Android Open Source - FxCameraApp Gl Shi Tomasi Feature Detection Shader

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Back to project page FxCameraApp.

License

The source code is released under:

MIT License

Java Source Code

package com.af.experiments.FxCameraApp.shaders;
/*from  www  . ja v  a2 s  . c  om*/
import static android.opengl.GLES20.glUniform1f;

public class GlShiTomasiFeatureDetectionShader extends GlShader {

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

      "varying highp vec2 vTextureCoord;" +
      "uniform lowp sampler2D sTexture;" +
      "uniform lowp float sensitivity;" +

      "void main() {" +
        "mediump vec3 derivativeElements = texture2D(sTexture, vTextureCoord).rgb;" +

        "mediump float derivativeDifference = derivativeElements.x - derivativeElements.y;" +
        "mediump float zElement = (derivativeElements.z * 2.0) - 1.0;" +

        // R = Ix^2 + Iy^2 - sqrt( (Ix^2 - Iy^2)^2 + 4 * Ixy * Ixy)
        "mediump float cornerness = derivativeElements.x + derivativeElements.y - sqrt(derivativeDifference * derivativeDifference + 4.0 * zElement * zElement);" +

        "gl_FragColor = vec4(vec3(cornerness * sensitivity), 1.0);" +
      "}";

  private float mSensitivity = 1.5f;

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


  public float getSensitivity() {
    return mSensitivity;
  }

  public void setSensitivity(final float sensitivity) {
    mSensitivity = sensitivity;
  }

  @Override
  public void onDraw() {
    glUniform1f(getHandle("sensitivity"), mSensitivity);
  }

}

Java Source Code List

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