From be5f1133bff5d4c551e2702211acb155d8819fd0 Mon Sep 17 00:00:00 2001
From: ladevieq <ladevie.quentin@gmail.com>
Date: Mon, 29 Mar 2021 22:25:29 +0200
Subject: BVH simple implementation

---
 include/bvh-node.hpp | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 include/bvh-node.hpp

(limited to 'include/bvh-node.hpp')

diff --git a/include/bvh-node.hpp b/include/bvh-node.hpp
new file mode 100644
index 0000000..78780e7
--- /dev/null
+++ b/include/bvh-node.hpp
@@ -0,0 +1,54 @@
+#ifndef __BVH_NODE_HPP_
+#define __BVH_NODE_HPP_
+
+#include <vector>
+#include <algorithm>
+
+#include "aabb.hpp"
+#include "sphere.hpp"
+
+class bvh_node {
+    public:
+        bvh_node() = default;
+        bvh_node(sphere& sphere, int32_t sphere_id): bounding_box(sphere.bounding_box), sphere_id(sphere_id){}
+        bvh_node(sphere* spheres, size_t start, size_t end, bvh_node* root_node, int32_t id) {
+            left_node_id = id * 2;
+            right_node_id = id * 2 + 1;
+
+            bvh_node left, right;
+
+            // int axis = randi(0, 2);
+            // auto comparator = (axis == 0) ? box_x_comparator : (axis == 1) ? box_y_comparator : box_z_comparator;
+
+            size_t span = end - start;
+
+            if (span == 1) {
+                root_node[left_node_id - 1] = root_node[right_node_id - 1] = { spheres[start], (int32_t)start };
+            } else if (span == 2) {
+                // if (comparator(spheres[start], spheres[start + 1]) {
+                    root_node[left_node_id - 1] = { spheres[start], (int32_t)start };
+                    root_node[right_node_id - 1] = { spheres[start], (int32_t)start + 1 };
+                // } else {
+                //     root_node[left_node_id - 1] = { spheres[start + 1], start + 1 };
+                //     root_node[right_node_id - 1] = { spheres[start], start };
+                // }
+            } else {
+                uint32_t mid = start + span / 2;
+                root_node[left_node_id - 1] = { spheres, start, mid, root_node, left_node_id };
+                root_node[right_node_id - 1] = { spheres, mid, end, root_node, right_node_id };
+            }
+
+            bounding_box = aabb::surrounding_box(root_node[left_node_id - 1].bounding_box, root_node[right_node_id -1].bounding_box);
+        }
+
+        aabb bounding_box;
+
+        // Store sphere id ?
+        int32_t left_node_id    = -1;
+        int32_t right_node_id   = -1;
+
+        int32_t sphere_id       = -1;
+        uint32_t padding;
+};
+
+#endif // !__BVH_NODE_HPP_
-- 
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