bevy/examples/shader/shader_material_glsl.rs
Boutillier 6b073ee412 Update shader_material_glsl example to include texture sampling (#5215)
# Objective

Add texture sampling to the GLSL shader example, as naga does not support the commonly used sampler2d type.
Fixes #5059

## Solution

- Align the shader_material_glsl example behaviour with the shader_material example,  as the later includes texture sampling.
- Update the GLSL shader to do texture sampling the way naga supports it, and document the way naga does not support it.

## Changelog

- The shader_material_glsl example has been updated to demonstrate texture sampling using the GLSL shading language.


Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2022-07-08 01:14:22 +00:00

90 lines
2.8 KiB
Rust

//! A shader that uses the GLSL shading language.
use bevy::{
pbr::{MaterialPipeline, MaterialPipelineKey},
prelude::*,
reflect::TypeUuid,
render::{
mesh::MeshVertexBufferLayout,
render_resource::{
AsBindGroup, RenderPipelineDescriptor, ShaderRef, SpecializedMeshPipelineError,
},
},
};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_plugin(MaterialPlugin::<CustomMaterial>::default())
.add_startup_system(setup)
.run();
}
/// set up a simple 3D scene
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<CustomMaterial>>,
asset_server: Res<AssetServer>,
) {
// cube
commands.spawn().insert_bundle(MaterialMeshBundle {
mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
transform: Transform::from_xyz(0.0, 0.5, 0.0),
material: materials.add(CustomMaterial {
color: Color::BLUE,
color_texture: Some(asset_server.load("branding/icon.png")),
alpha_mode: AlphaMode::Blend,
}),
..default()
});
// camera
commands.spawn_bundle(Camera3dBundle {
transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
..default()
});
}
// This is the struct that will be passed to your shader
#[derive(AsBindGroup, Clone, TypeUuid)]
#[uuid = "4ee9c363-1124-4113-890e-199d81b00281"]
pub struct CustomMaterial {
#[uniform(0)]
color: Color,
#[texture(1)]
#[sampler(2)]
color_texture: Option<Handle<Image>>,
alpha_mode: AlphaMode,
}
/// The Material trait is very configurable, but comes with sensible defaults for all methods.
/// You only need to implement functions for features that need non-default behavior. See the Material api docs for details!
/// When using the GLSL shading language for your shader, the specialize method must be overriden.
impl Material for CustomMaterial {
fn vertex_shader() -> ShaderRef {
"shaders/custom_material.vert".into()
}
fn fragment_shader() -> ShaderRef {
"shaders/custom_material.frag".into()
}
fn alpha_mode(&self) -> AlphaMode {
self.alpha_mode
}
// Bevy assumes by default that vertex shaders use the "vertex" entry point
// and fragment shaders use the "fragment" entry point (for WGSL shaders).
// GLSL uses "main" as the entry point, so we must override the defaults here
fn specialize(
_pipeline: &MaterialPipeline<Self>,
descriptor: &mut RenderPipelineDescriptor,
_layout: &MeshVertexBufferLayout,
_key: MaterialPipelineKey<Self>,
) -> Result<(), SpecializedMeshPipelineError> {
descriptor.vertex.entry_point = "main".into();
descriptor.fragment.as_mut().unwrap().entry_point = "main".into();
Ok(())
}
}