[imgui] imgui render wip

demo/tz/tz_triangle_demo.cpp

@@ -47,6 +47,13 @@ int tz_main()
 	while(tz::os::window_is_open())
 	{
 		tz::os::window_update();
+		auto windims = static_cast<tz::v2f>(tz::v2u{tz::os::window_get_width(), tz::os::window_get_height()});
+		ImGui::GetIO().DisplaySize = {windims[0], windims[1]};
+		ImGui::NewFrame();
+		ImGui::Begin("123");
+		ImGui::Text("hello world");
+		ImGui::End();
+		ImGui::EndFrame();
 		tz::gpu::execute(graph);
 	}
 

include/tz/core/vector.hpp

@@ -3,6 +3,7 @@
 #include <concepts>
 #include <array>
 #include <type_traits>
+#include <algorithm>
 
 namespace tz
 {
@@ -96,6 +97,14 @@ namespace tz
 		/// Divide one vector by another.
 		vector<T, N> operator/(const vector<T, N>& rhs) const{auto cpy = *this; return cpy /= rhs;}
 
+		template<typename C>
+		operator vector<C, N>() const requires(std::is_convertible_v<T, C>)
+		{
+			std::array<C, N> arr;
+			std::transform(this->arr.begin(), this->arr.end(), arr.begin(), [](const T& t)->C{return static_cast<C>(t);});
+			return {arr};
+		}
+
 		/// Retrieve the magnitude of the vector.
 		T length() const;
 		/// Retrieve the dot (scalar) product of two vectors.

src/tz/imgui.cpp

@@ -104,8 +104,14 @@ namespace tz
 		{
 			(void)graph;
 			// we have a graph that could be completely wrong.
+			ImGui::Render();
 			ImDrawData* draws = ImGui::GetDrawData();
-			(void)draws;
+			if(draws == nullptr)
+			{
+				return;
+			}
+
+			impl_write_vertices_and_indices(draws);
 		}
 
 		void impl_write_vertices_and_indices(ImDrawData* draw)