Make ripple sparkles less prominent

Test: visual
Bug: 184188444
Change-Id: Ieac0a7e7ff389f16bc4e42c14ea94182cec44c38

graphics/java/android/graphics/drawable/RippleShader.java

@@ -41,6 +41,7 @@ final class RippleShader extends RuntimeShader {
             + "    return fract(xy * 95.4307) + fract(xy * 75.04961) - 1.0;\n"
             + "}"
             + "const float PI = 3.1415926535897932384626;\n"
+            + "const float SPARKLE_OPACITY = 0.55;\n"
             + "\n"
             + "float sparkles(vec2 uv, float t) {\n"
             + "  float n = triangleNoise(uv);\n"
@@ -52,7 +53,7 @@ final class RippleShader extends RuntimeShader {
             + "    o *= abs(sin(PI * o * (t + 0.55 * i)));\n"
             + "    s += o;\n"
             + "  }\n"
-            + "  return saturate(s);\n"
+            + "  return saturate(s) * SPARKLE_OPACITY;\n"
             + "}\n"
             + "\n"
             + "float softCircle(vec2 uv, vec2 xy, float radius, float blur) {\n"