From 21c0e9c6091fc0876ea01d66c9deb8faa49a3236 Mon Sep 17 00:00:00 2001
From: karl <karl.bittner@hexaquo.at>
Date: Tue, 12 Jan 2021 18:44:53 +0100
Subject: [PATCH] Add KDTree::get_lines for visualizing the tree

---
 kdtree.h | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 73 insertions(+), 7 deletions(-)

diff --git a/kdtree.h b/kdtree.h
index 3ba49a5..2765e01 100644
--- a/kdtree.h
+++ b/kdtree.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "geometry.h"
 #include <algorithm>
 #include <glm/glm.hpp>
@@ -11,7 +13,7 @@ class KDTree {
 
     ~KDTree() = default; // TODO: Delete all allocated Nodes
 
-    Triangle *intersect_ray(Ray ray) { return intersect_ray_recurse(ray, root, 1000.0); }
+    Triangle *intersect_ray(Ray ray) { return intersect_ray_recurse(ray, root, 1000.0, 0); }
 
     std::string to_string() {
         std::string str = "";
@@ -19,6 +21,16 @@ class KDTree {
         return str;
     }
 
+    std::vector<Vector> get_lines() {
+        std::vector<Vector> lines;
+        float mins[3] = {-1000, -1000, -1000};
+        float maxs[3] = {1000, 1000, 1000};
+
+        get_lines_recursive(lines, root, mins, maxs);
+
+        return lines;
+    }
+
   private:
     Node *root;
 
@@ -75,7 +87,7 @@ class KDTree {
                         build(right_of_median, depth + 1));
     }
 
-    Triangle *intersect_ray_recurse(Ray ray, Node *node, float max_distance) {
+    Triangle *intersect_ray_recurse(Ray ray, Node *node, float max_distance, int depth) {
         // Exit condition: There was no collision
         if (node == nullptr) { return nullptr; }
 
@@ -84,9 +96,6 @@ class KDTree {
             ray.origin[node->axis] > node->point->pos[node->axis] ? node->right : node->left;
         Node *far = near == node->right ? node->left : node->right;
 
-        std::cout << "Checking " << node->point->pos[0] << ", " << node->point->pos[1] << ", "
-                  << node->point->pos[2] << std::endl;
-
         // Check for collisions in this order (stopping if an intersection is found):
         // 1. In the nearer section
         // 2. With the point in this current node
@@ -98,7 +107,7 @@ class KDTree {
                       ? (node->point->pos[node->axis] - ray.origin[node->axis]) /
                             ray.direction[node->axis]
                       : max_distance;
-        Triangle *near_result = intersect_ray_recurse(ray, near, t);
+        Triangle *near_result = intersect_ray_recurse(ray, near, t, depth + 1);
 
         // If the nearer segment had a collision, we're done! We're only interested in the closest
         // collision.
@@ -117,7 +126,7 @@ class KDTree {
             // For this, calculate a new ray origin and continue towards that direction, but with
             // the new origin (we can leave behind what we already checked)
             return intersect_ray_recurse(Ray(ray.origin + ray.direction * t, ray.direction), far,
-                                         max_distance - t);
+                                         max_distance - t, depth + 1);
         }
 
         // If nothing worked, return a nullptr
@@ -136,4 +145,61 @@ class KDTree {
         to_string_recurse(str, node->left, depth + 1);
         to_string_recurse(str, node->right, depth + 1);
     }
+
+    void get_lines_recursive(std::vector<Vector> &lines, Node *node, float mins[3], float maxs[3]) {
+        if (node == nullptr) return;
+
+        int axis = node->axis;
+
+        // Add lines for this node
+        // We add a whole bounding box, so we need 8 points -> 12 lines
+        lines.emplace_back(Vector(mins[0], mins[1], mins[2]));
+        lines.emplace_back(Vector(maxs[0], mins[1], mins[2]));
+
+        lines.emplace_back(Vector(maxs[0], mins[1], mins[2]));
+        lines.emplace_back(Vector(maxs[0], maxs[1], mins[2]));
+
+        lines.emplace_back(Vector(maxs[0], maxs[1], mins[2]));
+        lines.emplace_back(Vector(mins[0], maxs[1], mins[2]));
+
+        lines.emplace_back(Vector(mins[0], maxs[1], mins[2]));
+        lines.emplace_back(Vector(mins[0], mins[1], mins[2]));
+
+        lines.emplace_back(Vector(mins[0], mins[1], maxs[2]));
+        lines.emplace_back(Vector(maxs[0], mins[1], maxs[2]));
+
+        lines.emplace_back(Vector(maxs[0], mins[1], maxs[2]));
+        lines.emplace_back(Vector(maxs[0], maxs[1], maxs[2]));
+
+        lines.emplace_back(Vector(maxs[0], maxs[1], maxs[2]));
+        lines.emplace_back(Vector(mins[0], maxs[1], maxs[2]));
+
+        lines.emplace_back(Vector(mins[0], maxs[1], maxs[2]));
+        lines.emplace_back(Vector(mins[0], mins[1], maxs[2]));
+
+        lines.emplace_back(Vector(mins[0], mins[1], mins[2]));
+        lines.emplace_back(Vector(mins[0], mins[1], maxs[2]));
+
+        lines.emplace_back(Vector(maxs[0], mins[1], mins[2]));
+        lines.emplace_back(Vector(maxs[0], mins[1], maxs[2]));
+
+        lines.emplace_back(Vector(mins[0], maxs[1], mins[2]));
+        lines.emplace_back(Vector(mins[0], maxs[1], maxs[2]));
+
+        lines.emplace_back(Vector(maxs[0], maxs[1], mins[2]));
+        lines.emplace_back(Vector(maxs[0], maxs[1], maxs[2]));
+
+        // TODO: We don't actually have to add all as some are always going to overlap with the
+        // previous lines...
+
+        // Recurse on the left
+        float new_maxs[3] = {maxs[0], maxs[1], maxs[2]}; // Copy initially
+        new_maxs[axis] = node->point->pos[axis];
+        get_lines_recursive(lines, node->left, mins, new_maxs);
+
+        // Recurse on the right
+        float new_mins[3] = {mins[0], mins[1], mins[2]}; // Copy initially
+        new_mins[axis] = node->point->pos[axis];
+        get_lines_recursive(lines, node->right, new_mins, maxs);
+    }
 };