Good way to load resources? #2128
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Hi 👋 I was trying to implement a good way of loading resources (images, shaders, etc.) while also drawing a loading screen. What I did is I loaded resources in goroutine and with images it seems to be working, but for some reason loading shaders not in main thread (goroutine) causes the program to panic. What is the proper solution when you are loading resources not in main thread (goroutine)? Smallest example of panicking code (ebiten v2.3.3)package main
import (
"fmt"
"github.com/hajimehoshi/ebiten/v2"
)
type Game struct {
frame int
shader *ebiten.Shader
loaded bool
}
const testShaderData = `
package main
func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
return vec4(1)
}
`
func (g *Game) Update() error {
g.frame++
if g.frame == 1 {
go func() {
fmt.Println("Loading")
var err error
g.shader, err = ebiten.NewShader([]byte(testShaderData))
if err != nil {
panic(err)
}
g.loaded = true
fmt.Println("Loaded")
}()
} else {
if g.loaded {
g.shader.Dispose()
g.loaded = false
fmt.Println("Disposed")
}
}
return nil
}
func (g *Game) Draw(_ *ebiten.Image) {}
func (g *Game) Layout(_, _ int) (int, int) {
return 640, 480
}
func main() {
ebiten.SetWindowTitle("Test")
ebiten.SetWindowSize(640, 480)
if err := ebiten.RunGame(&Game{}); err != nil {
panic(err)
}
}StdoutSame code but loading in main thread work completely finepackage main
import (
"fmt"
"github.com/hajimehoshi/ebiten/v2"
)
type Game struct {
frame int
shader *ebiten.Shader
loaded bool
}
const testShaderData = `
package main
func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
return vec4(1)
}
`
func (g *Game) Update() error {
g.frame++
if g.frame == 1 {
//go func() { // <========
fmt.Println("Loading")
var err error
g.shader, err = ebiten.NewShader([]byte(testShaderData))
if err != nil {
panic(err)
}
g.loaded = true
fmt.Println("Loaded")
//}() // <========
} else {
if g.loaded {
g.shader.Dispose()
g.loaded = false
fmt.Println("Disposed")
}
}
return nil
}
func (g *Game) Draw(_ *ebiten.Image) {}
func (g *Game) Layout(_, _ int) (int, int) {
return 640, 480
}
func main() {
ebiten.SetWindowTitle("Test")
ebiten.SetWindowSize(640, 480)
if err := ebiten.RunGame(&Game{}); err != nil {
panic(err)
}
} |
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Replies: 1 comment 5 replies
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Hi, This seems a bug in Ebitengine. I'll take a look, thanks! |
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This still seems a bug in Ebitengine so I am taking a look, but in general, you don't have to use a goroutine for func (g *Game) Update() error {
g.frame++
if g.frame == 1 { // or simply `!g.loaded`
fmt.Println("Loading")
var err error
g.shader, err = ebiten.NewShader([]byte(testShaderData))
if err != nil {
panic(err)
}
g.loaded = true
fmt.Println("Loaded")
}
// use the shader!
return nil
}would work for you. |
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Yep, sure, it's definitely possible to use it without goroutine, just wanted to create some general logic for loading resources in parallel. Thanks for quick reply, really appreciate that )) |
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I've fixed the crash, which was definitely a bug. If you want to load a resource asynchronously, using a goroutine should work. Note that the variable if g.loaded == nil {
g.loaded = make(chan struct{})
go func() {
// Load something
close(g.loaded)
}()
}
select {
case <-g.loaded:
default:
// not loaded yet
return nil
}
// ... |
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Great, thanks) What do you suggest, create an issue for this discussion to track it or leave it as is? |
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The crash issue is already tracked at #2129, so you don't have to do anything. Thank you! |
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Hi,
This seems a bug in Ebitengine. I'll take a look, thanks!