Drezil/imgui
1
0
Fork 0
mirror of https://github.com/Drezil/imgui.git synced 2025-07-04 12:08:47 +02:00
Code Issues Packages Projects Releases Wiki Activity

Add ImBezierClosestPoint() function which returns a point on bezier curve which is closed to a specified point.

Browse Source
This commit is contained in:
Rokas Kupstys
2019-12-17 16:29:12 +02:00
committed by omar
parent 0f7105e156
commit 3831d50ab9
3 changed files with 81 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

66
imgui.cpp
View File

@ -1109,6 +1109,72 @@ void ImGuiIO::ClearInputCharacters()
// [SECTION] MISC HELPERS/UTILITIES (Geometry, String, Format, Hash, File functions)
//-----------------------------------------------------------------------------
ImVec2 ImBezierClosestPoint(const ImVec2& p, const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, const ImVec2& p4, int num_segments)
{
IM_ASSERT(num_segments > 0);
ImVec2 p_last = p1;
ImVec2 p_closest;
float p_closest_dist2 = FLT_MAX;
float t_step = 1.0f / (float)num_segments;
for (int i_step = 1; i_step <= num_segments; i_step++)
{
ImVec2 p_current = ImBezierCalc(p1, p2, p3, p4, t_step * i_step);
ImVec2 p_line = ImLineClosestPoint(p_last, p_current, p);
float dist2 = ImLengthSqr(p - p_line);
if (dist2 < p_closest_dist2)
{
p_closest = p_line;
p_closest_dist2 = dist2;
}
p_last = p_current;
}
return p_closest;
}
// Closely mimics PathBezierToCasteljau() in imgui_draw.cpp
static void ClosestPointBezierCasteljau(const ImVec2& p, ImVec2& p_closest, ImVec2& p_last, float& p_closest_dist2, float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4, float tess_tol, int level)
{
float dx = x4 - x1;
float dy = y4 - y1;
float d2 = ((x2 - x4) * dy - (y2 - y4) * dx);
float d3 = ((x3 - x4) * dy - (y3 - y4) * dx);
d2 = (d2 >= 0) ? d2 : -d2;
d3 = (d3 >= 0) ? d3 : -d3;
if ((d2+d3) * (d2+d3) < tess_tol * (dx*dx + dy*dy))
{
ImVec2 p_current(x4, y4);
ImVec2 p_line = ImLineClosestPoint(p_last, p_current, p);
float dist2 = ImLengthSqr(p - p_line);
if (dist2 < p_closest_dist2)
{
p_closest = p_line;
p_closest_dist2 = dist2;
}
p_last = p_current;
}
else if (level < 10)
{
float x12 = (x1+x2)*0.5f, y12 = (y1+y2)*0.5f;
float x23 = (x2+x3)*0.5f, y23 = (y2+y3)*0.5f;
float x34 = (x3+x4)*0.5f, y34 = (y3+y4)*0.5f;
float x123 = (x12+x23)*0.5f, y123 = (y12+y23)*0.5f;
float x234 = (x23+x34)*0.5f, y234 = (y23+y34)*0.5f;
float x1234 = (x123+x234)*0.5f, y1234 = (y123+y234)*0.5f;
ClosestPointBezierCasteljau(p, p_closest, p_last, p_closest_dist2, x1, y1, x12, y12, x123, y123, x1234, y1234, tess_tol, level + 1);
ClosestPointBezierCasteljau(p, p_closest, p_last, p_closest_dist2, x1234, y1234, x234, y234, x34, y34, x4, y4, tess_tol, level + 1);
}
}
ImVec2 ImBezierClosestPointCasteljau(const ImVec2& p, const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, const ImVec2& p4, float tess_tol)
{
IM_ASSERT(tess_tol > 0.0f);
ImVec2 p_last = p1;
ImVec2 p_closest;
float p_closest_dist2 = FLT_MAX;
ClosestPointBezierCasteljau(p, p_closest, p_last, p_closest_dist2, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y, p4.x, p4.y, tess_tol, 0);
return p_closest;
}
ImVec2 ImLineClosestPoint(const ImVec2& a, const ImVec2& b, const ImVec2& p)
{
ImVec2 ap = p - a;