Possible workaround for Intel GPU bug with nested structs

[kvark]

Potentially fixes #1939

@NiLSPACE would you be able to test? I suspect just as simple cd webrender && cargo run --example yuv should be sufficient. Thanks!

---

This change is 

[NiLSPACE]

I could try, but I've never compiled Servo before, so I'll have to figure that out first. Once I got that working how can I make sure I get this version of WebRender?

[kvark]

@NiLSPACE I don't think you even need Servo to test this.
You can just do:

git clone https://github.com/kvark/webrender -b glsl
cd webrender/webrender
cargo run --example yuv

Then wait till stuff apears in the window ~ 5-10 sec
If it works, we can confirm that the patch does the trick by doing:

git checkout HEAD^
cargo run --example yuv

This is supposed to fail.

[NiLSPACE]

Unfortunately I get lots of linking errors due to the machine type (x86) conflicting with the target (x64) so I'll need to figure that out first. I'll get back to this tomorrow.

[bors-servo]

☔ The latest upstream changes (presumably #1947) made this pull request unmergeable. Please resolve the merge conflicts.

[NiLSPACE]

I'm a day late, I apologise.

I managed to compile WebRender with the example, but unfortunately it doesn't seem like it worked. This was the output in the console:

    Finished dev [unoptimized + debuginfo] target(s) in 168.66 secs
     Running `D:\Projects\webrender_fixed\target\debug\examples\yuv.exe`
OpenGL version 3.2.0 - Build 22.20.16.4735
Shader resource path: None
Failed to compile shader: "cs_clip_image"
ERROR: 0:1110: 'constructor' :  cannot convert parameter 1 from 'float' to 'structure'
ERROR: 0:1109: 'return' : function return is not matching type:


thread 'main' panicked at 'renderer::deinit not called', src\device.rs:438:8
stack backtrace:
   0: std::sys_common::backtrace::_print
             at C:\projects\rust\src\libstd\sys_common\backtrace.rs:94
   1: std::panicking::default_hook::{{closure}}
             at C:\projects\rust\src\libstd\panicking.rs:380
   2: std::panicking::default_hook
             at C:\projects\rust\src\libstd\panicking.rs:397
   3: std::panicking::rust_panic_with_hook
             at C:\projects\rust\src\libstd\panicking.rs:611
   4: std::panicking::begin_panic<str*>
             at C:\projects\rust\src\libstd\panicking.rs:572
   5: webrender::device::{{impl}}::drop
             at .\src\device.rs:438
   6: core::ptr::drop_in_place<webrender::device::Program>
             at C:\projects\rust\src\libcore\ptr.rs:61
   7: core::ptr::drop_in_place<core::option::Option<webrender::device::Program>>
             at C:\projects\rust\src\libcore\ptr.rs:61
   8: core::ptr::drop_in_place<webrender::renderer::LazilyCompiledShader>
             at C:\projects\rust\src\libcore\ptr.rs:61
   9: webrender::renderer::Renderer::new
             at .\src\renderer.rs:1862
  10: yuv::boilerplate::main_wrapper
             at .\examples\common\boilerplate.rs:135
  11: yuv::main
             at .\examples\yuv.rs:267
  12: panic_unwind::__rust_maybe_catch_panic
             at C:\projects\rust\src\libpanic_unwind\lib.rs:99
  13: std::rt::lang_start
             at C:\projects\rust\src\libstd\rt.rs:54
  14: main
  15: __scrt_common_main_seh
             at f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:283
  16: BaseThreadInitThunk
error: process didn't exit successfully: `D:\Projects\webrender_fixed\target\debug\examples\yuv.exe` (exit code: 101)

[kvark]

@NiLSPACE could you verify that you are getting the original bug when running WR master branch as opposed to my fix?
If I read this correctly, the fix has actually worked, since your log indicates failure in cs_clip_image, which is initialized after brush_mask, which is what original bug is about. Thus, I suspect brush_mask is now fine, and we just need more fixing.

[kvark]

This one actually looks like https://github.com/servo/webrender/wiki/Driver-issues#1251---returning-with-struct-constructor:

return ClipVertexInfo(layer_pos.xyw, actual_pos, clipped_local_rect);

[kvark]

I re-implemented the fix on rebased code and added this other workaround.
@NiLSPACE Please test again! (same instructions)

[NiLSPACE]

It's still reporting the same error:

    Finished dev [unoptimized + debuginfo] target(s) in 171.79 secs
     Running `D:\Projects\webrender-fixed\target\debug\examples\yuv.exe`
OpenGL version 3.2.0 - Build 22.20.16.4735
Shader resource path: None
Failed to compile shader: "cs_clip_image"
ERROR: 0:1132: 'constructor' :  cannot convert parameter 1 from 'float' to 'structure'
ERROR: 0:1131: 'return' : function return is not matching type:


thread 'main' panicked at 'renderer::deinit not called', src\device.rs:438:8
stack backtrace:
   0: std::sys_common::backtrace::_print
             at C:\projects\rust\src\libstd\sys_common\backtrace.rs:94
   1: std::panicking::default_hook::{{closure}}
             at C:\projects\rust\src\libstd\panicking.rs:380
   2: std::panicking::default_hook
             at C:\projects\rust\src\libstd\panicking.rs:397
   3: std::panicking::rust_panic_with_hook
             at C:\projects\rust\src\libstd\panicking.rs:611
   4: std::panicking::begin_panic<str*>
             at C:\projects\rust\src\libstd\panicking.rs:572
   5: webrender::device::{{impl}}::drop
             at .\src\device.rs:438
   6: core::ptr::drop_in_place<webrender::device::Program>
             at C:\projects\rust\src\libcore\ptr.rs:61
   7: core::ptr::drop_in_place<core::option::Option<webrender::device::Program>>
             at C:\projects\rust\src\libcore\ptr.rs:61
   8: core::ptr::drop_in_place<webrender::renderer::LazilyCompiledShader>
             at C:\projects\rust\src\libcore\ptr.rs:61
   9: webrender::renderer::Renderer::new
             at .\src\renderer.rs:1862
  10: yuv::boilerplate::main_wrapper
             at .\examples\common\boilerplate.rs:135
  11: yuv::main
             at .\examples\yuv.rs:267
  12: panic_unwind::__rust_maybe_catch_panic
             at C:\projects\rust\src\libpanic_unwind\lib.rs:99
  13: std::rt::lang_start
             at C:\projects\rust\src\libstd\rt.rs:54
  14: main
  15: __scrt_common_main_seh
             at f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:283
  16: BaseThreadInitThunk
error: process didn't exit successfully: `D:\Projects\webrender-fixed\target\debug\examples\yuv.exe` (exit code: 101)

[kvark]

Thanks @NiLSPACE ! This is not exactly the same error - line numbers are different, they correspond to:

ImageMaskData fetch_mask_data(ivec2 address) {
    vec4 data = fetch_from_resource_cache_1_direct(address);
    return ImageMaskData(RectWithSize(data.xy, data.zw));
}

A fix for this function is now also pushed to the glsl branch. Please check again 🤞

[NiLSPACE]

It's working without errors or warnings now.

[kvark]

Marvelous!
@glennw this is ready to ship then

[glennw]

Thanks!

@bors-servo r+

[bors-servo]

📌 Commit ff242e7 has been approved by glennw

[bors-servo]

⌛ Testing commit ff242e7 with merge c06f298...

[bors-servo]

☀️ Test successful - status-appveyor, status-travis
Approved by: glennw
Pushing c06f298 to master...