GPUImageSwirlFilter

GPUImageSwirlFilter.java

/*
 * Copyright (C) 2012 CyberAgent
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package jp.co.cyberagent.android.gpuimage;

import android.graphics.PointF;
import android.opengl.GLES20;

public class GPUImageSwirlFilter extends GPUImageFilter {
  public static final String SWIRL_FRAGMENT_SHADER = "" +
			"varying highp vec2 textureCoordinate;\n" +
			"uniform sampler2D inputImageTexture;\n" +
			"uniform highp vec2 center;\n" +
			"uniform highp float radius;\n" +
			"uniform highp float angle;\n" +
			"void main()\n" +
			"{\n" +
			"	highp vec2 textureCoordinateToUse = textureCoordinate;\n" +
			"	highp float dist = distance(center, textureCoordinate);\n" +
			"	if (dist < radius)\n" +
			"	{\n" +
			"		textureCoordinateToUse -= center;\n" +
			"		highp float percent = (radius - dist) / radius;\n" +
			"		highp float theta = percent * percent * angle * 8.0;\n" +
			"		highp float s = sin(theta);\n" +
			"		highp float c = cos(theta);\n" +
			"		textureCoordinateToUse = vec2(dot(textureCoordinateToUse, vec2(c, -s)), dot(textureCoordinateToUse, vec2(s, c)));\n" +
			"		textureCoordinateToUse += center;\n" +
			"	}\n" +
			"	gl_FragColor = texture2D(inputImageTexture, textureCoordinateToUse);\n" +
			"}";

	private int mCenterLocation;
	private int mRadiusLocation;
	private int mAngleLocation;

	private float mRadius;
	private float mAngle;
	private PointF mCenter;

	public GPUImageSwirlFilter() {
		super(NO_FILTER_VERTEX_SHADER, SWIRL_FRAGMENT_SHADER);
	}

	@Override
	public void onInit() {
		super.onInit();

		mCenterLocation = GLES20.glGetUniformLocation(getProgram(), "center");
		mRadiusLocation = GLES20.glGetUniformLocation(getProgram(), "radius");
		mAngleLocation = GLES20.glGetUniformLocation(getProgram(), "angle");
	}

	@Override
	public void onInitialized() {
		super.onInitialized();
		
		setCenter(new PointF(0.5f, 0.5f));
		setRadius(0.5f);
		setAngle(1.0f);
	}

	public void setCenter(final PointF center) {
		mCenter = center;
		setPoint(mCenterLocation, mCenter);
	}
	
	public void setRadius(final float radius) {
		mRadius = radius;
		
		setFloat(mRadiusLocation, mRadius);
	}

	public void setAngle(final float angle) {
		mAngle = angle;
		setFloat(mAngleLocation, mAngle);
	}
}