tree 78564548fe8d235934e217d95e6eb021644ba673
parent bc818f513be494fb3ab0c211892c7dc4cfb6a3d7
author kkinnunen <kkinnunen@nvidia.com> 1409030476 -0700
committer Commit bot <commit-bot@chromium.org> 1409030476 -0700

Implement NV_path_rendering on OpenGL ES

Implement support for NV_path_rendering on OpenGL ES. Use
glProgramPathFragmentInputGenNV function call instead of glPathTexGenNV to
communicate transforms to fragment shader.

The intention is that the NVPR paths will be drawn with the same shader program
as non-NVPR geometry. For NVPR calls, the GPU will skip the vertex shader and
just run the fragment shader.

After program is linked, query the locations of the fragment shader inputs with
glGetResourceLocation. The location will be used to set the transforms with
glProgramPathFragmentInputGenNV.

The functions and their workings are documented in:

glProgramPathFragmentInputGenNV
https://www.opengl.org/registry/specs/NV/path_rendering.txt
(note: addition as of API version 1.3)

glGetResourceLocation
https://www.opengl.org/registry/specs/ARB/program_interface_query.txt
http://www.opengl.org/registry/doc/glspec44.core.pdf
(function is in core Open GL 4.4)

Note: glProgramPathFragmentInputGenNV could be used also for OpenGL. However,
using seems to trigger a bug in the driver. Disable this feature on OpenGL at
least until the driver is fixed and released. The bug manifests in shadertext
test, where the lower-left text pair is missing. Valgrind catches a bad read
for the test and causes the context to OOM reproducibly.

R=bsalomon@google.com, cdalton@nvidia.com, joshualitt@google.com, joshualitt@chromium.org

Author: kkinnunen@nvidia.com

Review URL: https://codereview.chromium.org/367643004