package jp.co.cyberagent.android.gpuimage;
import android.opengl.GLES20;
public class GPUImageSobelThresholdFilter extends
GPUImage3x3TextureSamplingFilter {
public static final String SOBEL_THRESHOLD_EDGE_DETECTION = "" +
"precision mediump float;\n" +
"\n" +
"varying vec2 textureCoordinate;\n" +
"varying vec2 leftTextureCoordinate;\n" +
"varying vec2 rightTextureCoordinate;\n" +
"\n" +
"varying vec2 topTextureCoordinate;\n" +
"varying vec2 topLeftTextureCoordinate;\n" +
"varying vec2 topRightTextureCoordinate;\n" +
"\n" +
"varying vec2 bottomTextureCoordinate;\n" +
"varying vec2 bottomLeftTextureCoordinate;\n" +
"varying vec2 bottomRightTextureCoordinate;\n" +
"\n" +
"uniform sampler2D inputImageTexture;\n" +
"uniform lowp float threshold;\n" +
"\n" +
"const highp vec3 W = vec3(0.2125, 0.7154, 0.0721);\n" +
"\n" +
"void main()\n" +
"{\n" +
" float bottomLeftIntensity = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;\n" +
" float topRightIntensity = texture2D(inputImageTexture, topRightTextureCoordinate).r;\n" +
" float topLeftIntensity = texture2D(inputImageTexture, topLeftTextureCoordinate).r;\n" +
" float bottomRightIntensity = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;\n" +
" float leftIntensity = texture2D(inputImageTexture, leftTextureCoordinate).r;\n" +
" float rightIntensity = texture2D(inputImageTexture, rightTextureCoordinate).r;\n" +
" float bottomIntensity = texture2D(inputImageTexture, bottomTextureCoordinate).r;\n" +
" float topIntensity = texture2D(inputImageTexture, topTextureCoordinate).r;\n" +
" float h = -topLeftIntensity - 2.0 * topIntensity - topRightIntensity + bottomLeftIntensity + 2.0 * bottomIntensity + bottomRightIntensity;\n" +
" float v = -bottomLeftIntensity - 2.0 * leftIntensity - topLeftIntensity + bottomRightIntensity + 2.0 * rightIntensity + topRightIntensity;\n" +
"\n" +
" float mag = 1.0 - length(vec2(h, v));\n" +
" mag = step(threshold, mag);\n" +
"\n" +
" gl_FragColor = vec4(vec3(mag), 1.0);\n" +
"}\n";
private int mUniformThresholdLocation;
private float mThreshold = 0.9f;
public GPUImageSobelThresholdFilter() {
this(0.9f);
}
public GPUImageSobelThresholdFilter(float threshold) {
super(SOBEL_THRESHOLD_EDGE_DETECTION);
mThreshold = threshold;
}
@Override
public void onInit() {
super.onInit();
mUniformThresholdLocation = GLES20.glGetUniformLocation(getProgram(), "threshold");
}
@Override
public void onInitialized() {
super.onInitialized();
setThreshold(mThreshold);
}
public void setThreshold(final float threshold) {
mThreshold = threshold;
setFloat(mUniformThresholdLocation, threshold);
}
}