Enabling Perlin Noise on Android
I enabled the Perlin Noise shader on Android after doing some minor modifications to the shader, specifically for Android (and #ifdefed for Android, to make sure none of this affects other platforms).
For Tegra devices (Nexus 7, Xoom), a precision issue related to the color values read from textures caused the noise to read the wrong indices and produce bad noise. I fixed this by adding a founding of the values read by simply doing the equivalent of "colorValue = floor(colorValue * 255.0) / 255.0" to make sure we retrieve the colors that were written in the texture originally.
For non-Tegra devices (Nexus 10), dealing with values in the order of 4096.0 was problematic without using the "highp" precision setting. To solve this, a few variables were given the high precision setting.
Since both fixes don't seem to do considerable harm to the platforms that are not being targetted, I left both fixes on all android devices for now.
I also reduced the Perlin noise gm so that it takes less time to test it on the Xoom (Original time was about 20 seconds, this shold take less than 10, hopefully)
BUG=
R=senorblanco@google.com, bsalomon@google.com, sugoi@google.com, senorblanco@chromium.org
Author: sugoi@chromium.org
Review URL: https://chromiumcodereview.appspot.com/16818013
git-svn-id: http://skia.googlecode.com/svn/trunk@9637 2bbb7eff-a529-9590-31e7-b0007b416f81
1 ) Added GPU simplex noise as a comparison to GPU Perlin noise. It can be enabled simply by using a #define (SK_USE_SIMPLEX_NOISE)
2 ) Enabled GPU Perlin noise tests
3 ) Added a small benchmark for noise
4 ) Disabled GPU Perlin noise on Android based on benchmarks
Review URL: https://codereview.chromium.org/14087002
git-svn-id: http://skia.googlecode.com/svn/trunk@8719 2bbb7eff-a529-9590-31e7-b0007b416f81
