GlColorMatrixShader.java

package com.af.experiments.FxCameraApp.shaders;

import static android.opengl.GLES20.glUniform1f;
import static android.opengl.GLES20.glUniformMatrix4fv;

public class GlColorMatrixShader  extends GlShader {

    private static final String FRAGMENT_SHADER =
            "precision mediump float;" +

                    "varying highp vec2 vTextureCoord;" +
                    "uniform lowp sampler2D sTexture;" +
                    "uniform lowp mat4 colorMatrix;" +
                    "uniform lowp float intensity;" +

                    "void main() {" +
                    "lowp vec4 color = texture2D(sTexture, vTextureCoord);" +
                    "lowp vec4 outputColor = color * colorMatrix;" +
                    "gl_FragColor = (intensity * outputColor) + ((1.0 - intensity) * color);" +
                    "}";

    private float[] mColorMatrix = new float[]{
            1f, 0f, 0f, 0f,
            0f, 1f, 0f, 0f,
            0f, 0f, 1f, 0f,
            0f, 0f, 0f, 1f
    };

    private float mIntensity = 1.0f;

    public GlColorMatrixShader() {
        super(DEFAULT_VERTEX_SHADER, FRAGMENT_SHADER);
    }


    public float[] getColorMatrix() {
        return mColorMatrix;
    }

    public void setColorMatrix(float[] colorMatrix) {
        mColorMatrix = colorMatrix;
    }

    public float getIntensity() {
        return mIntensity;
    }

    public void setIntensity(float intensity) {
        mIntensity = intensity;
    }


    @Override
    public void onDraw() {
        glUniformMatrix4fv(getHandle("colorMatrix"), 0, false, mColorMatrix, 0);
        glUniform1f(getHandle("intensity"), mIntensity);
    }
}