commit 77b6918c9fc5887c619c493e4675ad8049bc948d
Author: Dustin Pianalto <dustin@djpianalto.com>
Date:   Sun May 3 21:48:15 2020 -0800

    Initial commit

diff --git a/constants.go b/constants.go
new file mode 100644
index 0000000..d2e7681
--- /dev/null
+++ b/constants.go
@@ -0,0 +1,46 @@
+package main
+
+var nums = [][]byte{
+	{
+		1,1,1,
+		1,0,1,
+		1,0,1,
+		1,0,1,
+		1,1,1,
+	},
+	{
+		1,1,0,
+		0,1,0,
+		0,1,0,
+		0,1,0,
+		1,1,1,
+	},
+	{
+		1,1,1,
+		0,0,1,
+		1,1,1,
+		1,0,0,
+		1,1,1,
+	},
+	{
+		1,1,1,
+		0,0,1,
+		0,1,1,
+		0,0,1,
+		1,1,1,
+	},
+	{
+		1,0,1,
+		1,0,1,
+		1,1,1,
+		0,0,1,
+		0,0,1,
+	},
+	{
+		1,1,1,
+		1,0,0,
+		1,1,1,
+		0,0,1,
+		1,1,1,
+	},
+}
diff --git a/drawing.go b/drawing.go
new file mode 100644
index 0000000..c3f08cb
--- /dev/null
+++ b/drawing.go
@@ -0,0 +1,50 @@
+package main
+
+import "github.com/veandco/go-sdl2/sdl"
+
+func (p *paddle) draw(pixels []byte) {
+	startX := int(p.x - p.w / 2)
+	startY := int(p.y - p.h / 2)
+
+	for y := 0; y < int(p.h); y++ {
+		for x := 0; x < int(p.w); x++ {
+			setPixel(startX + x, startY + y, p.color, pixels)
+		}
+	}
+
+	numPos := pos{
+		x: lerp(p.x, getCenter().x, 0.2),
+		y: 50,
+	}
+	drawNumber(numPos, p.color, 10, p.score, pixels)
+}
+
+func (b *ball) draw(pixels []byte) {
+	for y := -b.radius; y < b.radius; y++ {
+		for x := -b.radius; x < b.radius; x++ {
+			if x * x + y * y < b.radius * b.radius {
+				setPixel(int(b.x+x), int(b.y+y), b.color, pixels)
+			}
+		}
+	}
+}
+
+func drawNumber(pos pos, color sdl.Color, size, num int, pixels []byte) {
+	startX := int(pos.x) - (size * 3) / 2
+	startY := int(pos.y) - (size * 5) / 2
+
+	for i, v := range nums[num] {
+		if v == 1 {
+			for y := startY; y < startY + size; y++ {
+				for x := startX; x < startX + size; x++ {
+					setPixel(x, y, color, pixels)
+				}
+			}
+		}
+		startX += size
+		if (i + 1) % 3 == 0 {
+			startY += size
+			startX -= size * 3
+		}
+	}
+}
\ No newline at end of file
diff --git a/main_loop.go b/main_loop.go
new file mode 100644
index 0000000..2b93788
--- /dev/null
+++ b/main_loop.go
@@ -0,0 +1,65 @@
+package main
+
+import (
+	"github.com/veandco/go-sdl2/sdl"
+	"log"
+	"time"
+)
+
+func gameLoop(pixels []byte, player1, player2 paddle, ball ball, renderer *sdl.Renderer, tex *sdl.Texture, keyState []uint8) {
+	var frameStart time.Time
+	var elapsedTime float32
+
+	for {
+		frameStart = time.Now()
+		for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
+			switch event.(type) {
+			case *sdl.QuitEvent:
+				return
+			}
+		}
+		if err := renderer.Clear(); err != nil {
+			log.Fatal(err)
+		}
+
+		if state == play {
+			if player1.score == 5 || player2.score == 5 {
+				state = start
+			}
+			player1.update(keyState, elapsedTime)
+			player2.aiUpdate(&ball, elapsedTime)
+			ball.update(&player1, &player2, elapsedTime)
+		} else if state == start {
+			if keyState[sdl.SCANCODE_SPACE] != 0 {
+				player1.score = 0
+				player2.score = 0
+				resetBall(&ball)
+				state = play
+			}
+		} else if state == pause {
+			if keyState[sdl.SCANCODE_SPACE] != 0 {
+				resetBall(&ball)
+				state = play
+			}
+		}
+
+		clearScreen(pixels)
+		player1.draw(pixels)
+		player2.draw(pixels)
+		ball.draw(pixels)
+
+		if err := tex.Update(nil, pixels, winWidth*4); err != nil {
+			log.Fatal(err)
+		}
+		if err := renderer.Copy(tex, nil, nil); err != nil {
+			log.Fatal(err)
+		}
+		renderer.Present()
+
+		elapsedTime = float32(time.Since(frameStart).Seconds())
+		if elapsedTime < 0.005 {
+			sdl.Delay(5 - uint32(elapsedTime / 1000))
+			elapsedTime = float32(time.Since(frameStart).Seconds())
+		}
+	}
+}
\ No newline at end of file
diff --git a/pong.go b/pong.go
new file mode 100644
index 0000000..940d470
--- /dev/null
+++ b/pong.go
@@ -0,0 +1,84 @@
+package main
+
+import (
+	"github.com/veandco/go-sdl2/sdl"
+	"log"
+)
+
+var (
+	winWidth = 800
+	winHeight = 600
+	state = start
+)
+
+func main() {
+	err := sdl.Init(sdl.INIT_EVERYTHING)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer sdl.Quit()
+
+	window, err := sdl.CreateWindow(
+		"PONG",
+		sdl.WINDOWPOS_CENTERED,
+		sdl.WINDOWPOS_CENTERED,
+		int32(winWidth),
+		int32(winHeight),
+		sdl.WINDOW_SHOWN)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer window.Destroy()
+
+	renderer, err := sdl.CreateRenderer(window, -1, sdl.RENDERER_ACCELERATED)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer renderer.Destroy()
+
+	tex, err := renderer.CreateTexture(
+		sdl.PIXELFORMAT_ABGR8888,
+		sdl.TEXTUREACCESS_STREAMING,
+		int32(winWidth),
+		int32(winHeight))
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer tex.Destroy()
+
+	player1 := paddle{
+		pos:   pos{50, 300},
+		w:     20,
+		h:     100,
+		speed: 300,
+		score: 0,
+		color: sdl.Color{255, 0, 0, 255},
+	}
+
+	player2 := paddle{
+		pos:   pos{750, 300},
+		w:     20,
+		h:     100,
+		speed: 300,
+		score: 0,
+		color: sdl.Color{0, 255, 0, 255},
+	}
+
+	ball := ball{
+		pos:    pos{400, 300},
+		radius: 20,
+		dx:     400,
+		dy:     400,
+		color:  sdl.Color{0, 0, 255, 255},
+	}
+
+	keyState := sdl.GetKeyboardState()
+	pixels := make([]byte, winHeight*winWidth*4)
+
+	resetBall(&ball)
+
+	gameLoop(pixels, player1, player2, ball, renderer, tex, keyState)
+
+}
+
+
diff --git a/types.go b/types.go
new file mode 100644
index 0000000..5b35c3c
--- /dev/null
+++ b/types.go
@@ -0,0 +1,32 @@
+package main
+
+import "github.com/veandco/go-sdl2/sdl"
+
+type pos struct {
+	x, y float32
+}
+
+type ball struct {
+	pos
+	radius 		float32
+	dx 			float32
+	dy 			float32
+	color 		sdl.Color
+}
+
+type paddle struct {
+	pos
+	w 			float32
+	h 			float32
+	speed		float32
+	score 		int
+	color 		sdl.Color
+}
+
+type gameState int
+const (
+	start gameState = iota
+	play
+	pause
+	end
+)
\ No newline at end of file
diff --git a/updating.go b/updating.go
new file mode 100644
index 0000000..7d0f6ff
--- /dev/null
+++ b/updating.go
@@ -0,0 +1,63 @@
+package main
+
+import (
+	"github.com/veandco/go-sdl2/sdl"
+	"math"
+)
+
+func (p *paddle) update(keyState []uint8, et float32) {
+	if keyState[sdl.SCANCODE_UP] != 0 && p.y - p.h / 2 > 0 {
+		p.y -= p.speed * et
+	}
+	if keyState[sdl.SCANCODE_DOWN] != 0 && p.y + p.h / 2 < float32(winHeight) {
+		p.y += p.speed * et
+	}
+}
+
+func (p *paddle) aiUpdate(ball *ball, et float32) {
+	if ball.y + p.h / 2 < float32(winHeight) && ball.y - p.h / 2 > 0 {
+		p.y = ball.y
+	}
+}
+
+func (b *ball) update(p1, p2 *paddle, et float32) {
+	if detectCollision(b, p1) {
+		if b.y < p1.y+p1.h/2 && b.y > p1.y-p1.h/2 && b.dx < 0{
+			b.dx = -b.dx
+		} else if b.x < p1.x + p1.w / 2 && b.x > p1.x - p1.w / 2 {
+			b.dy = -b.dy
+		} else {
+			testX, testY := closestCorner(b, p1)
+			vx, vy := testX - b.x, testY - b.y
+			vd := float32(math.Sqrt(float64(vx * vx + vy * vy)))
+			ux, uy := vx / vd, vy / vd
+			b.x, b.y = testX - b.radius * ux, testY - b.radius * uy
+
+			q := -(2 * (b.dx * (b.x - testX) + b.dy * (b.y - testY)) / (b.radius * b.radius))
+			b.dx = b.dx + q * (b.x - testX)
+			b.dy = b.dy + q * (b.y - testY)
+		}
+	}
+
+	b.x += b.dx * et
+	b.y += b.dy * et
+	if b.y - b.radius < 1 || b.y + b.radius > float32(winHeight) - 1 {
+		b.dy = -b.dy
+	}
+
+	if b.x - b.radius < 0 {
+		p2.score++
+		b.pos = getCenter()
+		state = pause
+	} else if b.x + b.radius > float32(winWidth) {
+		p1.score++
+		b.pos = getCenter()
+		state = pause
+	}
+
+	if b.x + b.radius >= p2.x - p2.w / 2 && b.dx > 0{
+		if b.y < p2.y+p2.h/2 && b.y > p2.y-p2.h/2 {
+			b.dx = -b.dx
+		}
+	}
+}
\ No newline at end of file
diff --git a/utils.go b/utils.go
new file mode 100644
index 0000000..91b35bf
--- /dev/null
+++ b/utils.go
@@ -0,0 +1,63 @@
+package main
+
+import (
+	"github.com/veandco/go-sdl2/sdl"
+	"math/rand"
+	"time"
+)
+
+func closestCorner(b *ball, p *paddle) (float32, float32) {
+	testX := b.x
+	testY := b.y
+	if b.x < p.x - p.w / 2 {
+		testX = p.x - p.w / 2
+	} else if b.x > p.x + p.w / 2 {
+		testX = p.x + p.w / 2
+	}
+	if b.y < p.y - p.h / 2 {
+		testY = p.y - p.h / 2
+	} else if b.y > p.y + p.h / 2 {
+		testY = p.y + p.h / 2
+	}
+	return testX, testY
+}
+
+func detectCollision(b *ball, p *paddle) bool {
+	testX, testY := closestCorner(b, p)
+
+	sideX := b.x - testX
+	sideY := b.y - testY
+	return b.radius * b.radius >= sideX * sideX + sideY * sideY
+}
+
+func setPixel(x, y int, c sdl.Color, pixels []byte) {
+	index := (y*winWidth + x) * 4
+	if index < len(pixels) - 4 && index >= 0 {
+		pixels[index] = c.R
+		pixels[index+1] = c.G
+		pixels[index+2] = c.B
+		//pixels[index+3] = c.A
+	}
+}
+
+func clearScreen(pixels []byte) {
+	for i := range pixels {
+		pixels[i] = 0
+	}
+}
+
+func getCenter() pos {
+	return pos{float32(winWidth) / 2, float32(winHeight) / 2}
+}
+
+func lerp(a, b, pct float32) float32 {
+	return a + pct * (b - a)
+}
+
+func resetBall(b *ball) {
+	choices := []float32{-400, -200, 200, 400}
+	s := rand.NewSource(time.Now().Unix())
+	r := rand.New(s)
+	b.dy = choices[r.Intn(len(choices))]
+	b.dx = choices[r.Intn(len(choices))]
+}
\ No newline at end of file