From 00b02b9955b60c1f25735f5fcda39ccd915ba83d Mon Sep 17 00:00:00 2001
From: omar <ocornut@users.noreply.github.com>
Date: Sun, 6 Mar 2016 17:13:47 +0100
Subject: [PATCH] Created plot_var_example (markdown)

---
 plot_var_example.md | 92 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 plot_var_example.md

diff --git a/plot_var_example.md b/plot_var_example.md
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+++ b/plot_var_example.md
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+Helper to store values so they can be plotted over time.
+
+Usage
+```
+// Call once a frame with current value
+ImGui::PlotVar("Speed", MyCharacter.Speed);
+```
+
+
+
+.h
+```
+// Plot value over time
+// Pass FLT_MAX value to draw without adding a new value
+void	PlotVar(const char* label, float value, float scale_min = FLT_MAX, float scale_max = FLT_MAX, size_t buffer_size = 120);
+
+// Call this periodically to discard old/unused data
+void	PlotVarFlushOldEntries();
+```
+
+.cpp
+```
+#include <map>
+struct PlotVarData
+{
+	ImGuiID        ID;
+	Vector<float>  Data;
+	int            DataInsertIdx;
+	int            LastFrame;
+
+	PlotVarData() : ID(0), DataInsertIdx(0), LastFrame(-1) {}
+};
+
+typedef std::map<ImGuiID, PlotVarData> PlotVarsMap;
+static PlotVarsMap	g_PlotVarsMap;
+
+// Plot value over time
+// Call with 'value == FLT_MAX' to draw without adding new value to the buffer
+void ImGui::PlotVar(const char* label, float value, float scale_min, float scale_max, size_t buffer_size)
+{
+	ASSERT(label);
+	if (buffer_size == 0)
+		buffer_size = 120;
+
+	ImGui::PushID(label);
+	ImGuiID id = ImGui::GetID("");
+
+	// Lookup O(log N)
+	PlotVarData& pvd = g_PlotVarsMap[id];
+
+	// Setup
+	if (pvd.Data.capacity() != buffer_size)
+	{
+		pvd.Data.resize(buffer_size);
+		memset(&pvd.Data[0], 0, sizeof(float) * buffer_size);
+		pvd.DataInsertIdx = 0;
+		pvd.LastFrame = -1;
+	}
+
+	// Insert (avoid unnecessary modulo operator)
+	if (pvd.DataInsertIdx == buffer_size)
+		pvd.DataInsertIdx = 0;
+	int display_idx = pvd.DataInsertIdx;
+	if (value != FLT_MAX)
+		pvd.Data[pvd.DataInsertIdx++] = value;
+
+	// Draw
+	int current_frame = ImGui::GetFrameCount();
+	if (pvd.LastFrame != current_frame)
+	{
+		ImGui::PlotLines("##plot", &pvd.Data[0], buffer_size, pvd.DataInsertIdx, NULL, scale_min, scale_max, ImVec2(0, 40));
+		ImGui::SameLine();
+		ImGui::Text("%s\n%-3.4f", label, pvd.Data[display_idx]);	// Display last value in buffer
+		pvd.LastFrame = current_frame;
+	}
+	
+	ImGui::PopID();
+}
+
+void ImGui::PlotVarFlushOldEntries()
+{
+	int current_frame = ImGui::GetFrameCount();
+	for (PlotVarsMap::iterator it = g_PlotVarsMap.begin(); it != g_PlotVarsMap.end(); )
+	{
+		PlotVarData& pvd = it->second;
+		if (pvd.LastFrame < current_frame - MAX(400,(int)pvd.Data.size()))
+			it = g_PlotVarsMap.erase(it);
+		else
+			++it;
+	}
+}
+```
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