Panic when drawing off the edge of an offscreen image

[kalexmills]

panic: runtime error: index out of range [28] with length 28

goroutine 10 [running]:
golang.org/x/image/vector.(*Rasterizer).rasterizeDstAlphaSrcOpaqueOpSrc(0x1400016cab0, 0x140010f9200, {{0x14000f715f8?, 0x100a74078?}, {0x14000f715f8?, 0x100a74018?}})
        /Users/kalexmills/go/pkg/mod/golang.org/x/image@v0.7.0/vector/vector.go:384 +0x1b4
golang.org/x/image/vector.(*Rasterizer).Draw(0x1400016cab0, {0x1012f21b8?, 0x140010f9200}, {{0x24?, 0x0?}, {0x0?, 0x0?}}, {0x1012f1820?, 0x14000192410?}, {0x0?, ...})
        /Users/kalexmills/go/pkg/mod/golang.org/x/image@v0.7.0/vector/vector.go:281 +0xf4
github.com/tinne26/etxt/emask.(*DefaultRasterizer).Rasterize(0x1400016cab0, {0x1400012d500, 0x24, 0x40}, {0xf71798?, 0x140?})
        /Users/kalexmills/go/pkg/mod/github.com/tinne26/etxt@v0.0.8/emask/impl_default.go:87 +0xf0
github.com/tinne26/etxt/emask.Rasterize({0x1400012d500?, 0x1008233d4?, 0x30000000028?}, {0x1012f0b30?, 0x1400016cab0?}, {0x36c?, 0x234?})
        /Users/kalexmills/go/pkg/mod/github.com/tinne26/etxt@v0.0.8/emask/rasterizer.go:105 +0x84
github.com/tinne26/etxt.(*Renderer).LoadGlyphMask(0x140003b4700, 0x28, {0x1?, 0x1?})
        /Users/kalexmills/go/pkg/mod/github.com/tinne26/etxt@v0.0.8/renderer_draw.go:73 +0x98
github.com/tinne26/etxt.(*Renderer).DrawFract.func1({0x18?, 0x0?}, 0x12a2980?, 0x1?)
        /Users/kalexmills/go/pkg/mod/github.com/tinne26/etxt@v0.0.8/renderer_draw.go:45 +0x58
github.com/tinne26/etxt.(*Renderer).Traverse.func1({0x28e013d8?, 0x1?})
        /Users/kalexmills/go/pkg/mod/github.com/tinne26/etxt@v0.0.8/renderer_traverse.go:112 +0x2c
github.com/tinne26/etxt.(*Renderer).traverseGlyphLTR(0x140003b4700, {0x12a2980?, 0x1?}, {0x1?, 0x0?, 0x0?}, 0x140007da198)
        /Users/kalexmills/go/pkg/mod/github.com/tinne26/etxt@v0.0.8/renderer_traverse.go:246 +0xcc
github.com/tinne26/etxt.(*Renderer).Traverse(0x140003b4700, {0x140019940e4, 0xa}, {0x8c0, 0x140?}, 0x140016d7020)
        /Users/kalexmills/go/pkg/mod/github.com/tinne26/etxt@v0.0.8/renderer_traverse.go:111 +0x3f8
github.com/tinne26/etxt.(*Renderer).DrawFract(0x140003b4700, {0x140019940e4, 0xa}, 0x1?, 0x0?)
        /Users/kalexmills/go/pkg/mod/github.com/tinne26/etxt@v0.0.8/renderer_draw.go:42 +0xa4
github.com/tinne26/etxt.(*Renderer).Draw(...)
        /Users/kalexmills/go/pkg/mod/github.com/tinne26/etxt@v0.0.8/renderer_draw.go:25
github.com/Frabjous-Studios/ebitengine-game-template/internal.(*MainScene).randCheck(0x1400011a000)
        /Users/kalexmills/repos/personal/ldjam-53/internal/main_scene.go:1276 +0x3ec
github.com/Frabjous-Studios/ebitengine-game-template/internal.(*MainScene).putCounter(0x1400011a000, {0x140007fe090?, 0x1, 0x1?})
        /Users/kalexmills/repos/personal/ldjam-53/internal/main_scene.go:1027 +0xb8
github.com/Frabjous-Studios/ebitengine-game-template/internal.(*MainScene).Command(0x1400011a000, {0x140001b63d8, 0x12})
        /Users/kalexmills/repos/personal/ldjam-53/internal/main_scene.go:847 +0x2e4
github.com/DrJosh9000/yarn.(*VirtualMachine).execRunCommand(0x1400088c980?, {0x140002b0350?, 0x1?, 0x14000714d20?})
        /Users/kalexmills/go/pkg/mod/github.com/!dr!josh9000/yarn@v0.5.0/vm.go:326 +0x234
github.com/DrJosh9000/yarn.(*VirtualMachine).execute(0x0?, 0x0?)
        /Users/kalexmills/go/pkg/mod/github.com/!dr!josh9000/yarn@v0.5.0/vm.go:228 +0x9c
github.com/DrJosh9000/yarn.(*VirtualMachine).Run(0x1400088c980, {0x100c42151, 0x12})
        /Users/kalexmills/go/pkg/mod/github.com/!dr!josh9000/yarn@v0.5.0/vm.go:186 +0x3bc
github.com/Frabjous-Studios/ebitengine-game-template/internal.(*DialogueRunner).DoNode(0x1400031bf10?, {0x100c42151?, 0x0?})
        /Users/kalexmills/repos/personal/ldjam-53/internal/dialogue_runner.go:86 +0xa0
github.com/Frabjous-Studios/ebitengine-game-template/internal.(*MainScene).startRunner(0x1400011a000)
        /Users/kalexmills/repos/personal/ldjam-53/internal/main_scene.go:746 +0x58
created by github.com/Frabjous-Studios/ebitengine-game-template/internal.(*MainScene).Update
        /Users/kalexmills/repos/personal/ldjam-53/internal/main_scene.go:262 +0x17c
exit status 2

Seen at commit24101a8

[tinne26]

It very much looks like the TODO in Golang's code at fault: https://cs.opensource.google/go/x/image/+/refs/tags/v0.7.0:vector/vector.go;l=268. We probably want to get the actual values of bounds and points and rects to debug. It should be patchable from etxt's end, but that's not very ideal; a more minimal example reported to Golang directly may be the way to go here. I'll look into it when I can, but it may take a few days.

I'm particularly interested in a more minimal example because since this doesn't seem to be etxt's fault, it may also affect ebiten/text. A temporary workaround may involve trying to render with https://pkg.go.dev/github.com/tinne26/etxt@v0.0.8/emask#EdgeMarkerRasterizer instead (though that's much less tested and slower and it doesn't give the best guarantees either).

[tinne26]

I tried to compile your project to reproduce the issue and try the quickfix with EdgeMarkRasterizer, but failed to do so. I installed ysc and compiled the yarn files, but then I got other errors for missing files:

2023/05/01 09:29:20 fonts available: Munro,Munro Narrow,Munro Small,Roustel Regular,Thesignature,Honey Script Light,Honey Script SemiBold
2023/05/01 09:29:20 error loading animation: scan_shreder.json: open gamedata\img\scan_shreder.png: file does not exist
2023/05/01 09:29:20 failed to load image: gamedata/img/head_psychoClown: open gamedata/img/head_psychoClown: file does not exist

[...]

Edit: I guess it's due to you testing on linux and me using windows at the moment, the paths may not be properly handled.
Edit 2: yeah, with linux it compiles.
Edit 3: yeah, actually a bit offtopic. But https://github.com/kalexmills/asebiten/blob/ed6ad7918bccfc3d0a8bf7d37715aaa939c8ff5c/aseprite.go#L157 this usage of filepath is incorrect. Since you used fs.FS you should use path instead. That causes the animation error. The other is due to head_psychoClown missing the .png extension in your files.

[kalexmills]

this usage of filepath is incorrect

Jesus; I literally did the same thing a few weeks ago and I think you pointed it out in the Ebitengine Discord. After this Game jam I'm making a resources library and never writing this code again. ;)

EDIT:

I installed ysc and compiled the yarn files, but then I got other errors for missing files:

You're trying too hard. Thanks! I really appreciate it. Feel free to kick it back to me next time, though. There ought to be precompiled yarn files in the repo.