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/*
* Copyright (C) 2011 The Android Open Source Project
*
* 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 android.filterpacks.imageproc;
import android.filterfw.core.Filter;
import android.filterfw.core.FilterContext;
import android.filterfw.core.Frame;
import android.filterfw.core.FrameFormat;
import android.filterfw.core.GenerateFieldPort;
import android.filterfw.core.KeyValueMap;
import android.filterfw.core.NativeProgram;
import android.filterfw.core.NativeFrame;
import android.filterfw.core.Program;
import android.filterfw.core.ShaderProgram;
import android.filterfw.format.ImageFormat;
import java.util.Date;
import java.util.Random;
public class BlackWhiteFilter extends Filter {
@GenerateFieldPort(name = "black", hasDefault = true)
private float mBlack = 0f;
@GenerateFieldPort(name = "white", hasDefault = true)
private float mWhite = 1f;
@GenerateFieldPort(name = "tile_size", hasDefault = true)
private int mTileSize = 640;
private Program mProgram;
private Random mRandom;
private int mTarget = FrameFormat.TARGET_UNSPECIFIED;
private final String mBlackWhiteShader =
"precision mediump float;\n" +
"uniform sampler2D tex_sampler_0;\n" +
"uniform vec2 seed;\n" +
"uniform float black;\n" +
"uniform float scale;\n" +
"uniform float stepsize;\n" +
"varying vec2 v_texcoord;\n" +
"float rand(vec2 loc) {\n" +
// Compute sin(theta), theta = 12.9898 x + 78.233y
// because floating point has limited range, make theta = theta1 + theta2
// where theta1 = 12x + 78y and theta2 = 0.9898x + 0.233y)
// Note that theta1 and theta2 cover diffent range of theta.
" float theta1 = dot(loc, vec2(0.9898, 0.233));\n" +
" float theta2 = dot(loc, vec2(12.0, 78.0));\n" +
// Use the property sin(theta) = cos(theta1)*sin(theta2)+sin(theta1)*cos(theta2)
// this approach also increases the precisions of sin(theta)
" float value = cos(theta1) * sin(theta2) + sin(theta1) * cos(theta2);\n" +
// fract(43758.5453 * x) = fract(43758 * x + 0.5453 * x)
// keep value of part1 in range: (2^-14 to 2^14). Since 43758 = 117 * 374
// fract(43758 * sin(theta)) = mod(221 * mod(198*sin(theta), 1.0), 1.0)
// also to keep as much decimal digits, use the property
// mod(mod(198*sin(theta)) = mod(mod(197*sin(theta) + sin(theta))
" float temp = mod(197.0 * value, 1.0) + value;\n" +
" float part1 = mod(220.0 * temp, 1.0) + temp;\n" +
" float part2 = value * 0.5453;\n" +
" float part3 = cos(theta1 + theta2) * 0.43758;\n" +
" return fract(part1 + part2 + part3);\n" +
"}\n" +
"void main() {\n" +
" vec4 color = texture2D(tex_sampler_0, v_texcoord);\n" +
" float dither = rand(v_texcoord + seed);\n" +
" vec3 xform = clamp((color.rgb - black) * scale, 0.0, 1.0);\n" +
" vec3 temp = clamp((color.rgb + stepsize - black) * scale, 0.0, 1.0);\n" +
" vec3 new_color = clamp(xform + (temp - xform) * (dither - 0.5), 0.0, 1.0);\n" +
" gl_FragColor = vec4(new_color, color.a);\n" +
"}\n";
public BlackWhiteFilter(String name) {
super(name);
mRandom = new Random(new Date().getTime());
}
@Override
public void setupPorts() {
addMaskedInputPort("image", ImageFormat.create(ImageFormat.COLORSPACE_RGBA));
addOutputBasedOnInput("image", "image");
}
@Override
public FrameFormat getOutputFormat(String portName, FrameFormat inputFormat) {
return inputFormat;
}
public void initProgram(FilterContext context, int target) {
switch (target) {
case FrameFormat.TARGET_GPU:
ShaderProgram shaderProgram = new ShaderProgram(context, mBlackWhiteShader);
shaderProgram.setMaximumTileSize(mTileSize);
mProgram = shaderProgram;
updateParameters();
break;
default:
throw new RuntimeException("Filter Sharpen does not support frames of " +
"target " + target + "!");
}
mTarget = target;
}
private void updateParameters() {
float scale = (mBlack != mWhite) ? 1.0f / (mWhite - mBlack) : 2000f;
float stepsize = 1.0f / 255.0f;
mProgram.setHostValue("black", mBlack);
mProgram.setHostValue("scale", scale);
mProgram.setHostValue("stepsize", stepsize);
float seed[] = { mRandom.nextFloat(), mRandom.nextFloat() };
mProgram.setHostValue("seed", seed);
}
@Override
public void fieldPortValueUpdated(String name, FilterContext context) {
if (mProgram != null) {
updateParameters();
}
}
@Override
public void process(FilterContext context) {
// Get input frame
Frame input = pullInput("image");
FrameFormat inputFormat = input.getFormat();
// Create program if not created already
if (mProgram == null || inputFormat.getTarget() != mTarget) {
initProgram(context, inputFormat.getTarget());
}
// Create output frame
Frame output = context.getFrameManager().newFrame(inputFormat);
// Process
mProgram.process(input, output);
// Push output
pushOutput("image", output);
// Release pushed frame
output.release();
}
}
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