Merge "Don't attempt to tone map content that is already in range." into sc-dev am: 263d778ae3

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/native/+/15159600

Change-Id: I04a1fad72d4b1ecc09b146028fe55d2f12d88c1d
diff --git a/libs/renderengine/skia/filters/LinearEffect.cpp b/libs/renderengine/skia/filters/LinearEffect.cpp
index 9b044e1..fc45af9 100644
--- a/libs/renderengine/skia/filters/LinearEffect.cpp
+++ b/libs/renderengine/skia/filters/LinearEffect.cpp
@@ -167,13 +167,12 @@
 
                                 float nits = xyz.y;
 
-                                // clamp to max input luminance
-                                nits = clamp(nits, 0.0, maxInLumi);
-
-                                // scale [0.0, maxInLumi] to [0.0, maxOutLumi]
+                                // if the max input luminance is less than what we can output then
+                                // no tone mapping is needed as all color values will be in range.
                                 if (maxInLumi <= maxOutLumi) {
-                                    return xyz * (maxOutLumi / maxInLumi);
+                                    return xyz;
                                 } else {
+
                                     // three control points
                                     const float x0 = 10.0;
                                     const float y0 = 17.0;