Show a popup error if love.window loads but love.graphics does not.

Also include backend-specific errors in graphics initalization error messages.
Improves visibility of errors related to vulkan/metal/opengl initialization.
Related to #2335.

src/modules/graphics/Graphics.cpp

@@ -36,6 +36,7 @@
 
 // C++
 #include <algorithm>
+#include <tuple>
 #include <stdlib.h>
 
 namespace love
@@ -106,12 +107,12 @@ bool isDebugEnabled()
 
 love::Type Graphics::type("graphics", &Module::type);
 
-namespace opengl { extern love::graphics::Graphics *createInstance(); }
+namespace opengl { extern std::tuple<love::graphics::Graphics *, std::string> createInstance(); }
 #ifdef LOVE_GRAPHICS_METAL
-namespace metal { extern love::graphics::Graphics *createInstance(); }
+namespace metal { extern std::tuple<love::graphics::Graphics *, std::string> createInstance(); }
 #endif
 #ifdef LOVE_GRAPHICS_VULKAN
-namespace vulkan { extern love::graphics::Graphics *createInstance(); }
+namespace vulkan { extern std::tuple<love::graphics::Graphics *, std::string> createInstance(); }
 #endif
 
 static const Renderer rendererOrder[] = {
@@ -164,6 +165,7 @@ bool isLowPowerPreferred()
 Graphics *Graphics::createInstance()
 {
 	Graphics *instance = Module::getInstance<Graphics>(M_GRAPHICS);
+	std::string errors;
 
 	if (instance != nullptr)
 		instance->retain();
@@ -171,25 +173,39 @@ Graphics *Graphics::createInstance()
 	{
 		for (auto r : rendererOrder)
 		{
-
 			if (std::find(_renderers.begin(), _renderers.end(), r) == _renderers.end())
 				continue;
 
+			std::string err;
+
 #ifdef LOVE_GRAPHICS_VULKAN
 			if (r == RENDERER_VULKAN)
-				instance = vulkan::createInstance();
+				std::tie(instance, err) = vulkan::createInstance();
 #endif
 			if (r == RENDERER_OPENGL)
-				instance = opengl::createInstance();
+				std::tie(instance, err) = opengl::createInstance();
 #ifdef LOVE_GRAPHICS_METAL
 			if (r == RENDERER_METAL)
-				instance = metal::createInstance();
+				std::tie(instance, err) = metal::createInstance();
 #endif
+
+			if (!err.empty())
+			{
+				errors += err;
+				if (isDebugEnabled())
+					::printf("%s", err.c_str());
+			}
+
 			if (instance != nullptr)
 				break;
 		}
 	}
 
+	if (instance == nullptr)
+	{
+		throw love::Exception("Cannot create graphics: no supported renderer on this system.\n%s", errors.c_str());
+	}
+
 	return instance;
 }
 

src/modules/graphics/metal/Graphics.mm

@@ -29,6 +29,8 @@
 #include "image/Image.h"
 #include "common/memory.h"
 
+#include <tuple>
+
 #import <QuartzCore/CAMetalLayer.h>
 
 #ifdef LOVE_MACOS
@@ -239,9 +241,10 @@ static inline void setSampler(id<MTLComputeCommandEncoder> encoder, Graphics::Re
 	}
 }
 
-love::graphics::Graphics *createInstance()
+std::tuple<love::graphics::Graphics *, std::string> createInstance()
 {
 	love::graphics::Graphics *instance = nullptr;
+	std::string err;
 
 	try
 	{
@@ -249,10 +252,10 @@ love::graphics::Graphics *createInstance()
 	}
 	catch (love::Exception &e)
 	{
-		printf("Cannot create Metal renderer: %s\n", e.what());
+		err = "Cannot create Metal renderer: " + std::string(e.what()) + "\n";
 	}
 
-	return instance;
+	return { instance, err };
 }
 
 struct DefaultVertexAttributes

src/modules/graphics/opengl/Graphics.cpp

@@ -39,6 +39,7 @@
 #include <sstream>
 #include <algorithm>
 #include <iterator>
+#include <tuple>
 
 // C
 #include <cmath>
@@ -89,9 +90,10 @@ static GLenum getGLBlendFactor(BlendFactor factor)
 	return 0;
 }
 
-love::graphics::Graphics *createInstance()
+std::tuple<love::graphics::Graphics *, std::string> createInstance()
 {
 	love::graphics::Graphics *instance = nullptr;
+	std::string err;
 
 	try
 	{
@@ -99,10 +101,10 @@ love::graphics::Graphics *createInstance()
 	}
 	catch (love::Exception &e)
 	{
-		printf("Cannot create OpenGL renderer: %s\n", e.what());
+		err = "Cannot create OpenGL renderer: " + std::string(e.what()) + "\n";
 	}
 
-	return instance;
+	return { instance, err };
 }
 
 Graphics::Graphics()

src/modules/graphics/vulkan/Graphics.cpp

@@ -39,6 +39,7 @@
 #include <set>
 #include <sstream>
 #include <array>
+#include <tuple>
 
 #define VOLK_IMPLEMENTATION
 #include "libraries/volk/volk.h"
@@ -3603,9 +3604,10 @@ void Graphics::recreateSwapChain()
 	transitionColorDepthLayouts = true;
 }
 
-love::graphics::Graphics *createInstance()
+std::tuple<love::graphics::Graphics *, std::string> createInstance()
 {
 	love::graphics::Graphics *instance = nullptr;
+	std::string err;
 
 	try
 	{
@@ -3613,11 +3615,10 @@ love::graphics::Graphics *createInstance()
 	}
 	catch (love::Exception &e)
 	{
-		if (isDebugEnabled())
-			printf("Cannot create Vulkan renderer: %s\n", e.what());
+		err = "Cannot create Vulkan renderer: " + std::string(e.what()) + "\n";
 	}
 
-	return instance;
+	return { instance, err };
 }
 
 } // vulkan

src/modules/graphics/wrap_Graphics.cpp

@@ -4208,13 +4208,8 @@ static const lua_CFunction types[] =
 
 extern "C" int luaopen_love_graphics(lua_State *L)
 {
-	Graphics *instance = Graphics::createInstance();
-
-	if (instance == nullptr)
-	{
-		printf("Cannot create graphics: no supported renderer on this system.\n");
-		return luaL_error(L, "Cannot create graphics: no supported renderer on this system.");
-	}
+	Graphics *instance = nullptr;
+	luax_catchexcept(L, [&]() { instance = Graphics::createInstance(); });
 
 	WrappedModule w;
 	w.module = instance;

src/modules/love/callbacks.lua

@@ -223,13 +223,17 @@ function love.errorhandler(msg)
 
 	error_printer(msg, 2)
 
-	if not love.window or not love.graphics or not love.event then
+	if not love.window then
 		return
 	end
 
-	if not love.graphics.isCreated() or not love.window.isOpen() then
-		local success, status = pcall(love.window.setMode, 800, 600)
+	if not love.graphics or not love.event or not love.graphics.isCreated() or not love.window.isOpen() then
+		local success, status
+		if love.graphics and love.event then
+			success, status = pcall(love.window.setMode, 800, 600)
+		end
 		if not success or not status then
+			love.window.showMessageBox("Error during startup", msg, "error", false)
 			return
 		end
 	end