Add example/platform (WIP)

example/platform/main.go

@@ -0,0 +1,40 @@
+// Copyright 2015 Hajime Hoshi
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"github.com/hajimehoshi/ebiten"
+	"github.com/hajimehoshi/ebiten/example/platform/platform"
+	"log"
+)
+
+const (
+	ScreenWidth  = 256
+	ScreenHeight = 240
+	ScreenScale  = 2
+)
+
+var game = platform.NewGame()
+
+func update(screen *ebiten.Image) error {
+	game.Update()
+	return game.Draw(screen)
+}
+
+func main() {
+	if err := ebiten.Run(update, ScreenWidth, ScreenHeight, ScreenScale, "Platform (Ebiten Demo)"); err != nil {
+		log.Fatal(err)
+	}
+}

example/platform/platform/game.go

@@ -0,0 +1,114 @@
+// Copyright 2015 Hajime Hoshi
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package platform
+
+import (
+	"github.com/hajimehoshi/ebiten"
+)
+
+// NOTE: It's painful to prepare a struct to draw an image part.
+type playerRect struct {
+	game *Game
+}
+
+func (p *playerRect) Len() int {
+	return 1
+}
+
+func (p *playerRect) Src(i int) (x0, y0, x1, y1 int) {
+	return 0, 128, TileSize, 128 + TileSize
+}
+
+func (p *playerRect) Dst(i int) (x0, y0, x1, y1 int) {
+	x, y := (p.game.player.x)/unit-8, (p.game.player.y)/unit-16
+	return x, y, x + TileSize, y + TileSize
+}
+
+type player struct {
+	x  int
+	y  int
+	vy int
+	ay int
+}
+
+type Game struct {
+	level        *Level
+	player       *player
+	jumpKeyState int
+}
+
+func NewGame() *Game {
+	x, y := (TileSize*3+8)*unit, (TileSize*13)*unit
+	return &Game{
+		level: &Level{},
+		player: &player{
+			x:  x,
+			y:  y,
+			vy: 0,
+			ay: 0,
+		},
+	}
+}
+
+// TODO: Rename
+const unit = 16
+
+func (g *Game) inAir() bool {
+	return g.player.y < 13*unit*TileSize
+}
+
+func (g *Game) Update() {
+	if ebiten.IsKeyPressed(ebiten.KeySpace) {
+		g.jumpKeyState++
+	} else {
+		g.jumpKeyState = 0
+	}
+	if ebiten.IsKeyPressed(ebiten.KeyLeft) {
+		g.player.x -= 2 * unit
+	} else if ebiten.IsKeyPressed(ebiten.KeyRight) {
+		g.player.x += 2 * unit
+	}
+	if g.inAir() {
+		g.player.ay = unit
+		if g.player.vy < 0 && 0 < g.jumpKeyState {
+			g.player.ay -= int(0.5 * unit)
+		}
+	} else if g.jumpKeyState == 1 {
+		g.player.ay = -10 * unit
+	} else {
+		g.player.vy = 0
+		g.player.ay = 0
+	}
+	if 5*unit < g.player.vy {
+		g.player.vy = 5 * unit
+	}
+	g.player.vy += g.player.ay
+	g.player.y += g.player.vy
+	if 13*unit*TileSize <= g.player.y {
+		g.player.y = 13 * unit * TileSize
+	}
+}
+
+func (g *Game) Draw(screen *ebiten.Image) error {
+	if err := g.level.Draw(screen); err != nil {
+		return err
+	}
+	if err := screen.DrawImage(tileSet, &ebiten.DrawImageOptions{
+		ImageParts: &playerRect{g},
+	}); err != nil {
+		return err
+	}
+	return nil
+}

example/platform/platform/level.go

@@ -0,0 +1,78 @@
+// Copyright 2015 Hajime Hoshi
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package platform
+
+import (
+	"github.com/hajimehoshi/ebiten"
+	"github.com/hajimehoshi/ebiten/ebitenutil"
+)
+
+const (
+	ScreenWidth  = 256
+	ScreenHeight = 240
+)
+
+var tileSet *ebiten.Image
+
+func init() {
+	var err error
+	tileSet, _, err = ebitenutil.NewImageFromFile("images/platform/tileset.png", ebiten.FilterNearest)
+	if err != nil {
+		panic(err)
+	}
+}
+
+const (
+	TileSize    = 16
+	TileSrcXNum = 8
+	TileDstXNum = ScreenWidth / TileSize
+	TileDstYNum = ScreenHeight / TileSize
+)
+
+type levelRects struct {
+	*Level
+}
+
+func (l *levelRects) Len() int {
+	return TileDstXNum * TileDstYNum
+}
+
+func tileRect(i int) (x0, y0, x1, y1 int) {
+	x := (i % TileSrcXNum) * TileSize
+	y := (i / TileSrcXNum) * TileSize
+	return x, y, x + TileSize, y + TileSize
+}
+
+func (l *levelRects) Src(i int) (x0, y0, x1, y1 int) {
+	if (i / TileDstXNum) < 13 {
+		return tileRect(1)
+	}
+	return tileRect(2)
+}
+
+func (l *levelRects) Dst(i int) (x0, y0, x1, y1 int) {
+	x := (i % TileDstXNum) * TileSize
+	y := (i / TileDstXNum) * TileSize
+	return x, y, x + TileSize, y + TileSize
+}
+
+type Level struct {
+}
+
+func (l *Level) Draw(screen *ebiten.Image) error {
+	return screen.DrawImage(tileSet, &ebiten.DrawImageOptions{
+		ImageParts: &levelRects{l},
+	})
+}