Reland "Vulkan: Generate gl_Position pre-rotation in SPIR-V" This reverts commit 3d39b7c5eab88c420d982155ffbb6181c678ceea. Reason for revert: Fixed interaction with the `forceDriverUniformOverSpecConst` workaround. Original change's description: > Revert "Vulkan: Generate gl_Position pre-rotation in SPIR-V" > > This reverts commit 0f86b196ffaffeeee3460e3188f20a7ac120796d. > > Reason for revert: > Breaks pre-rotation for all apps, so they are displayed in portrait instead of landscape. > > Original change's description: > > Vulkan: Generate gl_Position pre-rotation in SPIR-V > > > > Instead of having the translator output pre-rotation code in the vertex > > stage based on a specialization constant, this change makes the SPIR-V > > transformer perform pre-rotation of gl_Position on the last geometry > > stage. > > > > An alternative solution would be to generate pre-rotation code in the > > translator in every geometry stage, each controlled by a separate > > specialization constant. This change avoids unnecessary modifications > > to earlier stages. The generated shaders are also smaller, as they > > don't contain a mat2[8] pre-rotation constant matrix. The SPIR-V > > transformer knows the pre-rotation at transformation time, so it can > > simply use swizzles to achieve the same results. > > > > This also ties in with upcoming changes which move gl_Position.z > > correction to the last geometry shader stage, which is trivially done > > piggy-backing on the infrastructure in this change. > > > > Bug: angleproject:5478 > > Change-Id: I9d5d9d19f3ccda665f5504368ce5ddfa5f383faf > > Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2598584 > > Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> > > Reviewed-by: Charlie Lao <cclao@google.com> > > Reviewed-by: Jamie Madill <jmadill@chromium.org> > > TBR=syoussefi@chromium.org,jmadill@chromium.org,cclao@google.com > > Change-Id: I81f237fa6b10c7d59831363bee8999e7ad2f09be > No-Presubmit: true > No-Tree-Checks: true > No-Try: true > Bug: angleproject:5478 > Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2633694 > Reviewed-by: Tim Van Patten <timvp@google.com> > Commit-Queue: Tim Van Patten <timvp@google.com> TBR=timvp@google.com,syoussefi@chromium.org,jmadill@chromium.org,cclao@google.com Bug: angleproject:5478 Change-Id: I7c5eaeef03d9520abd36a1c4a766b6abbf4fdb45 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2633709 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>