contrast.rs revision 6939f7bf32ab2765dcedb8a8d6fd352e7d08540f 
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#pragma rs_fp_relaxed
19
20static float brightM = 0.f;
21static float brightC = 0.f;
22
23void setBright(float v) {
24    brightM = pow(2.f, v / 100.f);
25    brightC = 127.f - brightM * 127.f;
26}
27
28void contrast(const uchar4 *in, uchar4 *out)
29{
30#if 0
31    out->r = rsClamp((int)(brightM * in->r + brightC), 0, 255);
32    out->g = rsClamp((int)(brightM * in->g + brightC), 0, 255);
33    out->b = rsClamp((int)(brightM * in->b + brightC), 0, 255);
34#else
35    float3 v = convert_float3(in->rgb) * brightM + brightC;
36    out->rgb = convert_uchar3(clamp(v, 0.f, 255.f));
37#endif
38}
39