Android Open Source - FxCameraApp Gl Gaussian Blur Shader

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Back to project page FxCameraApp.

License

The source code is released under:

MIT License

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Java Source Code

package com.af.experiments.FxCameraApp.shaders;
/* w ww .j  ava 2  s .  com*/
import static android.opengl.GLES20.glUniform1f;

public class GlGaussianBlurShader extends GlShader {

  private static final String VERTEX_SHADER =
    "attribute vec4 aPosition;" +
    "attribute vec4 aTextureCoord;" +

    "const lowp int GAUSSIAN_SAMPLES = 9;" +

    "uniform highp float texelWidthOffset;" +
    "uniform highp float texelHeightOffset;" +
    "uniform highp float blurSize;" +

    "varying highp vec2 blurCoordinates[GAUSSIAN_SAMPLES];" +

    "void main() {" +
      "gl_Position = aPosition;" +
      "highp vec2 vTextureCoord = aTextureCoord.xy;" +

      // Calculate the positions for the blur
      "int multiplier = 0;" +
      "highp vec2 blurStep;" +
      "highp vec2 singleStepOffset = vec2(texelHeightOffset, texelWidthOffset) * blurSize;" +

      "for (lowp int i = 0; i < GAUSSIAN_SAMPLES; i++) {" +
        "multiplier = (i - ((GAUSSIAN_SAMPLES - 1) / 2));" +
        // Blur in x (horizontal)
        "blurStep = float(multiplier) * singleStepOffset;" +
        "blurCoordinates[i] = vTextureCoord.xy + blurStep;" +
      "}" +
    "}";

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

      "const lowp int GAUSSIAN_SAMPLES = 9;" +
      "varying highp vec2 blurCoordinates[GAUSSIAN_SAMPLES];" +

      "uniform lowp sampler2D sTexture;" +

      "void main() {" +
        "lowp vec4 sum = vec4(0.0);" +

        "sum += texture2D(sTexture, blurCoordinates[0]) * 0.05;" +
        "sum += texture2D(sTexture, blurCoordinates[1]) * 0.09;" +
        "sum += texture2D(sTexture, blurCoordinates[2]) * 0.12;" +
        "sum += texture2D(sTexture, blurCoordinates[3]) * 0.15;" +
        "sum += texture2D(sTexture, blurCoordinates[4]) * 0.18;" +
        "sum += texture2D(sTexture, blurCoordinates[5]) * 0.15;" +
        "sum += texture2D(sTexture, blurCoordinates[6]) * 0.12;" +
        "sum += texture2D(sTexture, blurCoordinates[7]) * 0.09;" +
        "sum += texture2D(sTexture, blurCoordinates[8]) * 0.05;" +

        "gl_FragColor = sum;" +
      "}";

  private float mTexelWidthOffset = 0.01f;
  private float mTexelHeightOffset = 0.01f;
  private float mBlurSize = 0.2f;

  public GlGaussianBlurShader() {
    super(VERTEX_SHADER, FRAGMENT_SHADER);
  }
  protected String mShaderName = "Gauss blur";

  public String getName() {
    return mShaderName;
  }

  public float getTexelWidthOffset() {
    return mTexelWidthOffset;
  }

  public void setTexelWidthOffset(final float texelWidthOffset) {
    mTexelWidthOffset = texelWidthOffset;
  }

  public float getTexelHeightOffset() {
    return mTexelHeightOffset;
  }

  public void setTexelHeightOffset(final float texelHeightOffset) {
    mTexelHeightOffset = texelHeightOffset;
  }

  public float getBlurSize() {
    return mBlurSize;
  }

  public void setBlurSize(final float blurSize) {
    mBlurSize = blurSize;
  }


  @Override
  public void onDraw() {
    glUniform1f(getHandle("texelWidthOffset"), mTexelWidthOffset);
    glUniform1f(getHandle("texelHeightOffset"), mTexelHeightOffset);
    glUniform1f(getHandle("blurSize"), mBlurSize);
  }

}

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