ebiten/examples/skipdraw/main.go
Hajime Hoshi b019a3723a internal/ui: optimize GPU usages when the screen doesn't have to be updated
This change skips rendering when 1) the screen is not cleared every frame
(`SetScreenClearedEveryFrame(false)`) and 2) Draw doesn't draw anything
onto the screen. The GPU usages decreased on some machines (e.g. GPU usage
was 10% with an empty Ebitengine project and became 2-3 % on a Windows
machine).

Updates #2341
2022-10-28 18:51:06 +09:00

108 lines
2.7 KiB
Go

// Copyright 2022 The Ebitengine Authors
//
// 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.
//go:build example
// +build example
package main
import (
"bytes"
"image"
_ "image/jpeg"
"log"
"math"
"github.com/hajimehoshi/ebiten/v2"
"github.com/hajimehoshi/ebiten/v2/ebitenutil"
"github.com/hajimehoshi/ebiten/v2/examples/resources/images"
"github.com/hajimehoshi/ebiten/v2/inpututil"
)
const (
screenWidth = 640
screenHeight = 480
)
var (
gophersImage *ebiten.Image
)
type Game struct {
count int
input bool
introShown bool
}
func (g *Game) Update() error {
g.count++
g.input = len(inpututil.AppendPressedKeys(nil)) > 0
if inpututil.IsKeyJustPressed(ebiten.KeyF) {
ebiten.SetFullscreen(!ebiten.IsFullscreen())
}
return nil
}
func (g *Game) Draw(screen *ebiten.Image) {
// If there is no inpnut, skip draw. Ebitengine skips GPU usages in this case.
if !g.input && g.introShown {
return
}
screen.Clear()
w, h := gophersImage.Size()
op := &ebiten.DrawImageOptions{}
// Move the image's center to the screen's upper-left corner.
// This is a preparation for rotating. When geometry matrices are applied,
// the origin point is the upper-left corner.
op.GeoM.Translate(-float64(w)/2, -float64(h)/2)
// Rotate the image. As a result, the anchor point of this rotate is
// the center of the image.
op.GeoM.Rotate(float64(g.count%360) * 2 * math.Pi / 360)
// Move the image to the screen's center.
op.GeoM.Translate(screenWidth/2, screenHeight/2)
screen.DrawImage(gophersImage, op)
ebitenutil.DebugPrint(screen, "Press any keys to keep animations.\nPress F to switch fullscreen.")
g.introShown = true
}
func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
return screenWidth, screenHeight
}
func main() {
ebiten.SetWindowResizingMode(ebiten.WindowResizingModeEnabled)
ebiten.SetScreenClearedEveryFrame(false)
// Decode an image from the image file's byte slice.
img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
if err != nil {
log.Fatal(err)
}
gophersImage = ebiten.NewImageFromImage(img)
ebiten.SetWindowSize(screenWidth, screenHeight)
ebiten.SetWindowTitle("Skip Draw (Ebitengine Demo)")
if err := ebiten.RunGame(&Game{}); err != nil {
log.Fatal(err)
}
}