go_chip8/main.go

113 lines
2.2 KiB
Go

package main
import (
"fmt"
"github.com/hajimehoshi/ebiten/v2"
"github.com/hajimehoshi/ebiten/v2/ebitenutil"
"github.com/micosilent/go_chip8/emulator"
"image/color"
"log"
"os"
"time"
)
const (
screenWidth = 640
screenHeight = 320
gridWidth = 64
gridHeight = 32
)
type Game struct {
counter int
lastFrameTime time.Time
debugText string
emulator *emulator.CHIP8
screenImage *ebiten.Image
}
func (g *Game) Update() error {
// We need the emulator to process around 700 instructions per second
for i := 0; i < 1; i++ {
g.emulator.EmulateCycle()
if g.emulator.DrawFlag {
g.screenImage = g.DrawPixels()
g.emulator.DrawFlag = false
}
}
return nil
}
func (g *Game) DrawPixels() *ebiten.Image {
img := ebiten.NewImage(gridWidth, gridHeight)
white := color.White
black := color.Black
// Draw the boolean array to the image
for x := 0; x < gridWidth; x++ {
for y := 0; y < gridHeight; y++ {
if g.emulator.GetPixelAtCoordinate(x, y) {
img.Set(x, y, white)
} else {
img.Set(x, y, black)
}
}
}
return img
}
func newGame() *Game {
return &Game{
counter: 1,
lastFrameTime: time.Now(),
debugText: "",
emulator: emulator.NewChip8(),
}
}
func check(err error) {
if err != nil {
log.Fatal(err)
}
}
func (g *Game) Draw(screen *ebiten.Image) {
deltaTime := time.Since(g.lastFrameTime)
fps := int(1 / deltaTime.Seconds())
g.debugText = fmt.Sprintf("Counter: %d, fps: %d", g.counter, fps)
ebitenutil.DebugPrint(screen, g.debugText)
g.counter++
g.lastFrameTime = time.Now()
scaleX := float64(screenWidth) / float64(gridWidth)
scaleY := float64(screenHeight) / float64(gridHeight)
op := &ebiten.DrawImageOptions{}
op.GeoM.Scale(scaleX, scaleY)
screen.DrawImage(g.screenImage, op)
}
func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
return screenWidth, screenHeight
}
func (g *Game) LoadROM(path string) {
dat, err := os.ReadFile(path)
check(err)
err = g.emulator.LoadROMIntoMemory(dat)
check(err)
}
func main() {
game := newGame()
game.LoadROM("roms/ibm_logo.ch8")
ebiten.SetWindowSize(screenWidth, screenHeight)
ebiten.SetWindowTitle("Go CHIP8 Emulator")
err := ebiten.RunGame(game)
check(err)
}