GPUImageHazeFilter.java

/*
 * Copyright (C) 2012 CyberAgent
 *
 * 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 jp.co.cyberagent.android.gpuimage;

import android.opengl.GLES20;

/**
 * The haze filter can be used to add or remove haze.
 *
 * This is similar to a UV filter.
 */
public class GPUImageHazeFilter extends GPUImageFilter {
    public static final String HAZE_FRAGMENT_SHADER = "" +
            "varying highp vec2 textureCoordinate;\n" +
            "\n" +
            "uniform sampler2D inputImageTexture;\n" +
            "\n" +
            "uniform lowp float distance;\n" +
            "uniform highp float slope;\n" +
            "\n" +
            "void main()\n" +
            "{\n" +
            "	//todo reconsider precision modifiers	 \n" +
            "	 highp vec4 color = vec4(1.0);//todo reimplement as a parameter\n" +
            "\n" +
            "	 highp float  d = textureCoordinate.y * slope  +  distance; \n" +
            "\n" +
            "	 highp vec4 c = texture2D(inputImageTexture, textureCoordinate) ; // consider using unpremultiply\n" +
            "\n" +
            "	 c = (c - d * color) / (1.0 -d);\n" +
            "\n" +
            "	 gl_FragColor = c; //consider using premultiply(c);\n" +
            "}\n";

    private float mDistance;
    private int mDistanceLocation;
    private float mSlope;
    private int mSlopeLocation;

    public GPUImageHazeFilter() {
        this(0.2f, 0.0f);
    }

    public GPUImageHazeFilter(float distance, float slope) {
        super(NO_FILTER_VERTEX_SHADER, HAZE_FRAGMENT_SHADER);
        mDistance = distance;
        mSlope = slope;
    }

    @Override
    public void onInit() {
        super.onInit();
        mDistanceLocation = GLES20.glGetUniformLocation(getProgram(), "distance");
        mSlopeLocation = GLES20.glGetUniformLocation(getProgram(), "slope");
    }

    @Override
    public void onInitialized() {
        super.onInitialized();
        setDistance(mDistance);
        setSlope(mSlope);
    }

    /**
     * Strength of the color applied. Default 0. Values between -.3 and .3 are best.
     *
     * @param distance -0.3 to 0.3 are best, default 0
     */
    public void setDistance(float distance) {
        mDistance = distance;
        setFloat(mDistanceLocation, distance);
    }

    /**
     * Amount of color change. Default 0. Values between -.3 and .3 are best.
     *
     * @param slope -0.3 to 0.3 are best, default 0
     */
    public void setSlope(float slope) {
        mSlope = slope;
        setFloat(mSlopeLocation, slope);
    }
}