libs/core/src/eu/core/scurve.cc
| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | #include "eu/core/scurve.h" | ||
| 2 | |||
| 3 | #include "eu/assert/assert.h" | ||
| 4 | #include "eu/base/cint.h" | ||
| 5 | |||
| 6 | #include <cmath> | ||
| 7 | |||
| 8 | namespace eu::core | ||
| 9 | { | ||
| 10 | |||
| 11 | 5 | float square(float x) | |
| 12 | { | ||
| 13 | 5 | return x * x; | |
| 14 | } | ||
| 15 | |||
| 16 | 3 | SCurve s_curve_from_input(float mx, float my) | |
| 17 | { | ||
| 18 | 3 | const auto p0 = mx; | |
| 19 | // gustav addition: switch p1 to match curve to xy | ||
| 20 | 3 | const auto p1 = mx > 0.5f ? my : 1 - my; | |
| 21 | |||
| 22 | 6 | const auto o = [](float x) | |
| 23 | { | ||
| 24 | 6 | return x < 0.5f ? -0.5f * (2.0f * x * (2.0f * x - 2.0f)) : 2.0f * (square(x - 0.5f)) + 0.5f; | |
| 25 | }; | ||
| 26 | 3 | const auto q0 = o(p0); | |
| 27 | 3 | const auto q1 = o(p1); | |
| 28 | |||
| 29 | 3 | const auto a = [](float x) | |
| 30 | { | ||
| 31 | 3 | return std::pow(3.0f, x); | |
| 32 | }; | ||
| 33 | 3 | const auto slope = a(10 * (q0 - 0.5f)); | |
| 34 | 3 | const auto threshold = 0.5f + (0.5f * (1.0f - q1)); | |
| 35 | 3 | return {slope, threshold}; | |
| 36 | } | ||
| 37 | |||
| 38 | ✗ | float calculate_s_curve(float x, float slope, float threshold) | |
| 39 | { | ||
| 40 | ✗ | constexpr float machine_epsilon = 0.00001f; | |
| 41 | ✗ | return x < threshold ? | |
| 42 | ✗ | threshold * x / (x + slope * (threshold - x) + machine_epsilon) : | |
| 43 | ✗ | ((1 - threshold) * (x - 1)) / (1 - x - slope * (threshold - x) + machine_epsilon) + 1 | |
| 44 | ; | ||
| 45 | } | ||
| 46 | |||
| 47 | } // namespace eu::core | ||
| 48 |