drawscreen.go

package main

import (
	"fmt"
	"image"
	"image/color"

	"github.com/hajimehoshi/ebiten/v2"
	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
	"github.com/hajimehoshi/ebiten/v2/text"
	"github.com/jcgraybill/it-costs-money/sys"
)

func (g *Game) Draw(screen *ebiten.Image) {

	// TODO objects should draw themselves - add a draw.go to coin, level, player
	// Pass framebuffer for them to decorate

	frameBuffer.Clear()
	parallax(g.level.BgImage1, -g.player.X, 4)
	parallax(g.level.BgImage2, -g.player.X, 3)
	parallax(g.level.BgImage3, -g.player.X, 2)

	viewPortOffset := g.player.X - (sys.ScreenWidth/2 + sys.FrameWidth/2)
	levelViewFinder := image.Rect(viewPortOffset, 0, viewPortOffset+sys.ScreenWidth, sys.ScreenHeight)
	frameBuffer.DrawImage(g.level.LevelBackgroundImage.SubImage(levelViewFinder).(*ebiten.Image), nil)
	frameBuffer.DrawImage(g.level.LevelImage.SubImage(levelViewFinder).(*ebiten.Image), nil)

	runnerOP := &ebiten.DrawImageOptions{}

	if g.player.FacingLeft {
		runnerOP.GeoM.Scale(-1, 1)
		runnerOP.GeoM.Translate(sys.FrameWidth, 0)
	}
	runnerOP.GeoM.Translate(-float64(sys.FrameWidth)/2, 0)
	runnerOP.GeoM.Translate(sys.ScreenWidth/2, float64(g.player.Y))
	i := (g.count / 5) % len(*g.player.Slides)

	for _, coin := range g.level.Coin.Coins {
		if coin.Uncollected {
			if coin.X > viewPortOffset || coin.X < viewPortOffset+sys.ScreenWidth/2-sys.FrameWidth {
				coinOp := &ebiten.DrawImageOptions{}
				coinOp.GeoM.Translate(-float64(viewPortOffset-coin.X), float64(coin.Y))
				frameBuffer.DrawImage(sys.CoinTiles[(g.count/sys.CoinAnimationSpeed)%sys.CoinSlides], coinOp)
			}
		}
	}

	frameBuffer.DrawImage((*g.player.Slides)[i], runnerOP)
	frameBuffer.DrawImage(g.level.LevelForegroundImage.SubImage(levelViewFinder).(*ebiten.Image), nil)

	if message != "" {
		ebitenutil.DebugPrint(frameBuffer, message)
	}
	screen.DrawImage(frameBuffer, nil)

	coins := fmt.Sprintf("Coins: %d", g.player.Coins)
	textBounds := text.BoundString(sys.Ttf, coins)
	text.Draw(screen, coins, sys.Ttf, sys.ScreenWidth-textBounds.Dx()-18, textBounds.Dy()+2, color.RGBA{0x00, 0x00, 0x00, 0xff})
	text.Draw(screen, coins, sys.Ttf, sys.ScreenWidth-textBounds.Dx()-20, textBounds.Dy(), color.RGBA{0xd4, 0xaf, 0x47, 0xff})

}

func parallax(image *ebiten.Image, offset int, speed int) {
	panelWidth := image.Bounds().Dx()
	position := (offset / speed) % panelWidth
	op := &ebiten.DrawImageOptions{}
	op.GeoM.Translate(float64(position), 0)
	frameBuffer.DrawImage(image, op)

	for i := 0; position+i*panelWidth+panelWidth < sys.ScreenWidth; i++ {
		op.GeoM.Translate(float64(panelWidth), 0)
		frameBuffer.DrawImage(image, op)
	}
}