-
-
Notifications
You must be signed in to change notification settings - Fork 2.9k
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Webpages not rendering on Android x86 and x86_64 emulators. #31726
Comments
mukilan
added
P-android
Android devices
I-bustage
The effect of the issue remaining unresolved.
and removed
C-untriaged
New issues that haven't been triaged yet
labels
Mar 18, 2024
mukilan
changed the title
Webpages not rendering on Android x86 emulators.
Webpages not rendering on Android x86 and x86_64 emulators.
Mar 18, 2024
mukilan
added a commit
to mukilan/servo
that referenced
this issue
Mar 18, 2024
Android's OpenGL emulation layer (goldfish-opengl) has pre-processing logic that looks for samplers of the type `samplerExternalOES` and does a simple textual [replacement to change the type][1] to `sampler2D` before compilation. It also [marks the sampler][2] as 'replaced' so it can emulate the correct type at runtime. However, this logic can lead to false positives when the sampler is declared inside conditional macros. Hence, the sampler's type can be incorrectly marked as `samplerExternalOES` even though the #if, #ifdef conditional logic would have declared the type as `sampler2D`. This seems to be a [known limitation][3]. WebRender (in particular the shared.glsl include) has such conditional declaration of the texture units used from the shaders. In particular, the sampler [sColor0 here][4] is declared within ifdefs to have different types depending on the flags enabled, to allow the shader to work with different image target kinds. WebRender also maintain two versions of the compiled shaders in its cache: 1. An unoptimized version with all the conditional logic preserved in the source until the shader is compiled at runtime on Android, when the shader is actually used. 2. Multiple optimized versions for combinations of features required These versions are produced during Servo [build][5]. Thus the optimized versions eliminate most of the conditional declarations at build time. The bug in Servo with current code is because, [by default][6], WebRender uses the *unoptimized* versions of the shaders. This means the conditional GLSL source is evaluated at runtime by the Android emulator and thus ends up with the incorrect type for the sColor0 sampler unit, which breaks the [texture sampling in the fragment shader][7], causing it to always return Vec4(0, 0, 0, 1) and rendering all elements on the page black. This change forces WebRender to use the *optimized* version as a workaround - the optimized versions have unconditional code for the sampler declarations so are not susceptible to the emulator issue. [1]: https://android.googlesource.com/device/generic/goldfish-opengl/+/refs/tags/android-platform-11.0.0_r40/system/GLESv2_enc/GL2Encoder.cpp#1644 [2]: https://android.googlesource.com/device/generic/goldfish-opengl/+/refs/tags/android-platform-11.0.0_r40/system/GLESv2_enc/GL2Encoder.cpp#1673 [3]: https://android.googlesource.com/device/generic/goldfish-opengl/+/refs/tags/android-platform-11.0.0_r40/system/GLESv2_enc/GL2Encoder.cpp#1571 [4]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/res/shared.glsl#L206 [5]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/build.rs#L289 [6]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/src/renderer/init.rs#L214 [7]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/res/composite.glsl#L189 Fixes servo#31726. Signed-off-by: Mukilan Thiyagarajan <mukilan@igalia.com>
mukilan
added a commit
to mukilan/servo
that referenced
this issue
Mar 18, 2024
Android's OpenGL emulation layer (goldfish-opengl) has pre-processing logic that looks for samplers of the type `samplerExternalOES` and does a simple textual [replacement to change the type][1] to `sampler2D` before compilation. It also [marks the sampler][2] as 'replaced' so it can emulate the correct type at runtime. However, this logic can lead to false positives when the sampler is declared inside conditional macros. Hence, the sampler's type can be incorrectly marked as `samplerExternalOES` even though the #if, #ifdef conditional logic would have declared the type as `sampler2D`. This seems to be a [known limitation][3]. WebRender (in particular the shared.glsl include) has such conditional declaration of the texture units used from the shaders. In particular, the sampler [sColor0 here][4] is declared within ifdefs to have different types depending on the flags enabled, to allow the shader to work with different image target kinds. WebRender also maintain two versions of the compiled shaders in its cache: 1. An unoptimized version with all the conditional logic preserved in the source until the shader is compiled at runtime on Android, when the shader is actually used. 2. Multiple optimized versions for combinations of features required These versions are produced during Servo [build][5]. Thus the optimized versions eliminate most of the conditional declarations at build time. The bug in Servo with current code is because, [by default][6], WebRender uses the *unoptimized* versions of the shaders. This means the conditional GLSL source is evaluated at runtime by the Android emulator and thus ends up with the incorrect type for the sColor0 sampler unit, which breaks the [texture sampling in the fragment shader][7], causing it to always return Vec4(0, 0, 0, 1) and rendering all elements on the page black. This change forces WebRender to use the *optimized* version as a workaround - the optimized versions have unconditional code for the sampler declarations so are not susceptible to the emulator issue. [1]: https://android.googlesource.com/device/generic/goldfish-opengl/+/refs/tags/android-platform-11.0.0_r40/system/GLESv2_enc/GL2Encoder.cpp#1644 [2]: https://android.googlesource.com/device/generic/goldfish-opengl/+/refs/tags/android-platform-11.0.0_r40/system/GLESv2_enc/GL2Encoder.cpp#1673 [3]: https://android.googlesource.com/device/generic/goldfish-opengl/+/refs/tags/android-platform-11.0.0_r40/system/GLESv2_enc/GL2Encoder.cpp#1571 [4]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/res/shared.glsl#L206 [5]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/build.rs#L289 [6]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/src/renderer/init.rs#L214 [7]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/res/composite.glsl#L189 Fixes servo#31726. Signed-off-by: Mukilan Thiyagarajan <mukilan@igalia.com>
3 tasks
github-merge-queue bot
pushed a commit
that referenced
this issue
Mar 18, 2024
Android's OpenGL emulation layer (goldfish-opengl) has pre-processing logic that looks for samplers of the type `samplerExternalOES` and does a simple textual [replacement to change the type][1] to `sampler2D` before compilation. It also [marks the sampler][2] as 'replaced' so it can emulate the correct type at runtime. However, this logic can lead to false positives when the sampler is declared inside conditional macros. Hence, the sampler's type can be incorrectly marked as `samplerExternalOES` even though the #if, #ifdef conditional logic would have declared the type as `sampler2D`. This seems to be a [known limitation][3]. WebRender (in particular the shared.glsl include) has such conditional declaration of the texture units used from the shaders. In particular, the sampler [sColor0 here][4] is declared within ifdefs to have different types depending on the flags enabled, to allow the shader to work with different image target kinds. WebRender also maintain two versions of the compiled shaders in its cache: 1. An unoptimized version with all the conditional logic preserved in the source until the shader is compiled at runtime on Android, when the shader is actually used. 2. Multiple optimized versions for combinations of features required These versions are produced during Servo [build][5]. Thus the optimized versions eliminate most of the conditional declarations at build time. The bug in Servo with current code is because, [by default][6], WebRender uses the *unoptimized* versions of the shaders. This means the conditional GLSL source is evaluated at runtime by the Android emulator and thus ends up with the incorrect type for the sColor0 sampler unit, which breaks the [texture sampling in the fragment shader][7], causing it to always return Vec4(0, 0, 0, 1) and rendering all elements on the page black. This change forces WebRender to use the *optimized* version as a workaround - the optimized versions have unconditional code for the sampler declarations so are not susceptible to the emulator issue. [1]: https://android.googlesource.com/device/generic/goldfish-opengl/+/refs/tags/android-platform-11.0.0_r40/system/GLESv2_enc/GL2Encoder.cpp#1644 [2]: https://android.googlesource.com/device/generic/goldfish-opengl/+/refs/tags/android-platform-11.0.0_r40/system/GLESv2_enc/GL2Encoder.cpp#1673 [3]: https://android.googlesource.com/device/generic/goldfish-opengl/+/refs/tags/android-platform-11.0.0_r40/system/GLESv2_enc/GL2Encoder.cpp#1571 [4]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/res/shared.glsl#L206 [5]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/build.rs#L289 [6]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/src/renderer/init.rs#L214 [7]: https://github.com/servo/webrender/blob/b36399019cadcadeeed53759c96870577d4da136/webrender/res/composite.glsl#L189 Fixes #31726. Signed-off-by: Mukilan Thiyagarajan <mukilan@igalia.com>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Describe the bug:
On Android emulators, all websites, including servo.org, produce just a black screen in Servo. This doesn't happen on real devices and the websites look correct. The logs don't have any obvious errors.
To Reproduce:
./mach build --target x86_64-linux-android
or./mach build --target i686-linux-android
./mach install --target <arch>
./mach run --android
Expected output: servo.org homepage is rendered correctly on the emulator.
Actual output: Black screen that covers the whole area of the ServoView widget.
Platform:
Android AVD images for x86 Atom or x86_64 Atom architecture, platform 30 or 33.
The text was updated successfully, but these errors were encountered: