Poisson-disk sampling, new org-roam content

.dir-locals.el

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+((nil . ((org-roam-directory . "/home/joe/Development/gaming-pads/content")
+         (org-roam-db-location . "/home/joe/Development/gaming-pads/org-roam.db"))))

.gitignore

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+/org-roam.db

content/20240813113042-gaming_pads.org

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+:PROPERTIES:
+:ID:       6793b3f2-32d1-46dc-b104-e2d446c9a66e
+:END:
+#+title: Gaming Pads
+
+It's how the acronym GAIMENPAAADS sounds, but that's a crappy acronym. Here is
+a hierarchical overview of the topics
+
+* [[id:f2b91852-e931-4026-a9a4-cc4188eecbb0][Math for Game Programmers]]
+* [[id:bdba2433-f92c-48cc-a401-a9d8f777df8f][Graphics]]
+* [[id:f548e57e-3d8e-4fe4-a5eb-5ebd338b1825][Artificial Intelligence]]
+

content/20240813113113-quadtree.org

@@ -1,24 +1,26 @@
-#+TEST: [[file:SpatialPartitioning.org][Spacial Partitioning]]
+:PROPERTIES:
+:ID:       4f3f07d3-a05e-40ad-94f9-cb35dad69ef1
+:END:
+#+title: Quadtree
 
-* Quadtree
 Recursively subdivide an AABB into 4 regions, hence Quad. They are usually
 denoted as North West, North East, South West, and South East (NW, NE, SW, SE).
 Several things can be created with this;
-** Linked Implementation                                     :datastructure:
+* Linked Implementation                                       :datastructure:
-** Array Implementation                                      :datastructure:
+* Array Implementation                                        :datastructure:
-** Insertion                                                     :algorithm:
+* Insertion                                                       :algorithm:
-** Query                                                         :algorithm:
+* Query                                                           :algorithm:
-** Find Nearest Neighbor                                         :algorithm:
+* Find Nearest Neighbor                                           :algorithm:
-** Morton codes
+* Morton codes
 This is a technique that allows us to convert coordinates into an array index,
 allowing us to pack them contiguously in memory
 http://johnsietsma.com/2019/12/05/morton-order-introduction/
-** Resources
+* Resources
 [[http://ericandrewlewis.github.io/how-a-quadtree-works/][Visualize a Quadtree]]
 [[http://donar.umiacs.umd.edu/quadtree/][Academic Interactive Demo]]
 [[https://codepen.io/_bm/pen/ExPBMrW][Codepen (Js example)]]
 [[https://gist.github.com/patricksurry/6478178][D3.js Example]]
-** Notes
+* Notes
 #+begin_src js
 // exclude node if point is farther away than best distance in either axis
 if (x < x1 - best.d || x > x2 + best.d || y < y1 - best.d || y > y2 + best.d) {

content/20240813113150-math_for_game_programmers.org

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+:PROPERTIES:
+:ID:       f2b91852-e931-4026-a9a4-cc4188eecbb0
+:END:
+#+title: Math for Game Programmers
+
+* [[id:42583e83-bc7d-4428-8228-c1c04f91806f][Geometry]]

content/20240813113239-geometry.org

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+:PROPERTIES:
+:ID:       42583e83-bc7d-4428-8228-c1c04f91806f
+:END:
+#+title: Geometry
+
+* [[id:62ab48ad-9a26-4fb7-a41b-dd341165cdec][Spatial Partitioning]]
+* [[id:729ccfcc-8015-4438-b0c6-3097f311e505][Triangulation]]

content/20240813113258-spatial_partitioning.org

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+:PROPERTIES:
+:ID:       62ab48ad-9a26-4fb7-a41b-dd341165cdec
+:END:
+#+title: Spatial Partitioning
+
+* [[id:4f3f07d3-a05e-40ad-94f9-cb35dad69ef1][Quadtree]]
+* [[id:9d793370-5e77-4ae6-bf7a-6f3e6377a79c][KD-Tree]]
+* [[id:137d9b32-c670-4b30-89ff-4b2da47006db][Poisson-disk sampling]]

content/20240813113355-kd_tree.org

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+:PROPERTIES:
+:ID:       9d793370-5e77-4ae6-bf7a-6f3e6377a79c
+:END:
+#+title: KD-Tree
+
+Info about a KD-Tree
+* Linked Implementation                                       :datastructure:
+* Array Implementation                                        :datastructure:
+* Insertion                                                       :algorithm:
+* Find Nearest Neighbor                                           :algorithm:

content/20240813113536-triangulation.org

@@ -1,12 +1,14 @@
-#+TEST: [[file:Geometry][Geometry]]
+:PROPERTIES:
+:ID:       729ccfcc-8015-4438-b0c6-3097f311e505
+:END:
+#+title: Triangulation
 
-* Triangulation
 Generate triangles from points
-** Convex Hull Jarvis March (Gift wrapping)                      :algorithm:
+* Convex Hull Jarvis March (Gift wrapping)                        :algorithm:
 [[file:~/Development/gaming-pads/convexhull-jarvismarch.py][Python Code]]
-** Resources
+* Resources
 https://www.youtube.com/watch?v=Vu84lmMzP2o
 https://www.habrador.com/tutorials/math/8-convex-hull/
 https://www.youtube.com/watch?v=B2AJoQSZf4M
 https://www.geometrictools.com/Documentation/TriangulationByEarClipping.pdf
-** Notes
+* Notes

content/20240813113634-procedural_generation.org

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+:PROPERTIES:
+:ID:       98eb9900-fead-478c-8db4-29310ced82fb
+:END:
+#+title: Procedural Generation
+
+These are used to divide a space in either a 2D or 3D world into smaller spaces
+that can make operations like searching and filtering more efficient.
+
+* [[id:137d9b32-c670-4b30-89ff-4b2da47006db][Poisson-disk sampling]]

content/20240813113652-poisson_disk_sampling.org

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+:PROPERTIES:
+:ID:       137d9b32-c670-4b30-89ff-4b2da47006db
+:END:
+#+title: Poisson-disk sampling
+

content/20240813114155-graphics.org

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+:PROPERTIES:
+:ID:       bdba2433-f92c-48cc-a401-a9d8f777df8f
+:END:
+#+title: Graphics
+
+* [[id:98eb9900-fead-478c-8db4-29310ced82fb][Procedural Generation]]
+* [[id:729ccfcc-8015-4438-b0c6-3097f311e505][Triangulation]]

content/20240813114306-artificial_intelligence.org

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+:PROPERTIES:
+:ID:       f548e57e-3d8e-4fe4-a5eb-5ebd338b1825
+:END:
+#+title: Artificial Intelligence
+
+* [[id:98eb9900-fead-478c-8db4-29310ced82fb][Procedural Generation]]

content/GamingPads.org

@@ -1,19 +0,0 @@
-* Gaming Pads
-It's how the acronym GAIMENPAAADS sounds, but that's a crappy acronym. Here is
-a hierarchical overview of the topics
-** Math
-*** Trigonometry
-*** Data Structures
-*** Algorithms
-*** Linear Algebra
-*** Geometry
-**** Bezier Curves
-**** Triangulation
-**** Spatial Partitioning
-#+transclude: [[file:Quadtree.org]] :level 5 :exclude-elements "keyword"
-#+transclude: [[file:KD-Tree.org]] :level 5 :exclude-elements "keyword"
-** Engineering
-*** Machine Architecture
-*** Networking
-*** Compilers
-*** Operating Systems

content/Geometry.org

@@ -1,6 +0,0 @@
-#+TODO: ⬜ 🟩️ | ✅
-
-* Geometry
-** [[file:SpatialPartitioning.org][Spatial Partitioning]]
-** [[file:Triangulation.org][Triangulation]]
-** Bezier Curves

content/KD-Tree.org

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-#+NAVIGATION_UP: [[file:SpatialPartitioning.org][Spacial Partitioning]]
-
-* KD-Tree
-Info about a KD-Tree
-** Linked Implementation                                     :datastructure:
-** Array Implementation                                      :datastructure:
-** Insertion                                                     :algorithm:
-** Find Nearest Neighbor                                         :algorithm:

content/Math.org

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-* Math

content/SpatialPartitioning.org

@@ -1,9 +0,0 @@
-# -*- mode: Org; eval: (org-transclusion-mode 0) -*- #
-#+NAVIGATION-UP: [[file:Geometry.org][Geometry]]
-
-* Spatial Partitioning
-These are used to divide a space in either a 2D or 3D world into smaller spaces
-that can make operations like searching and filtering more efficient.
-
-#+transclude: [[file:Quadtree.org]] :level 2
-#+transclude: [[file:KD-Tree.org]] :level 2

poisson-disk-sampling.py

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+import pyray as RL
+from pyray import (Rectangle as Rect, Vector2 as Vec2, Vector3 as Vec3, Camera3D, BoundingBox, Color)
+import math
+import pdb
+import random
+from typing import Optional, Tuple, List
+from dataclasses import dataclass, field
+
+def dump(struct):
+    s = f"{RL.ffi.typeof(struct)}: (".replace('<ctype ', '').replace('>', '')
+    for field in dir(struct):
+        data = struct.__getattribute__(field)
+        if str(data).startswith("<cdata"):
+            data = dump(data)
+        s += f"{field}:{data} "
+    s += ")"
+    return s
+
+screen_width = 1024
+screen_height = 512
+r = 10
+k = 30
+cell_size = r / math.sqrt(2)
+cols = int(screen_width // cell_size)
+rows = int(screen_height // cell_size)
+
+@dataclass
+class World:
+    grid: List[Vec2]
+    points: List[Vec2]
+    active: List[Vec2]
+    pidx = 0
+    start = False
+    point_count = 0
+    frame_count: int = 0
+    debug_draw: bool = False
+
+def init() -> World:
+    grid = [None] * rows * cols
+    points = [Vec2(screen_width // 2, screen_height // 2)]
+    # points = []
+    active = points.copy()
+    for p in points:
+        idx = int(p.y // cell_size * cols + p.x // cell_size)
+        grid[idx] = p
+    return World(grid, points, active)
+
+def player_input(w: World):
+    if RL.is_mouse_button_pressed(0):
+        p = RL.get_mouse_position()
+        w.points.append(p)
+        idx = int(p.y // cell_size * cols + p.x // cell_size)
+        if idx < len(w.grid):
+            w.grid[idx] = 1
+    if RL.is_key_pressed(RL.KEY_SPACE):
+        w.debug_draw = not w.debug_draw
+    if RL.is_key_pressed(RL.KEY_ENTER):
+        w.start = True
+
+def update(w: World):
+    # if w.frame_count % 1 != 0:
+    #     return
+    if not w.start or not w.points or not w.active:
+        return
+    for _ in range(25):
+        if not w.active:
+            break
+        point = w.active[-1]
+        w.pidx = (w.pidx + 1) % len(w.points)
+        found = False
+        for i in range(k):
+            r_angle = random.random() * math.pi * 2
+            r_dist = random.uniform(r, 2 * r)
+            new_point = Vec2(point.x + math.cos(r_angle) * r_dist, point.y + math.sin(r_angle) * r_dist)
+            new_point_idx = int(new_point.y // cell_size * cols + new_point.x // cell_size)
+            if (new_point_idx >= len(w.grid) or w.grid[new_point_idx] is not None
+                or new_point.x < 0 or new_point.x > cell_size * cols
+                or new_point.y < 0 or new_point.y > cell_size * rows):
+                continue
+            new_point_row = new_point_idx // cols
+            new_point_col = new_point_idx % cols
+            collides = False
+            for i in range(-2, 3):
+                for j in range(-2, 3):
+                    if collides:
+                        break
+                    row = new_point_row + i
+                    col = new_point_col + j
+                    if row < 0 or row >= rows or col < 0 or col >= cols:
+                        continue
+                    idx = row * cols + col
+                    if w.grid[idx] is not None:
+                        # Check distance
+                        dist_sqr = RL.vector_2distance_sqr(w.grid[idx], new_point)
+                        if dist_sqr < r * r:
+                            collides = True
+
+            if collides:
+                continue
+            w.grid[new_point_idx] = new_point
+            w.points.append(new_point)
+            w.point_count += 1
+            w.active.append(new_point)
+            found = True
+            break
+        if not found:
+            w.active.pop()
+
+
+def draw_2d(w: World):
+    # for p in w.points:
+    #     prx = p.x // cell_size * cell_size
+    #     pry = p.y // cell_size * cell_size
+    #     rect = Rect(prx, pry, cell_size, cell_size)
+    #     RL.draw_rectangle_rec(rect, Color(230, 230, 230, 255))
+    if w.debug_draw:
+        for i,c in enumerate(w.grid):
+            if c != -1:
+                cell_x = (i % cols) * cell_size
+                cell_y = (i // cols) * cell_size
+                rect = Rect(cell_x, cell_y, cell_size, cell_size)
+                RL.draw_rectangle_rec(rect, Color(230, 230, 230, 255))
+
+        for i in range(int((screen_width // cell_size) + 1) - 1):
+            for j in range(int((screen_height // cell_size) + 1) - 1):
+                rect = Rect(cell_size * i, cell_size * j, cell_size, cell_size)
+                RL.draw_rectangle_lines_ex(rect, 2, RL.GREEN)
+    for i,p in enumerate(w.points):
+        red = min(200, i % 255)
+        green = min(200, i * 2 % 255)
+        blue = min(200, i * 3 % 255)
+        RL.draw_circle_v(p, 2, Color(red, green, blue, 255))
+
+
+RL.init_window(screen_width, screen_height, "Poisson-disk Sampling");
+RL.set_target_fps(60)
+
+w = init()
+while not RL.window_should_close():
+    player_input(w)
+    update(w)
+
+    # Drawing
+    RL.begin_drawing()
+    RL.clear_background(RL.WHITE)
+
+    draw_2d(w)
+
+    RL.end_drawing()
+    w.frame_count += 1
+