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/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MATHUTILS_H
#define MATHUTILS_H
namespace android {
namespace uirenderer {
#define NON_ZERO_EPSILON (0.001f)
#define ALPHA_EPSILON (0.001f)
class MathUtils {
public:
/**
* Check for floats that are close enough to zero.
*/
inline static bool isZero(float value) {
return (value >= -NON_ZERO_EPSILON) && (value <= NON_ZERO_EPSILON);
}
inline static bool isPositive(float value) {
return value >= NON_ZERO_EPSILON;
}
/**
* Clamps alpha value, and snaps when very near 0 or 1
*/
inline static float clampAlpha(float alpha) {
if (alpha <= ALPHA_EPSILON) {
return 0;
} else if (alpha >= (1 - ALPHA_EPSILON)) {
return 1;
} else {
return alpha;
}
}
/*
* Clamps positive tessellation scale values
*/
inline static float clampTessellationScale(float scale) {
const float MIN_SCALE = 0.0001;
const float MAX_SCALE = 1e10;
if (scale < MIN_SCALE) {
return MIN_SCALE;
} else if (scale > MAX_SCALE) {
return MAX_SCALE;
}
return scale;
}
inline static bool areEqual(float valueA, float valueB) {
return isZero(valueA - valueB);
}
template<typename T>
static inline T max(T a, T b) {
return a > b ? a : b;
}
template<typename T>
static inline T min(T a, T b) {
return a < b ? a : b;
}
template<typename T>
static inline T clamp(T a, T minValue, T maxValue) {
return min(max(a, minValue), maxValue);
}
inline static float lerp(float v1, float v2, float t) {
return v1 + ((v2 - v1) * t);
}
}; // class MathUtils
} /* namespace uirenderer */
} /* namespace android */
#endif /* MATHUTILS_H */
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