Atlas build use GetCustomRectByIndex() + comments, rename, and shallow merge from tex_antialiasing_lines branch.

imgui.cpp

@@ -934,8 +934,8 @@ ImGuiStyle::ImGuiStyle()
     DisplayWindowPadding    = ImVec2(19,19);    // Window position are clamped to be visible within the display area or monitors by at least this amount. Only applies to regular windows.
     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-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.)
+    AntiAliasedLines        = true;             // Enable anti-aliased lines/borders. Disable if you are really tight on CPU/GPU.
+    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.
 

imgui.h

@@ -151,7 +151,7 @@ typedef int ImGuiMouseCursor;       // -> enum ImGuiMouseCursor_     // Enum: A
 typedef int ImGuiStyleVar;          // -> enum ImGuiStyleVar_        // Enum: A variable identifier for styling
 typedef int ImDrawCornerFlags;      // -> enum ImDrawCornerFlags_    // Flags: for ImDrawList::AddRect(), AddRectFilled() etc.
 typedef int ImDrawListFlags;        // -> enum ImDrawListFlags_      // Flags: for ImDrawList
-typedef int ImFontAtlasFlags;       // -> enum ImFontAtlasFlags_     // Flags: for ImFontAtlas
+typedef int ImFontAtlasFlags;       // -> enum ImFontAtlasFlags_     // Flags: for ImFontAtlas build
 typedef int ImGuiBackendFlags;      // -> enum ImGuiBackendFlags_    // Flags: for io.BackendFlags
 typedef int ImGuiColorEditFlags;    // -> enum ImGuiColorEditFlags_  // Flags: for ColorEdit4(), ColorPicker4() etc.
 typedef int ImGuiConfigFlags;       // -> enum ImGuiConfigFlags_     // Flags: for io.ConfigFlags
@@ -1438,8 +1438,8 @@ 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-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.)
+    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.
     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];
@@ -1994,10 +1994,10 @@ enum ImDrawCornerFlags_
 
 enum ImDrawListFlags_
 {
-    ImDrawListFlags_None             = 0,
-    ImDrawListFlags_AntiAliasedLines = 1 << 0,  // Lines are anti-aliased (*2 the number of triangles for 1.0f wide line, otherwise *3 the number of triangles)
-    ImDrawListFlags_AntiAliasedFill  = 1 << 1,  // Filled shapes have anti-aliased edges (*2 the number of vertices)
-    ImDrawListFlags_AllowVtxOffset   = 1 << 2   // Can emit 'VtxOffset > 0' to allow large meshes. Set when 'ImGuiBackendFlags_RendererHasVtxOffset' is enabled.
+    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.
 };
 
 // Draw command list
@@ -2211,11 +2211,12 @@ struct ImFontAtlasCustomRect
     bool IsPacked() const           { return X != 0xFFFF; }
 };
 
+// Flags for ImFontAtlas build
 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
+    ImFontAtlasFlags_NoMouseCursors     = 1 << 1    // Don't build software mouse cursors into the atlas (save a little texture memory)
 };
 
 // Load and rasterize multiple TTF/OTF fonts into a same texture. The font atlas will build a single texture holding:
@@ -2289,7 +2290,7 @@ struct ImFontAtlas
     // Note: this API may be redesigned later in order to support multi-monitor varying DPI settings.
     IMGUI_API int               AddCustomRectRegular(int width, int height);
     IMGUI_API int               AddCustomRectFontGlyph(ImFont* font, ImWchar id, int width, int height, float advance_x, const ImVec2& offset = ImVec2(0, 0));
-    const ImFontAtlasCustomRect*GetCustomRectByIndex(int index) const { if (index < 0) return NULL; return &CustomRects[index]; }
+    ImFontAtlasCustomRect*      GetCustomRectByIndex(int index) { IM_ASSERT(index >= 0); return &CustomRects[index]; }
 
     // [Internal]
     IMGUI_API void              CalcCustomRectUV(const ImFontAtlasCustomRect* rect, ImVec2* out_uv_min, ImVec2* out_uv_max) const;
@@ -2315,8 +2316,10 @@ struct ImFontAtlas
     ImVec2                      TexUvWhitePixel;    // Texture coordinates to a white pixel
     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;         // Internal data
-    int                         CustomRectIds[1];   // Identifiers of custom texture rectangle used by ImFontAtlas/ImDrawList
+    ImVector<ImFontConfig>      ConfigData;         // Configuration data
+
+    // [Internal] Packing data
+    int                         PackIdMouseCursors; // Custom texture rectangle ID for white pixel and mouse cursors
 
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
     typedef ImFontAtlasCustomRect    CustomRect;         // OBSOLETED in 1.72+

imgui_demo.cpp

@@ -405,6 +405,7 @@ void ImGui::ShowDemoWindow(bool* p_open)
             ImGui::Checkbox("io.ConfigWindowsMoveFromTitleBarOnly", &io.ConfigWindowsMoveFromTitleBarOnly);
             ImGui::Checkbox("io.MouseDrawCursor", &io.MouseDrawCursor);
             ImGui::SameLine(); HelpMarker("Instruct Dear ImGui to render a mouse cursor itself. Note that a mouse cursor rendered via your application GPU rendering path will feel more laggy than hardware cursor, but will be more in sync with your other visuals.\n\nSome desktop applications may use both kinds of cursors (e.g. enable software cursor only when resizing/dragging something).");
+            ImGui::Text("Also see Style->Rendering for rendering options.");
             ImGui::TreePop();
             ImGui::Separator();
         }

imgui_draw.cpp

@@ -666,11 +666,9 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
         return;
 
     const ImVec2 opaque_uv = _Data->TexUvWhitePixel;
-    int count = points_count;
-    if (!closed)
-        count = points_count - 1;
-
+    const int count = closed ? points_count : points_count - 1; // The number of line segments we need to draw
     const bool thick_line = (thickness > 1.0f);
+
     if (Flags & ImDrawListFlags_AntiAliasedLines)
     {
         // Anti-aliased stroke
@@ -682,9 +680,11 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
         PrimReserve(idx_count, vtx_count);
 
         // Temporary buffer
+        // The first <points_count> items are normals at each line point, then after that there are either 2 or 4 temp points for each line point
         ImVec2* temp_normals = (ImVec2*)alloca(points_count * (thick_line ? 5 : 3) * sizeof(ImVec2)); //-V630
         ImVec2* temp_points = temp_normals + points_count;
 
+        // Calculate normals (tangents) for each line segment
         for (int i1 = 0; i1 < count; i1++)
         {
             const int i2 = (i1 + 1) == points_count ? 0 : i1 + 1;
@@ -707,12 +707,14 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
                 temp_points[(points_count-1)*2+1] = points[points_count-1] - temp_normals[points_count-1] * AA_SIZE;
             }
 
+            // Generate the indices to form a number of triangles for each line segment, and the vertices for the line edges
+            // This takes points n and n+1 and writes into n+1, with the first point in a closed line being generated from the final one (as n+1 wraps)
             // FIXME-OPT: Merge the different loops, possibly remove the temporary buffer.
-            unsigned int idx1 = _VtxCurrentIdx;
-            for (int i1 = 0; i1 < count; i1++)
+            unsigned int idx1 = _VtxCurrentIdx; // Vertex index for start of line segment
+            for (int i1 = 0; i1 < count; i1++) // i1 is the first point of the line segment
             {
                 const int i2 = (i1 + 1) == points_count ? 0 : i1 + 1;
-                unsigned int idx2 = (i1 + 1) == points_count ? _VtxCurrentIdx : idx1 + 3;
+                const unsigned int idx2 = (i1 + 1) == points_count ? _VtxCurrentIdx : idx1 + 3;
 
                 // Average normals
                 float dm_x = (temp_normals[i1].x + temp_normals[i2].x) * 0.5f;
@@ -721,14 +723,14 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
                 dm_x *= AA_SIZE;
                 dm_y *= AA_SIZE;
 
-                // Add temporary vertices
+                // Add temporary vertexes for the outer edges
                 ImVec2* out_vtx = &temp_points[i2 * 2];
                 out_vtx[0].x = points[i2].x + dm_x;
                 out_vtx[0].y = points[i2].y + dm_y;
                 out_vtx[1].x = points[i2].x - dm_x;
                 out_vtx[1].y = points[i2].y - dm_y;
 
-                // Add indexes
+                // Add indexes for four triangles
                 _IdxWritePtr[0] = (ImDrawIdx)(idx2+0); _IdxWritePtr[1] = (ImDrawIdx)(idx1+0); _IdxWritePtr[2] = (ImDrawIdx)(idx1+2);
                 _IdxWritePtr[3] = (ImDrawIdx)(idx1+2); _IdxWritePtr[4] = (ImDrawIdx)(idx2+2); _IdxWritePtr[5] = (ImDrawIdx)(idx2+0);
                 _IdxWritePtr[6] = (ImDrawIdx)(idx2+1); _IdxWritePtr[7] = (ImDrawIdx)(idx1+1); _IdxWritePtr[8] = (ImDrawIdx)(idx1+0);
@@ -738,7 +740,7 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
                 idx1 = idx2;
             }
 
-            // Add vertices
+            // Add vertexes for each point on the line
             for (int i = 0; i < points_count; i++)
             {
                 _VtxWritePtr[0].pos = points[i];          _VtxWritePtr[0].uv = opaque_uv; _VtxWritePtr[0].col = col;
@@ -749,7 +751,10 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
         }
         else
         {
+            // Non texture-based lines (thick): we need to draw the solid line core and thus require four vertices per point
             const float half_inner_thickness = (thickness - AA_SIZE) * 0.5f;
+
+            // If line is not closed, the first and last points need to be generated differently as there are no normals to blend
             if (!closed)
             {
                 const int points_last = points_count - 1;
@@ -763,9 +768,11 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
                 temp_points[points_last * 4 + 3] = points[points_last] - temp_normals[points_last] * (half_inner_thickness + AA_SIZE);
             }
 
+            // Generate the indices to form a number of triangles for each line segment, and the vertices for the line edges
+            // This takes points n and n+1 and writes into n+1, with the first point in a closed line being generated from the final one (as n+1 wraps)
             // FIXME-OPT: Merge the different loops, possibly remove the temporary buffer.
-            unsigned int idx1 = _VtxCurrentIdx;
-            for (int i1 = 0; i1 < count; i1++)
+            unsigned int idx1 = _VtxCurrentIdx; // Vertex index for start of line segment
+            for (int i1 = 0; i1 < count; i1++) // i1 is the first point of the line segment
             {
                 const int i2 = (i1 + 1) == points_count ? 0 : (i1 + 1); // i2 is the second point of the line segment
                 const unsigned int idx2 = (i1 + 1) == points_count ? _VtxCurrentIdx : (idx1 + 4); // Vertex index for end of segment
@@ -816,7 +823,7 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
     }
     else
     {
-        // Non Anti-aliased Stroke
+        // Non texture-based, Non anti-aliased lines
         const int idx_count = count * 6;
         const int vtx_count = count * 4;    // FIXME-OPT: Not sharing edges
         PrimReserve(idx_count, vtx_count);
@@ -1656,8 +1663,7 @@ ImFontAtlas::ImFontAtlas()
     TexWidth = TexHeight = 0;
     TexUvScale = ImVec2(0.0f, 0.0f);
     TexUvWhitePixel = ImVec2(0.0f, 0.0f);
-    for (int n = 0; n < IM_ARRAYSIZE(CustomRectIds); n++)
-        CustomRectIds[n] = -1;
+    PackIdMouseCursors = -1;
 }
 
 ImFontAtlas::~ImFontAtlas()
@@ -1685,8 +1691,7 @@ void    ImFontAtlas::ClearInputData()
         }
     ConfigData.clear();
     CustomRects.clear();
-    for (int n = 0; n < IM_ARRAYSIZE(CustomRectIds); n++)
-        CustomRectIds[n] = -1;
+    PackIdMouseCursors = -1;
 }
 
 void    ImFontAtlas::ClearTexData()
@@ -1926,9 +1931,9 @@ bool ImFontAtlas::GetMouseCursorTexData(ImGuiMouseCursor cursor_type, ImVec2* ou
     if (Flags & ImFontAtlasFlags_NoMouseCursors)
         return false;
 
-    IM_ASSERT(CustomRectIds[0] != -1);
-    ImFontAtlasCustomRect& r = CustomRects[CustomRectIds[0]];
-    ImVec2 pos = FONT_ATLAS_DEFAULT_TEX_CURSOR_DATA[cursor_type][0] + ImVec2((float)r.X, (float)r.Y);
+    IM_ASSERT(PackIdMouseCursors != -1);
+    ImFontAtlasCustomRect* r = GetCustomRectByIndex(PackIdMouseCursors);
+    ImVec2 pos = FONT_ATLAS_DEFAULT_TEX_CURSOR_DATA[cursor_type][0] + ImVec2((float)r->X, (float)r->Y);
     ImVec2 size = FONT_ATLAS_DEFAULT_TEX_CURSOR_DATA[cursor_type][1];
     *out_size = size;
     *out_offset = FONT_ATLAS_DEFAULT_TEX_CURSOR_DATA[cursor_type][2];
@@ -2256,17 +2261,6 @@ bool    ImFontAtlasBuildWithStbTruetype(ImFontAtlas* atlas)
     return true;
 }
 
-// Register default custom rectangles (this is called/shared by both the stb_truetype and the FreeType builder)
-void ImFontAtlasBuildInit(ImFontAtlas* atlas)
-{
-    if (atlas->CustomRectIds[0] >= 0)
-        return;
-    if (!(atlas->Flags & ImFontAtlasFlags_NoMouseCursors))
-        atlas->CustomRectIds[0] = atlas->AddCustomRectRegular(FONT_ATLAS_DEFAULT_TEX_DATA_W_HALF * 2 + 1, FONT_ATLAS_DEFAULT_TEX_DATA_H);
-    else
-        atlas->CustomRectIds[0] = atlas->AddCustomRectRegular(2, 2);
-}
-
 void ImFontAtlasBuildSetupFont(ImFontAtlas* atlas, ImFont* font, ImFontConfig* font_config, float ascent, float descent)
 {
     if (!font_config->MergeMode)
@@ -2310,20 +2304,18 @@ void ImFontAtlasBuildPackCustomRects(ImFontAtlas* atlas, void* stbrp_context_opa
 
 static void ImFontAtlasBuildRenderDefaultTexData(ImFontAtlas* atlas)
 {
-    IM_ASSERT(atlas->CustomRectIds[0] >= 0);
-    IM_ASSERT(atlas->TexPixelsAlpha8 != NULL);
-    ImFontAtlasCustomRect& r = atlas->CustomRects[atlas->CustomRectIds[0]];
-    IM_ASSERT(r.IsPacked());
+    ImFontAtlasCustomRect* r = atlas->GetCustomRectByIndex(atlas->PackIdMouseCursors);
+    IM_ASSERT(r->IsPacked());
 
     const int w = atlas->TexWidth;
     if (!(atlas->Flags & ImFontAtlasFlags_NoMouseCursors))
     {
         // Render/copy pixels
-        IM_ASSERT(r.Width == FONT_ATLAS_DEFAULT_TEX_DATA_W_HALF * 2 + 1 && r.Height == FONT_ATLAS_DEFAULT_TEX_DATA_H);
+        IM_ASSERT(r->Width == FONT_ATLAS_DEFAULT_TEX_DATA_W_HALF * 2 + 1 && r->Height == FONT_ATLAS_DEFAULT_TEX_DATA_H);
         for (int y = 0, n = 0; y < FONT_ATLAS_DEFAULT_TEX_DATA_H; y++)
             for (int x = 0; x < FONT_ATLAS_DEFAULT_TEX_DATA_W_HALF; x++, n++)
             {
-                const int offset0 = (int)(r.X + x) + (int)(r.Y + y) * w;
+                const int offset0 = (int)(r->X + x) + (int)(r->Y + y) * w;
                 const int offset1 = offset0 + FONT_ATLAS_DEFAULT_TEX_DATA_W_HALF + 1;
                 atlas->TexPixelsAlpha8[offset0] = FONT_ATLAS_DEFAULT_TEX_DATA_PIXELS[n] == '.' ? 0xFF : 0x00;
                 atlas->TexPixelsAlpha8[offset1] = FONT_ATLAS_DEFAULT_TEX_DATA_PIXELS[n] == 'X' ? 0xFF : 0x00;
@@ -2331,29 +2323,46 @@ static void ImFontAtlasBuildRenderDefaultTexData(ImFontAtlas* atlas)
     }
     else
     {
-        IM_ASSERT(r.Width == 2 && r.Height == 2);
-        const int offset = (int)(r.X) + (int)(r.Y) * w;
+        // Render 4 white pixels
+        IM_ASSERT(r->Width == 2 && r->Height == 2);
+        const int offset = (int)r->X + (int)r->Y * w;
         atlas->TexPixelsAlpha8[offset] = atlas->TexPixelsAlpha8[offset + 1] = atlas->TexPixelsAlpha8[offset + w] = atlas->TexPixelsAlpha8[offset + w + 1] = 0xFF;
     }
-    atlas->TexUvWhitePixel = ImVec2((r.X + 0.5f) * atlas->TexUvScale.x, (r.Y + 0.5f) * atlas->TexUvScale.y);
+    atlas->TexUvWhitePixel = ImVec2((r->X + 0.5f) * atlas->TexUvScale.x, (r->Y + 0.5f) * atlas->TexUvScale.y);
 }
 
+
+// Note: this is called / shared by both the stb_truetype and the FreeType builder
+void ImFontAtlasBuildInit(ImFontAtlas* atlas)
+{
+    // Register texture region for mouse cursors or standard white pixels
+    if (atlas->PackIdMouseCursors < 0)
+    {
+        if (!(atlas->Flags & ImFontAtlasFlags_NoMouseCursors))
+            atlas->PackIdMouseCursors = atlas->AddCustomRectRegular(FONT_ATLAS_DEFAULT_TEX_DATA_W_HALF * 2 + 1, FONT_ATLAS_DEFAULT_TEX_DATA_H);
+        else
+            atlas->PackIdMouseCursors = atlas->AddCustomRectRegular(2, 2);
+    }
+}
+
+// This is called/shared by both the stb_truetype and the FreeType builder.
 void ImFontAtlasBuildFinish(ImFontAtlas* atlas)
 {
-    // Render into our custom data block
+    // Render into our custom data blocks
+    IM_ASSERT(atlas->TexPixelsAlpha8 != NULL);
     ImFontAtlasBuildRenderDefaultTexData(atlas);
 
     // Register custom rectangle glyphs
     for (int i = 0; i < atlas->CustomRects.Size; i++)
     {
-        const ImFontAtlasCustomRect& r = atlas->CustomRects[i];
-        if (r.Font == NULL || r.GlyphID == 0)
+        const ImFontAtlasCustomRect* r = &atlas->CustomRects[i];
+        if (r->Font == NULL || r->GlyphID == 0)
             continue;
 
-        IM_ASSERT(r.Font->ContainerAtlas == atlas);
+        IM_ASSERT(r->Font->ContainerAtlas == atlas);
         ImVec2 uv0, uv1;
-        atlas->CalcCustomRectUV(&r, &uv0, &uv1);
-        r.Font->AddGlyph((ImWchar)r.GlyphID, r.GlyphOffset.x, r.GlyphOffset.y, r.GlyphOffset.x + r.Width, r.GlyphOffset.y + r.Height, uv0.x, uv0.y, uv1.x, uv1.y, r.GlyphAdvanceX);
+        atlas->CalcCustomRectUV(r, &uv0, &uv1);
+        r->Font->AddGlyph((ImWchar)r->GlyphID, r->GlyphOffset.x, r->GlyphOffset.y, r->GlyphOffset.x + r->Width, r->GlyphOffset.y + r->Height, uv0.x, uv0.y, uv1.x, uv1.y, r->GlyphAdvanceX);
     }
 
     // Build all fonts lookup tables