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diff --git a/src/org/cyanogenmod/wallpapers/photophase/effects/HalftoneEffect.java b/src/org/cyanogenmod/wallpapers/photophase/effects/HalftoneEffect.java
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+/*
+ * Copyright (C) 2013 The CyanogenMod Project
+ *
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+//
+// Based on the shaders of kodemongki:
+//   http://kodemongki.blogspot.com.es/2011/06/kameraku-custom-shader-effects-example.html
+//
+
+package org.cyanogenmod.wallpapers.photophase.effects;
+
+import android.media.effect.EffectContext;
+import android.opengl.GLES20;
+import android.util.Log;
+
+import org.cyanogenmod.wallpapers.photophase.utils.GLESUtil;
+
+/**
+ * A halftone effect<br/>
+ * <table>
+ * <tr><td>Parameter name</td><td>Meaning</td><td>Valid values</td></tr>
+ * <tr>
+ *   <td><code>strength</code></td>
+ *   <td>The halftone strength.</td>
+ *   <td>Positive float (>0). Higher numbers produce smallest points.</td>
+ * </tr>
+ * </table>
+ */
+public class HalftoneEffect extends PhotoPhaseEffect {
+
+    private static final String TAG = "HalftoneEffect";
+
+    private static final String STRENGTH_PARAMETER = "strength";
+
+    private static final String FRAGMENT_SHADER =
+            "precision mediump float;\n" +
+            "uniform sampler2D tex_sampler;\n" +
+            "varying vec2 v_texcoord;\n" +
+            "const float step_w = 0.0015625;\n" +
+            "const float step_h = 0.0027778;\n" +
+            "uniform float strength;\n" +
+            "void main(void)\n" +
+            "{\n" +
+            "    float offx = floor(v_texcoord.s  / (strength * step_w));\n" +
+            "    float offy = floor(v_texcoord.t  / (strength * step_h));\n" +
+            "    vec3 res = texture2D(tex_sampler, vec2(offx * strength * step_w , offy * strength * step_h)).bgr;\n" +
+            "    vec2 prc = fract(v_texcoord.st / vec2(strength * step_w, strength * step_h));\n" +
+            "    vec2 pw = pow(abs(prc - 0.5), vec2(2.0));\n" +
+            "    float  rs = pow(0.45, 2.0);\n" +
+            "    float gr = smoothstep(rs - 0.1, rs + 0.1, pw.x + pw.y);\n" +
+            "    float y = (res.r + res.g + res.b) / 3.0; \n" +
+            "    vec3 ra = res / y;\n" +
+            "    float ls = 0.3;\n" +
+            "    float lb = ceil(y / ls);\n" +
+            "    float lf = ls * lb + 0.3;\n" +
+            "    res = lf * res;\n" +
+            "    gl_FragColor.a = 1.0;\n" +
+            "    gl_FragColor.rgb = mix(res, vec3(0.1, 0.1, 0.1), gr);\n" +
+            "}";
+
+    private float mStrength = 16.0f;
+    private int mStepsHandle;
+
+    /**
+     * Constructor of <code>HalftoneEffect</code>.
+     *
+     * @param ctx The effect context
+     * @param name The effect name
+     */
+    public HalftoneEffect(EffectContext ctx, String name) {
+        super(ctx, HalftoneEffect.class.getName());
+        init(VERTEX_SHADER, FRAGMENT_SHADER);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    void init(String vertexShader, String fragmentShader) {
+        super.init(vertexShader, fragmentShader);
+
+        // Parameters
+        mStepsHandle = GLES20.glGetUniformLocation(mProgram, "strength");
+        GLESUtil.glesCheckError("glGetUniformLocation");
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    void applyParameters() {
+        // Set parameters
+        GLES20.glUniform1f(mStepsHandle, mStrength);
+        GLESUtil.glesCheckError("glUniform1f");
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void setParameter(String parameterKey, Object value) {
+        if (parameterKey.compareTo(STRENGTH_PARAMETER) == 0) {
+            try {
+                float strength = Float.parseFloat(value.toString());
+                if (strength <= 0) {
+                    Log.w(TAG, "strength parameter must be >= 0");
+                    return;
+                }
+                mStrength = strength;
+            } catch (NumberFormatException ex) {
+                // Ignore
+            }
+        }
+    }
+
+}