| commit | 853dc1abd3ba5f43fdf6b34784795b1d0857d2fc | [log] [tgz] |
|---|---|---|
| author | Olli Etuaho <oetuaho@nvidia.com> | Thu Nov 06 17:25:48 2014 +0200 |
| committer | Nicolas Capens <capn@chromium.org> | Wed Nov 26 14:57:35 2014 +0000 |
| tree | 7d0d5d9fa67d2ec5d9a3c2d98fd380e10bb10d0d | |
| parent | 1c9ecfd7cd439039487dff8c0d6d7c410b8f95d3 [diff] |
Add mediump and lowp precision emulation support for GLSL output This implements the rounding as specified in WEBGL_debug_shader_precision extension proposal for desktop GLSL and ESSL output. The bulk of the new functionality is added in the form of a new EmulatePrecision AST traverser, which inserts calls to the rounding routines angle_frm and angle_frl in the appropriate places, and writes the rounding routines themselves to the shader. Compound assignments which are subject to emulation are transformed from "x op= y" to "angle_compound_op_frm(x, y)", a call to a function which does the appropriate rounding and places the result of the operation to x. The angle_ prefixed names should not clash with user-defined names if name hashing is on. If name hashing is not on, the precision emulation can only be used if the angle_ prefix is reserved for use by ANGLE. To support the rounding routines in output, a new operator type is added for internal helper function calls, which are not subject to name hashing. In ESSL output, all variables are forced to highp when precision emulation is on to ensure consistency with how precision emulation performs on desktop. Comprehensive tests for the added code generation are included. BUG=angle:787 Change-Id: I0d0ad9327888f803a32e79b64b08763c654c913b Reviewed-on: https://chromium-review.googlesource.com/229631 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Olli Etuaho <oetuaho@nvidia.com>
#ANGLE The goal of ANGLE is to allow Windows users to seamlessly run WebGL and other OpenGL ES content by translating OpenGL ES API calls to DirectX 9 or DirectX 11 API calls.
ANGLE is a conformant implementation of the OpenGL ES 2.0 specification that is hardware‐accelerated via Direct3D. ANGLE v1.0.772 was certified compliant by passing the ES 2.0.3 conformance tests in October 2011. ANGLE also provides an implementation of the EGL 1.4 specification. Work on ANGLE's OpenGL ES 3.0 implementation is currently in progress, but should not be considered stable.
ANGLE is used as the default WebGL backend for both Google Chrome and Mozilla Firefox on Windows platforms. Chrome uses ANGLE for all graphics rendering on Windows, including the accelerated Canvas2D implementation and the Native Client sandbox environment.
Portions of the ANGLE shader compiler are used as a shader validator and translator by WebGL implementations across multiple platforms. It is used on Mac OS X, Linux, and in mobile variants of the browsers. Having one shader validator helps to ensure that a consistent set of GLSL ES shaders are accepted across browsers and platforms. The shader translator can be used to translate shaders to other shading languages, and to optionally apply shader modifications to work around bugs or quirks in the native graphics drivers. The translator targets Desktop GLSL, Direct3D HLSL, and even ESSL for native GLES2 platforms.
##Building For building instructions, visit the dev setup wiki.
##Contributing