commit 20798e55bbda9d0b5686171737322040aa7d6f21
author Ethan Nicholas <ethannicholas@google.com> Tue Dec 04 12:30:50 2018 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Tue Dec 04 21:35:18 2018 +0000
tree 045577b92ced58374c8f0e065edbef21cc5e62cc
parent add7bd97972f8566627dfe4552f3012b56cdc9ff

passing fragcoord.w in SPIR-V and Metal

Bug: skia:
Change-Id: I94447ae74a1709c789b8d70dfd7f9572bbb2c3cf
Reviewed-on: https://skia-review.googlesource.com/c/174303
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>

src/sksl/SkSLSPIRVCodeGenerator.cpp

diff --git a/src/sksl/SkSLSPIRVCodeGenerator.cpp b/src/sksl/SkSLSPIRVCodeGenerator.cpp
index 2878296..5d92e2b 100644
--- a/src/sksl/SkSLSPIRVCodeGenerator.cpp
+++ b/src/sksl/SkSLSPIRVCodeGenerator.cpp
@@ -1742,7 +1742,7 @@
             fRTHeightFieldIndex = 0;
         }
         SkASSERT(fRTHeightFieldIndex != (SpvId) -1);
-        // write float4(gl_FragCoord.x, u_skRTHeight - gl_FragCoord.y, 0.0, 1.0)
+        // write float4(gl_FragCoord.x, u_skRTHeight - gl_FragCoord.y, 0.0, gl_FragCoord.w)
         SpvId xId = this->nextId();
         this->writeInstruction(SpvOpCompositeExtract, this->getType(*fContext.fFloat_Type), xId,
                                result, 0, out);
@@ -1766,7 +1766,9 @@
         FloatLiteral zero(fContext, -1, 0.0);
         SpvId zeroId = writeFloatLiteral(zero);
         FloatLiteral one(fContext, -1, 1.0);
-        SpvId oneId = writeFloatLiteral(one);
+        SpvId wId = this->nextId();
+        this->writeInstruction(SpvOpCompositeExtract, this->getType(*fContext.fFloat_Type), wId,
+                               result, 3, out);
         SpvId flipped = this->nextId();
         this->writeOpCode(SpvOpCompositeConstruct, 7, out);
         this->writeWord(this->getType(*fContext.fFloat4_Type), out);
@@ -1774,7 +1776,7 @@
         this->writeWord(xId, out);
         this->writeWord(flippedYId, out);
         this->writeWord(zeroId, out);
-        this->writeWord(oneId, out);
+        this->writeWord(wId, out);
         return flipped;
     }
     if (ref.fVariable.fModifiers.fLayout.fBuiltin == SK_CLOCKWISE_BUILTIN &&