From e7da74e9743f449d7d66cfac1f66fa110b2a38cd Mon Sep 17 00:00:00 2001
From: Ben Cragg <bcvery1@gmail.com>
Date: Wed, 10 Apr 2019 11:26:34 +0100
Subject: [PATCH 1/5] Added line collisions example

---
 community/line-collisions/main.go | 99 +++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 community/line-collisions/main.go

diff --git a/community/line-collisions/main.go b/community/line-collisions/main.go
new file mode 100644
index 0000000..46b6fbf
--- /dev/null
+++ b/community/line-collisions/main.go
@@ -0,0 +1,99 @@
+package main
+
+import (
+	"image/color"
+
+	"github.com/faiface/pixel"
+	"github.com/faiface/pixel/imdraw"
+	"github.com/faiface/pixel/pixelgl"
+)
+
+const (
+	modeR = iota
+	modeL
+)
+
+const (
+	clickLineA = iota
+	clickLineB
+)
+
+var (
+	winBounds = pixel.R(0, 0, 1024, 768)
+
+	r = pixel.R(10, 10, 70, 50)
+	l = pixel.L(pixel.V(20, 20), pixel.V(100, 30))
+
+	mode      = modeR
+	clickLine = clickLineA
+)
+
+func run() {
+	cfg := pixelgl.WindowConfig{
+		Title:  "Line collision",
+		Bounds: winBounds,
+		VSync:  true,
+	}
+
+	win, err := pixelgl.NewWindow(cfg)
+	if err != nil {
+		panic(err)
+	}
+
+	imd := imdraw.New(nil)
+
+	for !win.Closed() {
+		if mode == modeR {
+			win.Clear(color.RGBA{R: 23, G: 39, B: 58, A: 125})
+		} else {
+			win.Clear(color.RGBA{R: 21, G: 55, B: 18, A: 125})
+		}
+		imd.Clear()
+
+		if win.JustPressed(pixelgl.KeyR) {
+			mode = modeR
+		}
+		if win.JustPressed(pixelgl.KeyL) {
+			mode = modeL
+			clickLine = clickLineA
+		}
+
+		if win.JustPressed(pixelgl.MouseButtonLeft) {
+			if mode == modeR {
+				rectToMouse := r.Center().To(win.MousePosition())
+				r = r.Moved(rectToMouse)
+			}
+
+			if mode == modeL {
+				if clickLine == clickLineA {
+					l = pixel.L(win.MousePosition(), win.MousePosition().Add(pixel.V(1, 1)))
+					clickLine = clickLineB
+				} else {
+					l = pixel.L(l.A, win.MousePosition())
+					clickLine = clickLineA
+				}
+			}
+		}
+
+		imd.Color = color.Black
+		imd.Push(r.Min, r.Max)
+		imd.Rectangle(3)
+
+		imd.Color = color.RGBA{R: 10, G: 10, B: 250, A: 255}
+		imd.Push(l.A, l.B)
+		imd.Line(3)
+
+		imd.Color = color.RGBA{R: 250, G: 10, B: 10, A: 255}
+		for _, i := range r.IntersectionPoints(l) {
+			imd.Push(i)
+			imd.Circle(4, 0)
+		}
+
+		imd.Draw(win)
+		win.Update()
+	}
+}
+
+func main() {
+	pixelgl.Run(run)
+}

From 65f91d5cea25f7ca536900a1b58e1e7466587f37 Mon Sep 17 00:00:00 2001
From: Ben Cragg <bcvery1@gmail.com>
Date: Wed, 10 Apr 2019 11:34:20 +0100
Subject: [PATCH 2/5] Better structure

---
 community/line-collisions/main.go | 52 +++++++++++++------------------
 1 file changed, 21 insertions(+), 31 deletions(-)

diff --git a/community/line-collisions/main.go b/community/line-collisions/main.go
index 46b6fbf..2cc0ce6 100644
--- a/community/line-collisions/main.go
+++ b/community/line-collisions/main.go
@@ -8,11 +8,7 @@ import (
 	"github.com/faiface/pixel/pixelgl"
 )
 
-const (
-	modeR = iota
-	modeL
-)
-
+// These hold the state of whether we're placing the first or second point of the line.
 const (
 	clickLineA = iota
 	clickLineB
@@ -24,7 +20,6 @@ var (
 	r = pixel.R(10, 10, 70, 50)
 	l = pixel.L(pixel.V(20, 20), pixel.V(100, 30))
 
-	mode      = modeR
 	clickLine = clickLineA
 )
 
@@ -43,47 +38,42 @@ func run() {
 	imd := imdraw.New(nil)
 
 	for !win.Closed() {
-		if mode == modeR {
-			win.Clear(color.RGBA{R: 23, G: 39, B: 58, A: 125})
-		} else {
-			win.Clear(color.RGBA{R: 21, G: 55, B: 18, A: 125})
-		}
+		win.Clear(color.RGBA{R: 23, G: 39, B: 58, A: 125})
 		imd.Clear()
 
-		if win.JustPressed(pixelgl.KeyR) {
-			mode = modeR
-		}
-		if win.JustPressed(pixelgl.KeyL) {
-			mode = modeL
-			clickLine = clickLineA
-		}
-
+		// When mouse left-click, move the rectangle so its' center is at the mouse position
 		if win.JustPressed(pixelgl.MouseButtonLeft) {
-			if mode == modeR {
-				rectToMouse := r.Center().To(win.MousePosition())
-				r = r.Moved(rectToMouse)
-			}
+			rectToMouse := r.Center().To(win.MousePosition())
+			r = r.Moved(rectToMouse)
+		}
 
-			if mode == modeL {
-				if clickLine == clickLineA {
-					l = pixel.L(win.MousePosition(), win.MousePosition().Add(pixel.V(1, 1)))
-					clickLine = clickLineB
-				} else {
-					l = pixel.L(l.A, win.MousePosition())
-					clickLine = clickLineA
-				}
+		// When mouse right-click, set either the beginning or end of the line.
+		if win.JustPressed(pixelgl.MouseButtonRight) {
+			if clickLine == clickLineA {
+				// Set the beginning of the line to the mouse position.
+				// To make it clearer to the user, set the end position 1 pixel (in each direction) away from the first
+				// point.
+				l = pixel.L(win.MousePosition(), win.MousePosition().Add(pixel.V(1, 1)))
+				clickLine = clickLineB
+			} else {
+				// Set the end point of the line.
+				l = pixel.L(l.A, win.MousePosition())
+				clickLine = clickLineA
 			}
 		}
 
+		// Draw the rectangle.
 		imd.Color = color.Black
 		imd.Push(r.Min, r.Max)
 		imd.Rectangle(3)
 
+		// Draw the line.
 		imd.Color = color.RGBA{R: 10, G: 10, B: 250, A: 255}
 		imd.Push(l.A, l.B)
 		imd.Line(3)
 
 		imd.Color = color.RGBA{R: 250, G: 10, B: 10, A: 255}
+		// Draw any intersection points.
 		for _, i := range r.IntersectionPoints(l) {
 			imd.Push(i)
 			imd.Circle(4, 0)

From 6b052dfa37b37a672fec1f35f3ee7f7e3684460f Mon Sep 17 00:00:00 2001
From: Ben Cragg <bcvery1@gmail.com>
Date: Wed, 10 Apr 2019 11:34:31 +0100
Subject: [PATCH 3/5] Intial commit

---
 community/line-collisions/README.md | 10 ++++++++++
 1 file changed, 10 insertions(+)
 create mode 100644 community/line-collisions/README.md

diff --git a/community/line-collisions/README.md b/community/line-collisions/README.md
new file mode 100644
index 0000000..248351c
--- /dev/null
+++ b/community/line-collisions/README.md
@@ -0,0 +1,10 @@
+# Line Collisions
+Line collisions is a basic example of how to detect line collisions with a rectangle.
+
+## Instructions
+You can set the rectangle position using a left-click of the mouse.
+
+You can set the line position with two right-clicks of the mouse; the first right-click will set the beginning of the
+line the second will set the end of the line.
+
+Any intersection points where the rectangle and line intersection will appear as red dots. 

From dc53166dd9f4ebf7639c0057aa0d0211896c25b3 Mon Sep 17 00:00:00 2001
From: Ben Cragg <bcvery1@gmail.com>
Date: Mon, 15 Apr 2019 11:15:14 +0100
Subject: [PATCH 4/5] Initial commit

---
 .../line-collisions/lineCollisionScreenshot.png  | Bin 0 -> 2022 bytes
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 community/line-collisions/lineCollisionScreenshot.png

diff --git a/community/line-collisions/lineCollisionScreenshot.png b/community/line-collisions/lineCollisionScreenshot.png
new file mode 100644
index 0000000000000000000000000000000000000000..d6af3060e33caf0ad9a46fa871068a4da26578b3
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From bb7baf0c7c6796e7c2f7cdf791f4cb6a1c1f3333 Mon Sep 17 00:00:00 2001
From: Ben Cragg <bcvery1@gmail.com>
Date: Mon, 15 Apr 2019 11:17:10 +0100
Subject: [PATCH 5/5] Added screenshot

---
 community/line-collisions/README.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/community/line-collisions/README.md b/community/line-collisions/README.md
index 248351c..399034d 100644
--- a/community/line-collisions/README.md
+++ b/community/line-collisions/README.md
@@ -1,6 +1,8 @@
 # Line Collisions
 Line collisions is a basic example of how to detect line collisions with a rectangle.
 
+![Screenshot](lineCollisionScreenshot.png)
+
 ## Instructions
 You can set the rectangle position using a left-click of the mouse.