bevy/crates/bevy_pbr/src/render/mesh.wgsl
robtfm 10f5c92068
improve shader import model (#5703)
# Objective

operate on naga IR directly to improve handling of shader modules.
- give codespan reporting into imported modules
- allow glsl to be used from wgsl and vice-versa

the ultimate objective is to make it possible to 
- provide user hooks for core shader functions (to modify light
behaviour within the standard pbr pipeline, for example)
- make automatic binding slot allocation possible

but ... since this is already big, adds some value and (i think) is at
feature parity with the existing code, i wanted to push this now.

## Solution

i made a crate called naga_oil (https://github.com/robtfm/naga_oil -
unpublished for now, could be part of bevy) which manages modules by
- building each module independantly to naga IR
- creating "header" files for each supported language, which are used to
build dependent modules/shaders
- make final shaders by combining the shader IR with the IR for imported
modules

then integrated this into bevy, replacing some of the existing shader
processing stuff. also reworked examples to reflect this.

## Migration Guide

shaders that don't use `#import` directives should work without changes.

the most notable user-facing difference is that imported
functions/variables/etc need to be qualified at point of use, and
there's no "leakage" of visible stuff into your shader scope from the
imports of your imports, so if you used things imported by your imports,
you now need to import them directly and qualify them.

the current strategy of including/'spreading' `mesh_vertex_output`
directly into a struct doesn't work any more, so these need to be
modified as per the examples (e.g. color_material.wgsl, or many others).
mesh data is assumed to be in bindgroup 2 by default, if mesh data is
bound into bindgroup 1 instead then the shader def `MESH_BINDGROUP_1`
needs to be added to the pipeline shader_defs.
2023-06-27 00:29:22 +00:00

106 lines
2.6 KiB
WebGPU Shading Language

#import bevy_pbr::mesh_functions as mesh_functions
#import bevy_pbr::skinning
#import bevy_pbr::morph
#import bevy_pbr::mesh_bindings mesh
#import bevy_pbr::mesh_vertex_output MeshVertexOutput
struct Vertex {
#ifdef VERTEX_POSITIONS
@location(0) position: vec3<f32>,
#endif
#ifdef VERTEX_NORMALS
@location(1) normal: vec3<f32>,
#endif
#ifdef VERTEX_UVS
@location(2) uv: vec2<f32>,
#endif
#ifdef VERTEX_TANGENTS
@location(3) tangent: vec4<f32>,
#endif
#ifdef VERTEX_COLORS
@location(4) color: vec4<f32>,
#endif
#ifdef SKINNED
@location(5) joint_indices: vec4<u32>,
@location(6) joint_weights: vec4<f32>,
#endif
#ifdef MORPH_TARGETS
@builtin(vertex_index) index: u32,
#endif
};
#ifdef MORPH_TARGETS
fn morph_vertex(vertex_in: Vertex) -> Vertex {
var vertex = vertex_in;
let weight_count = bevy_pbr::morph::layer_count();
for (var i: u32 = 0u; i < weight_count; i ++) {
let weight = bevy_pbr::morph::weight_at(i);
if weight == 0.0 {
continue;
}
vertex.position += weight * bevy_pbr::morph::morph(vertex.index, bevy_pbr::morph::position_offset, i);
#ifdef VERTEX_NORMALS
vertex.normal += weight * bevy_pbr::morph::morph(vertex.index, bevy_pbr::morph::normal_offset, i);
#endif
#ifdef VERTEX_TANGENTS
vertex.tangent += vec4(weight * bevy_pbr::morph::morph(vertex.index, bevy_pbr::morph::tangent_offset, i), 0.0);
#endif
}
return vertex;
}
#endif
@vertex
fn vertex(vertex_no_morph: Vertex) -> MeshVertexOutput {
var out: MeshVertexOutput;
#ifdef MORPH_TARGETS
var vertex = morph_vertex(vertex_no_morph);
#else
var vertex = vertex_no_morph;
#endif
#ifdef SKINNED
var model = bevy_pbr::skinning::skin_model(vertex.joint_indices, vertex.joint_weights);
#else
var model = mesh.model;
#endif
#ifdef VERTEX_NORMALS
#ifdef SKINNED
out.world_normal = bevy_pbr::skinning::skin_normals(model, vertex.normal);
#else
out.world_normal = mesh_functions::mesh_normal_local_to_world(vertex.normal);
#endif
#endif
#ifdef VERTEX_POSITIONS
out.world_position = mesh_functions::mesh_position_local_to_world(model, vec4<f32>(vertex.position, 1.0));
out.position = mesh_functions::mesh_position_world_to_clip(out.world_position);
#endif
#ifdef VERTEX_UVS
out.uv = vertex.uv;
#endif
#ifdef VERTEX_TANGENTS
out.world_tangent = mesh_functions::mesh_tangent_local_to_world(model, vertex.tangent);
#endif
#ifdef VERTEX_COLORS
out.color = vertex.color;
#endif
return out;
}
@fragment
fn fragment(
mesh: MeshVertexOutput,
) -> @location(0) vec4<f32> {
#ifdef VERTEX_COLORS
return mesh.color;
#else
return vec4<f32>(1.0, 0.0, 1.0, 1.0);
#endif
}