GPUImageExposureFilter.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;

/**
 * exposure: The adjusted exposure (-10.0 - 10.0, with 0.0 as the default)
 */
public class GPUImageExposureFilter extends GPUImageFilter {
    public static final String EXPOSURE_FRAGMENT_SHADER = "" +
            " varying highp vec2 textureCoordinate;\n" +
            " \n" +
            " uniform sampler2D inputImageTexture;\n" +
            " uniform highp float exposure;\n" +
            " \n" +
            " void main()\n" +
            " {\n" +
            "     highp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);\n" +
            "     \n" +
            "     gl_FragColor = vec4(textureColor.rgb * pow(2.0, exposure), textureColor.w);\n" +
            " } ";

    private int mExposureLocation;
    private float mExposure;

    public GPUImageExposureFilter() {
        this(1.0f);
    }

    public GPUImageExposureFilter(final float exposure) {
        super(NO_FILTER_VERTEX_SHADER, EXPOSURE_FRAGMENT_SHADER);
        mExposure = exposure;
    }

    @Override
    public void onInit() {
        super.onInit();
        mExposureLocation = GLES20.glGetUniformLocation(getProgram(), "exposure");
    }

    @Override
    public void onInitialized() {
        super.onInitialized();
        setExposure(mExposure);
    }

    public void setExposure(final float exposure) {
        mExposure = exposure;
        setFloat(mExposureLocation, mExposure);
    }
}