VerticalFilmBorder.java

/*
 * Copyright (C) 2016 Jorge Ruesga
 *
 *
 * 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.
 */

package com.ruesga.android.wallpapers.photophase.borders;

import android.media.effect.EffectContext;
import android.opengl.GLES20;
import android.util.Log;

import com.ruesga.android.wallpapers.photophase.utils.GLESUtil;

/**
 * This vertical film border around the texture.<br/>
 * <table>
 * <tr><td>Parameter name</td><td>Meaning</td><td>Valid values</td></tr>
 * </table>
 */
public class VerticalFilmBorder extends Border {

    private static final String TAG = "VerticalFilmBorder";

    public static final String STRENGTH_PARAMETER = "strength";
    public static final String COLOR_PARAMETER = "color";

    private static final String FRAGMENT_SHADER =
            "precision mediump float;\n" +
            "uniform sampler2D tex_sampler;\n" +
            "uniform float w;\n" +
            "uniform float h;\n" +
            "uniform vec4 color;\n" +
            "uniform float strength;\n" +
            "varying vec2 v_texcoord;\n" +
            "const float m1 = 0.175;\n" +
            "const float m2 = 0.06;\n" +
            "bool is_film_border(vec2 p, float b) {\n" +
            "  return p.x < (0.0 + b)\n" +
            "      || p.x > (1.0 - b);\n" +
            "}\n" +
            "bool is_film_track(vec2 p, float b, float t) {\n" +
            "  if (!((p.x < (0.0 + b/2.0 + t/2.0)\n" +
            "        && p.x > (0.0 + b/2.0 - t/2.0))\n" +
            "        || (p.x < (1.0 - b/2.0 + t/2.0)\n" +
            "        && p.x > (1.0 - b/2.0 - t/2.0)))) {\n" +
            "    return false;\n" +
            "  }\n" +
            "  return (mod(p.y, m1) < m2);\n" +
            "}" +
            "void main(void)\n" +
            "{\n" +
            "  float b = strength / w;\n" +
            "  float t = b / 5.0;\n" +
            "  if (is_film_border(v_texcoord, b) && !is_film_track(v_texcoord, b, t)) {\n" +
            "    vec4 tex = texture2D (tex_sampler, v_texcoord);\n" +
            "    float r = tex.r + (color.r - tex.r) * color.a;\n" +
            "    float g = tex.g + (color.g - tex.g) * color.a;\n" +
            "    float b = tex.b + (color.b - tex.b) * color.a;\n" +
            "    gl_FragColor = vec4(r, g, b, tex.a);\n" +
            "  } else {\n" +
            "    gl_FragColor = texture2D(tex_sampler, v_texcoord);\n" +
            "  }\n" +
            "}";

    private float mStrength = 75;

    private final int mColorHandle;
    private final int mWidthHandle;
    private final int mHeightHandle;
    private final int mStrengthHandle;

    /**
     * Constructor of <code>VerticalFilmBorder</code>.
     *
     * @param ctx The effect context
     * @param name The effect name
     */
    public VerticalFilmBorder(EffectContext ctx, String name) {
        super(ctx, VerticalFilmBorder.class.getName());
        init(VERTEX_SHADER, FRAGMENT_SHADER);

        // Parameters
        mWidthHandle = GLES20.glGetUniformLocation(mProgram[0], "w");
        GLESUtil.glesCheckError("glGetUniformLocation");
        mHeightHandle = GLES20.glGetUniformLocation(mProgram[0], "h");
        GLESUtil.glesCheckError("glGetUniformLocation");
        mStrengthHandle = GLES20.glGetUniformLocation(mProgram[0], STRENGTH_PARAMETER);
        GLESUtil.glesCheckError("glGetUniformLocation");
        mColorHandle = GLES20.glGetUniformLocation(mProgram[0], COLOR_PARAMETER);
        GLESUtil.glesCheckError("glGetUniformLocation");
    }

    /**
     * {@inheritDoc}
     */
    @Override
    void applyParameters(int width, int height) {
        // Set parameters
        GLES20.glUniform1f(mWidthHandle, (float) width);
        GLESUtil.glesCheckError("glUniform1f");
        GLES20.glUniform1f(mHeightHandle, (float) height);
        GLESUtil.glesCheckError("glUniform1f");
        GLES20.glUniform1f(mStrengthHandle, mStrength);
        GLESUtil.glesCheckError("glUniform1f");
        GLES20.glUniform4fv(mColorHandle, 1, mColor.asVec4(), 0);
        GLESUtil.glesCheckError("glUniform4fv");
    }

    /**
     * {@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
            }
        }
    }
}