From 93fa0b2e214fbb70e6c03f5ca7536c7c32544aa7 Mon Sep 17 00:00:00 2001
From: ladevieq <ladevie.quentin@gmail.com>
Date: Sun, 1 Aug 2021 18:45:50 +0200
Subject: Pack bvh nodes, optimize vertices size

---
 include/aabb.hpp     | 11 ++++++++---
 include/bvh-node.hpp | 38 ++++++++++++++++++++++++--------------
 include/scene.hpp    |  2 +-
 include/triangle.hpp |  7 +------
 4 files changed, 34 insertions(+), 24 deletions(-)

(limited to 'include')

diff --git a/include/aabb.hpp b/include/aabb.hpp
index 3a4e680..9bc69d1 100644
--- a/include/aabb.hpp
+++ b/include/aabb.hpp
@@ -2,15 +2,20 @@
 #define __AABB_HPP_
 
 #include "vec3.hpp"
+#include "triangle.hpp"
 #include <cmath>
 #include <limits.h>
 
 class aabb {
     public:
         aabb() = default;
-        aabb(vec3 min_point, vec3 max_point): minimum(min_point), maximum(max_point) {}
-        aabb(vec3 position, float radius): minimum(position - vec3(radius)), maximum(position + vec3(radius)) {}
-        aabb(point3 &v1, point3 &v2, point3 &v3) {
+        aabb(vec3 &min_point, vec3 &max_point): minimum(min_point), maximum(max_point) {}
+        aabb(vec3 &position, float radius): minimum(position - vec3(radius)), maximum(position + vec3(radius)) {}
+        aabb(triangle &tri) {
+            auto &v1 = tri.v1.position;
+            auto &v2 = tri.v2.position;
+            auto &v3 = tri.v3.position;
+
             minimum.x = fmin(fmin(v1.x, v2.x), v3.x);
             minimum.y = fmin(fmin(v1.y, v2.y), v3.y);
             minimum.z = fmin(fmin(v1.z, v2.z), v3.z);
diff --git a/include/bvh-node.hpp b/include/bvh-node.hpp
index 72c4bdf..09c9420 100644
--- a/include/bvh-node.hpp
+++ b/include/bvh-node.hpp
@@ -20,6 +20,13 @@ class bvh_node {
         uint32_t padding[2];
 };
 
+struct packed_bvh_node {
+    float min[3];
+    int32_t next_id = -1;
+    float max[3];
+    int32_t primitive_id = -1;
+};
+
 struct temp_node : public bvh_node {
     int32_t left_id;
     int32_t df_id;
@@ -60,14 +67,14 @@ public:
     //     // exporter();
     // }
 
-    bvh(std::vector<triangle>& triangles, std::vector<bvh_node>& nodes)
-        :triangles(triangles), nodes(nodes) {
-        nodes.resize(2 * triangles.size() - 1);
+    bvh(std::vector<triangle>& triangles, std::vector<packed_bvh_node>& packed_nodes)
+        :triangles(triangles) {
+        packed_nodes.resize(2 * triangles.size() - 1);
         temp_nodes = std::vector<temp_node>(2 * triangles.size() - 1);
         leafs = std::vector<temp_node>(triangles.size());
 
         for (uint32_t id = 0; id < triangles.size(); id++) {
-            leafs[id].bounding_box = triangles[id].bounding_box;
+            leafs[id].bounding_box = aabb(triangles[id]);
             leafs[id].primitive_id = id;
         }
 
@@ -80,18 +87,23 @@ public:
 
         for (uint32_t id = 0; id < temp_nodes.size(); id++) {
             auto old_node = temp_nodes[id];
-            auto &node = nodes[old_node.df_id];
+            auto &node = packed_nodes[old_node.df_id];
 
             node.primitive_id = old_node.primitive_id;
-            node.bounding_box = old_node.bounding_box;
+
+            node.min[0] = old_node.bounding_box.minimum.x;
+            node.min[1] = old_node.bounding_box.minimum.y;
+            node.min[2] = old_node.bounding_box.minimum.z;
+
+            node.max[0] = old_node.bounding_box.maximum.x;
+            node.max[1] = old_node.bounding_box.maximum.y;
+            node.max[2] = old_node.bounding_box.maximum.z;
 
             if (old_node.next_id != -1) {
                 node.next_id = temp_nodes[old_node.next_id].df_id;
             }
         }
 
-        // TODO: Pack nodes
-
         // exporter();
     }
 
@@ -148,7 +160,6 @@ public:
         return -1;
     }
 
-    std::vector<bvh_node>& nodes;
     std::vector<temp_node> temp_nodes;
     std::vector<temp_node> leafs;
 
@@ -164,10 +175,9 @@ private:
     aabb compute_bounds(uint32_t begin, uint32_t end) {
         aabb global_box = aabb();
 
-        for (uint32_t box_id = begin; box_id < end; box_id++) {
-            auto leaf = leafs[box_id];
-            // global_box = aabb::surrounding_box(global_box, spheres[leaf.primitive_id].bounding_box);
-            global_box.union_with(triangles[leaf.primitive_id].bounding_box);
+        for (uint32_t id = begin; id < end; id++) {
+            // global_box.union_with(spheres[leaf.primitive_id].bounding_box);
+            global_box.union_with(leafs[id].bounding_box);
         }
 
         return global_box;
@@ -235,7 +245,7 @@ private:
                     }
 
                     buckets[bucket_index].count++;
-                    buckets[bucket_index].bb.union_with(primitive.bounding_box);
+                    buckets[bucket_index].bb.union_with(leafs[i].bounding_box);
                 }
 
                 // Compute each potential split axis cost
diff --git a/include/scene.hpp b/include/scene.hpp
index 2a9ebf2..0002b1d 100644
--- a/include/scene.hpp
+++ b/include/scene.hpp
@@ -44,7 +44,7 @@ public:
     // Geometry & BVH
     // std::vector<sphere> spheres;
     std::vector<triangle> triangles;
-    std::vector<bvh_node> nodes;
+    std::vector<packed_bvh_node> packed_nodes;
 };
 
 #endif // !__SCENE_HPP_
diff --git a/include/triangle.hpp b/include/triangle.hpp
index f1af241..9993efe 100644
--- a/include/triangle.hpp
+++ b/include/triangle.hpp
@@ -1,9 +1,6 @@
 #ifndef __TRIANGLE_HPP_
 #define __TRIANGLE_HPP_
 
-#include "aabb.hpp"
-#include "material.hpp"
-
 struct vertex {
     vec3 position;
 };
@@ -11,7 +8,7 @@ struct vertex {
 struct triangle {
     triangle() = default;
     triangle(vertex v1, vertex v2, vertex v3)
-        : v1(v1), v2(v2), v3(v3), bounding_box(v1.position, v2.position, v3.position)
+        : v1(v1), v2(v2), v3(v3)
     {}
 
     vec3 center() {
@@ -21,8 +18,6 @@ struct triangle {
     vertex v1;
     vertex v2;
     vertex v3;
-
-    aabb bounding_box;
 };
 
 #endif // !__TRIANGLE_HPP_
-- 
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