Re-enable path-tracer.

In #313 I disabled all the code relying on OptiX. I subsequently learned
that `path-tracer`'s use of OptiX is optional. `path-tracer` is a big
and good example, so this commit re-enables it, but with the
OptiX-specific bits commented out. (Commenting out code is crude, but I
had trouble with features, as detailed within the commit. This is better
than nothing.)

Author: nnethercote

Cargo.lock

@@ -18,8 +18,18 @@ members = [
   "crates/rustc_codegen_nvvm",
   "crates/rustc_codegen_nvvm_macros",
 
-  # These crates that rely on OptiX are disabled because OptiX is less important than CUDA and the
-  # OptiX SDK is a pain to install.
+  # OPTIX_DISABLED: These crates that rely on OptiX are disabled because OptiX is less important
+  # than CUDA and the OptiX SDK is a pain to install.
+  #
+  # The `path-tracer` crates are an exception because the OptiX use is currently commented out. I
+  # originally tried putting the OptiX use within these crates behind a feature, but `crates/optix`
+  # would be built by `cargo build` even when the feature was disabled, even though it's not listed
+  # in `members`. This would break the build if you don't have OptiX installed. (There were also
+  # problems with `cargo doc --all-features`.) Commenting out the OptiX-specific code is crude, but
+  # at least that way the non-OptiX-specific code (which is a majority of it) can be built and
+  # tested, and the OptiX-specific code is still available to be used if necessary with only
+  # moderate effort required to uncomment it. (Search for comments mentioning `OPTIX_DISABLED`.)
+  #
   # "crates/optix",
   # "crates/optix_device",
   # "crates/optix_device_macros",
@@ -30,8 +40,8 @@ members = [
   # "crates/optix/examples/ex03_window",
   # "crates/optix/examples/ex04_mesh",
   # "crates/optix/examples/ex04_mesh/kernels",
-  # "crates/optix/examples/path_tracer",
-  # "crates/optix/examples/path_tracer/kernels",
+  "crates/optix/examples/path_tracer",
+  "crates/optix/examples/path_tracer/kernels",
 
   "examples/gemm",
   "examples/gemm/kernels",

Cargo.toml

@@ -10,7 +10,8 @@ cust = { version = "0.3", path = "../../../cust", features = ["impl_glam"] }
 image = "0.25.5"
 path-tracer-kernels = { path = "kernels" }
 gpu_rand = { version = "0.1", path = "../../../gpu_rand" }
-optix = { version = "0.1", path = "../../../optix" }
+# See the OPTIX_DISABLED comment.
+# optix = { version = "0.1", path = "../../../optix" }
 glium = "0.32.0"
 glutin = "0.28.0"
 imgui = "0.9.0"

crates/optix/examples/path_tracer/Cargo.toml

@@ -14,9 +14,12 @@ fn main() {
         .copy_to(out_path.join("kernels.ptx"))
         .build()
         .unwrap();
-    CudaBuilder::new(manifest_dir.join("kernels"))
-        .copy_to(out_path.join("kernels_optix.ptx"))
-        .build_args(&["--features", "optix"])
-        .build()
-        .unwrap();
+
+    // See the OPTIX_DISABLED comment.
+    // #[cfg(feature = "optix")]
+    // CudaBuilder::new(manifest_dir.join("kernels"))
+    //     .copy_to(out_path.join("kernels_optix.ptx"))
+    //     .build_args(&["--features", "optix"])
+    //     .build()
+    //     .unwrap();
 }

crates/optix/examples/path_tracer/build.rs

@@ -9,7 +9,8 @@ glam = { version = "0.30", default-features = false, features = ["libm", "cuda"]
 enum_dispatch = "0.3.13"
 gpu_rand = { version = "0.1", path = "../../../../gpu_rand" }
 cust_core = { path = "../../../../cust_core", features = ["glam"] }
-optix_device = { path = "../../../../optix_device" }
+# See the OPTIX_DISABLED comment.
+# optix_device = { path = "../../../../optix_device", optional = true }
 approx = { version = "0.5" }
 
 [lib]

crates/optix/examples/path_tracer/kernels/Cargo.toml

@@ -5,7 +5,8 @@ extern crate alloc;
 pub mod hittable;
 pub mod material;
 pub mod math;
-pub mod optix;
+// See the OPTIX_DISABLED comment.
+// pub mod optix;
 pub mod render;
 pub mod render_kernels;
 pub mod scene;
@@ -51,12 +52,13 @@ impl Ray {
         self.origin + t * self.dir
     }
 
-    pub fn from_optix() -> Self {
-        use optix_device::intersection;
-
-        Self {
-            dir: Vec3::from(intersection::ray_world_direction().to_array()),
-            origin: Vec3::from(intersection::ray_world_origin().to_array()),
-        }
-    }
+    // See the OPTIX_DISABLED comment.
+    // pub fn from_optix() -> Self {
+    //     use optix_device::intersection;
+    //
+    //     Self {
+    //         dir: Vec3::from(intersection::ray_world_direction().to_array()),
+    //         origin: Vec3::from(intersection::ray_world_origin().to_array()),
+    //     }
+    // }
 }

crates/optix/examples/path_tracer/kernels/src/lib.rs

@@ -5,7 +5,9 @@ use imgui::Ui;
 
 use std::time::Duration;
 
-use crate::{common::Camera, optix::OptixRenderer};
+use crate::common::Camera;
+// See the OPTIX_DISABLED comment.
+// use crate::optix::OptixRenderer;
 use anyhow::Result;
 use cust::{
     error::CudaResult,
@@ -15,10 +17,11 @@ use cust::{
     prelude::*,
 };
 use glam::{U8Vec3, USizeVec2};
-use optix::{
-    context::DeviceContext,
-    denoiser::{Denoiser, DenoiserModelKind, Image, ImageFormat},
-};
+// See the OPTIX_DISABLED comment.
+// use optix::{
+//     context::DeviceContext,
+//     denoiser::{Denoiser, DenoiserModelKind, Image, ImageFormat},
+// };
 use path_tracer_kernels::scene::Scene;
 /// Seed for the random states
 pub const SEED: u64 = 932174513921034;
@@ -33,45 +36,51 @@ pub(crate) static PTX: &str = include_str!(concat!(env!("OUT_DIR"), "/kernels.pt
 pub struct CudaRenderer {
     stream: Stream,
     module: Module,
-    denoiser: Denoiser,
-    _optix_context: DeviceContext,
+    // See the OPTIX_DISABLED comment.
+    // denoiser: Denoiser,
+    // _optix_context: DeviceContext,
     _context: Context,
 
     buffers: CudaRendererBuffers,
     cpu_image: Vec<U8Vec3>,
-    optix_renderer: OptixRenderer,
+    // See the OPTIX_DISABLED comment.
+    // optix_renderer: OptixRenderer,
 }
 
 impl CudaRenderer {
     pub fn new(dimensions: USizeVec2, camera: &Camera, scene: &Scene) -> Result<Self> {
         let context = cust::quick_init()?;
-        optix::init().unwrap();
-
-        let mut optix_context = DeviceContext::new(&context, false).unwrap();
+        // See the OPTIX_DISABLED comment.
+        // optix::init().unwrap();
+        // let mut optix_context = DeviceContext::new(&context, false).unwrap();
 
         let module = Module::from_ptx(PTX, &[]).unwrap();
         let stream = Stream::new(StreamFlags::NON_BLOCKING, None)?;
-        let mut denoiser =
-            Denoiser::new(&optix_context, DenoiserModelKind::Ldr, Default::default()).unwrap();
 
-        denoiser
-            .setup_state(&stream, dimensions.x as u32, dimensions.y as u32, false)
-            .unwrap();
+        // See the OPTIX_DISABLED comment.
+        // let mut denoiser =
+        //     Denoiser::new(&optix_context, DenoiserModelKind::Ldr, Default::default()).unwrap();
+        // denoiser
+        //     .setup_state(&stream, dimensions.x as u32, dimensions.y as u32, false)
+        //     .unwrap();
 
         let buffers = CudaRendererBuffers::new(dimensions, camera, scene)?;
         let cpu_image = vec![U8Vec3::ZERO; dimensions.element_product()];
 
-        let optix_renderer = OptixRenderer::new(&mut optix_context, &stream, scene)?;
+        // See the OPTIX_DISABLED comment.
+        // let optix_renderer = OptixRenderer::new(&mut optix_context, &stream, scene)?;
 
         Ok(Self {
             _context: context,
-            _optix_context: optix_context,
-            denoiser,
+            // See the OPTIX_DISABLED comment.
+            // _optix_context: optix_context,
+            // denoiser,
             module,
             stream,
             buffers,
             cpu_image,
-            optix_renderer,
+            // See the OPTIX_DISABLED comment.
+            // optix_renderer,
         })
     }
 
@@ -97,9 +106,11 @@ impl CudaRenderer {
         self.cpu_image
             .resize(new_size.element_product(), U8Vec3::ZERO);
 
-        self.denoiser
-            .setup_state(&self.stream, new_size.x as u32, new_size.y as u32, false)
-            .unwrap();
+        // See the OPTIX_DISABLED comment.
+        // self.denoiser
+        //     .setup_state(&self.stream, new_size.x as u32, new_size.y as u32, false)
+        //     .unwrap();
+
         Ok(())
     }
 
@@ -123,8 +134,9 @@ impl CudaRenderer {
         let stream = &self.stream;
 
         let (blocks, threads) = self.launch_dimensions();
-        let width = self.buffers.viewport.bounds.x as u32;
-        let height = self.buffers.viewport.bounds.y as u32;
+        // See the OPTIX_DISABLED comment.
+        // let width = self.buffers.viewport.bounds.x as u32;
+        // let height = self.buffers.viewport.bounds.y as u32;
 
         let start = Event::new(EventFlags::DEFAULT)?;
         let denoising_stop = Event::new(EventFlags::DEFAULT)?;
@@ -144,23 +156,24 @@ impl CudaRenderer {
         }
 
         let input_buf = if denoise {
-            let input_image = Image::new(
-                &self.buffers.scaled_buffer,
-                ImageFormat::Float3,
-                width,
-                height,
-            );
-
-            self.denoiser
-                .invoke(
-                    stream,
-                    Default::default(),
-                    input_image,
-                    Default::default(),
-                    &mut self.buffers.denoised_buffer,
-                )
-                .unwrap();
-
+            // See the OPTIX_DISABLED comment.
+            // let input_image = Image::new(
+            //     &self.buffers.scaled_buffer,
+            //     ImageFormat::Float3,
+            //     width,
+            //     height,
+            // );
+            //
+            // self.denoiser
+            //     .invoke(
+            //         stream,
+            //         Default::default(),
+            //         input_image,
+            //         Default::default(),
+            //         &mut self.buffers.denoised_buffer,
+            //     )
+            //     .unwrap();
+            //
             self.buffers.denoised_buffer.as_device_ptr()
         } else {
             self.buffers.scaled_buffer.as_device_ptr()
@@ -204,7 +217,8 @@ impl CudaRenderer {
         start.record(stream)?;
 
         if use_optix {
-            self.optix_renderer.render(stream, &mut self.buffers)?;
+            // See the OPTIX_DISABLED comment.
+            // self.optix_renderer.render(stream, &mut self.buffers)?;
         } else {
             unsafe {
                 let scene = DeviceBox::new_async(

crates/optix/examples/path_tracer/src/cuda/mod.rs

@@ -1,7 +1,8 @@
 pub mod common;
 pub mod cpu;
 pub mod cuda;
-pub mod optix;
+// See the OPTIX_DISABLED comment.
+// pub mod optix;
 pub mod renderer;
 pub mod viewer;