Revert "Revert "Added SkSL workaround for devices which cannot safely access gl_FragCoord""

This reverts commit 9d6929cccfc3e64e75e6ef5b37f284b01b68fb28.

Reason for revert: Re-landing, backfill reveals none of the red was related to this CL.

Original change's description:
> Revert "Added SkSL workaround for devices which cannot safely access gl_FragCoord"
> 
> This reverts commit 1001f843a45e95f6df1d44242b6b06c77898e870.
> 
> Reason for revert: Many failures.
> 
> Original change's description:
> > Added SkSL workaround for devices which cannot safely access gl_FragCoord
> > 
> > This is the root cause of https://github.com/flutter/flutter/issues/13216
> > I've got a GM that demonstrates the bug, but only in Viewer.
> > 
> > Bug: skia:7410
> > Change-Id: Iaa1f27b10166aa09e4dc5949e5a6ca1bd14c99ac
> > Reviewed-on: https://skia-review.googlesource.com/93920
> > Reviewed-by: Brian Salomon <bsalomon@google.com>
> > Commit-Queue: Brian Osman <brianosman@google.com>
> 
> TBR=bsalomon@google.com,brianosman@google.com,ethannicholas@google.com
> 
> Change-Id: I2a2edc0a8fa11fe9dac1045dc79ae91106518b02
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: skia:7410
> Reviewed-on: https://skia-review.googlesource.com/94281
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>

TBR=bsalomon@google.com,brianosman@google.com,ethannicholas@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: skia:7410
Change-Id: Ib22bda7ff25bb7c8630cc6fa6dc809bf628ea853
Reviewed-on: https://skia-review.googlesource.com/94800
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/tests/SkSLGLSLTest.cpp b/tests/SkSLGLSLTest.cpp
index 1ae421f8af..9b0571bcdc 100644
--- a/tests/SkSLGLSLTest.cpp
+++ b/tests/SkSLGLSLTest.cpp
@@ -1059,6 +1059,42 @@ DEF_TEST(SkSLFragCoord, r) {
          "}\n",
          &inputs);
     REPORTER_ASSERT(r, !inputs.fRTHeight);
+
+    test(r,
+         "in float4 pos; void main() { sk_Position = pos; }",
+         *SkSL::ShaderCapsFactory::CannotUseFragCoord(),
+         "#version 400\n"
+         "out vec4 sk_FragCoord_Workaround;\n"
+         "in vec4 pos;\n"
+         "void main() {\n"
+         "    sk_FragCoord_Workaround = (gl_Position = pos);\n"
+         "}\n",
+         SkSL::Program::kVertex_Kind);
+
+    test(r,
+         "in uniform float4 sk_RTAdjust; in float4 pos; void main() { sk_Position = pos; }",
+         *SkSL::ShaderCapsFactory::CannotUseFragCoord(),
+         "#version 400\n"
+         "out vec4 sk_FragCoord_Workaround;\n"
+         "in uniform vec4 sk_RTAdjust;\n"
+         "in vec4 pos;\n"
+         "void main() {\n"
+         "    sk_FragCoord_Workaround = (gl_Position = pos);\n"
+         "    gl_Position = vec4(gl_Position.x * sk_RTAdjust.x + gl_Position.w * sk_RTAdjust.y, "
+              "gl_Position.y * sk_RTAdjust.z + gl_Position.w * sk_RTAdjust.w, 0, gl_Position.w);\n"
+         "}\n",
+         SkSL::Program::kVertex_Kind);
+
+    test(r,
+         "void main() { sk_FragColor.xy = sk_FragCoord.xy; }",
+         *SkSL::ShaderCapsFactory::CannotUseFragCoord(),
+         "#version 400\n"
+         "in vec4 sk_FragCoord_Workaround;\n"
+         "out vec4 sk_FragColor;\n"
+         "void main() {\n"
+         "    sk_FragColor.xy = vec4(sk_FragCoord_Workaround.xyz / sk_FragCoord_Workaround.w, "
+             "1.0 / sk_FragCoord_Workaround.w).xy;\n"
+         "}\n");
 }
 
 DEF_TEST(SkSLVertexID, r) {