Merge branch 'features/tex_antialiased_lines' (#3245)

docs/CHANGELOG.txt

@@ -35,6 +35,15 @@ HOW TO UPDATE?
  VERSION 1.78 WIP (In Progress)
 -----------------------------------------------------------------------
 
+Other Changes:
+
+- ImDrawList: Thick anti-aliased strokes (> 1.0f) with integer thickness now use a texture-based 
+  path, reducing the amount of vertices/indices and CPU/GPU usage. (#3245) [@Shironekoben]
+  - This change will facilitate the wider use of thick borders in future style changes. 
+  - Requires an extra bit of texture space (~64x64 by default), relies on GPU bilinear filtering.
+  - Clear io.AntiAliasedLinesUseTex = false; to disable rendering using this method.
+  - Clear ImFontAtlasFlags_NoBakedLines in ImFontAtlas::Flags to disable baking data in texture.
+
 
 -----------------------------------------------------------------------
  VERSION 1.77 (Released 2020-06-29)

imgui.cpp

@@ -935,6 +935,7 @@ ImGuiStyle::ImGuiStyle()
     DisplaySafeAreaPadding  = ImVec2(3,3);      // If you cannot see the edge of your screen (e.g. on a TV) increase the safe area padding. Covers popups/tooltips as well regular windows.
     MouseCursorScale        = 1.0f;             // Scale software rendered mouse cursor (when io.MouseDrawCursor is enabled). May be removed later.
     AntiAliasedLines        = true;             // Enable anti-aliased lines/borders. Disable if you are really tight on CPU/GPU.
+    AntiAliasedLinesUseTex  = true;             // Enable anti-aliased lines/borders using textures where possible. Require back-end to render with bilinear filtering.
     AntiAliasedFill         = true;             // Enable anti-aliased 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   = 1.60f;            // 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.
@@ -3688,6 +3689,8 @@ void ImGui::NewFrame()
     g.DrawListSharedData.InitialFlags = ImDrawListFlags_None;
     if (g.Style.AntiAliasedLines)
         g.DrawListSharedData.InitialFlags |= ImDrawListFlags_AntiAliasedLines;
+    if (g.Style.AntiAliasedLinesUseTex && !(g.Font->ContainerAtlas->Flags & ImFontAtlasFlags_NoBakedLines))
+        g.DrawListSharedData.InitialFlags |= ImDrawListFlags_AntiAliasedLinesUseTex;
     if (g.Style.AntiAliasedFill)
         g.DrawListSharedData.InitialFlags |= ImDrawListFlags_AntiAliasedFill;
     if (g.IO.BackendFlags & ImGuiBackendFlags_RendererHasVtxOffset)
@@ -6158,6 +6161,7 @@ void ImGui::SetCurrentFont(ImFont* font)
 
     ImFontAtlas* atlas = g.Font->ContainerAtlas;
     g.DrawListSharedData.TexUvWhitePixel = atlas->TexUvWhitePixel;
+    g.DrawListSharedData.TexUvLines = atlas->TexUvLines;
     g.DrawListSharedData.Font = g.Font;
     g.DrawListSharedData.FontSize = g.FontSize;
 }

imgui.h

@@ -60,7 +60,7 @@ Index of this file:
 // Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals. Work in progress versions typically starts at XYY99 then bounce up to XYY00, XYY01 etc. when release tagging happens)
 #define IMGUI_VERSION               "1.78 WIP"
-#define IMGUI_VERSION_NUM           17702
+#define IMGUI_VERSION_NUM           17703
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert), sizeof(ImDrawIdx))
 
 // Define attributes of all API symbols declarations (e.g. for DLL under Windows)
@@ -1438,8 +1438,9 @@ struct ImGuiStyle
     ImVec2      DisplayWindowPadding;       // Window position are clamped to be visible within the display area by at least this amount. Only applies to regular windows.
     ImVec2      DisplaySafeAreaPadding;     // If you cannot see the edges of your screen (e.g. on a TV) increase the safe area padding. Apply to popups/tooltips as well regular windows. NB: Prefer configuring your TV sets correctly!
     float       MouseCursorScale;           // Scale software rendered mouse cursor (when io.MouseDrawCursor is enabled). May be removed later.
-    bool        AntiAliasedLines;           // Enable anti-aliased lines/borders. Disable if you are really tight on CPU/GPU.
-    bool        AntiAliasedFill;            // Enable anti-aliased edges around filled shapes (rounded rectangles, circles, etc.). Disable if you are really tight on CPU/GPU.
+    bool        AntiAliasedLines;           // Enable anti-aliased lines/borders. Disable if you are really tight on CPU/GPU. Latched at the beginning of the frame (copied to ImDrawList).
+    bool        AntiAliasedLinesUseTex;     // Enable anti-aliased lines/borders using textures where possible. Require back-end to render with bilinear filtering. Latched at the beginning of the frame (copied to ImDrawList).
+    bool        AntiAliasedFill;            // Enable anti-aliased edges around filled shapes (rounded rectangles, circles, etc.). Disable if you are really tight on CPU/GPU. Latched at the beginning of the frame (copied to ImDrawList).
     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];
@@ -1896,6 +1897,11 @@ struct ImColor
 // Hold a series of drawing commands. The user provides a renderer for ImDrawData which essentially contains an array of ImDrawList.
 //-----------------------------------------------------------------------------
 
+// The maximum line width to bake anti-aliased textures for. Build atlas with ImFontAtlasFlags_NoBakedLines to disable baking.
+#ifndef IM_DRAWLIST_TEX_LINES_WIDTH_MAX
+#define IM_DRAWLIST_TEX_LINES_WIDTH_MAX     (63)
+#endif
+
 // ImDrawCallback: Draw callbacks for advanced uses [configurable type: override in imconfig.h]
 // NB: You most likely do NOT need to use draw callbacks just to create your own widget or customized UI rendering,
 // you can poke into the draw list for that! Draw callback may be useful for example to:
@@ -1992,12 +1998,15 @@ enum ImDrawCornerFlags_
     ImDrawCornerFlags_All       = 0xF     // In your function calls you may use ~0 (= all bits sets) instead of ImDrawCornerFlags_All, as a convenience
 };
 
+// Flags for ImDrawList. Those are set automatically by ImGui:: functions from ImGuiIO settings, and generally not manipulated directly.
+// It is however possible to temporarily alter flags between calls to ImDrawList:: functions.
 enum ImDrawListFlags_
 {
     ImDrawListFlags_None                    = 0,
     ImDrawListFlags_AntiAliasedLines        = 1 << 0,  // Enable anti-aliased lines/borders (*2 the number of triangles for 1.0f wide line or lines thin enough to be drawn using textures, otherwise *3 the number of triangles)
-    ImDrawListFlags_AntiAliasedFill         = 1 << 1,  // Enable anti-aliased edge around filled shapes (rounded rectangles, circles).
-    ImDrawListFlags_AllowVtxOffset          = 1 << 2   // Can emit 'VtxOffset > 0' to allow large meshes. Set when 'ImGuiBackendFlags_RendererHasVtxOffset' is enabled.
+    ImDrawListFlags_AntiAliasedLinesUseTex  = 1 << 1,  // Enable anti-aliased lines/borders using textures when possible. Require back-end to render with bilinear filtering.
+    ImDrawListFlags_AntiAliasedFill         = 1 << 2,  // Enable anti-aliased edge around filled shapes (rounded rectangles, circles).
+    ImDrawListFlags_AllowVtxOffset          = 1 << 3   // Can emit 'VtxOffset > 0' to allow large meshes. Set when 'ImGuiBackendFlags_RendererHasVtxOffset' is enabled.
 };
 
 // Draw command list
@@ -2216,7 +2225,8 @@ enum ImFontAtlasFlags_
 {
     ImFontAtlasFlags_None               = 0,
     ImFontAtlasFlags_NoPowerOfTwoHeight = 1 << 0,   // Don't round the height to next power of two
-    ImFontAtlasFlags_NoMouseCursors     = 1 << 1    // Don't build software mouse cursors into the atlas (save a little texture memory)
+    ImFontAtlasFlags_NoMouseCursors     = 1 << 1,   // Don't build software mouse cursors into the atlas (save a little texture memory)
+    ImFontAtlasFlags_NoBakedLines       = 1 << 2    // Don't build thick line textures into the atlas (save a little texture memory). The AntiAliasedLinesUseTex features uses them, otherwise they will be rendered using polygons (more expensive for CPU/GPU).
 };
 
 // Load and rasterize multiple TTF/OTF fonts into a same texture. The font atlas will build a single texture holding:
@@ -2317,9 +2327,11 @@ struct ImFontAtlas
     ImVector<ImFont*>           Fonts;              // Hold all the fonts returned by AddFont*. Fonts[0] is the default font upon calling ImGui::NewFrame(), use ImGui::PushFont()/PopFont() to change the current font.
     ImVector<ImFontAtlasCustomRect> CustomRects;    // Rectangles for packing custom texture data into the atlas.
     ImVector<ImFontConfig>      ConfigData;         // Configuration data
+    ImVec4                      TexUvLines[IM_DRAWLIST_TEX_LINES_WIDTH_MAX + 1];  // UVs for baked anti-aliased lines
 
     // [Internal] Packing data
     int                         PackIdMouseCursors; // Custom texture rectangle ID for white pixel and mouse cursors
+    int                         PackIdLines;        // Custom texture rectangle ID for baked anti-aliased lines
 
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
     typedef ImFontAtlasCustomRect    CustomRect;         // OBSOLETED in 1.72+

imgui_demo.cpp

@@ -3831,6 +3831,8 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
         {
             ImGui::Checkbox("Anti-aliased lines", &style.AntiAliasedLines);
             ImGui::SameLine(); HelpMarker("When disabling anti-aliasing lines, you'll probably want to disable borders in your style as well.");
+            ImGui::Checkbox("Anti-aliased lines use texture", &style.AntiAliasedLinesUseTex);
+            ImGui::SameLine(); HelpMarker("Faster lines using texture data. Require back-end to render with bilinear filtering (not point/nearest filtering).");
             ImGui::Checkbox("Anti-aliased fill", &style.AntiAliasedFill);
             ImGui::PushItemWidth(100);
             ImGui::DragFloat("Curve Tessellation Tolerance", &style.CurveTessellationTol, 0.02f, 0.10f, 10.0f, "%.2f");