grain.rs revision 23e1074f29f431f68c6b3230c1315ea0f7c7bc86 
1/*
2 * Copyright (C) 2012 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
17#include "ip.rsh"
18
19uchar __attribute__((kernel)) genRand() {
20    return (uchar)rsRand(0xff);
21}
22
23/*
24 * Convolution matrix of distance 2 with fixed point of 'kShiftBits' bits
25 * shifted. Thus the sum of this matrix should be 'kShiftValue'. Entries of
26 * small values are not calculated to gain efficiency.
27 * The order ot pixels represented in this matrix is:
28 *  1  2  3
29 *  4  0  5
30 *  6  7  8
31 *  and the matrix should be: {230, 56, 114, 56, 114, 114, 56, 114, 56}.
32 *  However, since most of the valus are identical, we only use the first three
33 *  entries and the entries corresponding to the pixels is:
34 *  1  2  1
35 *  2  0  2
36 *  1  2  1
37 */
38
39int32_t gWMask;
40int32_t gHMask;
41
42rs_allocation gBlendSource;
43uchar __attribute__((kernel)) blend9(uint32_t x, uint32_t y) {
44    uint32_t x1 = (x-1) & gWMask;
45    uint32_t x2 = (x+1) & gWMask;
46    uint32_t y1 = (y-1) & gHMask;
47    uint32_t y2 = (y+1) & gHMask;
48
49    uint p00 = 56 *  rsGetElementAt_uchar(gBlendSource, x1, y1);
50    uint p01 = 114 * rsGetElementAt_uchar(gBlendSource, x, y1);
51    uint p02 = 56 *  rsGetElementAt_uchar(gBlendSource, x2, y1);
52    uint p10 = 114 * rsGetElementAt_uchar(gBlendSource, x1, y);
53    uint p11 = 230 * rsGetElementAt_uchar(gBlendSource, x, y);
54    uint p12 = 114 * rsGetElementAt_uchar(gBlendSource, x2, y);
55    uint p20 = 56 *  rsGetElementAt_uchar(gBlendSource, x1, y2);
56    uint p21 = 114 * rsGetElementAt_uchar(gBlendSource, x, y2);
57    uint p22 = 56 *  rsGetElementAt_uchar(gBlendSource, x2, y2);
58
59    p00 += p01;
60    p02 += p10;
61    p11 += p12;
62    p20 += p21;
63
64    p22 += p00;
65    p02 += p11;
66
67    p20 += p22;
68    p20 += p02;
69
70    p20 = min(p20 >> 10, (uint)255);
71    return (uchar)p20;
72}
73
74float gNoiseStrength;
75
76rs_allocation gNoise;
77uchar4 __attribute__((kernel)) root(uchar4 in, uint32_t x, uint32_t y) {
78    float4 ip = convert_float4(in);
79    float pnoise = (float) rsGetElementAt_uchar(gNoise, x & gWMask, y & gHMask);
80
81    float energy_level = ip.r + ip.g + ip.b;
82    float energy_mask = (28.f - sqrt(energy_level)) * 0.03571f;
83    pnoise = (pnoise - 128.f) * energy_mask;
84
85    ip += pnoise * gNoiseStrength;
86    ip = clamp(ip, 0.f, 255.f);
87
88    uchar4 p = convert_uchar4(ip);
89    p.a = 0xff;
90    return p;
91}
92