Add raytracingbasic rust shaders

Author: LegNeato

shaders/rust/Cargo.lock

@@ -146,6 +146,7 @@ members = [
     "conservativeraster/triangle",
     "conservativeraster/triangleoverlay",
     "conservativeraster/fullscreen",
+    "raytracingbasic",
 ]
 
 [workspace.package]

shaders/rust/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "raytracingbasic"
+version = "0.1.0"
+edition.workspace = true
+
+[lib]
+crate-type = ["dylib"]
+
+[dependencies]
+spirv-std = { workspace = true }
+
+[package.metadata.rust-gpu.build]
+capabilities = ["RayTracingKHR", "StorageImageWriteWithoutFormat"]
+extensions = ["SPV_KHR_ray_tracing"]

shaders/rust/raytracingbasic/Cargo.toml

@@ -0,0 +1,76 @@
+#![cfg_attr(target_arch = "spirv", no_std)]
+#![allow(clippy::missing_safety_doc)]
+
+use spirv_std::{spirv, glam::{vec2, vec3, vec4, Mat4, Vec2, Vec3, IVec3}};
+use spirv_std::glam::Vec4Swizzles;
+use spirv_std::ray_tracing::{AccelerationStructure, RayFlags};
+use spirv_std::Image;
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct CameraProperties {
+    pub view_inverse: Mat4,
+    pub proj_inverse: Mat4,
+}
+
+#[spirv(ray_generation)]
+pub fn main_rgen(
+    #[spirv(launch_id)] launch_id: IVec3,
+    #[spirv(launch_size)] launch_size: IVec3,
+    #[spirv(descriptor_set = 0, binding = 0)] top_level_as: &AccelerationStructure,
+    #[spirv(descriptor_set = 0, binding = 1)] image: &Image!(2D, type=f32, sampled=false),
+    #[spirv(uniform, descriptor_set = 0, binding = 2)] cam: &CameraProperties,
+    #[spirv(ray_payload)] hit_value: &mut Vec3,
+) {
+    let pixel_center = vec2(launch_id.x as f32, launch_id.y as f32) + vec2(0.5, 0.5);
+    let in_uv = pixel_center / vec2(launch_size.x as f32, launch_size.y as f32);
+    let d = in_uv * 2.0 - 1.0;
+
+    let origin = cam.view_inverse * vec4(0.0, 0.0, 0.0, 1.0);
+    let target = cam.proj_inverse * vec4(d.x, d.y, 1.0, 1.0);
+    let normalized_target = target.xyz().normalize();
+    let direction = cam.view_inverse * vec4(normalized_target.x, normalized_target.y, normalized_target.z, 0.0);
+
+    let tmin = 0.001;
+    let tmax = 10000.0;
+
+    *hit_value = vec3(0.0, 0.0, 0.0);
+
+    unsafe {
+        top_level_as.trace_ray(
+            RayFlags::OPAQUE,
+            0xff,
+            0,
+            0,
+            0,
+            origin.xyz(),
+            tmin,
+            direction.xyz(),
+            tmax,
+            hit_value,
+        );
+    }
+
+    unsafe {
+        image.write(
+            spirv_std::glam::IVec2::new(launch_id.x, launch_id.y),
+            vec4(hit_value.x, hit_value.y, hit_value.z, 0.0)
+        );
+    }
+}
+
+#[spirv(closest_hit)]
+pub fn main_rchit(
+    #[spirv(hit_attribute)] attribs: &Vec2,
+    #[spirv(incoming_ray_payload)] hit_value: &mut Vec3,
+) {
+    let barycentric_coords = vec3(1.0 - attribs.x - attribs.y, attribs.x, attribs.y);
+    *hit_value = barycentric_coords;
+}
+
+#[spirv(miss)]
+pub fn main_rmiss(
+    #[spirv(incoming_ray_payload)] hit_value: &mut Vec3,
+) {
+    *hit_value = vec3(0.0, 0.0, 0.2);
+}