From 3d4ac7f57b1068cdecbe7efcf9cbbc42d52b9a03 Mon Sep 17 00:00:00 2001
From: Nathan Vegdahl <cessen@cessen.com>
Date: Fri, 21 Jun 2019 23:02:44 +0900
Subject: [PATCH] Created a RayBatch type, which stores multiple rays is SoA
 layout.

---
 src/ray.rs | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 95 insertions(+), 4 deletions(-)

diff --git a/src/ray.rs b/src/ray.rs
index cf91b74..d2cf51f 100644
--- a/src/ray.rs
+++ b/src/ray.rs
@@ -4,8 +4,99 @@ use float4::Float4;
 
 use crate::math::{Matrix4x4, Point, Vector};
 
-const OCCLUSION_FLAG: u32 = 1;
-const DONE_FLAG: u32 = 1 << 1;
+type FlagType = u8;
+const OCCLUSION_FLAG: FlagType = 1;
+const DONE_FLAG: FlagType = 1 << 1;
+
+/// A batch of rays, stored in SoA layout.
+#[derive(Debug)]
+pub struct RayBatch {
+    pub orig_world: Vec<Point>,
+    pub dir_world: Vec<Vector>,
+    pub orig_accel: Vec<Point>,
+    pub dir_inv_accel: Vec<Vector>,
+    pub max_t: Vec<f32>,
+    pub time: Vec<f32>,
+    pub wavelength: Vec<f32>,
+    pub flags: Vec<FlagType>,
+}
+
+impl RayBatch {
+    /// Creates a new empty ray batch.
+    pub fn new() -> RayBatch {
+        RayBatch {
+            orig_world: Vec::new(),
+            dir_world: Vec::new(),
+            orig_accel: Vec::new(),
+            dir_inv_accel: Vec::new(),
+            max_t: Vec::new(),
+            time: Vec::new(),
+            wavelength: Vec::new(),
+            flags: Vec::new(),
+        }
+    }
+
+    /// Creates a new empty ray batch, with pre-allocated capacity for
+    /// `n` rays.
+    pub fn with_capacity(n: usize) -> RayBatch {
+        RayBatch {
+            orig_world: Vec::with_capacity(n),
+            dir_world: Vec::with_capacity(n),
+            orig_accel: Vec::with_capacity(n),
+            dir_inv_accel: Vec::with_capacity(n),
+            max_t: Vec::with_capacity(n),
+            time: Vec::with_capacity(n),
+            wavelength: Vec::with_capacity(n),
+            flags: Vec::with_capacity(n),
+        }
+    }
+
+    /// Clear all rays, settings the size of the batch back to zero.
+    ///
+    /// Capacity is maintained.
+    pub fn clear(&mut self) {
+        self.orig_world.clear();
+        self.dir_world.clear();
+        self.orig_accel.clear();
+        self.dir_inv_accel.clear();
+        self.max_t.clear();
+        self.time.clear();
+        self.wavelength.clear();
+        self.flags.clear();
+    }
+
+    /// Returns whether the given ray (at index `idx`) is an occlusion ray.
+    pub fn is_occlusion(&self, idx: usize) -> bool {
+        (self.flags[idx] & OCCLUSION_FLAG) != 0
+    }
+
+    /// Returns whether the given ray (at index `idx`) has finished traversal.
+    pub fn is_done(&self, idx: usize) -> bool {
+        (self.flags[idx] & DONE_FLAG) != 0
+    }
+
+    /// Marks the given ray (at index `idx`) as an occlusion ray.
+    pub fn mark_occlusion(&mut self, idx: usize) {
+        self.flags[idx] |= OCCLUSION_FLAG
+    }
+
+    /// Marks the given ray (at index `idx`) as having finished traversal.
+    pub fn mark_done(&mut self, idx: usize) {
+        self.flags[idx] |= DONE_FLAG
+    }
+
+    /// Updates the accel data of the given ray (at index `idx`) with the
+    /// given world-to-local-space transform matrix.
+    ///
+    /// This should be called when entering (and exiting) traversal of a
+    /// new transform space.
+    pub fn update_accel(&mut self, idx: usize, xform: &Matrix4x4) {
+        self.orig_accel[idx] = self.orig_world[idx] * *xform;
+        self.dir_inv_accel[idx] = Vector {
+            co: Float4::splat(1.0) / (self.dir_world[idx] * *xform).co,
+        };
+    }
+}
 
 #[derive(Debug, Copy, Clone)]
 pub struct Ray {
@@ -14,7 +105,7 @@ pub struct Ray {
     pub max_t: f32,
     pub time: f32,
     pub wavelength: f32,
-    pub flags: u32,
+    pub flags: FlagType,
 }
 
 impl Ray {
@@ -56,7 +147,7 @@ pub struct AccelRay {
     pub dir_inv: Vector,
     pub max_t: f32,
     pub time: f32,
-    pub flags: u32,
+    pub flags: FlagType,
     pub id: u32,
 }