Commit 83f3411da456faac8570892e3dd7d76edf4095e5
2015-06-18T15:47:46
Remove dynamic indexing of matrices and vectors in HLSL 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: I024722ef4ca1e14d5ad47fdc540397e18858bed6 Reviewed-on: https://chromium-review.googlesource.com/290515 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Olli Etuaho <oetuaho@nvidia.com>