From 1df4ac6c7245d02bfe92c562c0f42a51697dc9dc Mon Sep 17 00:00:00 2001
From: woclass <inkydragon@users.noreply.github.com>
Date: Sun, 1 Sep 2019 18:40:03 +0800
Subject: [PATCH] workaround for draw_list 2^16 limit

xref: https://github.com/ocornut/imgui/issues/2591
---
 test/Fractals.jl | 67 ++++++++++++++++++++++++++++++++++++------------
 1 file changed, 51 insertions(+), 16 deletions(-)

diff --git a/test/Fractals.jl b/test/Fractals.jl
index 8dfd80b..c4e3c7e 100644
--- a/test/Fractals.jl
+++ b/test/Fractals.jl
@@ -49,7 +49,6 @@ ImGui_ImplOpenGL3_Init(glsl_version)
 rule_list = getAllRules()
 
 while !GLFW.WindowShouldClose(window)
-
     GLFW.PollEvents()
     # start the Dear ImGui frame
     ImGui_ImplOpenGL3_NewFrame()
@@ -64,11 +63,11 @@ while !GLFW.WindowShouldClose(window)
     CImGui.Text("L-Systems")
     listbox_item_current, listbox_items = @cstatic listbox_item_current=Cint(0) listbox_items=rule_list begin
         # list box
-        @c CImGui.ListBox("L-Systems\n(click to select one)", &listbox_item_current, listbox_items, length(listbox_items), 3)
+        @c CImGui.ListBox("L-Systems\n(click to select one)", &listbox_item_current, listbox_items, length(listbox_items), 5)
     end
     CImGui.Text("L-System parameters")
     iter, angle, slen = @cstatic iter=Cint(4) angle=Cfloat(0.0) slen=Cfloat(10) begin 
-        @c CImGui.CImGui.SliderInt("Iteration times", &iter, 1, 6, "%d")
+        @c CImGui.CImGui.SliderInt("Iteration times", &iter, 1, 8, "%d")
         @c CImGui.DragFloat("Initial angle", &angle, 1, -180.0, 180.0, "%.0f")
         @c CImGui.DragFloat("Step length",  &slen, 0.5, 0.5, 30, "%.0f")
     end
@@ -78,17 +77,22 @@ while !GLFW.WindowShouldClose(window)
     thickness, col = @cstatic thickness=Cfloat(2.0)  col=Cfloat[1.0,1.0,0.4,1.0] begin
         @c CImGui.DragFloat("Width", &thickness, 0.05, 1.0, 8.0, "%.02f")
         CImGui.ColorEdit4("Color", col)
-    end
+    end 
     CImGui.Text("Adjust Original Point")
     dx, dy = @cstatic dx=Cfloat(256.0) dy=Cfloat(128.0) begin 
-        @c CImGui.DragFloat("dx ->", &dx, 4, 0.0, 512.0, "%.0f")
-        @c CImGui.DragFloat("dy V",  &dy, 4, 0.0, 512.0, "%.0f")
+        @c CImGui.DragFloat("dx ->", &dx, 4, 0.0, 4096.0, "%.0f")
+        @c CImGui.DragFloat("dy V",  &dy, 4, 0.0, 2048.0, "%.0f")
     end
     CImGui.Separator()
-
+    
+    @cstatic currentChild = 0
+    wpos = CImGui.GetWindowPos()
+    backupPos = CImGui.GetCursorScreenPos()
+    
     # draw lines
     p = CImGui.GetCursorScreenPos()
     col32 = CImGui.ColorConvertFloat4ToU32(ImVec4(col...))
+    
     begin
         x::Cfloat = p.x + 4.0 + dx
         y::Cfloat = p.y + 4.0 + dy
@@ -102,17 +106,48 @@ while !GLFW.WindowShouldClose(window)
 
         # L System
         steps = genStep(RULES[listbox_item_current+1], param)
-        for ((sx, sy), (ex, ey)) in steps
-            CImGui.AddLine(draw_list,
-                ImVec2(sx, sy),
-                ImVec2(ex, ey),
-                col32,
-                th
-            );
+        slen = length(steps)
+        if slen > (2^13 - 8)
+            times = Int(floor(slen/(2^13 - 8)))
+            idxm = (2^13 - 8)
+            for i in 0:(times-1)
+                CImGui.SetCursorScreenPos(backupPos)
+                CImGui.BeginChild(currentChild+=1)
+                draw_list = CImGui.GetWindowDrawList()
+                for ((sx, sy), (ex, ey)) in steps[(1+idxm*i):idxm*(1+i)]
+                    CImGui.AddLine(draw_list,
+                        ImVec2(sx, sy),
+                        ImVec2(ex, ey),
+                        col32,
+                        th
+                    );
+                end
+                CImGui.EndChild()
+            end
+            CImGui.SetCursorScreenPos(backupPos)
+            CImGui.BeginChild(currentChild+=1)
+            draw_list = CImGui.GetWindowDrawList()
+                for ((sx, sy), (ex, ey)) in steps[(1+idxm*times):end]
+                    CImGui.AddLine(draw_list,
+                        ImVec2(sx, sy),
+                        ImVec2(ex, ey),
+                        col32,
+                        th
+                    );
+                end
+            CImGui.EndChild()
+        else
+            for ((sx, sy), (ex, ey)) in steps
+                CImGui.AddLine(draw_list,
+                    ImVec2(sx, sy),
+                    ImVec2(ex, ey),
+                    col32,
+                    th
+                );
+            end
         end
-
     end
-
+    
     CImGui.End() #= widgets end ---------------------------------------------=#
 
     # rendering