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>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/sksl/SkSLUtil.h b/src/sksl/SkSLUtil.h
index 7a39386269..787698f2c6 100644
--- a/src/sksl/SkSLUtil.h
+++ b/src/sksl/SkSLUtil.h
@@ -174,6 +174,10 @@ public:
     bool canUseFractForNegativeValues() const {
         return true;
     }
+
+    bool canUseFragCoord() const {
+        return true;
+    }
 };
 
 extern StandaloneShaderCaps standaloneCaps;
@@ -300,6 +304,13 @@ public:
         result->fCanUseAnyFunctionInShader = false;
         return result;
     }
+
+    static sk_sp<GrShaderCaps> CannotUseFragCoord() {
+        sk_sp<GrShaderCaps> result = sk_make_sp<GrShaderCaps>(GrContextOptions());
+        result->fVersionDeclString = "#version 400";
+        result->fCanUseFragCoord = false;
+        return result;
+    }
 };
 #endif