From 3df30a2b778f24ab6b3dbd4d8327e96a013dd45d Mon Sep 17 00:00:00 2001
From: Kayne Ruse <ratstail91@yahoo.com.au>
Date: Sat, 27 Dec 2014 04:15:03 +1100
Subject: [PATCH] Fixed formatting issues

---
 collision-logic.md | 79 +++++++++++++++++++++++-----------------------
 1 file changed, 40 insertions(+), 39 deletions(-)

diff --git a/collision-logic.md b/collision-logic.md
index 9569907..62270b1 100644
--- a/collision-logic.md
+++ b/collision-logic.md
@@ -1,4 +1,4 @@
-Abstract:
+## Abstract
 
 The goal of this pseudocode is to create a collision system that brings several
 colliding bodies to a near-contact state (no space between the bodies, but not
@@ -6,7 +6,7 @@ overlapping), while preserving the motion of said bodies. For simplicity, I've
 decided to use a square box (BoundingBox, or BBox for short) for the collidable
 bodies.
 
-Example:
+## Goal
 
 My current game has a tiled-map, where the tiles are arranged on a 2D grid. The
 tiles each have a flag indicating if they are solid (i.e. collidable) or not. I
@@ -22,19 +22,21 @@ Obviously, there are many in depth issues that I will need to  take into
 account when writing this logic, that have been glossed over or omitted in this
 article.
 
--------------------------
+## Design
+
+### Basic Example
 
 ```
-	velocity = motion + speed
-	if (collision(position + velocity)) then
-		if (collision(position + {velocity.x, 0})) then
-			velocity.x = 0
-		end
-		if (collision(position + {0, velocity.y})) then
-			velocity.y = 0
-		end
+velocity = motion + speed
+if (collision(position + velocity)) then
+	if (collision(position + {velocity.x, 0})) then
+		velocity.x = 0
 	end
-	position = position + velocity
+	if (collision(position + {0, velocity.y})) then
+		velocity.y = 0
+	end
+end
+position = position + velocity
 ```
 
 This code is a basic outline for a collision system that preserves the object's
@@ -42,15 +44,15 @@ motion, but it still leaves several pixels of space between the bounding boxes.
 Notably, it also treats "collision" as an abstract concept, rather than as an
 event that could happen multiple times per frame.
 
--------------------------
+### Better Example
 
 ```
-	velocity = motion + speed
-	if (collisionSimple(BOXSET, position + velocity)) then
-		velocity.x = collisionX(BOXSET, velocity.x)
-		velocity.y = collisionY(BOXSET, velocity.y)
-	end
-	position = position + velocity
+velocity = motion + speed
+if (collisionSimple(BOXSET, position + velocity)) then
+	velocity.x = collisionX(BOXSET, velocity.x)
+	velocity.y = collisionY(BOXSET, velocity.y)
+end
+position = position + velocity
 ```
 
 Here, collisions are still abstract, but "BOXSET" is defined externally
@@ -62,17 +64,17 @@ If there are any collisions between the player object and the given box set,
 then collisionX() and collisionY() are called to calculate the new distance
 that the character will move.
 
--------------------------
+### Simple Collision Check
 
 ```
-	bool collisionSimple(BOXSET, newPos):
-		for_each box in BOXSET do
-			if (box.overlap(PLAYER.box + newPos)) then
-				return true
-			end
+bool collisionSimple(BOXSET, newPos):
+	for_each box in BOXSET do
+		if (box.overlap(PLAYER.box + newPos)) then
+			return true
 		end
-		return false
 	end
+	return false
+end
 ```
 
 collisionSimple() first runs through the BOXSET, checking if any of the given
@@ -90,24 +92,23 @@ would not have been checked against the removed elements.
 
 Just something to note.
 
--------------------------
+### Velocity Correction
 
 ```
-	var collisionX(BOXSET, velocityX):
-		var ret = velocityX
+var collisionX(BOXSET, velocityX):
+	var ret = velocityX
 
-		for_each box in BOXSET do
-			if (box.overlap(PLAYER.box + PLAYER.position + {velocityX,0})) then
-				if (velocityX > 0) then
-					ret = min(ret, box.west - PLAYER.position.x)
-				else
-					ret = max(ret, box.east - PLAYER.position.x)
-				end
+	for_each box in BOXSET do
+		if (box.overlap(PLAYER.box + PLAYER.position + {velocityX, 0})) then
+			if (velocityX > 0) then
+				ret = min(ret, box.west - PLAYER.position.x)
+			else
+				ret = max(ret, box.east - PLAYER.position.x)
 			end
 		end
-
-		return ret
 	end
+	return ret
+end
 ```
 
 Two things: 1. collisionX() and collisionY() should be identical except for the
@@ -122,4 +123,4 @@ right (or up or down).
 An unfortunate bug I can already see is that this logic doesn't check corners;
 it might be possible to get stuck on a corner of a wall, but if this becomes an
 issue in my implementation I will update this article with that information,
-and you can promptly ignore it.
\ No newline at end of file
+and you can promptly ignore it.