Render ImageWallpaper with OpenGL ES and apply visual effects. (Fix bug)

We have to render image wallpaper with OpenGL ES to apply some amazing
visual effects.

Bug: 122803209
Bug: 124073420
Bug: 123616712
Bug: 123615467
Test: Manually.
Change-Id: I0123d4ba2acb5a84b709c0468910e006c8e49563

packages/SystemUI/res/raw/image_wallpaper_fragment_shader.glsl

@@ -0,0 +1,27 @@
+precision mediump float;
+
+uniform sampler2D uTexture;
+uniform float uCenterReveal;
+uniform float uReveal;
+uniform float uAod2Opacity;
+varying vec2 vTextureCoordinates;
+
+vec3 luminosity(vec3 color) {
+    float lum = 0.2126 * color.r + 0.7152 * color.g + 0.0722 * color.b;
+    return vec3(lum);
+}
+
+vec4 transform(vec3 diffuse) {
+    // TODO: Add well comments here, tracking on b/123615467.
+    vec3 lum = luminosity(diffuse);
+    diffuse = mix(diffuse, lum, smoothstep(0., uCenterReveal, uReveal));
+    float val = mix(uReveal, uCenterReveal, step(uCenterReveal, uReveal));
+    diffuse = smoothstep(val, 1.0, diffuse);
+    diffuse *= uAod2Opacity * (1. - smoothstep(uCenterReveal, 1., uReveal));
+    return vec4(diffuse.r, diffuse.g, diffuse.b, 1.);
+}
+
+void main() {
+    vec4 fragColor = texture2D(uTexture, vTextureCoordinates);
+    gl_FragColor = transform(fragColor.rgb);
+}

packages/SystemUI/res/raw/image_wallpaper_vertex_shader.glsl

@@ -0,0 +1,8 @@
+attribute vec4 aPosition;
+attribute vec2 aTextureCoordinates;
+varying vec2 vTextureCoordinates;
+
+void main() {
+    vTextureCoordinates = aTextureCoordinates;
+    gl_Position = aPosition;
+}