tree 78b34ac300515da3103c730345d4f0390959fb97
parent 40dc8a71f5d55dd7ed4e64c883664efae6da70ca
author Jim Van Verth <jvanverth@google.com> 1511199376 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> 1511201228 +0000

Use int when possible to calculate atlas indices in shaders.

On certain iOS devices half has a mantissa of only 10 bits, which is not
enough to perform the floating point trickery to get the lower bits
out of the "texture coordinates". Instead we use int if available, and
float if not available.

Also re-enables multitexturing for iOS and adds a sample which
stresses the issue.

Bug: skia:7285
Change-Id: I365532c7cbbcca7c7753af209bef46e05be49e11
Reviewed-on: https://skia-review.googlesource.com/71181
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>