bi: Add SDL renderer report

This includes information on the renderer's name, whether it's
a software renderer or it's hardware accelerated, whether vsync
is enabled, and the maximum texture size.

(The other items in SDL_RendererInfo do not seem particularly
relevant to us right now.)

src/build_info.cpp

@@ -568,6 +568,12 @@ list_formatter video_settings_report_internal(const std::string& heading = "")
 	fmt.insert("Final render target size", geometry_to_string(video::output_size()));
 	fmt.insert("Screen refresh rate", std::to_string(video::current_refresh_rate()));
 
+	const auto& renderer_report = video::renderer_report();
+
+	for(const auto& info : renderer_report) {
+		fmt.insert(info.first, info.second);
+	}
+
 	return fmt;
 }
 

src/video.cpp

@@ -828,4 +828,33 @@ void update_buffers(bool autoupdate)
 	}
 }
 
+std::vector<std::pair<std::string, std::string>> renderer_report()
+{
+	std::vector<std::pair<std::string, std::string>> res;
+	SDL_Renderer* rnd;
+	SDL_RendererInfo ri;
+
+	if(window && (rnd = *window) && SDL_GetRendererInfo(rnd, &ri) == 0) {
+		std::string renderer_name = ri.name ? ri.name : "<unknown>";
+
+		if(ri.flags & SDL_RENDERER_SOFTWARE) {
+			renderer_name += " (sw)";
+		}
+
+		if(ri.flags & SDL_RENDERER_ACCELERATED) {
+			renderer_name += " (hw)";
+		}
+
+		std::string renderer_max = std::to_string(ri.max_texture_width) +
+								   'x' +
+								   std::to_string(ri.max_texture_height);
+
+		res.emplace_back("Renderer", renderer_name);
+		res.emplace_back("Maximum texture size", renderer_max);
+		res.emplace_back("VSync", ri.flags & SDL_RENDERER_PRESENTVSYNC ? "on" : "off");
+	}
+
+	return res;
+}
+
 } // namespace video

src/video.hpp

@@ -322,6 +322,21 @@ private:
 	IMPLEMENT_LUA_JAILBREAK_EXCEPTION(quit)
 };
 
+
+/***************/
+/* Diagnostics */
+/***************/
+
+/**
+ * Provides diagnostic information about the current renderer for the @a build_info API.
+ */
+std::vector<std::pair<std::string, std::string>> renderer_report();
+
+
+/**************************/
+/* Implementation details */
+/**************************/
+
 /* This should only be used by draw.cpp for drawing, and texture.cpp for
  * texture creation. Try not to use it for anything else. */
 SDL_Renderer* get_renderer();