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.Program;
25import android.filterfw.core.ShaderProgram;
26import android.filterfw.format.ImageFormat;
27
28public class VignetteFilter extends Filter {
29
30    @GenerateFieldPort(name = "scale", hasDefault = true)
31    private float mScale = 0f;
32
33    @GenerateFieldPort(name = "tile_size", hasDefault = true)
34    private int mTileSize = 640;
35
36    private Program mProgram;
37
38    private int mWidth = 0;
39    private int mHeight = 0;
40    private int mTarget = FrameFormat.TARGET_UNSPECIFIED;
41
42    private final float mSlope = 20.0f;
43    private final float mShade = 0.85f;
44
45    private final String mVignetteShader =
46            "precision mediump float;\n" +
47            "uniform sampler2D tex_sampler_0;\n" +
48            "uniform float range;\n" +
49            "uniform float inv_max_dist;\n" +
50            "uniform float shade;\n" +
51            "uniform vec2 scale;\n" +
52            "varying vec2 v_texcoord;\n" +
53            "void main() {\n" +
54            "  const float slope = 20.0;\n" +
55            "  vec2 coord = v_texcoord - vec2(0.5, 0.5);\n" +
56            "  float dist = length(coord * scale);\n" +
57            "  float lumen = shade / (1.0 + exp((dist * inv_max_dist - range) * slope)) + (1.0 - shade);\n" +
58            "  vec4 color = texture2D(tex_sampler_0, v_texcoord);\n" +
59            "  gl_FragColor = vec4(color.rgb * lumen, color.a);\n" +
60            "}\n";
61
62    public VignetteFilter(String name) {
63        super(name);
64    }
65
66    @Override
67    public void setupPorts() {
68        addMaskedInputPort("image", ImageFormat.create(ImageFormat.COLORSPACE_RGBA));
69        addOutputBasedOnInput("image", "image");
70    }
71
72    @Override
73    public FrameFormat getOutputFormat(String portName, FrameFormat inputFormat) {
74        return inputFormat;
75    }
76
77    public void initProgram(FilterContext context, int target) {
78        switch (target) {
79            case FrameFormat.TARGET_GPU:
80                ShaderProgram shaderProgram = new ShaderProgram(context, mVignetteShader);
81                shaderProgram.setMaximumTileSize(mTileSize);
82                mProgram = shaderProgram;
83                break;
84
85            default:
86                throw new RuntimeException("Filter Sharpen does not support frames of " +
87                    "target " + target + "!");
88        }
89        mTarget = target;
90    }
91
92    private void initParameters() {
93        if (mProgram != null) {
94            float scale[] = new float[2];
95            if (mWidth > mHeight) {
96                scale[0] = 1f;
97                scale[1] = ((float) mHeight) / mWidth;
98            } else {
99                scale[0] = ((float) mWidth) / mHeight;
100                scale[1] = 1f;
101            }
102            float max_dist = ((float) Math.sqrt(scale[0] * scale[0] + scale[1] * scale[1])) * 0.5f;
103            mProgram.setHostValue("scale", scale);
104            mProgram.setHostValue("inv_max_dist", 1f / max_dist);
105            mProgram.setHostValue("shade", mShade);
106
107            updateParameters();
108        }
109    }
110
111    private void updateParameters() {
112        // The 'range' is between 1.3 to 0.6. When scale is zero then range is 1.3
113        // which means no vignette at all because the luminousity difference is
114        // less than 1/256 and will cause nothing.
115        mProgram.setHostValue("range", 1.30f - (float) Math.sqrt(mScale) * 0.7f);
116    }
117
118    @Override
119    public void fieldPortValueUpdated(String name, FilterContext context) {
120        if (mProgram != null) {
121            updateParameters();
122        }
123    }
124
125    @Override
126    public void process(FilterContext context) {
127        // Get input frame
128        Frame input = pullInput("image");
129        FrameFormat inputFormat = input.getFormat();
130
131        // Create program if not created already
132        if (mProgram == null || inputFormat.getTarget() != mTarget) {
133            initProgram(context, inputFormat.getTarget());
134        }
135
136        // Check if the frame size has changed
137        if (inputFormat.getWidth() != mWidth || inputFormat.getHeight() != mHeight) {
138            mWidth = inputFormat.getWidth();
139            mHeight = inputFormat.getHeight();
140            initParameters();
141        }
142
143        // Create output frame
144        Frame output = context.getFrameManager().newFrame(inputFormat);
145
146        // Process
147        mProgram.process(input, output);
148
149        // Push output
150        pushOutput("image", output);
151
152        // Release pushed frame
153        output.release();
154    }
155}
156