BlackWhiteFilter.java revision 0a1013229254cdc146d4ce2f4b4aef301b018f09
1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.filterpacks.imageproc; 18 19import android.filterfw.core.Filter; 20import android.filterfw.core.FilterContext; 21import android.filterfw.core.Frame; 22import android.filterfw.core.FrameFormat; 23import android.filterfw.core.GenerateFieldPort; 24import android.filterfw.core.KeyValueMap; 25import android.filterfw.core.NativeProgram; 26import android.filterfw.core.NativeFrame; 27import android.filterfw.core.Program; 28import android.filterfw.core.ShaderProgram; 29import android.filterfw.format.ImageFormat; 30 31import java.util.Date; 32import java.util.Random; 33 34public class BlackWhiteFilter extends Filter { 35 36 @GenerateFieldPort(name = "black", hasDefault = true) 37 private float mBlack = 0f; 38 39 @GenerateFieldPort(name = "white", hasDefault = true) 40 private float mWhite = 1f; 41 42 @GenerateFieldPort(name = "tile_size", hasDefault = true) 43 private int mTileSize = 640; 44 45 private Program mProgram; 46 private Random mRandom; 47 48 private int mTarget = FrameFormat.TARGET_UNSPECIFIED; 49 50 private final String mBlackWhiteShader = 51 "precision mediump float;\n" + 52 "uniform sampler2D tex_sampler_0;\n" + 53 "uniform vec2 seed;\n" + 54 "uniform float black;\n" + 55 "uniform float scale;\n" + 56 "uniform float stepsize;\n" + 57 "varying vec2 v_texcoord;\n" + 58 "float rand(vec2 loc) {\n" + 59 // Compute sin(theta), theta = 12.9898 x + 78.233y 60 // because floating point has limited range, make theta = theta1 + theta2 61 // where theta1 = 12x + 78y and theta2 = 0.9898x + 0.233y) 62 // Note that theta1 and theta2 cover diffent range of theta. 63 " float theta1 = dot(loc, vec2(0.9898, 0.233));\n" + 64 " float theta2 = dot(loc, vec2(12.0, 78.0));\n" + 65 // Use the property sin(theta) = cos(theta1)*sin(theta2)+sin(theta1)*cos(theta2) 66 // this approach also increases the precisions of sin(theta) 67 " float value = cos(theta1) * sin(theta2) + sin(theta1) * cos(theta2);\n" + 68 // fract(43758.5453 * x) = fract(43758 * x + 0.5453 * x) 69 // keep value of part1 in range: (2^-14 to 2^14). Since 43758 = 117 * 374 70 // fract(43758 * sin(theta)) = mod(221 * mod(198*sin(theta), 1.0), 1.0) 71 // also to keep as much decimal digits, use the property 72 // mod(mod(198*sin(theta)) = mod(mod(197*sin(theta) + sin(theta)) 73 " float temp = mod(197.0 * value, 1.0) + value;\n" + 74 " float part1 = mod(220.0 * temp, 1.0) + temp;\n" + 75 " float part2 = value * 0.5453;\n" + 76 " float part3 = cos(theta1 + theta2) * 0.43758;\n" + 77 " return fract(part1 + part2 + part3);\n" + 78 "}\n" + 79 "void main() {\n" + 80 " vec4 color = texture2D(tex_sampler_0, v_texcoord);\n" + 81 " float dither = rand(v_texcoord + seed);\n" + 82 " vec3 xform = clamp((color.rgb - black) * scale, 0.0, 1.0);\n" + 83 " vec3 temp = clamp((color.rgb + stepsize - black) * scale, 0.0, 1.0);\n" + 84 " vec3 new_color = clamp(xform + (temp - xform) * (dither - 0.5), 0.0, 1.0);\n" + 85 " gl_FragColor = vec4(new_color, color.a);\n" + 86 "}\n"; 87 88 public BlackWhiteFilter(String name) { 89 super(name); 90 mRandom = new Random(new Date().getTime()); 91 } 92 93 @Override 94 public void setupPorts() { 95 addMaskedInputPort("image", ImageFormat.create(ImageFormat.COLORSPACE_RGBA)); 96 addOutputBasedOnInput("image", "image"); 97 } 98 99 @Override 100 public FrameFormat getOutputFormat(String portName, FrameFormat inputFormat) { 101 return inputFormat; 102 } 103 104 public void initProgram(FilterContext context, int target) { 105 switch (target) { 106 case FrameFormat.TARGET_GPU: 107 ShaderProgram shaderProgram = new ShaderProgram(context, mBlackWhiteShader); 108 shaderProgram.setMaximumTileSize(mTileSize); 109 mProgram = shaderProgram; 110 updateParameters(); 111 break; 112 113 default: 114 throw new RuntimeException("Filter Sharpen does not support frames of " + 115 "target " + target + "!"); 116 } 117 mTarget = target; 118 } 119 120 private void updateParameters() { 121 float scale = (mBlack != mWhite) ? 1.0f / (mWhite - mBlack) : 2000f; 122 float stepsize = 1.0f / 255.0f; 123 mProgram.setHostValue("black", mBlack); 124 mProgram.setHostValue("scale", scale); 125 mProgram.setHostValue("stepsize", stepsize); 126 127 float seed[] = { mRandom.nextFloat(), mRandom.nextFloat() }; 128 mProgram.setHostValue("seed", seed); 129 } 130 131 @Override 132 public void fieldPortValueUpdated(String name, FilterContext context) { 133 if (mProgram != null) { 134 updateParameters(); 135 } 136 } 137 138 @Override 139 public void process(FilterContext context) { 140 // Get input frame 141 Frame input = pullInput("image"); 142 FrameFormat inputFormat = input.getFormat(); 143 144 // Create program if not created already 145 if (mProgram == null || inputFormat.getTarget() != mTarget) { 146 initProgram(context, inputFormat.getTarget()); 147 } 148 149 // Create output frame 150 Frame output = context.getFrameManager().newFrame(inputFormat); 151 152 // Process 153 mProgram.process(input, output); 154 155 // Push output 156 pushOutput("image", output); 157 158 // Release pushed frame 159 output.release(); 160 } 161} 162