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DrawList: added explanation for IM_POLYLINE_CONVEX_POLY_MAX_BEVELS.

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Mikko Mononen
2026-08-06 19:52:54 +03:00
committed by ocornut
parent a38ce24427
commit 108bc3b060
1 changed files with 13 additions and 2 deletions
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15
imgui_draw.cpp
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@@ -886,9 +886,20 @@ IM_MSVC_RUNTIME_CHECKS_RESTORE
#define IM_FIXNORMAL2F_MAX_INVLEN2 100.0f // 500.0f (see #4053, #3366)
#define IM_FIXNORMAL2F(VX,VY) { float d2 = VX*VX + VY*VY; if (d2 > 0.000001f) { float inv_len2 = 1.0f / d2; if (inv_len2 > IM_FIXNORMAL2F_MAX_INVLEN2) inv_len2 = IM_FIXNORMAL2F_MAX_INVLEN2; VX *= inv_len2; VY *= inv_len2; } } (void)0
// - The miter limit describes how much the miter cross section can be scaled before we turn it into a bevel instead.
// The minimum value of miter limit is 1.0, which translates to 180 (all corners are bevels), the higher the number,
// the closer to zero the angle is (never bevel a corner). The miter limit angle can be calculated as:
// miter_limit_angle = 2 * acos(1 / miter_limit)
// - We can use the miter limit angle to figure maximum number of beveled corners in a convex polygon,
// to prevent having allocate much extra memory (for a reasonable miter limit).
// (n - 2) * 360 > k * miter_limit_angle + (n - k) * 360
// Where, n = number of corners in a polygon, k = beveled corners. Solved for k, simplifies to:
// k < 360 / (180 - miter_limit_angle)
// To find value strictly less than:
// max_bevels = k = floor(360/(180-miter_limit_angle))
#define IM_POLYLINE_MITER_ANGLE_LIMIT (-0.9999619f) // Safeguard for miter corner calculation to avoid div by zero. cos(179.5)
#define IM_POLYLINE_MITER_LIMIT (4.0f) // How much the miter can be scaled before we turn it into a bevel instead. (equals ~29 deg corner)
#define IM_POLYLINE_CONVEX_POLY_MAX_BEVELS (2) // How many bevels there can be in a convex polygon. (int)(360/floor(180-29))
#define IM_POLYLINE_MITER_LIMIT (4.0f) // (~29 deg corner)
#define IM_POLYLINE_CONVEX_POLY_MAX_BEVELS (2) // For miter value 4.0
// In debug builds the functions are likely not inlined, so inlined check is cheaper.
#if defined(DEBUG) || defined(_DEBUG)