` could have been used, but including all the functions depends on the mesh binding so I chose to not use the function there
- NOTE: The `mesh_` and `mesh2d_` functions are currently identical. However, if I had defined only `bevy_pbr::mesh_functions` and used that in bevy_sprite, then bevy_sprite would have a runtime dependency on bevy_pbr, which seems undesirable. I also expect that when we have a proper 2D rendering API, these functions will diverge between 2D and 3D.

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## Changelog

- Added: `bevy_pbr::mesh_functions` and `bevy_sprite::mesh2d_functions` shader imports containing `mesh_` and `mesh2d_` versions of the following functions:
  - `mesh_position_local_to_world`
  - `mesh_position_world_to_clip`
  - `mesh_position_local_to_clip`
  - `mesh_normal_local_to_world`
  - `mesh_tangent_local_to_world`

## Migration Guide

- The `skin_tangents` function from the `bevy_pbr::skinning` shader import has been replaced with the `mesh_tangent_local_to_world` function from the `bevy_pbr::mesh_functions` shader import
2022-06-14 00:32:33 +00:00

74 lines
2.0 KiB
WebGPU Shading Language

#import bevy_pbr::mesh_types
#import bevy_pbr::mesh_view_bindings
[[group(1), binding(0)]]
var<uniform> mesh: Mesh;
// NOTE: Bindings must come before functions that use them!
#import bevy_pbr::mesh_functions
struct Vertex {
[[location(0)]] position: vec3<f32>;
[[location(1)]] normal: vec3<f32>;
[[location(2)]] uv: vec2<f32>;
};
struct VertexOutput {
[[builtin(position)]] clip_position: vec4<f32>;
[[location(0)]] uv: vec2<f32>;
};
[[stage(vertex)]]
fn vertex(vertex: Vertex) -> VertexOutput {
var out: VertexOutput;
out.clip_position = mesh_position_local_to_clip(mesh.model, vec4<f32>(vertex.position, 1.0));
out.uv = vertex.uv;
return out;
}
struct Time {
time_since_startup: f32;
};
[[group(2), binding(0)]]
var<uniform> time: Time;
fn oklab_to_linear_srgb(c: vec3<f32>) -> vec3<f32> {
let L = c.x;
let a = c.y;
let b = c.z;
let l_ = L + 0.3963377774 * a + 0.2158037573 * b;
let m_ = L - 0.1055613458 * a - 0.0638541728 * b;
let s_ = L - 0.0894841775 * a - 1.2914855480 * b;
let l = l_*l_*l_;
let m = m_*m_*m_;
let s = s_*s_*s_;
return vec3<f32>(
4.0767416621 * l - 3.3077115913 * m + 0.2309699292 * s,
-1.2684380046 * l + 2.6097574011 * m - 0.3413193965 * s,
-0.0041960863 * l - 0.7034186147 * m + 1.7076147010 * s,
);
}
[[stage(fragment)]]
fn fragment(in: VertexOutput) -> [[location(0)]] vec4<f32> {
let speed = 2.0;
let t_1 = sin(time.time_since_startup * speed) * 0.5 + 0.5;
let t_2 = cos(time.time_since_startup * speed);
let distance_to_center = distance(in.uv, vec2<f32>(0.5)) * 1.4;
// blending is done in a perceptual color space: https://bottosson.github.io/posts/oklab/
let red = vec3<f32>(0.627955, 0.224863, 0.125846);
let green = vec3<f32>(0.86644, -0.233887, 0.179498);
let blue = vec3<f32>(0.701674, 0.274566, -0.169156);
let white = vec3<f32>(1.0, 0.0, 0.0);
let mixed = mix(mix(red, blue, t_1), mix(green, white, t_2), distance_to_center);
return vec4<f32>(oklab_to_linear_srgb(mixed), 1.0);
}