tweak the electron beam animation a bit

we make the "beam" vanish in the center of the screen.

Bug: 10641933

Change-Id: I61fdb4d46e9f62dc80d65356a884dff0b177384a

1 files changed, 5 insertions, 5 deletions

diff --git a/services/java/com/android/server/power/ElectronBeam.java b/services/java/com/android/server/power/ElectronBeam.java
index 379e704..0d92f66 100644
--- a/services/java/com/android/server/power/ElectronBeam.java
+++ b/services/java/com/android/server/power/ElectronBeam.java
@@ -319,10 +319,10 @@ final class ElectronBeam {
 
     /**
      * Draws a frame where the electron beam has been stretched out into
-     * a thin white horizontal line that fades as it expands outwards.
+     * a thin white horizontal line that fades as it collapses inwards.
      *
-     * @param stretch The stretch factor.  0.0 is no stretch / no fade,
-     * 1.0 is maximum stretch / maximum fade.
+     * @param stretch The stretch factor.  0.0 is maximum stretch / no fade,
+     * 1.0 is collapsed / maximum fade.
      */
     private void drawHStretch(float stretch) {
         // compute interpolation scale factor
@@ -338,7 +338,7 @@ final class ElectronBeam {
 
             // draw narrow fading white line
             setHStretchQuad(mVertexBuffer, mDisplayWidth, mDisplayHeight, ag);
-            GLES10.glColor4f(1.0f - ag, 1.0f - ag, 1.0f - ag, 1.0f);
+            GLES10.glColor4f(1.0f - ag*0.75f, 1.0f - ag*0.75f, 1.0f - ag*0.75f, 1.0f);
             GLES10.glDrawArrays(GLES10.GL_TRIANGLE_FAN, 0, 4);
 
             // clean up
@@ -355,7 +355,7 @@ final class ElectronBeam {
     }
 
     private static void setHStretchQuad(FloatBuffer vtx, float dw, float dh, float a) {
-        final float w = dw + (dw * a);
+        final float w = 2 * dw * (1.0f - a);
         final float h = 1.0f;
         final float x = (dw - w) * 0.5f;
         final float y = (dh - h) * 0.5f;