ImDrawList: add PathFillConcave(), AddConcavePolyFilled() (#760)
Extracted from 2023/12/29 post. WIP add PathFillConcave(), AddConcavePolyFilled() * remove use of 'auto' * IsConvex -> ImPathIsConvex * Triangulator -> ImTriangulator * ImTriangulator: split declaration from definition, ImTriangulator can be put in the header if necessary * ImTriangulator: Add node list flip to reverse winding order and handle degenerate cases * ImTriangulator: Remove _HeapStorage, always require scratch buffer to be provided * ImTriangulator: Use ImTriangleContainsPoint * AddConcavePolyFilled: Clone AddConvexPolyFilled and use triangulator * AddConcavePolyFilled: Remove ImDrawListEx_AddPolyFilled_xxx * AddConcavePolyFilled: Use _Data->TempBuffer in triangulator * AddConcavePolyFilled:
This commit is contained in:
thedmd
ocornut
parent
04f40014a6
commit
1ff90c52d5
8
imgui.h
8
imgui.h
@ -2756,11 +2756,14 @@ struct ImDrawList
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IMGUI_API void AddEllipseFilled(const ImVec2& center, float radius_x, float radius_y, ImU32 col, float rot = 0.0f, int num_segments = 0);
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IMGUI_API void AddText(const ImVec2& pos, ImU32 col, const char* text_begin, const char* text_end = NULL);
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IMGUI_API void AddText(const ImFont* font, float font_size, const ImVec2& pos, ImU32 col, const char* text_begin, const char* text_end = NULL, float wrap_width = 0.0f, const ImVec4* cpu_fine_clip_rect = NULL);
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IMGUI_API void AddPolyline(const ImVec2* points, int num_points, ImU32 col, ImDrawFlags flags, float thickness);
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IMGUI_API void AddConvexPolyFilled(const ImVec2* points, int num_points, ImU32 col);
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IMGUI_API void AddBezierCubic(const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, const ImVec2& p4, ImU32 col, float thickness, int num_segments = 0); // Cubic Bezier (4 control points)
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IMGUI_API void AddBezierQuadratic(const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, ImU32 col, float thickness, int num_segments = 0); // Quadratic Bezier (3 control points)
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// General polygon
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IMGUI_API void AddPolyline(const ImVec2* points, int num_points, ImU32 col, ImDrawFlags flags, float thickness);
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IMGUI_API void AddConvexPolyFilled(const ImVec2* points, int num_points, ImU32 col);
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IMGUI_API void AddConcavePolyFilled(const ImVec2* points, const int points_count, ImU32 col);
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// Image primitives
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// - Read FAQ to understand what ImTextureID is.
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// - "p_min" and "p_max" represent the upper-left and lower-right corners of the rectangle.
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@ -2776,6 +2779,7 @@ struct ImDrawList
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inline void PathLineTo(const ImVec2& pos) { _Path.push_back(pos); }
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inline void PathLineToMergeDuplicate(const ImVec2& pos) { if (_Path.Size == 0 || memcmp(&_Path.Data[_Path.Size - 1], &pos, 8) != 0) _Path.push_back(pos); }
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inline void PathFillConvex(ImU32 col) { AddConvexPolyFilled(_Path.Data, _Path.Size, col); _Path.Size = 0; }
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inline void PathFillConcave(ImU32 col) { AddConcavePolyFilled(_Path.Data, _Path.Size, col); _Path.Size = 0; }
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inline void PathStroke(ImU32 col, ImDrawFlags flags = 0, float thickness = 1.0f) { AddPolyline(_Path.Data, _Path.Size, col, flags, thickness); _Path.Size = 0; }
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IMGUI_API void PathArcTo(const ImVec2& center, float radius, float a_min, float a_max, int num_segments = 0);
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IMGUI_API void PathArcToFast(const ImVec2& center, float radius, int a_min_of_12, int a_max_of_12); // Use precomputed angles for a 12 steps circle
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434
imgui_draw.cpp
434
imgui_draw.cpp
@ -8,6 +8,7 @@ Index of this file:
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// [SECTION] STB libraries implementation
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// [SECTION] Style functions
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// [SECTION] ImDrawList
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// [SECTION] ImDrawList concave polygon fill
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// [SECTION] ImDrawListSplitter
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// [SECTION] ImDrawData
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// [SECTION] Helpers ShadeVertsXXX functions
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@ -1700,6 +1701,439 @@ void ImDrawList::AddImageRounded(ImTextureID user_texture_id, const ImVec2& p_mi
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PopTextureID();
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}
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//-----------------------------------------------------------------------------
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// [SECTION] ImDrawList concave polygon fill
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//-----------------------------------------------------------------------------
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static bool ImPathIsConvex(const ImVec2& a, const ImVec2& b, const ImVec2& c)
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{
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const float dx0 = b.x - a.x;
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const float dy0 = b.y - a.y;
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const float dx1 = c.x - b.x;
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const float dy1 = c.y - b.y;
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return dx0 * dy1 - dx1 * dy0 > 0.0f;
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}
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struct ImTriangulator
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{
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struct Triangle { int Index[3]; };
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static int EstimateTriangleCount(int points_count);
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static int EstimateScratchBufferSize(int points_count);
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ImTriangulator(const ImVec2* points, int points_count, void* scratch_buffer);
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ImTriangulator(const ImVec2* points, int points_count, int points_stride_bytes, void* scratch_buffer);
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bool HasNext() const;
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Triangle Next();
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private:
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enum Type { Convex, Ear, Reflex };
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struct Node;
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struct alignas(void*) Span
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{
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Node** Data = nullptr;
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int Size = 0;
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void PushBack(Node* node);
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void RemoveByIndex(int index);
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};
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void BuildNodes();
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void BuildReflexes();
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void BuildEars();
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void FlipNodeList();
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bool IsEar(const Node* node, int i0, int i1, int i2, const ImVec2& v0, const ImVec2& v1, const ImVec2& v2) const;
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Type ClassifyNode(const Node* node) const;
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void ReclasifyNode(Node* node);
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const ImVec2* _Points = nullptr;
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int _PointsCount = 0;
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int _PointsStrideBytes = 0;
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int _TrianglesLeft = 0;
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Node* _Nodes = nullptr;
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Span _Ears;
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Span _Reflexes;
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};
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struct alignas(void*) ImTriangulator::Node
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{
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Type Type = Convex;
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int Index = 0;
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const ImVec2* Point = nullptr;
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Node* Next = nullptr;
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Node* Prev = nullptr;
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void Unlink()
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{
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Next->Prev = Prev;
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Prev->Next = Next;
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}
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};
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int ImTriangulator::EstimateTriangleCount(int points_count)
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{
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if (points_count < 3)
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return 0;
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return points_count - 2;
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}
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int ImTriangulator::EstimateScratchBufferSize(int points_count)
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{
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return sizeof(Node*) * points_count * 2 + sizeof(Node) * points_count;
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}
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ImTriangulator::ImTriangulator(const ImVec2* points, int points_count, void* scratch_buffer)
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: ImTriangulator(points, points_count, sizeof(ImVec2), scratch_buffer)
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{
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}
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ImTriangulator::ImTriangulator(const ImVec2* points, int points_count, int points_stride_bytes, void* scratch_buffer)
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: _Points(points)
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, _PointsCount(points_count)
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, _PointsStrideBytes(points_stride_bytes)
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, _TrianglesLeft(EstimateTriangleCount(points_count))
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{
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IM_ASSERT(scratch_buffer != nullptr && "Must provide scratch buffer.");
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IM_ASSERT(points_count >= 3);
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// Disable triangulator if scratch buffer isn't provided.
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if (scratch_buffer == nullptr)
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{
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_TrianglesLeft = 0;
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points_count = 0;
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return;
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}
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// Distribute storage for nodes, ears and reflexes.
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_Nodes = reinterpret_cast<Node*>(scratch_buffer);
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_Ears.Data = reinterpret_cast<Node**>(_Nodes + points_count);
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_Reflexes.Data = _Ears.Data + points_count;
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BuildNodes();
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BuildReflexes();
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BuildEars();
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}
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void ImTriangulator::BuildNodes()
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{
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# define IM_POINT_PTR(idx) reinterpret_cast<const ImVec2*>(reinterpret_cast<const ImU8*>(_Points) + (idx) * _PointsStrideBytes)
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for (int i = 0; i < _PointsCount; ++i)
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{
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_Nodes[i].Type = Convex;
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_Nodes[i].Index = static_cast<int>(i);
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_Nodes[i].Point = IM_POINT_PTR(i);
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_Nodes[i].Next = _Nodes + i + 1;
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_Nodes[i].Prev = _Nodes + i - 1;
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}
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_Nodes[0].Prev = _Nodes + _PointsCount - 1;
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_Nodes[_PointsCount - 1].Next = _Nodes;
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# undef IM_POINT_PTR
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}
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void ImTriangulator::BuildReflexes()
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{
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Node* node = _Nodes;
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for (int i = 0; i < _TrianglesLeft; ++i, node = node->Next)
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{
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const ImVec2& v0 = *node->Prev->Point;
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const ImVec2& v1 = *node->Point;
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const ImVec2& v2 = *node->Next->Point;
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if (ImPathIsConvex(v0, v1, v2))
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continue;
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node->Type = Reflex;
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_Reflexes.PushBack(node);
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}
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}
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void ImTriangulator::BuildEars()
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{
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Node* node = _Nodes;
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for (int i = 0; i < _TrianglesLeft; ++i, node = node->Next)
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{
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if (node->Type != Convex)
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continue;
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const int i0 = node->Prev->Index;
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const int i1 = node->Index;
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const int i2 = node->Next->Index;
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const ImVec2& v0 = *node->Prev->Point;
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const ImVec2& v1 = *node->Point;
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const ImVec2& v2 = *node->Next->Point;
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if (!IsEar(node, i0, i1, i2, v0, v1, v2))
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continue;
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node->Type = Ear;
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_Ears.PushBack(node);
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}
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}
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bool ImTriangulator::HasNext() const
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{
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return _TrianglesLeft > 0;
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}
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ImTriangulator::Triangle ImTriangulator::Next()
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{
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IM_ASSERT(_TrianglesLeft > 0 && "Do not call Next() until HasNext() return true");
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if (_Ears.Size == 0)
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{
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FlipNodeList();
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Node* node = _Nodes;
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for (int i = 0; i < _TrianglesLeft; ++i, node = node->Next)
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node->Type = Convex;
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_Reflexes.Size = 0;
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BuildReflexes();
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BuildEars();
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// If we still don't have ears, it means geometry is degenerated.
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if (_Ears.Size == 0)
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{
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IM_ASSERT(_TrianglesLeft > 0 && "Geometry is degenerated");
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// Return first triangle available, mimicking the behavior of convex fill.
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_Ears.Data[0] = _Nodes;
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_Ears.Size = 1;
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}
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}
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Node* ear = _Ears.Data[--_Ears.Size];
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const int i0 = ear->Prev->Index;
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const int i1 = ear->Index;
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const int i2 = ear->Next->Index;
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ear->Unlink();
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if (ear == _Nodes)
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_Nodes = ear->Next;
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ReclasifyNode(ear->Prev);
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ReclasifyNode(ear->Next);
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--_TrianglesLeft;
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return Triangle{ { i0, i1, i2 } };
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}
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void ImTriangulator::Span::PushBack(Node* node)
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{
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Data[Size++] = node;
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}
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void ImTriangulator::Span::RemoveByIndex(int index)
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{
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for (int i = Size - 1; i >= 0; --i)
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{
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if (Data[i]->Index == index)
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{
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Data[i] = Data[Size - 1];
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--Size;
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break;
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}
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}
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}
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void ImTriangulator::FlipNodeList()
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{
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Node* prev = _Nodes;
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Node* temp = _Nodes;
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Node* current = _Nodes->Next;
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prev->Next = prev;
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prev->Prev = prev;
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while (current != _Nodes)
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{
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temp = current->Next;
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current->Next = prev;
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prev->Prev = current;
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_Nodes->Next = current;
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current->Prev = _Nodes;
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prev = current;
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current = temp;
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}
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_Nodes = prev;
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}
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bool ImTriangulator::IsEar(const Node* node, int i0, int i1, int i2, const ImVec2& v0, const ImVec2& v1, const ImVec2& v2) const
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{
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for (int i = 0; i < _Reflexes.Size; ++i)
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{
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Node* reflex = _Reflexes.Data[i];
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if (reflex->Index == i0 || reflex->Index == i1 || reflex->Index == i2)
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continue;
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if (ImTriangleContainsPoint(v0, v1, v2, *reflex->Point))
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return false;
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}
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return true;
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}
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ImTriangulator::Type ImTriangulator::ClassifyNode(const Node* node) const
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{
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const int i0 = node->Prev->Index;
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const int i1 = node->Index;
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const int i2 = node->Next->Index;
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const ImVec2& v0 = *node->Prev->Point;
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const ImVec2& v1 = *node->Point;
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const ImVec2& v2 = *node->Next->Point;
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if (ImPathIsConvex(v0, v1, v2))
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{
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if (IsEar(node, i0, i1, i2, v0, v1, v2))
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return Ear;
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else
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return Convex;
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}
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else
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{
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return Reflex;
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}
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}
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void ImTriangulator::ReclasifyNode(Node* node)
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{
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Type type = ClassifyNode(node);
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if (type == node->Type)
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return;
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if (node->Type == Reflex)
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_Reflexes.RemoveByIndex(node->Index);
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else if (node->Type == Ear)
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_Ears.RemoveByIndex(node->Index);
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if (type == Reflex)
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_Reflexes.PushBack(node);
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else if (type == Ear)
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_Ears.PushBack(node);
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node->Type = type;
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}
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void ImDrawList::AddConcavePolyFilled(const ImVec2* points, const int points_count, ImU32 col)
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{
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if (points_count < 3 || (col & IM_COL32_A_MASK) == 0)
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return;
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// coarse culling against viewport to avoid processing triangles outside of the visible area
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ImVec2 bounds_min = ImVec2(FLT_MAX, FLT_MAX);
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ImVec2 bounds_max = ImVec2(-FLT_MAX, -FLT_MAX);
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for (int i = 0; i < points_count; ++i)
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{
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const ImVec2& pos = points[i];
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bounds_min = ImMin(bounds_min, pos);
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bounds_max = ImMax(bounds_max, pos);
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}
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if (!ImRect(_ClipRectStack.back()).Overlaps(ImRect(bounds_min, bounds_max)))
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return;
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const ImVec2 uv = _Data->TexUvWhitePixel;
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if (Flags & ImDrawListFlags_AntiAliasedFill)
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{
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// Anti-aliased Fill
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const float AA_SIZE = _FringeScale;
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const ImU32 col_trans = col & ~IM_COL32_A_MASK;
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const int idx_count = (points_count - 2)*3 + points_count * 6;
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const int vtx_count = (points_count * 2);
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PrimReserve(idx_count, vtx_count);
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// Add indexes for fill
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unsigned int vtx_inner_idx = _VtxCurrentIdx;
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unsigned int vtx_outer_idx = _VtxCurrentIdx + 1;
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_Data->TempBuffer.reserve_discard((ImTriangulator::EstimateScratchBufferSize(points_count) + sizeof(ImVec2)) / sizeof(ImVec2));
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ImTriangulator triangulator = ImTriangulator(points, points_count, _Data->TempBuffer.Data);
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while (triangulator.HasNext())
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{
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ImTriangulator::Triangle triangle = triangulator.Next();
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_IdxWritePtr[0] = (ImDrawIdx)(vtx_inner_idx + (triangle.Index[0] << 1)); _IdxWritePtr[1] = (ImDrawIdx)(vtx_inner_idx + (triangle.Index[1] << 1)); _IdxWritePtr[2] = (ImDrawIdx)(vtx_inner_idx + (triangle.Index[2] << 1));
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_IdxWritePtr += 3;
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}
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// Compute normals
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_Data->TempBuffer.reserve_discard(points_count);
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ImVec2* temp_normals = _Data->TempBuffer.Data;
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for (int i0 = points_count - 1, i1 = 0; i1 < points_count; i0 = i1++)
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{
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const ImVec2& p0 = points[i0];
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const ImVec2& p1 = points[i1];
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float dx = p1.x - p0.x;
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float dy = p1.y - p0.y;
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IM_NORMALIZE2F_OVER_ZERO(dx, dy);
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temp_normals[i0].x = dy;
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temp_normals[i0].y = -dx;
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}
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for (int i0 = points_count - 1, i1 = 0; i1 < points_count; i0 = i1++)
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{
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// Average normals
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const ImVec2& n0 = temp_normals[i0];
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const ImVec2& n1 = temp_normals[i1];
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float dm_x = (n0.x + n1.x) * 0.5f;
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float dm_y = (n0.y + n1.y) * 0.5f;
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IM_FIXNORMAL2F(dm_x, dm_y);
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dm_x *= AA_SIZE * 0.5f;
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dm_y *= AA_SIZE * 0.5f;
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// Add vertices
|
||||
_VtxWritePtr[0].pos.x = (points[i1].x - dm_x); _VtxWritePtr[0].pos.y = (points[i1].y - dm_y); _VtxWritePtr[0].uv = uv; _VtxWritePtr[0].col = col; // Inner
|
||||
_VtxWritePtr[1].pos.x = (points[i1].x + dm_x); _VtxWritePtr[1].pos.y = (points[i1].y + dm_y); _VtxWritePtr[1].uv = uv; _VtxWritePtr[1].col = col_trans; // Outer
|
||||
_VtxWritePtr += 2;
|
||||
|
||||
// Add indexes for fringes
|
||||
_IdxWritePtr[0] = (ImDrawIdx)(vtx_inner_idx + (i1 << 1)); _IdxWritePtr[1] = (ImDrawIdx)(vtx_inner_idx + (i0 << 1)); _IdxWritePtr[2] = (ImDrawIdx)(vtx_outer_idx + (i0 << 1));
|
||||
_IdxWritePtr[3] = (ImDrawIdx)(vtx_outer_idx + (i0 << 1)); _IdxWritePtr[4] = (ImDrawIdx)(vtx_outer_idx + (i1 << 1)); _IdxWritePtr[5] = (ImDrawIdx)(vtx_inner_idx + (i1 << 1));
|
||||
_IdxWritePtr += 6;
|
||||
}
|
||||
_VtxCurrentIdx += (ImDrawIdx)vtx_count;
|
||||
}
|
||||
else
|
||||
{
|
||||
// Non Anti-aliased Fill
|
||||
const int idx_count = (points_count - 2)*3;
|
||||
const int vtx_count = points_count;
|
||||
PrimReserve(idx_count, vtx_count);
|
||||
for (int i = 0; i < vtx_count; i++)
|
||||
{
|
||||
_VtxWritePtr[0].pos = points[i]; _VtxWritePtr[0].uv = uv; _VtxWritePtr[0].col = col;
|
||||
_VtxWritePtr++;
|
||||
}
|
||||
_Data->TempBuffer.reserve_discard((ImTriangulator::EstimateScratchBufferSize(points_count) + sizeof(ImVec2)) / sizeof(ImVec2));
|
||||
ImTriangulator triangulator = ImTriangulator(points, points_count, _Data->TempBuffer.Data);
|
||||
while (triangulator.HasNext())
|
||||
{
|
||||
ImTriangulator::Triangle triangle = triangulator.Next();
|
||||
_IdxWritePtr[0] = (ImDrawIdx)(_VtxCurrentIdx + triangle.Index[0]); _IdxWritePtr[1] = (ImDrawIdx)(_VtxCurrentIdx + triangle.Index[1]); _IdxWritePtr[2] = (ImDrawIdx)(_VtxCurrentIdx + triangle.Index[2]);
|
||||
_IdxWritePtr += 3;
|
||||
}
|
||||
_VtxCurrentIdx += (ImDrawIdx)vtx_count;
|
||||
}
|
||||
}
|
||||
|
||||
//-----------------------------------------------------------------------------
|
||||
// [SECTION] ImDrawListSplitter
|
||||
|
||||
Loading…
Reference in New Issue
Block a user