| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | //------------------------------------------------------------------------------ | ||
| 2 | // VERSION 0.1 | ||
| 3 | // | ||
| 4 | // LICENSE | ||
| 5 | // This software is dual-licensed to the public domain and under the following | ||
| 6 | // license: you are granted a perpetual, irrevocable license to copy, modify, | ||
| 7 | // publish, and distribute this file as you see fit. | ||
| 8 | // | ||
| 9 | // CREDITS | ||
| 10 | // Written by Michal Cichon | ||
| 11 | //------------------------------------------------------------------------------ | ||
| 12 | |||
| 13 | #define IMGUI_DEFINE_MATH_OPERATORS | ||
| 14 | #include "imgui_extra_math.h" | ||
| 15 | #include "bezier.h" | ||
| 16 | |||
| 17 | ImProjectResult ImProjectOnCubicBezier(const ImVec2& point, const ImVec2& p0, const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, const int subdivisions) | ||
| 18 | { | ||
| 19 | // http://pomax.github.io/bezierinfo/#projections | ||
| 20 | |||
| 21 | ✗ | const float epsilon = 1e-5f; | |
| 22 | ✗ | const float fixed_step = 1.0f / static_cast<float>(subdivisions - 1); | |
| 23 | |||
| 24 | ✗ | ImProjectResult result; | |
| 25 | ✗ | result.Point = point; | |
| 26 | ✗ | result.Time = 0.0f; | |
| 27 | ✗ | result.Distance = FLT_MAX; | |
| 28 | |||
| 29 | // Step 1: Coarse check | ||
| 30 | ✗ | for (int i = 0; i < subdivisions; ++i) | |
| 31 | { | ||
| 32 | ✗ | auto t = i * fixed_step; | |
| 33 | ✗ | auto p = ImCubicBezier(p0, p1, p2, p3, t); | |
| 34 | ✗ | auto s = point - p; | |
| 35 | ✗ | auto d = ImDot(s, s); | |
| 36 | |||
| 37 | ✗ | if (d < result.Distance) | |
| 38 | { | ||
| 39 | ✗ | result.Point = p; | |
| 40 | ✗ | result.Time = t; | |
| 41 | ✗ | result.Distance = d; | |
| 42 | } | ||
| 43 | } | ||
| 44 | |||
| 45 | ✗ | if (result.Time == 0.0f || ImFabs(result.Time - 1.0f) <= epsilon) | |
| 46 | { | ||
| 47 | ✗ | result.Distance = ImSqrt(result.Distance); | |
| 48 | ✗ | return result; | |
| 49 | } | ||
| 50 | |||
| 51 | // Step 2: Fine check | ||
| 52 | ✗ | auto left = result.Time - fixed_step; | |
| 53 | ✗ | auto right = result.Time + fixed_step; | |
| 54 | ✗ | auto step = fixed_step * 0.1f; | |
| 55 | |||
| 56 | ✗ | for (auto t = left; t < right + step; t += step) | |
| 57 | { | ||
| 58 | ✗ | auto p = ImCubicBezier(p0, p1, p2, p3, t); | |
| 59 | ✗ | auto s = point - p; | |
| 60 | ✗ | auto d = ImDot(s, s); | |
| 61 | |||
| 62 | ✗ | if (d < result.Distance) | |
| 63 | { | ||
| 64 | ✗ | result.Point = p; | |
| 65 | ✗ | result.Time = t; | |
| 66 | ✗ | result.Distance = d; | |
| 67 | } | ||
| 68 | } | ||
| 69 | |||
| 70 | ✗ | result.Distance = ImSqrt(result.Distance); | |
| 71 | |||
| 72 | ✗ | return result; | |
| 73 | } | ||
| 74 |