Restrict graphics functions to graphics contexts

gfx.textSize/getColors/getHexColor are exempt because they don't change any state that we care about and seem easy to deal with in general.

src/gui/game/GameControllerEvents.h

@@ -10,6 +10,7 @@ enum EventTraits : uint32_t
 	eventTraitSimGraphics       = UINT32_C(0x00000002),
 	eventTraitHindersSrt        = UINT32_C(0x00000004),
 	eventTraitInterface         = UINT32_C(0x00000008),
+	eventTraitInterfaceGraphics = UINT32_C(0x00000010),
 };
 constexpr EventTraits operator |(EventTraits lhs, EventTraits rhs)
 {
@@ -85,7 +86,7 @@ struct MouseWheelEvent
 
 struct TickEvent
 {
-	static constexpr EventTraits traits = eventTraitInterface;
+	static constexpr EventTraits traits = eventTraitInterface | eventTraitInterfaceGraphics;
 };
 
 struct BlurEvent

src/lua/LuaGraphics.cpp

@@ -2,6 +2,62 @@
 #include "graphics/Graphics.h"
 #include "graphics/Renderer.h"
 
+void NonGraphicsContext::Die()
+{
+	luaL_error(GetLSI()->L, "this functionality is restricted to graphics events");
+}
+
+void NonGraphicsContext::BlendPixel(Vec2<int>, RGBA)
+{
+	Die();
+}
+
+Vec2<int> NonGraphicsContext::BlendText(Vec2<int>, const String &, RGBA)
+{
+	Die();
+	return { 0, 0 };
+}
+
+void NonGraphicsContext::DrawLine(Vec2<int>, Vec2<int>, RGB)
+{
+	Die();
+}
+
+void NonGraphicsContext::BlendLine(Vec2<int>, Vec2<int>, RGBA)
+{
+	Die();
+}
+
+void NonGraphicsContext::DrawRect(Rect<int>, RGB)
+{
+	Die();
+}
+
+void NonGraphicsContext::BlendRect(Rect<int>, RGBA)
+{
+	Die();
+}
+
+void NonGraphicsContext::DrawFilledRect(Rect<int>, RGB)
+{
+	Die();
+}
+
+void NonGraphicsContext::BlendFilledRect(Rect<int>, RGBA)
+{
+	Die();
+}
+
+void NonGraphicsContext::BlendEllipse(Vec2<int>, Vec2<int>, RGBA)
+{
+	Die();
+}
+
+void NonGraphicsContext::BlendFilledEllipse(Vec2<int>, Vec2<int>, RGBA)
+{
+	Die();
+}
+
 static int32_t int32Truncate(double n)
 {
 	if (n >= 0x1p31)
@@ -255,6 +311,10 @@ static int setClipRect(lua_State *L)
 	{
 		return luaL_error(L, "simulation graphics do not support clip rects");
 	}
+	if (!(lsi->eventTraits & eventTraitInterfaceGraphics))
+	{
+		NonGraphicsContext::Die();
+	}
 	int x = luaL_optinteger(L, 1, 0);
 	int y = luaL_optinteger(L, 2, 0);
 	int w = luaL_optinteger(L, 3, WINDOWW);

src/lua/LuaScriptInterface.h

@@ -3,6 +3,7 @@
 #include "LuaSmartRef.h"
 #include "CommandInterface.h"
 #include "gui/game/GameControllerEvents.h"
+#include "graphics/Pixel.h"
 #include "simulation/StructProperty.h"
 #include "simulation/ElementDefs.h"
 #include <cstdint>
@@ -69,6 +70,22 @@ struct CustomTool
 	LuaSmartRef select;
 };
 
+struct NonGraphicsContext
+{
+	static void Die();
+
+	void BlendPixel(Vec2<int>, RGBA);
+	Vec2<int> BlendText(Vec2<int>, const String &, RGBA);
+	void DrawLine(Vec2<int>, Vec2<int>, RGB);
+	void BlendLine(Vec2<int>, Vec2<int>, RGBA);
+	void DrawRect(Rect<int>, RGB);
+	void BlendRect(Rect<int>, RGBA);
+	void DrawFilledRect(Rect<int>, RGB);
+	void BlendFilledRect(Rect<int>, RGBA);
+	void BlendEllipse(Vec2<int>, Vec2<int>, RGBA);
+	void BlendFilledEllipse(Vec2<int>, Vec2<int>, RGBA);
+};
+
 class LuaScriptInterface : public CommandInterface
 {
 	LuaStatePtr luaState;
@@ -84,7 +101,9 @@ public:
 	Simulation *sim;
 	Graphics *g;
 
-	std::variant<Graphics *, Renderer *> GetGraphics()
+	NonGraphicsContext ngc;
+
+	std::variant<Graphics *, Renderer *, NonGraphicsContext *> GetGraphics()
 	{
 		if (eventTraits & eventTraitSimGraphics)
 		{
@@ -93,8 +112,12 @@ public:
 			// installed for eventTraitSimGraphics and *SimDraw events.
 			return ren;
 		}
+		if (eventTraits & eventTraitInterfaceGraphics)
+		{
 			return g;
 		}
+		return &ngc;
+	}
 
 	std::vector<CustomElement> customElements; // must come after luaState
 	std::vector<CustomTool> customTools;

src/lua/LuaWindow.cpp

@@ -232,7 +232,7 @@ void LuaWindow::triggerOnTick()
 	{
 		lua_rawgeti(L, LUA_REGISTRYINDEX, onTickFunction);
 		lua_pushnumber(L, 1); // this used to be dt, which was measured in 60ths of a second; this hardcodes 60fps
-		if(tpt_lua_pcall(L, 1, 0, 0, eventTraitInterface))
+		if(tpt_lua_pcall(L, 1, 0, 0, eventTraitInterface | eventTraitInterfaceGraphics))
 		{
 			ci->Log(CommandInterface::LogError, tpt_lua_toString(L, -1));
 		}
@@ -244,7 +244,7 @@ void LuaWindow::triggerOnDraw()
 	if(onDrawFunction)
 	{
 		lua_rawgeti(L, LUA_REGISTRYINDEX, onDrawFunction);
-		if(tpt_lua_pcall(L, 0, 0, 0, eventTraitInterface))
+		if(tpt_lua_pcall(L, 0, 0, 0, eventTraitInterface | eventTraitInterfaceGraphics))
 		{
 			ci->Log(CommandInterface::LogError, tpt_lua_toString(L, -1));
 		}