bevy/crates/bevy_sprite/src/render/sprite.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

45 lines
1 KiB
WebGPU Shading Language

struct View {
view_proj: mat4x4<f32>;
world_position: vec3<f32>;
};
[[group(0), binding(0)]]
var<uniform> view: View;
struct VertexOutput {
[[location(0)]] uv: vec2<f32>;
#ifdef COLORED
[[location(1)]] color: vec4<f32>;
#endif
[[builtin(position)]] position: vec4<f32>;
};
[[stage(vertex)]]
fn vertex(
[[location(0)]] vertex_position: vec3<f32>,
[[location(1)]] vertex_uv: vec2<f32>,
#ifdef COLORED
[[location(2)]] vertex_color: vec4<f32>,
#endif
) -> VertexOutput {
var out: VertexOutput;
out.uv = vertex_uv;
out.position = view.view_proj * vec4<f32>(vertex_position, 1.0);
#ifdef COLORED
out.color = vertex_color;
#endif
return out;
}
[[group(1), binding(0)]]
var sprite_texture: texture_2d<f32>;
[[group(1), binding(1)]]
var sprite_sampler: sampler;
[[stage(fragment)]]
fn fragment(in: VertexOutput) -> [[location(0)]] vec4<f32> {
var color = textureSample(sprite_texture, sprite_sampler, in.uv);
#ifdef COLORED
color = in.color * color;
#endif
return color;
}