```/* <![CDATA[ */
function get_sym_list(){return [];} /* ]]> */1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
9 *
10 * Unless required by applicable law or agreed to in writing, software
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#pragma rs_fp_relaxed
19
20int height;
21int width;
23
24rs_allocation InPixel;
25rs_allocation ScratchPixel1;
26rs_allocation ScratchPixel2;
27
29
30// Store our coefficients here
31static float gaussian[MAX_RADIUS * 2 + 1];
32
35    // Compute gaussian weights for the blur
36    // e is the euler's number
37    float e = 2.718281828459045f;
38    float pi = 3.1415926535897932f;
39    // g(x) = ( 1 / sqrt( 2 * pi ) * sigma) * e ^ ( -x^2 / 2 * sigma^2 )
40    // x is of the form [-radius .. 0 .. radius]
41    // and sigma varies with radius.
42    // Based on some experimental radius values and sigma's
43    // we approximately fit sigma = f(radius) as
44    // sigma = radius * 0.4  + 0.6
45    // The larger the radius gets, the more our gaussian blur
46    // will resemble a box blur since with large sigma
47    // the gaussian curve begins to lose its shape
48    float sigma = 0.4f * (float)radius + 0.6f;
49
50    // Now compute the coefficints
51    // We will store some redundant values to save some math during
52    // the blur calculations
53    // precompute some values
54    float coeff1 = 1.0f / (sqrt( 2.0f * pi ) * sigma);
55    float coeff2 = - 1.0f / (2.0f * sigma * sigma);
56
57    float normalizeFactor = 0.0f;
58    float floatR = 0.0f;
59    for (int r = -radius; r <= radius; r ++) {
60        floatR = (float)r;
61        gaussian[r + radius] = coeff1 * pow(e, floatR * floatR * coeff2);
62        normalizeFactor += gaussian[r + radius];
63    }
64
65    //Now we need to normalize the weights because all our coefficients need to add up to one
66    normalizeFactor = 1.0f / normalizeFactor;
67    for (int r = -radius; r <= radius; r ++) {
68        floatR = (float)r;
69        gaussian[r + radius] *= normalizeFactor;
70    }
71}
72
73float4 RS_KERNEL copyIn(uchar4 in) {
74    return convert_float4(in);
75}
76
77uchar4 RS_KERNEL vert(uint32_t x, uint32_t y) {
78    float3 blurredPixel = 0;
79    int gi = 0;
80    uchar4 out;
81    if ((y > radius) && (y < (height - radius))) {
82        for (int r = -radius; r <= radius; r ++) {
83            float4 i = rsGetElementAt_float4(ScratchPixel2, x, y + r);
84            blurredPixel += i.xyz * gaussian[gi++];
85        }
86    } else {
87        for (int r = -radius; r <= radius; r ++) {
88            int validH = rsClamp((int)y + r, (int)0, (int)(height - 1));
89            float4 i = rsGetElementAt_float4(ScratchPixel2, x, validH);
90            blurredPixel += i.xyz * gaussian[gi++];
91        }
92    }
93
94    out.xyz = convert_uchar3(clamp(blurredPixel, 0.f, 255.f));
95    out.w = 0xff;
96    return out;
97}
98
99float4 RS_KERNEL horz(uint32_t x, uint32_t y) {
100    float4 blurredPixel = 0;
101    int gi = 0;
102    if ((x > radius) && (x < (width - radius))) {
103        for (int r = -radius; r <= radius; r ++) {
104            float4 i = rsGetElementAt_float4(ScratchPixel1, x + r, y);
105            blurredPixel += i * gaussian[gi++];
106        }
107    } else {
108        for (int r = -radius; r <= radius; r ++) {
109            // Stepping left and right away from the pixel
110            int validX = rsClamp((int)x + r, (int)0, (int)(width - 1));
111            float4 i = rsGetElementAt_float4(ScratchPixel1, validX, y);
112            blurredPixel += i * gaussian[gi++];
113        }
114    }
115
116    return blurredPixel;
117}
118
119```