WebVR: Add explicit precision to all shaders to avoid Mali GPU crash

WebVR: Add explicit precision to all shaders to avoid Mali GPU crash

On Mali GPUs as used on Samsung S7 and other devices, precision qualifiers
are mandatory in GLSL shaders, there's no default. This causes a browser
crash due to failing shader compilation:

chromium: [FATAL:vr_shell_renderer.cc(246)] Check failed:
fragment_shader_handle. Error compiling shader: 0:1: S0032: no default
precision defined for variable 'v_TexCoordinate'

To fix this, add explicit "mediump" to all shaders.

Also update the v_TexCoordinate precision in vertex shaders to be "highp" to
match the fragment shader. In practice this doesn't currently make a difference
since the vertex coordinate values used are just 0, 0.5, or 1, all of which can
be precisely represented in a mediump, but it seems cleaner to keep this
consistent.

BUG=713516
Review-Url: https://codereview.chromium.org/2833823002
Cr-Commit-Position: refs/heads/master@{#466153}
Committed: https://chromium.googlesource.com/chromium/src/+/577ecb1d07b3990adc456b13143046561dd86ccc

[klausw, 2017-04-20 16:52:46]

klausw@chromium.org changed reviewers:
+ mthiesse@chromium.org

[klausw, 2017-04-20 16:52:46]

FYI, one of the shaders uses "mediump" in many declarations which would now be
redundant, but I wanted to keep the patch small in case it needs to be
cherry-picked.

[bajones, 2017-04-20 18:05:26]

On 2017/04/20 16:52:46, klausw wrote:
> FYI, one of the shaders uses "mediump" in many declarations which would now be
> redundant, but I wanted to keep the patch small in case it needs to be
> cherry-picked.

LGTM

[klausw, 2017-04-20 18:12:02]

The CQ bit was checked by klausw@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-04-20 18:12:36]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[mthiesse, 2017-04-20 18:33:39]

lgtm

[commit-bot: I haz the power, 2017-04-20 19:34:04]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-04-20 19:34:05]

Dry run: This issue passed the CQ dry run.

[klausw, 2017-04-20 21:52:05]

The CQ bit was checked by klausw@chromium.org

[commit-bot: I haz the power, 2017-04-20 21:52:52]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-20 21:57:39]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1492725125083530, "parent_rev":
"97258284ce55cf50a1dca7f0558450c3c593d2cc", "commit_rev":
"577ecb1d07b3990adc456b13143046561dd86ccc"}

[commit-bot: I haz the power, 2017-04-20 21:57:47]

Description was changed from

==========
WebVR: Add explicit precision to all shaders to avoid Mali GPU crash

On Mali GPUs as used on Samsung S7 and other devices, precision qualifiers
are mandatory in GLSL shaders, there's no default. This causes a browser
crash due to failing shader compilation:

chromium: [FATAL:vr_shell_renderer.cc(246)] Check failed:
fragment_shader_handle. Error compiling shader: 0:1: S0032: no default
precision defined for variable 'v_TexCoordinate'

To fix this, add explicit "mediump" to all shaders.

Also update the v_TexCoordinate precision in vertex shaders to be "highp" to
match the fragment shader. In practice this doesn't currently make a difference
since the vertex coordinate values used are just 0, 0.5, or 1, all of which can
be precisely represented in a mediump, but it seems cleaner to keep this
consistent.

BUG=713516
==========

to

==========
WebVR: Add explicit precision to all shaders to avoid Mali GPU crash

On Mali GPUs as used on Samsung S7 and other devices, precision qualifiers
are mandatory in GLSL shaders, there's no default. This causes a browser
crash due to failing shader compilation:

chromium: [FATAL:vr_shell_renderer.cc(246)] Check failed:
fragment_shader_handle. Error compiling shader: 0:1: S0032: no default
precision defined for variable 'v_TexCoordinate'

To fix this, add explicit "mediump" to all shaders.

Also update the v_TexCoordinate precision in vertex shaders to be "highp" to
match the fragment shader. In practice this doesn't currently make a difference
since the vertex coordinate values used are just 0, 0.5, or 1, all of which can
be precisely represented in a mediump, but it seems cleaner to keep this
consistent.

BUG=713516

Review-Url: https://codereview.chromium.org/2833823002
Cr-Commit-Position: refs/heads/master@{#466153}
Committed:
https://chromium.googlesource.com/chromium/src/+/577ecb1d07b3990adc456b131430...
==========

[commit-bot: I haz the power, 2017-04-20 21:57:49]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/577ecb1d07b3990adc456b131430...