add arena memory gooey widget

src/gooey.cpp

@@ -8,6 +8,7 @@ using namespace ImGui;
 
 #include "gooey.h"
 #include "orbits.h"
+#include "util.h"
 
 
 const static int G_WIDTH = 400;
@@ -17,6 +18,7 @@ const int H_FLAGS = ImGuiTreeNodeFlags_DefaultOpen;
 // forward declarations
 
 void drawSimulationWindow(bool& running, u64 sim_time_ms, float& sim_speed);
+void drawMemoryWindow(MemoryArena* arena);
 void drawOrbitWindow(GameState* gs);
 void drawEllipseParameters(EllipseParameters& ep);
 void drawGravitationalBody(GravBody& body);
@@ -74,12 +76,13 @@ gooDraw(SDL_Window* window, GameState* gs)
 	Begin("Gooey");
 
 	drawSimulationWindow(gs->running, gs->sim_time_ms, gs->sim_speed);
+	drawMemoryWindow(gs->arena);
 	Separator();
 
-	// FIXME: slit up orbit window into function calls here
+	// FIXME: split up orbit window into function calls here
 	drawOrbitWindow(gs);
 
-	BeginChild("impulsive maneuver", ImVec2(G_WIDTH - 20, 150), true);
+	BeginChild("impulsive maneuver", ImVec2(G_WIDTH - 20, 125), true);
 	drawManeuverWindow(gs);
 	EndChild();
 #if 0
@@ -113,11 +116,26 @@ void drawSimulationWindow(bool& running, u64 sim_time_ms, float& sim_speed)
 	InputFloat("sim speed", &sim_speed, 0.1, 4.0, "%.1f");
 }
 
+void drawMemoryWindow(MemoryArena* arena)
+{
+	BeginChild("memory", ImVec2(G_WIDTH - 20, 50), true);
+		Text("GameState Memory Arena");
+		float freeMB = (float) arena->free_size / (float) (1024 * 1024);
+		float maxMB = (float) arena->max_size / (float) (1024 * 1024);
+		float usedMB = maxMB - freeMB;
+		Text("%.2f MB", usedMB);
+		SameLine();
+		ProgressBar(usedMB / maxMB, ImVec2(100, 15));
+		SameLine();
+		Text("%.2f MB", maxMB);
+	EndChild();
+}
+
 void drawOrbitWindow(GameState* gs)
 {
 	Text("Orbit Selection");
 
-	BeginChild("orbit selection", ImVec2(G_WIDTH - 20, 100), true);
+	BeginChild("orbit selection", ImVec2(G_WIDTH - 20, 70), true);
 	static u32 selected = UINT_MAX;
 
 	for (u32 i = 0; i < gs->num_orbits; i++) {
@@ -146,8 +164,8 @@ void drawOrbitWindow(GameState* gs)
 		//Text("Orbital Period:  %.2fs", sys.orbital_period);
 		drawSystemWindow(sys);
 		Separator();
-		drawGravitationalBody(sys.body);
-		Separator();
+		//drawGravitationalBody(sys.body);
+		//Separator();
 		drawSatelliteWindow(sys.sat);
 		Separator();
 		drawOrbitalElements(sys.elements);