mirror of
https://github.com/openharmony/graphic_utils.git
synced 2026-07-01 21:44:51 -04:00
mamingshuai
96 lines
3.4 KiB
C++
Executable File
96 lines
3.4 KiB
C++
Executable File
/*
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* Copyright (c) 2020-2021 Huawei Device Co., Ltd.
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "graphic_math.h"
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namespace OHOS {
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static float g_sinValues[] = {
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0.000000, 0.017452, 0.034899, 0.052336, 0.069756, 0.087156, 0.104528, 0.121869, 0.139173, 0.156434, 0.173648,
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0.190809, 0.207912, 0.224951, 0.241922, 0.258819, 0.275637, 0.292372, 0.309017, 0.325568, 0.342020, 0.358368,
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0.374607, 0.390731, 0.406737, 0.422618, 0.438371, 0.453990, 0.469472, 0.484810, 0.500000, 0.515038, 0.529919,
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0.544639, 0.559193, 0.573576, 0.587785, 0.601815, 0.615661, 0.629320, 0.642788, 0.656059, 0.669131, 0.681998,
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0.694658, 0.707107, 0.719340, 0.731354, 0.743145, 0.754710, 0.766044, 0.777146, 0.788011, 0.798636, 0.809017,
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0.819152, 0.829038, 0.838671, 0.848048, 0.857167, 0.866025, 0.874620, 0.882948, 0.891007, 0.898794, 0.906308,
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0.913545, 0.920505, 0.927184, 0.933580, 0.939693, 0.945519, 0.951057, 0.956305, 0.961262, 0.965926, 0.970296,
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0.974370, 0.978148, 0.981627, 0.984808, 0.987688, 0.990268, 0.992546, 0.994522, 0.996195, 0.997564, 0.998630,
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0.999391, 0.999848, 1.000000
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};
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float Sin(int16_t angle)
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{
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angle = angle % CIRCLE_IN_DEGREE;
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if (angle < 0) {
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angle = CIRCLE_IN_DEGREE + angle;
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}
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if (angle <= QUARTER_IN_DEGREE) {
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return g_sinValues[angle];
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} else if (angle <= SEMICIRCLE_IN_DEGREE) {
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return g_sinValues[SEMICIRCLE_IN_DEGREE - angle];
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} else if (angle <= THREE_QUARTER_IN_DEGREE) {
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return -g_sinValues[angle - SEMICIRCLE_IN_DEGREE];
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} else {
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return -g_sinValues[CIRCLE_IN_DEGREE - angle];
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}
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}
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/* arctan(x) = x - p3 * x^3 + p5 * x^5 - p7 * x^7 */
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uint16_t FastAtan2(int16_t x, int16_t y)
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{
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if (x == 0 && y == 0) {
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return 0;
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}
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int16_t absX = MATH_ABS(x);
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int16_t absY = MATH_ABS(y);
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float t;
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float t2;
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uint16_t angle;
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if (absX <= absY) {
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t = static_cast<float>(absX) / absY;
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t2 = t * t;
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angle = static_cast<uint16_t>(t * (1 + t2 * (ATAN2_P3 + t2 * (ATAN2_P5 + t2 * ATAN2_P7))) * RADIAN_TO_ANGLE);
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} else {
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t = static_cast<float>(absY) / absX;
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t2 = t * t;
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angle = QUARTER_IN_DEGREE -
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static_cast<uint16_t>(t * (1 + t2 * (ATAN2_P3 + t2 * (ATAN2_P5 + t2 * ATAN2_P7))) * RADIAN_TO_ANGLE);
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}
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if (y < 0) {
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if (x < 0) {
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angle = SEMICIRCLE_IN_DEGREE + angle;
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} else {
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angle = SEMICIRCLE_IN_DEGREE - angle;
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}
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} else if (x < 0) {
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angle = CIRCLE_IN_DEGREE - angle;
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}
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return angle;
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}
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float Sqrt(float x)
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{
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const float xhalf = 0.5f * x;
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int32_t i = *(int32_t*)&x;
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i = 0x5f375a86 - (i / 2); // 0x5f375a86 : Initial value of Newton Iterator. 2 : inital parameter for iterator.
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float y = *(float*)&i;
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y = y * (1.5f - (xhalf * y * y));
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y = y * (1.5f - (xhalf * y * y));
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y = y * (1.5f - (xhalf * y * y));
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return x * y;
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}
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} // namespace OHOS
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