main.go

package main

import (
	"cart/game"
	"cart/palettes"
	"cart/w4"
	"strconv"
)

const (
	tracingEnabled = false
	soundEnabled   = true
	musicEnabled   = true
)

var ui *UI

//go:export start
func start() {
	seed := uint32(478194671)

	ui = NewUI(game.New(seed), w4.GAMEPAD1, palettes.IceCreamGB)
}

//go:export update
func update() {
	ui.frame++
	ui.show()
	ui.sound()
	ui.music()
	ui.input()
}

type UI struct {
	game.Board

	frame uint
	old   uint8
	pad   *uint8
	pal   [4]uint32
}

func NewUI(board game.Board, pad *uint8, pal [4]uint32) *UI {
	return &UI{
		Board: board,
		pad:   pad,
		pal:   pal,
	}
}

// ┌───────────────────────────────────────────────────────────────────────────┐
// │                                                                           │
// │ Rendering                                                                 │
// │                                                                           │
// └───────────────────────────────────────────────────────────────────────────┘

func (ui *UI) show() {
	setPalette(ui.pal)

	dotbg(0, 0, 160, 27, 3, 0x3, 0x4)

	// Pts border
	color(0x32)
	rect(0, 6, 84, 12)

	// Bottom background
	color(0x4)
	rect(0, 157, 160, 3)

	color(0x24)
	text("Total"+leftpad(itoa(ui.Total()), " ", 5), 2, 8)

	color(0x41)
	text(" -+-+-+- ", 88, 0)
	color(0x42)
	text(" 2|0|4|8 ", 88, 8)
	color(0x43)
	text(" -+-+-+- ", 88, 16)

	for r := 0; r < 4; r++ {
		for c := 0; c < 4; c++ {
			if v := ui.Get(r, c); v > 0 {
				showTile(r, c, v)
			}
		}
	}

	color(0x3)

	// Horizontal lines on the board
	line(0, 28, 160, 28)
	line(0, 60, 160, 60)
	line(0, 92, 160, 92)
	line(0, 124, 160, 124)
	line(0, 156, 160, 156)

	color(0x2)
	line(0, 27, 160, 27)
	line(0, 59, 160, 59)
	line(0, 91, 160, 91)
	line(0, 123, 160, 123)
	line(0, 155, 160, 155)

	// Vertical lines on the board
	line(39, 28, 39, 155)
	line(80, 28, 80, 155)
	line(120, 28, 120, 155)

	if ui.frame < 124 {
		var (
			s  string
			fg uint16
			bg uint16
			a  int
			h  uint
		)

		switch {
		case ui.frame < 6 || ui.frame > 118:
			s = "L   E   T   S      G   O."
			fg, bg, a, h = 0x2, 0x21, 120, 10
		case ui.frame < 12 || ui.frame > 112:
			s = "L  E  T  S    G  O!"
			fg, bg, a, h = 0x3, 0x21, 115, 15
		case ui.frame < 18 || ui.frame > 106:
			s = "L E T S  G O!"
			fg, bg, a, h = 0x3, 0x32, 110, 20
		case ui.frame < 24 || ui.frame > 100:
			s = "LETS GO!"
			fg, bg, a, h = 0x4, 0x23, 105, 25
		default:
			s = "LETS GO!"
			fg, bg, a, h = 0x1, 0x34, 100, 30
		}

		color(bg)
		rect(8, a, 144, h)
		color(fg)
		text(s, 80-(len(s)*8/2), a+(int(h)/2)-5)
	}
}

func showTile(col, row, val int) {
	x, y := 2+(col*41), 32+row*32
	w, h := uint(35), uint(27)
	s := 8

	tileShadow(val)
	rect(x-1, y-1, w, h)

	set(x, y, 0x43)

	color(0x1)
	line(x-1, y, x, y-1)
	line(x+int(w-3), y-1, x+int(w-2), y)

	set(x-1, y-1, 0x1)               // Top-Left
	set(x+int(w-2), y-1, 0x1)        // Top-Right
	set(x-1, y+int(h)-2, 0x1)        // Bottom-Left
	set(x+int(w-2), y+int(h)-2, 0x1) // Bottom-Right

	tileColor(val)
	text("    ", x, y)
	text(leftpad(itoa(val), " ", 4), x, y+s)
	text("    ", x, y+s*2)
}

func tileColor(val int) {
	switch val {
	case 2:
		color(0x21)
	case 4:
		color(0x32)
	case 8:
		color(0x24)
	case 16:
		color(0x32)
	case 32:
		color(0x34)
	case 64:
		color(0x32)
	case 128:
		color(0x40)
	case 256:
		color(0x42)
	case 512:
		color(0x43)
	case 1024:
		color(0x34)
	case 2048:
		color(0x24)
	}
}

func tileShadow(val int) {
	switch val {
	case 2:
		color(0x43)
	case 4:
		color(0x43)
	case 8:
		color(0x42)
	case 16:
		color(0x32)
	case 32:
		color(0x34)
	case 64:
		color(0x32)
	case 128:
		color(0x43)
	case 256:
		color(0x42)
	case 512:
		color(0x24)
	case 1024:
		color(0x44)
	case 2048:
		color(0x44)
	}
}

// ┌───────────────────────────────────────────────────────────────────────────┐
// │                                                                           │
// │ Palette                                                                   │
// │                                                                           │
// └───────────────────────────────────────────────────────────────────────────┘

func setPalette(p [4]uint32) {
	w4.PALETTE[0] = p[0]
	w4.PALETTE[1] = p[1]
	w4.PALETTE[2] = p[2]
	w4.PALETTE[3] = p[3]
}

func (ui *UI) randomPalette() {
	ui.pal = palettes.All[int(ui.frame)%len(palettes.All)]
}

// ┌───────────────────────────────────────────────────────────────────────────┐
// │                                                                           │
// │ Music and Sound                                                           │
// │                                                                           │
// └───────────────────────────────────────────────────────────────────────────┘

func (ui *UI) music() {
	if !musicEnabled {
		return
	}

	switch {
	case ui.beat(24):
		play(Sound{40, 0, 0, 8, 0, 0, 0, 2, 0})
	case ui.beat(32):
		play(Sound{80, 0, 0, 8, 0, 0, 0, 2, 0})
	case ui.beat(96):
		play(Sound{160, 0, 0, 8, 0, 0, 0, 2, 0})
	}
}

func (ui *UI) beat(n uint) bool {
	return ui.frame%n == 0
}

func (ui *UI) sound() {
	if !soundEnabled {
		return
	}

	switch {
	case ui.btn1():
	case ui.btn2():
	case ui.up():
		play(sfxUp)
	case ui.down():
		play(sfxDown)
	case ui.right():
		play(sfxRight)
	case ui.left():
		play(sfxLeft)
	}
}

// ┌───────────────────────────────────────────────────────────────────────────┐
// │                                                                           │
// │ Input                                                                     │
// │                                                                           │
// └───────────────────────────────────────────────────────────────────────────┘

func (ui *UI) input() {
	switch {
	case ui.btn1():
		log("BTN1")
		ui.Input(game.KeyBTN1)
		ui.randomPalette()
	case ui.btn2():
		log("BTN2")
		ui.Input(game.KeyBTN2)
	case ui.up():
		log("🡱")
		ui.Input(game.KeyUp)
	case ui.down():
		log("🡳")
		ui.Input(game.KeyDown)
	case ui.right():
		log("🡲")
		ui.Input(game.KeyRight)
	case ui.left():
		log("🡰")
		ui.Input(game.KeyLeft)
	}

	ui.old = *ui.pad
}

func (ui *UI) up() bool {
	return *ui.pad&w4.BUTTON_UP != 0 && ui.old&w4.BUTTON_UP == 0
}

func (ui *UI) down() bool {
	return *ui.pad&w4.BUTTON_DOWN != 0 && ui.old&w4.BUTTON_DOWN == 0
}

func (ui *UI) right() bool {
	return *ui.pad&w4.BUTTON_RIGHT != 0 && ui.old&w4.BUTTON_RIGHT == 0
}

func (ui *UI) left() bool {
	return *ui.pad&w4.BUTTON_LEFT != 0 && ui.old&w4.BUTTON_LEFT == 0
}

func (ui *UI) btn1() bool {
	return *ui.pad&w4.BUTTON_1 != 0 && ui.old&w4.BUTTON_1 == 0
}

func (ui *UI) btn2() bool {
	return *ui.pad&w4.BUTTON_2 != 0 && ui.old&w4.BUTTON_2 == 0
}

func dotbg(x1, y1, w, h, s int, dc, bg uint16) {
	for x := x1; x < w; x++ {
		for y := y1; y < h; y++ {
			if x%s == 0 && y%s == 0 {
				set(x, y, dc)
			} else {
				set(x, y, bg)
			}
		}
	}
}

func (ui *UI) log(s string) {
	log(leftpad(utoa(ui.frame), " ", 5) + " - " + s)
}

func log(s string) {
	if !tracingEnabled {
		return
	}

	w4.Trace(s)
}

func set(x, y int, c uint16) {
	color(c)
	line(x, y, x, y)
}

func color(c uint16) {
	*w4.DRAW_COLORS = c
}

func line(x1, y1, x2, y2 int) {
	w4.Line(x1, y1, x2, y2)
}

func rect(x, y int, w, h uint) {
	w4.Rect(x, y, w, h)
}

func text(s string, x, y int) {
	w4.Text(s, x, y)
}

// ┌───────────────────────────────────────────────────────────────────────────┐
// │                                                                           │
// │ Sound Effects                                                             │
// │                                                                           │
// └───────────────────────────────────────────────────────────────────────────┘

type Sound struct {
	freq1   uint
	freq2   uint
	attack  uint
	decay   uint
	sustain uint
	release uint
	volume  uint
	channel uint
	mode    uint
}

func play(s Sound) {
	var (
		freq     = s.freq1 | s.freq2<<16
		duration = s.attack<<24 | s.decay<<16 | s.sustain | s.release<<8
		flags    = s.channel | s.mode<<2
	)

	w4.Tone(freq, duration, s.volume, flags)
}

var (
	//sfxUp    = Sound{40, 0, 0, 8, 0, 0, 0, 2, 0}
	//sfxDown  = Sound{80, 0, 0, 8, 0, 0, 0, 2, 0}
	//sfxRight = Sound{120, 0, 0, 8, 0, 0, 0, 2, 0}
	//sfxLeft  = Sound{160, 0, 0, 8, 0, 0, 0, 2, 0}

	sfxUp    = Sound{140, 20, 4, 10, 0, 0, 0, 0, 2}
	sfxDown  = Sound{140, 20, 4, 10, 0, 0, 0, 0, 2}
	sfxRight = Sound{140, 20, 4, 10, 0, 0, 0, 0, 2}
	sfxLeft  = Sound{140, 20, 4, 10, 0, 0, 0, 0, 2}
)

// ┌───────────────────────────────────────────────────────────────────────────┐
// │                                                                           │
// │ String functions                                                          │
// │                                                                           │
// └───────────────────────────────────────────────────────────────────────────┘

func leftpad(s, c string, w int) string {
	n := w - len(s)

	if n <= 0 {
		return s
	}

	var p string

	for i := 0; i < n; i++ {
		p += c
	}

	return p + s
}

func itoa(i int) string {
	return strconv.Itoa(i)
}

func utoa(u uint) string {
	return strconv.FormatUint(uint64(u), 10)
}