examples: add snek (a snake game) (#8257)

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shadowninja55 2021-01-21 11:34:42 -05:00 committed by GitHub
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import gg
import gx
import sokol.sapp
import time
import rand
import os
// constants
const (
top_height = 100
canvas_size = 700
game_size = 17
tile_size = canvas_size / game_size
tick_rate_ms = 100
)
// types
struct Pos {
x int
y int
}
fn (a Pos) + (b Pos) Pos {
return Pos{a.x + b.x, a.y + b.y}
}
fn (a Pos) - (b Pos) Pos {
return Pos{a.x - b.x, a.y - b.y}
}
enum Direction {
up
down
left
right
}
struct App {
mut:
gg &gg.Context
score int
snake []Pos
dir Direction
food Pos
start_time i64
last_tick i64
}
// utility
fn (mut app App) reset_game() {
app.score = 0
app.snake = [
Pos{3, 8},
Pos{2, 8},
Pos{1, 8},
Pos{0, 8},
]
app.dir = .right
app.food = Pos{10, 8}
app.start_time = time.ticks()
app.last_tick = time.ticks()
}
fn (mut app App) move_food() {
for {
x := rand.int_in_range(0, game_size)
y := rand.int_in_range(0, game_size)
app.food = Pos{x, y}
if app.food !in app.snake {
return
}
}
}
// events
fn on_keydown(key sapp.KeyCode, mod sapp.Modifier, mut app App) {
match key {
.w, .up {
if app.dir != .down {
app.dir = .up
}
}
.s, .down {
if app.dir != .up {
app.dir = .down
}
}
.a, .left {
if app.dir != .right {
app.dir = .left
}
}
.d, .right {
if app.dir != .left {
app.dir = .right
}
}
else {}
}
}
fn on_frame(mut app App) {
app.gg.begin()
now := time.ticks()
if now - app.last_tick >= tick_rate_ms {
app.last_tick = now
// finding delta direction
delta_dir := match app.dir {
.up { Pos{0, -1} }
.down { Pos{0, 1} }
.left { Pos{-1, 0} }
.right { Pos{1, 0} }
}
// "snaking" along
mut prev := app.snake[0]
app.snake[0] = app.snake[0] + delta_dir
for i in 1 .. app.snake.len {
tmp := app.snake[i]
app.snake[i] = prev
prev = tmp
}
// adding last segment
if app.snake[0] == app.food {
app.move_food()
app.score++
app.snake << app.snake.last() + app.snake.last() - app.snake[app.snake.len - 2]
}
}
// drawing snake
for pos in app.snake {
app.gg.draw_rect(tile_size * pos.x, tile_size * pos.y + top_height, tile_size,
tile_size, gx.blue)
}
// drawing food
app.gg.draw_rect(tile_size * app.food.x, tile_size * app.food.y + top_height, tile_size,
tile_size, gx.red)
// drawing top
app.gg.draw_rect(0, 0, canvas_size, top_height, gx.black)
app.gg.draw_text(canvas_size / 2, top_height / 2, app.score.str(), gx.TextCfg{
color: gx.white
align: .center
vertical_align: .middle
size: 75
})
// checking if snake bit itself
if app.snake[0] in app.snake[1..] {
app.reset_game()
}
// checking if snake hit a wall
if app.snake[0].x < 0 ||
app.snake[0].x >= game_size || app.snake[0].y < 0 || app.snake[0].y >= game_size
{
app.reset_game()
}
app.gg.end()
}
// setup
fn main() {
mut app := App{
gg: 0
}
app.reset_game()
app.gg = gg.new_context(
bg_color: gx.white
frame_fn: on_frame
keydown_fn: on_keydown
user_data: &app
width: canvas_size
height: top_height + canvas_size
use_ortho: true
create_window: true
resizable: false
window_title: 'snek'
font_path: os.resource_abs_path(os.join_path('../assets/fonts/', 'RobotoMono-Regular.ttf'))
)
app.gg.run()
}