commit 6789b824015373104bc3282c971e435a9f542f59
author Jim Van Verth <jvanverth@google.com> Thu Jul 15 11:37:09 2021 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Thu Jul 15 17:22:05 2021 +0000
tree db2001c00e899890069ef7e5bef54956b672a5f9
parent dfec4f98ef9181ea117faeac4556c95526313b6c

Fix directional shadows.

The xy offset calculation for drawShadow was not quite correct. Rather
than normalizing the light vector and using the xy values of that as the
base offset value, we should scale the light vector by 1/z.

See https://github.com/flutter/engine/pull/27124#issuecomment-880182653
for more detail.

Bug: skia:10781
Change-Id: Ib69a313cb96a532f8d89644e3d69f666a184e897
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/428880
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>

samplecode/SampleMaterialShadows.cpp

diff --git a/samplecode/SampleMaterialShadows.cpp b/samplecode/SampleMaterialShadows.cpp
index e84c5cf..8cb951f 100644
--- a/samplecode/SampleMaterialShadows.cpp
+++ b/samplecode/SampleMaterialShadows.cpp
@@ -34,7 +34,7 @@
         fLargeRRPath.addRRect(SkRRect::MakeRectXY(SkRect::MakeXYWH(-64, -64, 128, 128), 4, 4));
         fSmallRRPath.addRRect(SkRRect::MakeRectXY(SkRect::MakeXYWH(-40, -40, 80, 80), 4, 4));
 
-        fLightPos = SkPoint3::Make(0, -700, 600);
+        fLightPos = SkPoint3::Make(0, -700, 700);
     }
 
     SkString name() override { return SkString("MaterialShadows"); }