From c46b79846c18d131f00ee299c811bb7afd125e66 Mon Sep 17 00:00:00 2001
From: Chris Savoie <chris@chrissavoie.com>
Date: Sat, 9 May 2020 22:18:10 -0700
Subject: [PATCH] Metrics: Fix metrics crash with viewports.

---
 imgui.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/imgui.cpp b/imgui.cpp
index db1fb892..f16aa3d3 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -15318,10 +15318,9 @@ void ImGui::ShowMetricsWindow(bool* p_open)
             return ImRect();
         }
 
-        static void NodeDrawCmdShowMeshAndBoundingBox(ImGuiWindow* window, const ImDrawList* draw_list, const ImDrawCmd* draw_cmd, int elem_offset, bool show_mesh, bool show_aabb)
+        static void NodeDrawCmdShowMeshAndBoundingBox(ImDrawList* fg_draw_list, const ImDrawList* draw_list, const ImDrawCmd* draw_cmd, int elem_offset, bool show_mesh, bool show_aabb)
         {
             IM_ASSERT(show_mesh || show_aabb);
-            ImDrawList* fg_draw_list = GetForegroundDrawList(window); // Render additional visuals into the top-most draw list
             ImDrawIdx* idx_buffer = (draw_list->IdxBuffer.Size > 0) ? draw_list->IdxBuffer.Data : NULL;
 
             // Draw wire-frame version of all triangles
@@ -15350,6 +15349,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
             fg_draw_list->Flags = backup_flags;
         }
 
+        // Note that both 'window' and 'viewport' may be NULL here. Viewport is generally null of destroyed popups which previously owned a viewport.
         static void NodeDrawList(ImGuiWindow* window, ImGuiViewportP* viewport, ImDrawList* draw_list, const char* label)
         {
             bool node_open = ImGui::TreeNode(draw_list, "%s: '%s' %d vtx, %d indices, %d cmds", label, draw_list->_OwnerName ? draw_list->_OwnerName : "", draw_list->VtxBuffer.Size, draw_list->IdxBuffer.Size, draw_list->CmdBuffer.Size);
@@ -15388,7 +15388,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
                     pcmd->ClipRect.x, pcmd->ClipRect.y, pcmd->ClipRect.z, pcmd->ClipRect.w);
                 bool pcmd_node_open = ImGui::TreeNode((void*)(pcmd - draw_list->CmdBuffer.begin()), "%s", buf);
                 if (ImGui::IsItemHovered() && (show_drawcmd_mesh || show_drawcmd_aabb) && fg_draw_list)
-                    NodeDrawCmdShowMeshAndBoundingBox(window, draw_list, pcmd, elem_offset, show_drawcmd_mesh, show_drawcmd_aabb);
+                    NodeDrawCmdShowMeshAndBoundingBox(fg_draw_list, draw_list, pcmd, elem_offset, show_drawcmd_mesh, show_drawcmd_aabb);
                 if (!pcmd_node_open)
                     continue;
 
@@ -15407,7 +15407,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
                 ImFormatString(buf, IM_ARRAYSIZE(buf), "Mesh: ElemCount: %d, VtxOffset: +%d, IdxOffset: +%d, Area: ~%0.f px", pcmd->ElemCount, pcmd->VtxOffset, pcmd->IdxOffset, total_area);
                 ImGui::Selectable(buf);
                 if (ImGui::IsItemHovered() && fg_draw_list)
-                    NodeDrawCmdShowMeshAndBoundingBox(window, draw_list, pcmd, elem_offset, true, false);
+                    NodeDrawCmdShowMeshAndBoundingBox(fg_draw_list, draw_list, pcmd, elem_offset, true, false);
 
                 // Display individual triangles/vertices. Hover on to get the corresponding triangle highlighted.
                 ImGuiListClipper clipper(pcmd->ElemCount/3); // Manually coarse clip our print out of individual vertices to save CPU, only items that may be visible.