Added randomly generated background.

game.go

@@ -1,13 +1,17 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
+	"image"
 	"image/color"
 	"log"
 	"math"
 	"math/rand/v2"
 	"mover/fonts"
 
+	_ "embed"
+
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/inpututil"
 	"github.com/hajimehoshi/ebiten/v2/text"
@@ -19,7 +23,15 @@ const (
 	MOVER_HEIGHT = 48
 )
 
+var (
+	tilesetImage *ebiten.Image
+
+	//go:embed grasstile.png
+	tileset_img []byte
+)
+
 type Game struct {
+	background        *ebiten.Image
 	collisionMask     *ebiten.Image
 	projectileMask    *ebiten.Image
 	heroCollisionMask *ebiten.Image
@@ -46,10 +58,19 @@ type Game struct {
 	//pressedButtons map[ebiten.GamepadID][]string
 }
 
+func init() {
+	img, _, err := image.Decode(bytes.NewReader(tileset_img))
+	if err != nil {
+		log.Fatal(err)
+	}
+	tilesetImage = ebiten.NewImageFromImage(img)
+}
+
 func (g *Game) Initialize() {
 
 	origin := Coordinates{X: 640 / 2, Y: 480 / 2}
 
+	g.ConstructBackground()
 	g.hero = NewHero()
 	g.hero.SetOrigin(origin)
 	g.hero.ToggleRotate()
@@ -113,6 +134,9 @@ func (g *Game) Update() error {
 
 func (g *Game) Draw(screen *ebiten.Image) {
 
+	screen.Clear()
+	screen.DrawImage(g.background, nil)
+
 	g.hero.Draw()
 
 	op := &ebiten.DrawImageOptions{}
@@ -269,6 +293,8 @@ func (g *Game) UpdateProjectiles() {
 			if p.Pos.X >= target.Pos.X-MOVER_WIDTH/2 && p.Pos.X <= target.Pos.X+MOVER_WIDTH/2 && p.Pos.Y >= target.Pos.Y-MOVER_HEIGHT/2 && p.Pos.Y <= target.Pos.Y+MOVER_HEIGHT/2 && target.Action == MoverActionDamaged {
 				//fmt.Println("potential collision")
 
+				//the following computes total collisions in the image using a projectile mask that is a duplicate of what is on screen
+				//there's definitely room for optimization here
 				g.collisionMask.Clear()
 				g.collisionMask.DrawImage(g.projectileMask, nil)
 
@@ -398,3 +424,26 @@ func (g *Game) UpdateHeroPosition() {
 		g.hero.Pos.Y += ebiten.GamepadAxisValue(0, 1) * 5
 	}
 }
+
+func (g *Game) ConstructBackground() {
+	g.background = ebiten.NewImage(screenWidth, screenHeight)
+
+	for i := 0; i < 640/16; i++ {
+		for j := 0; j < 480/16; j++ {
+
+			//select random tile in x and y from tileset
+			idx_x := rand.IntN(256 / 16)
+			idx_y := rand.IntN(256 / 16)
+
+			x0 := 16 * idx_x
+			y0 := 16 * idx_y
+			x1 := x0 + 16
+			y1 := y0 + 16
+
+			//translate for grid element we're painting
+			op := &ebiten.DrawImageOptions{}
+			op.GeoM.Translate(float64(i)*16, float64(j)*16)
+			g.background.DrawImage(tilesetImage.SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), op)
+		}
+	}
+}