initial commit

game.go

@@ -0,0 +1,155 @@
+/*
+Copyright © 2024 Thomas von Dein
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package main
+
+import (
+	"fmt"
+	"image"
+	_ "image/png"
+	"log/slog"
+	"os"
+
+	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/inpututil"
+)
+
+type Game struct {
+	Conf   *Config
+	Images []*ebiten.Image
+	Shader *ebiten.Shader
+	Ticks  int
+	Slider float64
+	Flag   int
+}
+
+func LoadImage(name string) (*ebiten.Image, error) {
+	fd, err := os.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	defer fd.Close()
+
+	img, _, err := image.Decode(fd)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load image %s: %s", name, err)
+	}
+
+	return ebiten.NewImageFromImage(img), nil
+}
+
+func (game *Game) Init() error {
+	for _, image := range game.Conf.Image {
+		slog.Debug("Loading images", "image", image)
+		img, err := LoadImage(image)
+		if err != nil {
+			return err
+		}
+
+		game.Images = append(game.Images, img)
+	}
+
+	data, err := os.ReadFile(game.Conf.Shader)
+	if err != nil {
+		return fmt.Errorf("failed to load shader %s: %s", game.Conf.Shader, err)
+	}
+
+	shader, err := ebiten.NewShader(data)
+	if err != nil {
+		return fmt.Errorf("failed to create new shader %s: %s", game.Conf.Shader, err)
+	}
+
+	game.Shader = shader
+
+	return nil
+}
+
+func (g *Game) CheckInput() bool {
+	pressed := false
+
+	switch {
+	case inpututil.IsMouseButtonJustPressed(ebiten.MouseButton0):
+		fallthrough
+	case inpututil.IsKeyJustPressed(ebiten.KeySpace):
+		g.Toggle()
+		pressed = true
+	case inpututil.IsKeyJustPressed(ebiten.KeyUp):
+		g.Up()
+		pressed = true
+	case inpututil.IsKeyJustPressed(ebiten.KeyDown):
+		g.Down()
+		pressed = true
+	case inpututil.IsKeyJustPressed(ebiten.KeyQ):
+		os.Exit(0)
+	}
+
+	return pressed
+}
+
+func (g *Game) Toggle() {
+	g.Flag = 1 - g.Flag
+}
+
+func (g *Game) Up() {
+	g.Slider += 0.1
+	if g.Slider > 1.0 {
+		g.Slider = 1.0
+	}
+}
+
+func (g *Game) Down() {
+	g.Slider -= 0.1
+
+	if g.Slider < 0 {
+		g.Slider = 0.0
+	}
+}
+
+func (game *Game) Update() error {
+	if game.CheckInput() {
+		slog.Debug("Key pressed", "Slider", game.Slider, "Flag", game.Flag)
+	}
+
+	game.Ticks++
+
+	return nil
+}
+
+func (game *Game) Draw(screen *ebiten.Image) {
+	op := &ebiten.DrawRectShaderOptions{}
+
+	mousex, mousey := ebiten.CursorPosition()
+
+	op.Uniforms = map[string]any{
+		"Flag":   game.Flag,
+		"Slider": game.Slider,
+		"Ticks":  game.Ticks,
+		"Mouse":  []float64{float64(mousex), float64(mousey)},
+	}
+
+	for idx, image := range game.Images {
+		op.Images[idx] = image
+	}
+
+	op.GeoM.Translate(float64(game.Conf.X), float64(game.Conf.Y))
+
+	screen.DrawRectShader(game.Conf.Width, game.Conf.Height, game.Shader, op)
+}
+
+func (game *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
+	return game.Conf.Width, game.Conf.Height
+}