gistfile1.txt

package project.android.imageprocessing.filter.processing;

import android.opengl.GLES20;

import project.android.imageprocessing.filter.TwoPassMultiPixelFilter;

/**
 * A more generalized 3x3 Gaussian blur filter
 * blurSize: A multiplier for the size of the blur, ranging from 0.0 on up
 * @author Chris Batt
 */
public class GaussianBlurFilter extends TwoPassMultiPixelFilter {
	private static final String UNIFORM_BLUR_SIZE = "u_BlurSize";

	private int blurSizeHandle;
	private float blurSize;

	public GaussianBlurFilter(float blurSize) {
		this.blurSize = blurSize;
	}

	@Override
	protected String getFragmentShader() {
		return
				"precision mediump float;\n"
						+"uniform sampler2D "+UNIFORM_TEXTURE0+";\n"
						+"varying vec2 "+VARYING_TEXCOORD+";\n"
						+"uniform float "+UNIFORM_BLUR_SIZE+";\n"
						+"uniform float "+UNIFORM_TEXELWIDTH+";\n"
						+"uniform float "+UNIFORM_TEXELHEIGHT+";\n"


						+"void main(){\n"
						+"   vec2 singleStepOffset = vec2("+UNIFORM_TEXELWIDTH+", "+UNIFORM_TEXELHEIGHT+");\n"
						+"   int multiplier = 0;\n"
						+"   vec2 blurStep = vec2(0,0);\n"
						+"   vec2 blurCoordinates[9];"
						+"   for(int i = 0; i < 9; i++) {\n"
						+"     multiplier = (i - 4);\n"
						+"     blurStep = float(multiplier) * "+UNIFORM_BLUR_SIZE+" * singleStepOffset;\n"
						+"     blurCoordinates[i] = "+VARYING_TEXCOORD+".xy + blurStep;\n"
						+"   }\n"
						+"   vec3 sum = vec3(0,0,0);\n"
						+"   vec4 color = texture2D("+UNIFORM_TEXTURE0+", blurCoordinates[4]);\n"
						+"   sum += textur" +
						"" +
						"" +
						"e2D("+UNIFORM_TEXTURE0+", blurCoordinates[0]).rgb * 0.05;\n"
						+"   sum += texture2D("+UNIFORM_TEXTURE0+", blurCoordinates[1]).rgb * 0.09;\n"
						+"   sum += texture2D("+UNIFORM_TEXTURE0+", blurCoordinates[2]).rgb * 0.12;\n"
						+"   sum += texture2D("+UNIFORM_TEXTURE0+", blurCoordinates[3]).rgb * 0.15;\n"
						+"   sum += color.rgb * 0.18;\n"
						+"   sum += texture2D("+UNIFORM_TEXTURE0+", blurCoordinates[5]).rgb * 0.15;\n"
						+"   sum += texture2D("+UNIFORM_TEXTURE0+", blurCoordinates[6]).rgb * 0.12;\n"
						+"   sum += texture2D("+UNIFORM_TEXTURE0+", blurCoordinates[7]).rgb * 0.09;\n"
						+"   sum += texture2D("+UNIFORM_TEXTURE0+", blurCoordinates[8]).rgb * 0.05;\n"
						+"   gl_FragColor = vec4(sum, color.a);\n"
						+"}\n";
	}

	@Override
	protected void initShaderHandles() {
		super.initShaderHandles();
		blurSizeHandle = GLES20.glGetUniformLocation(programHandle, UNIFORM_BLUR_SIZE);
	}

	@Override
	protected void passShaderValues() {
		super.passShaderValues();
		GLES20.glUniform1f(blurSizeHandle, blurSize);
	}
}