commit a225d21f7d586d1484af38a55f8d949d076a4d5c
author Nader Jawad <njawad@google.com> Wed Mar 17 15:12:58 2021 -0700
committer Nader Jawad <njawad@google.com> Thu Mar 18 22:41:42 2021 -0700
tree f5dc60ec0ec35c4d8adb69a3a476020d2874ced6
parent 78af4257ecebcf73c113ef927942a062aefef3e6

Updated EdgeEffect parameters for overscroll stretch

Added dampening logic to caluclate the distance to
overscroll.
Updated StretchEffect to support independent
maximum stretch amounts for the x/y axis

Removed debugging parameters to configure
stretch distance since they are no longer
used. Removed hidden API calls to configure
stretch distance in ScrollView/HorizontalScrollView

Bug: 179047472
Test: re-ran EdgeEffectTests
Change-Id: I4698669273d364695a21c2cce00ec2cfec41b2cc

libs/hwui/effects/StretchEffect.cpp

diff --git a/libs/hwui/effects/StretchEffect.cpp b/libs/hwui/effects/StretchEffect.cpp
index d4fd105..9e4fb8f 100644
--- a/libs/hwui/effects/StretchEffect.cpp
+++ b/libs/hwui/effects/StretchEffect.cpp
@@ -33,7 +33,8 @@
     uniform float uMaxStretchIntensity;
 
     // Maximum percentage to stretch beyond bounds  of target
-    uniform float uStretchAffectedDist;
+    uniform float uStretchAffectedDistX;
+    uniform float uStretchAffectedDistY;
 
     // Distance stretched as a function of the normalized overscroll times
     // scale intensity
@@ -138,7 +139,7 @@
             outU,
             inU,
             uOverscrollX,
-            uStretchAffectedDist,
+            uStretchAffectedDistX,
             uDistanceStretchedX,
             uDistDiffX
         );
@@ -146,7 +147,7 @@
             outV,
             inV,
             uOverscrollY,
-            uStretchAffectedDist,
+            uStretchAffectedDistY,
             uDistanceStretchedY,
             uDistDiffY
         );
@@ -166,16 +167,14 @@
         return mStretchFilter;
     }
 
-    float distanceNotStretchedX = maxStretchAmount / stretchArea.width();
-    float distanceNotStretchedY = maxStretchAmount / stretchArea.height();
-    float normOverScrollDistX = mStretchDirection.x();
-    float normOverScrollDistY = mStretchDirection.y();
-    float distanceStretchedX = maxStretchAmount / (1 + abs(normOverScrollDistX));
-    float distanceStretchedY = maxStretchAmount / (1 + abs(normOverScrollDistY));
-    float diffX = distanceStretchedX - distanceNotStretchedX;
-    float diffY = distanceStretchedY - distanceNotStretchedY;
     float viewportWidth = stretchArea.width();
     float viewportHeight = stretchArea.height();
+    float normOverScrollDistX = mStretchDirection.x();
+    float normOverScrollDistY = mStretchDirection.y();
+    float distanceStretchedX = maxStretchAmountX / (1 + abs(normOverScrollDistX));
+    float distanceStretchedY = maxStretchAmountY / (1 + abs(normOverScrollDistY));
+    float diffX = distanceStretchedX;
+    float diffY = distanceStretchedY;
 
     if (mBuilder == nullptr) {
         mBuilder = std::make_unique<SkRuntimeShaderBuilder>(getStretchEffect());
@@ -183,7 +182,8 @@
 
     mBuilder->child("uContentTexture") = snapshotImage->makeShader(
             SkTileMode::kClamp, SkTileMode::kClamp, SkSamplingOptions(SkFilterMode::kLinear));
-    mBuilder->uniform("uStretchAffectedDist").set(&maxStretchAmount, 1);
+    mBuilder->uniform("uStretchAffectedDistX").set(&maxStretchAmountX, 1);
+    mBuilder->uniform("uStretchAffectedDistY").set(&maxStretchAmountY, 1);
     mBuilder->uniform("uDistanceStretchedX").set(&distanceStretchedX, 1);
     mBuilder->uniform("uDistanceStretchedY").set(&distanceStretchedY, 1);
     mBuilder->uniform("uDistDiffX").set(&diffX, 1);