Revert "Remove dynamic indexing of matrices and vectors in HLSL"

This reverts commit 3766a40d6fda7e7190514ab7838a3f37169d863f.

This CL was causing crashes in UniformHLSL.cpp, where an internal
uniform "base" was attempted to be declared in HLSL. Was crashing
on an external WebGL 3D canvas page (http://www.taccgl.org/?dbg=t).

BUG=546686

Original commit message:

Re-landing after fixing D3D9 specific issues.

HLSL doesn't support dynamic indexing of matrices and vectors, so replace
that with helper functions that unroll dynamic indexing into switch/case
and static indexing.

Both the indexed vector/matrix expression and the index may have side
effects, and these will be evaluated correctly. If necessary, index
expressions that have side effects will be written to a temporary
variable that will replace the index.

Besides dEQP tests, this change is tested by a WebGL 2 conformance test.

In the case that a dynamic index is out-of-range, the base ESSL 3.00 spec
allows undefined behavior. KHR_robust_buffer_access_behavior adds the
requirement that program termination should not occur and that
out-of-range reads must return either a value from the active program's
memory or zero, and out-of-range writes should only affect the active
program's memory or do nothing. This patch clamps out-of-range indices so
that either the first or last item of the matrix/vector is accessed.

The code is not transformed in case the it fits within the limited subset
of ESSL 1.00 given in Appendix A of the spec. If the code isn't within
the restricted subset, even ESSL 1.00 shaders may require this
workaround.

BUG=angleproject:1116
TEST=dEQP-GLES3.functional.shaders.indexing.* (all pass after change)
     WebGL 2 conformance tests (glsl3/vector-dynamic-indexing.html)

Change-Id: I1d4b2e3888e91af7d5eebf743d12778698b6b903
Reviewed-on: https://chromium-review.googlesource.com/310270
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
10 files changed
tree: a21a2f8e8bd5a540e65738558ce673d37cfbdde3
  1. build/
  2. doc/
  3. extensions/
  4. include/
  5. samples/
  6. src/
  7. util/
  8. .clang-format
  9. .gitattributes
  10. .gitignore
  11. angle.isolate
  12. angle_on_all_platforms.isolate
  13. AUTHORS
  14. BUILD.gn
  15. codereview.settings
  16. CONTRIBUTORS
  17. DEPS
  18. LICENSE
  19. README.chromium
  20. README.md
README.md

#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 View the Dev setup instructions.

##Contributing