From 051ce0765ef8569729c9ae9b3d466132f9010b89 Mon Sep 17 00:00:00 2001 From: Ben Carter Date: Mon, 9 Dec 2019 15:57:24 +0900 Subject: [PATCH] AddCircle, AddCircleFilled: Add auto-calculation of circle segment counts --- imgui.cpp | 7 +++++++ imgui.h | 9 +++++---- imgui_demo.cpp | 5 +++-- imgui_draw.cpp | 41 +++++++++++++++++++++++++++++++++++++++-- imgui_internal.h | 8 ++++++++ 5 files changed, 62 insertions(+), 8 deletions(-) diff --git a/imgui.cpp b/imgui.cpp index 86bbd1465..75b95ba50 100644 --- a/imgui.cpp +++ b/imgui.cpp @@ -988,6 +988,7 @@ ImGuiStyle::ImGuiStyle() AntiAliasedLines = true; // Enable anti-aliasing on lines/borders. Disable if you are really short on CPU/GPU. AntiAliasedFill = true; // Enable anti-aliasing on filled shapes (rounded rectangles, circles, etc.) CurveTessellationTol = 1.25f; // Tessellation tolerance when using PathBezierCurveTo() without a specific number of segments. Decrease for highly tessellated curves (higher quality, more polygons), increase to reduce quality. + CircleSegmentMaxError = 0.75f; // Maximum error (in pixels) allowed when using AddCircle()/AddCircleFilled() or drawing rounded corner rectangles with no explicit segment count specified. Decrease for higher quality but more geometry. // Default theme ImGui::StyleColorsDark(this); @@ -3560,6 +3561,7 @@ static void NewFrameSanityChecks() IM_ASSERT(g.IO.Fonts->Fonts.Size > 0 && "Font Atlas not built. Did you call io.Fonts->GetTexDataAsRGBA32() / GetTexDataAsAlpha8() ?"); IM_ASSERT(g.IO.Fonts->Fonts[0]->IsLoaded() && "Font Atlas not built. Did you call io.Fonts->GetTexDataAsRGBA32() / GetTexDataAsAlpha8() ?"); IM_ASSERT(g.Style.CurveTessellationTol > 0.0f && "Invalid style setting!"); + IM_ASSERT(g.Style.CircleSegmentMaxError > 0.0f && "Invalid style setting!"); IM_ASSERT(g.Style.Alpha >= 0.0f && g.Style.Alpha <= 1.0f && "Invalid style setting. Alpha cannot be negative (allows us to avoid a few clamps in color computations)!"); IM_ASSERT(g.Style.WindowMinSize.x >= 1.0f && g.Style.WindowMinSize.y >= 1.0f && "Invalid style setting."); IM_ASSERT(g.Style.WindowMenuButtonPosition == ImGuiDir_None || g.Style.WindowMenuButtonPosition == ImGuiDir_Left || g.Style.WindowMenuButtonPosition == ImGuiDir_Right); @@ -3622,6 +3624,7 @@ void ImGui::NewFrame() IM_ASSERT(g.Font->IsLoaded()); g.DrawListSharedData.ClipRectFullscreen = ImVec4(0.0f, 0.0f, g.IO.DisplaySize.x, g.IO.DisplaySize.y); g.DrawListSharedData.CurveTessellationTol = g.Style.CurveTessellationTol; + g.DrawListSharedData.CircleSegmentMaxError = g.Style.CircleSegmentMaxError; g.DrawListSharedData.InitialFlags = ImDrawListFlags_None; if (g.Style.AntiAliasedLines) g.DrawListSharedData.InitialFlags |= ImDrawListFlags_AntiAliasedLines; @@ -3630,6 +3633,10 @@ void ImGui::NewFrame() if (g.IO.BackendFlags & ImGuiBackendFlags_RendererHasVtxOffset) g.DrawListSharedData.InitialFlags |= ImDrawListFlags_AllowVtxOffset; + // Recalculate circle segment counts if the segment error has changed + if (g.DrawListSharedData.CircleSegmentMaxError != g.DrawListSharedData.CircleSegmentCountsMaxCircleSegmentError) + g.DrawListSharedData.RecalculateCircleSegmentCounts(); + g.BackgroundDrawList.Clear(); g.BackgroundDrawList.PushTextureID(g.IO.Fonts->TexID); g.BackgroundDrawList.PushClipRectFullScreen(); diff --git a/imgui.h b/imgui.h index 32468168f..7582aafcb 100644 --- a/imgui.h +++ b/imgui.h @@ -1359,6 +1359,7 @@ struct ImGuiStyle bool AntiAliasedLines; // Enable anti-aliasing on lines/borders. Disable if you are really tight on CPU/GPU. bool AntiAliasedFill; // Enable anti-aliasing on filled shapes (rounded rectangles, circles, etc.) float CurveTessellationTol; // Tessellation tolerance when using PathBezierCurveTo() without a specific number of segments. Decrease for highly tessellated curves (higher quality, more polygons), increase to reduce quality. + float CircleSegmentMaxError; // Maximum error (in pixels) allowed when using AddCircle()/AddCircleFilled() or drawing rounded corner rectangles with no explicit segment count specified. Decrease for higher quality but more geometry. ImVec4 Colors[ImGuiCol_COUNT]; IMGUI_API ImGuiStyle(); @@ -1948,10 +1949,10 @@ struct ImDrawList IMGUI_API void AddQuadFilled(const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, const ImVec2& p4, ImU32 col); IMGUI_API void AddTriangle(const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, ImU32 col, float thickness = 1.0f); IMGUI_API void AddTriangleFilled(const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, ImU32 col); - IMGUI_API void AddCircle(const ImVec2& center, float radius, ImU32 col, int num_segments = 12, float thickness = 1.0f); - IMGUI_API void AddCircleFilled(const ImVec2& center, float radius, ImU32 col, int num_segments = 12); - IMGUI_API void AddNgon(const ImVec2& center, float radius, ImU32 col, int num_segments, float thickness = 1.0f); - IMGUI_API void AddNgonFilled(const ImVec2& center, float radius, ImU32 col, int num_segments); + IMGUI_API void AddCircle(const ImVec2& center, float radius, ImU32 col, int num_segments = 12, float thickness = 1.0f); // Draw a circle - use num_segments <= 0 to automatically calculate tessellation (preferred). Use AddNgon() instead if you need a specific segment count. + IMGUI_API void AddCircleFilled(const ImVec2& center, float radius, ImU32 col, int num_segments = 12); // Draw a filled circle - use num_segments <= 0 to automatically calculate tessellation (preferred). Use AddNgonFilled() instead if you need a specific segment count. + IMGUI_API void AddNgon(const ImVec2& center, float radius, ImU32 col, int num_segments, float thickness = 1.0f); // Draw an n-gon with a specific number of sides. Use AddCircle() instead if you want an actual circle and don't care about the exact side count. + IMGUI_API void AddNgonFilled(const ImVec2& center, float radius, ImU32 col, int num_segments); // Draw a filled n-gon with a specific number of sides. Use AddCircleFilled() instead if you want an actual circle and don't care about the exact side count. IMGUI_API void AddText(const ImVec2& pos, ImU32 col, const char* text_begin, const char* text_end = NULL); 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); IMGUI_API void AddPolyline(const ImVec2* points, int num_points, ImU32 col, bool closed, float thickness); diff --git a/imgui_demo.cpp b/imgui_demo.cpp index ec8c142f7..8ce917842 100644 --- a/imgui_demo.cpp +++ b/imgui_demo.cpp @@ -3502,6 +3502,7 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref) ImGui::PushItemWidth(100); ImGui::DragFloat("Curve Tessellation Tolerance", &style.CurveTessellationTol, 0.02f, 0.10f, FLT_MAX, "%.2f", 2.0f); if (style.CurveTessellationTol < 0.10f) style.CurveTessellationTol = 0.10f; + ImGui::DragFloat("Max circle segment error", &style.CircleSegmentMaxError, 0.01f, 0.1f, 10.0f, "%.2f", 1.0f); ImGui::DragFloat("Global Alpha", &style.Alpha, 0.005f, 0.20f, 1.0f, "%.2f"); // Not exposing zero here so user doesn't "lose" the UI (zero alpha clips all widgets). But application code could have a toggle to switch between zero and non-zero. ImGui::PopItemWidth(); @@ -4471,7 +4472,7 @@ static void ShowExampleAppCustomRendering(bool* p_open) // First line uses a thickness of 1.0f, second line uses the configurable thickness float th = (n == 0) ? 1.0f : thickness; draw_list->AddNgon(ImVec2(x + sz*0.5f, y + sz*0.5f), sz*0.5f, col, ngon_sides, th); x += sz + spacing; // n-gon - draw_list->AddCircle(ImVec2(x + sz*0.5f, y + sz*0.5f), sz*0.5f, col, 20, th); x += sz + spacing; // Circle + draw_list->AddCircle(ImVec2(x + sz*0.5f, y + sz*0.5f), sz*0.5f, col, 0, th); x += sz + spacing; // Circle draw_list->AddRect(ImVec2(x, y), ImVec2(x + sz, y + sz), col, 0.0f, corners_none, th); x += sz + spacing; // Square draw_list->AddRect(ImVec2(x, y), ImVec2(x + sz, y + sz), col, 10.0f, corners_all, th); x += sz + spacing; // Square with all rounded corners draw_list->AddRect(ImVec2(x, y), ImVec2(x + sz, y + sz), col, 10.0f, corners_tl_br, th); x += sz + spacing; // Square with two rounded corners @@ -4485,7 +4486,7 @@ static void ShowExampleAppCustomRendering(bool* p_open) y += sz + spacing; } draw_list->AddNgonFilled(ImVec2(x + sz * 0.5f, y + sz * 0.5f), sz*0.5f, col, ngon_sides); x += sz + spacing; // n-gon - draw_list->AddCircleFilled(ImVec2(x + sz*0.5f, y + sz*0.5f), sz*0.5f, col, 32); x += sz + spacing; // Circle + draw_list->AddCircleFilled(ImVec2(x + sz*0.5f, y + sz*0.5f), sz*0.5f, col, 0); x += sz + spacing; // Circle draw_list->AddRectFilled(ImVec2(x, y), ImVec2(x + sz, y + sz), col); x += sz + spacing; // Square draw_list->AddRectFilled(ImVec2(x, y), ImVec2(x + sz, y + sz), col, 10.0f); x += sz + spacing; // Square with all rounded corners draw_list->AddRectFilled(ImVec2(x, y), ImVec2(x + sz, y + sz), col, 10.0f, corners_tl_br); x += sz + spacing; // Square with two rounded corners diff --git a/imgui_draw.cpp b/imgui_draw.cpp index 62cf26910..435e689b5 100644 --- a/imgui_draw.cpp +++ b/imgui_draw.cpp @@ -348,6 +348,8 @@ ImDrawListSharedData::ImDrawListSharedData() Font = NULL; 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; @@ -1083,11 +1085,34 @@ 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 || num_segments <= 2) + if ((col & IM_COL32_A_MASK) == 0 || (radius <= 0.0f)) return; + // Calculate number of segments if required + if (num_segments <= 0) + { + int radius_int = (int)radius; + if (radius_int <= ImDrawListSharedData::NumCircleSegmentCounts) + num_segments = _Data->CircleSegmentCounts[radius_int - 1]; // Use cached value + else + num_segments = ImClamp((int)((IM_PI * 2.0f) / ImAcos((radius - _Data->CircleSegmentMaxError) / radius)), 3, 10000); + } + 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); @@ -1096,9 +1121,21 @@ void ImDrawList::AddCircle(const ImVec2& center, float radius, ImU32 col, int nu void ImDrawList::AddCircleFilled(const ImVec2& center, float radius, ImU32 col, int num_segments) { - if ((col & IM_COL32_A_MASK) == 0 || num_segments <= 2) + if ((col & IM_COL32_A_MASK) == 0 || (radius <= 0.0f)) return; + // Calculate number of segments if required + if (num_segments <= 0) + { + int radius_int = (int)radius; + if (radius_int <= ImDrawListSharedData::NumCircleSegmentCounts) + num_segments = _Data->CircleSegmentCounts[radius_int - 1]; // Use cached value + else + num_segments = ImClamp((int)((IM_PI * 2.0f) / ImAcos((radius - _Data->CircleSegmentMaxError) / radius)), 3, 10000); + } + 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, 0.0f, a_max, num_segments - 1); diff --git a/imgui_internal.h b/imgui_internal.h index 5065255c1..6679219d4 100644 --- a/imgui_internal.h +++ b/imgui_internal.h @@ -855,6 +855,7 @@ struct IMGUI_API ImDrawListSharedData ImFont* Font; // Current/default font (optional, for simplified AddText overload) float FontSize; // Current/default font size (optional, for simplified AddText overload) float CurveTessellationTol; // Tessellation tolerance when using PathBezierCurveTo() + float CircleSegmentMaxError; // Number of circle segments to use per pixel of radius for AddCircle() etc ImVec4 ClipRectFullscreen; // Value for PushClipRectFullscreen() ImDrawListFlags InitialFlags; // Initial flags at the beginning of the frame (it is possible to alter flags on a per-drawlist basis afterwards) @@ -862,6 +863,13 @@ struct IMGUI_API ImDrawListSharedData // FIXME: Bake rounded corners fill/borders in atlas ImVec2 CircleVtx12[12]; + // Cached circle segment counts for the first radii (to avoid calculation overhead) + static const int NumCircleSegmentCounts = 64;// Number of circle segment counts to cache (i.e. the maximum radius before we calculate dynamically) + int CircleSegmentCounts[NumCircleSegmentCounts]; // The segment count for radius (array index + 1) + float CircleSegmentCountsMaxCircleSegmentError; // The MaxCircleSegmentError used to calculate these counts + + void RecalculateCircleSegmentCounts(); // Recalculate circle segment counts based on the current MaxCircleSegmentError + ImDrawListSharedData(); };