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
This commit is contained in:
Hajime Hoshi 2022-10-24 01:51:37 +09:00
parent fcda4143a5
commit b019a3723a
6 changed files with 152 additions and 16 deletions

107
examples/skipdraw/main.go Normal file
View File

@ -0,0 +1,107 @@
// 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)
}
}

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@ -147,7 +147,7 @@ func (g *gameForUI) DrawOffscreen() error {
return nil
}
func (g *gameForUI) DrawScreen() {
func (g *gameForUI) DrawFinalScreen() {
scale, offsetX, offsetY := g.ScreenScaleAndOffsets()
var geoM GeoM
geoM.Scale(scale, scale)

View File

@ -168,7 +168,8 @@ func (q *commandQueue) Flush(graphicsDriver graphicsdriver.Graphics, endFrame bo
// flush must be called the main thread.
func (q *commandQueue) flush(graphicsDriver graphicsdriver.Graphics, endFrame bool) (err error) {
if len(q.commands) == 0 {
// If endFrame is true, Begin/End should be called to ensure the framebuffer is swapped.
if len(q.commands) == 0 && !endFrame {
return nil
}

View File

@ -199,11 +199,15 @@ func (g *Graphics) SetVertices(vertices []float32, indices []uint16) error {
}
func (g *Graphics) flushIfNeeded(present bool) {
if g.cb == (mtl.CommandBuffer{}) {
if g.cb == (mtl.CommandBuffer{}) && !present {
return
}
g.flushRenderCommandEncoderIfNeeded()
if present && g.screenDrawable == (ca.MetalDrawable{}) {
g.screenDrawable = g.view.nextDrawable()
}
if !g.view.presentsWithTransaction() && present && g.screenDrawable != (ca.MetalDrawable{}) {
g.cb.PresentDrawable(g.screenDrawable)
}

View File

@ -38,7 +38,7 @@ type Game interface {
Layout(outsideWidth, outsideHeight int) (int, int)
Update() error
DrawOffscreen() error
DrawScreen()
DrawFinalScreen()
ScreenScaleAndOffsets() (scale, offsetX, offsetY float64)
}
@ -53,6 +53,8 @@ type context struct {
// The following members must be protected by the mutex m.
outsideWidth float64
outsideHeight float64
skipCount int
}
func newContext(game Game) *context {
@ -63,7 +65,7 @@ func newContext(game Game) *context {
func (c *context) updateFrame(graphicsDriver graphicsdriver.Graphics, outsideWidth, outsideHeight float64, deviceScaleFactor float64, ui *userInterfaceImpl) error {
// TODO: If updateCount is 0 and vsync is disabled, swapping buffers can be skipped.
return c.updateFrameImpl(graphicsDriver, clock.UpdateFrame(), outsideWidth, outsideHeight, deviceScaleFactor, ui)
return c.updateFrameImpl(graphicsDriver, clock.UpdateFrame(), outsideWidth, outsideHeight, deviceScaleFactor, ui, false)
}
func (c *context) forceUpdateFrame(graphicsDriver graphicsdriver.Graphics, outsideWidth, outsideHeight float64, deviceScaleFactor float64, ui *userInterfaceImpl) error {
@ -74,14 +76,14 @@ func (c *context) forceUpdateFrame(graphicsDriver graphicsdriver.Graphics, outsi
n = 2
}
for i := 0; i < n; i++ {
if err := c.updateFrameImpl(graphicsDriver, 1, outsideWidth, outsideHeight, deviceScaleFactor, ui); err != nil {
if err := c.updateFrameImpl(graphicsDriver, 1, outsideWidth, outsideHeight, deviceScaleFactor, ui, true); err != nil {
return err
}
}
return nil
}
func (c *context) updateFrameImpl(graphicsDriver graphicsdriver.Graphics, updateCount int, outsideWidth, outsideHeight float64, deviceScaleFactor float64, ui *userInterfaceImpl) (err error) {
func (c *context) updateFrameImpl(graphicsDriver graphicsdriver.Graphics, updateCount int, outsideWidth, outsideHeight float64, deviceScaleFactor float64, ui *userInterfaceImpl, forceDraw bool) (err error) {
if err := theGlobalState.error(); err != nil {
return err
}
@ -142,14 +144,14 @@ func (c *context) updateFrameImpl(graphicsDriver graphicsdriver.Graphics, update
}
// Draw the game.
if err := c.drawGame(graphicsDriver); err != nil {
if err := c.drawGame(graphicsDriver, forceDraw); err != nil {
return err
}
return nil
}
func (c *context) drawGame(graphicsDriver graphicsdriver.Graphics) error {
func (c *context) drawGame(graphicsDriver graphicsdriver.Graphics, forceDraw bool) error {
if (c.offscreen.imageType == atlas.ImageTypeVolatile) != theGlobalState.isScreenClearedEveryFrame() {
w, h := c.offscreen.width, c.offscreen.height
c.offscreen.MarkDisposed()
@ -162,20 +164,35 @@ func (c *context) drawGame(graphicsDriver graphicsdriver.Graphics) error {
if theGlobalState.isScreenClearedEveryFrame() {
c.offscreen.clear()
}
c.offscreen.dirty = false
if err := c.game.DrawOffscreen(); err != nil {
return err
}
const maxSkipCount = 3
if !forceDraw && !theGlobalState.isScreenClearedEveryFrame() && !c.offscreen.dirty {
if c.skipCount < maxSkipCount {
c.skipCount++
}
} else {
c.skipCount = 0
}
// If the offscreen is not updated and the framebuffers don't have to be updated, skip rendering to save GPU power.
if c.skipCount < maxSkipCount {
if graphicsDriver.NeedsClearingScreen() {
// This clear is needed for fullscreen mode or some mobile platforms (#622).
c.screen.clear()
}
c.game.DrawScreen()
c.game.DrawFinalScreen()
// The final screen is never used as the rendering source.
// Flush its buffer here just in case.
c.screen.flushBufferIfNeeded()
}
return nil
}

View File

@ -45,6 +45,8 @@ type Image struct {
bigOffscreenBuffer *Image
bigOffscreenBufferBlend graphicsdriver.Blend
bigOffscreenBufferDirty bool
dirty bool
}
func NewImage(width, height int, imageType atlas.ImageType) *Image {
@ -68,9 +70,12 @@ func (i *Image) MarkDisposed() {
i.mipmap.MarkDisposed()
i.mipmap = nil
i.dotsBuffer = nil
i.dirty = false
}
func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices []float32, indices []uint16, blend graphicsdriver.Blend, dstRegion, srcRegion graphicsdriver.Region, subimageOffsets [graphics.ShaderImageCount - 1][2]float32, shader *Shader, uniforms [][]float32, evenOdd bool, canSkipMipmap bool, antialias bool) {
i.dirty = true
if antialias {
// Flush the other buffer to make the buffers exclusive.
i.flushDotsBufferIfNeeded()
@ -141,6 +146,8 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices [
}
func (i *Image) WritePixels(pix []byte, x, y, width, height int) {
i.dirty = true
if width == 1 && height == 1 {
// Flush the other buffer to make the buffers exclusive.
i.flushBigOffscreenBufferIfNeeded()