Fix crashes when creating a Buffer.

src/modules/graphics/Buffer.cpp

@@ -91,6 +91,8 @@ Buffer::Buffer(Graphics *gfx, const Settings &settings, const std::vector<DataDe
 		dataMembers.push_back(member);
 	}
 
+	stride = offset;
+
 	if (size != 0)
 	{
 		size_t remainder = size % stride;

src/modules/graphics/opengl/Buffer.cpp

@@ -38,6 +38,9 @@ namespace opengl
 Buffer::Buffer(love::graphics::Graphics *gfx, const Settings &settings, const std::vector<DataDeclaration> &format, const void *data, size_t size, size_t arraylength)
 	: love::graphics::Buffer(gfx, settings, format, size, arraylength)
 {
+	size = getSize();
+	arraylength = getArrayLength();
+
 	if (typeFlags & TYPEFLAG_VERTEX)
 		mapType = BUFFERTYPE_VERTEX;
 	else if (typeFlags & TYPEFLAG_INDEX)

src/modules/graphics/wrap_Graphics.cpp

@@ -1523,10 +1523,12 @@ int w_newIndexBuffer(lua_State *L)
 	size_t bytesize = 0;
 	DataFormat format = DATAFORMAT_UINT16;
 	Data *data = nullptr;
+	const void *initialdata = nullptr;
 
 	if (luax_istype(L, 1, Data::type))
 	{
 		data = luax_checktype<Data>(L, 1);
+		initialdata = data->getData();
 		bytesize = data->getSize();
 	}
 
@@ -1565,7 +1567,7 @@ int w_newIndexBuffer(lua_State *L)
 	}
 
 	Buffer *b = nullptr;
-	luax_catchexcept(L, [&] { b = instance()->newBuffer(settings, format, nullptr, bytesize, arraylength); });
+	luax_catchexcept(L, [&] { b = instance()->newBuffer(settings, format, initialdata, bytesize, arraylength); });
 
 	if (lua_istable(L, 1))
 	{
@@ -1584,11 +1586,6 @@ int w_newIndexBuffer(lua_State *L)
 				u32data[i] = (uint32) v;
 		}
 	}
-	else if (data != nullptr)
-	{
-		Buffer::Mapper mapper(*b);
-		memcpy(mapper.data, data->getData(), std::min(data->getSize(), b->getSize()));
-	}
 
 	luax_pushtype(L, b);
 	b->release();