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AddCircle, AddCircleFilled: Add auto-calculation of circle segment counts (amends)

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Tweak default max error value, Changelog, comments, path-fast for 12 segments circles, made LUT store ImU8
This commit is contained in:
omar
2020-01-08 00:10:18 +01:00
parent 051ce0765e
commit 5363af7f47
6 changed files with 89 additions and 61 deletions
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76
imgui_draw.cpp
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@ -349,16 +349,29 @@ ImDrawListSharedData::ImDrawListSharedData()
FontSize = 0.0f;
CurveTessellationTol = 0.0f;
CircleSegmentMaxError = 0.0f;
CircleSegmentCountsMaxCircleSegmentError = -FLT_MIN; // Impossible value to force recalculation
ClipRectFullscreen = ImVec4(-8192.0f, -8192.0f, +8192.0f, +8192.0f);
InitialFlags = ImDrawListFlags_None;
// Const data
// Lookup tables
for (int i = 0; i < IM_ARRAYSIZE(CircleVtx12); i++)
{
const float a = ((float)i * 2 * IM_PI) / (float)IM_ARRAYSIZE(CircleVtx12);
CircleVtx12[i] = ImVec2(ImCos(a), ImSin(a));
}
memset(CircleSegmentCounts, 0, sizeof(CircleSegmentCounts)); // This will be set by
}
void ImDrawListSharedData::SetCircleSegmentMaxError(float max_error)
{
if (CircleSegmentMaxError == max_error)
return;
CircleSegmentMaxError = max_error;
for (int i = 0; i < IM_ARRAYSIZE(CircleSegmentCounts); i++)
{
const float radius = i + 1.0f;
const int segment_count = IM_DRAWLIST_CIRCLE_AUTO_SEGMENT_CALC(radius, CircleSegmentMaxError);
CircleSegmentCounts[i] = (ImU8)ImMin(segment_count, 255);
}
}
void ImDrawList::Clear()
@ -1085,60 +1098,63 @@ void ImDrawList::AddTriangleFilled(const ImVec2& p1, const ImVec2& p2, const ImV
PathFillConvex(col);
}
void ImDrawListSharedData::RecalculateCircleSegmentCounts()
{
for (int i = 0; i < NumCircleSegmentCounts; i++)
{
const float radius = i + 1.0f;
CircleSegmentCounts[i] = ImClamp((int)((IM_PI * 2.0f) / ImAcos((radius - CircleSegmentMaxError) / radius)), 3, 10000);
}
CircleSegmentCountsMaxCircleSegmentError = CircleSegmentMaxError;
}
void ImDrawList::AddCircle(const ImVec2& center, float radius, ImU32 col, int num_segments, float thickness)
{
if ((col & IM_COL32_A_MASK) == 0 || (radius <= 0.0f))
if ((col & IM_COL32_A_MASK) == 0 || radius <= 0.0f)
return;
// Calculate number of segments if required
// Obtain segment count
if (num_segments <= 0)
{
int radius_int = (int)radius;
if (radius_int <= ImDrawListSharedData::NumCircleSegmentCounts)
num_segments = _Data->CircleSegmentCounts[radius_int - 1]; // Use cached value
// Automatic segment count
const int radius_idx = (int)radius - 1;
if (radius_idx < IM_ARRAYSIZE(_Data->CircleSegmentCounts))
num_segments = _Data->CircleSegmentCounts[radius_idx]; // Use cached value
else
num_segments = ImClamp((int)((IM_PI * 2.0f) / ImAcos((radius - _Data->CircleSegmentMaxError) / radius)), 3, 10000);
num_segments = IM_DRAWLIST_CIRCLE_AUTO_SEGMENT_CALC(radius, _Data->CircleSegmentMaxError);
}
else
{
// Explicit segment count (still clamp to avoid drawing insanely tessellated shapes)
num_segments = ImClamp(num_segments, 3, IM_DRAWLIST_CIRCLE_AUTO_SEGMENT_MAX);
}
else
num_segments = ImClamp(num_segments, 3, 10000); // Clamp to avoid drawing insanely tessellated shapes
// Because we are filling a closed shape we remove 1 from the count of segments/points
const float a_max = (IM_PI * 2.0f) * ((float)num_segments - 1.0f) / (float)num_segments;
PathArcTo(center, radius - 0.5f, 0.0f, a_max, num_segments - 1);
if (num_segments == 12)
PathArcToFast(center, radius - 0.5f, 0, 12);
else
PathArcTo(center, radius - 0.5f, 0.0f, a_max, num_segments - 1);
PathStroke(col, true, thickness);
}
void ImDrawList::AddCircleFilled(const ImVec2& center, float radius, ImU32 col, int num_segments)
{
if ((col & IM_COL32_A_MASK) == 0 || (radius <= 0.0f))
if ((col & IM_COL32_A_MASK) == 0 || radius <= 0.0f)
return;
// Calculate number of segments if required
// Obtain segment count
if (num_segments <= 0)
{
int radius_int = (int)radius;
if (radius_int <= ImDrawListSharedData::NumCircleSegmentCounts)
num_segments = _Data->CircleSegmentCounts[radius_int - 1]; // Use cached value
// Automatic segment count
const int radius_idx = (int)radius - 1;
if (radius_idx < IM_ARRAYSIZE(_Data->CircleSegmentCounts))
num_segments = _Data->CircleSegmentCounts[radius_idx]; // Use cached value
else
num_segments = ImClamp((int)((IM_PI * 2.0f) / ImAcos((radius - _Data->CircleSegmentMaxError) / radius)), 3, 10000);
num_segments = IM_DRAWLIST_CIRCLE_AUTO_SEGMENT_CALC(radius, _Data->CircleSegmentMaxError);
}
else
num_segments = ImClamp(num_segments, 3, 10000); // Clamp to avoid drawing insanely tessellated shapes
{
// Explicit segment count (still clamp to avoid drawing insanely tessellated shapes)
num_segments = ImClamp(num_segments, 3, IM_DRAWLIST_CIRCLE_AUTO_SEGMENT_MAX);
}
// Because we are filling a closed shape we remove 1 from the count of segments/points
const float a_max = (IM_PI * 2.0f) * ((float)num_segments - 1.0f) / (float)num_segments;
PathArcTo(center, radius, 0.0f, a_max, num_segments - 1);
if (num_segments == 12)
PathArcToFast(center, radius, 0, 12);
else
PathArcTo(center, radius, 0.0f, a_max, num_segments - 1);
PathFillConvex(col);
}