From 37418d482e66276281d52b9b4e004e4a869dfbaa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Leclercq?= <lynix680@gmail.com>
Date: Thu, 17 Sep 2020 20:11:10 +0200
Subject: [PATCH] Renderer: Allow to set a preferred render api using
 configuration

---
 include/Nazara/Renderer/Renderer.hpp |  8 +++++++-
 src/Nazara/Renderer/Renderer.cpp     | 27 ++++++++++++++++++++++-----
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/include/Nazara/Renderer/Renderer.hpp b/include/Nazara/Renderer/Renderer.hpp
index 363a9ae76..72d51b3a7 100644
--- a/include/Nazara/Renderer/Renderer.hpp
+++ b/include/Nazara/Renderer/Renderer.hpp
@@ -11,6 +11,7 @@
 #include <Nazara/Core/DynLib.hpp>
 #include <Nazara/Platform/Platform.hpp>
 #include <Nazara/Renderer/Config.hpp>
+#include <Nazara/Renderer/Enums.hpp>
 #include <Nazara/Renderer/RendererImpl.hpp>
 #include <Nazara/Shader/Shader.hpp>
 
@@ -26,13 +27,18 @@ namespace Nz
 		public:
 			using Dependencies = TypeList<Platform, Shader>;
 
-			struct Config {};
+			struct Config;
 
 			Renderer(Config /*config*/);
 			~Renderer();
 
 			inline RendererImpl* GetRendererImpl();
 
+			struct Config
+			{
+				Nz::RenderAPI preferredAPI = Nz::RenderAPI::Unknown;
+			};
+
 		private:
 			std::unique_ptr<RendererImpl> m_rendererImpl;
 			DynLib m_rendererLib;
diff --git a/src/Nazara/Renderer/Renderer.cpp b/src/Nazara/Renderer/Renderer.cpp
index 8a021234a..04fa06029 100644
--- a/src/Nazara/Renderer/Renderer.cpp
+++ b/src/Nazara/Renderer/Renderer.cpp
@@ -30,7 +30,20 @@
 
 namespace Nz
 {
-	Renderer::Renderer(Config /*config*/) :
+	namespace
+	{
+		std::array<const char*, UnderlyingCast(RenderAPI::Max) + 1> s_rendererPaths = {
+			NazaraRendererPrefix "NazaraDirect3DRenderer" NazaraRendererDebugSuffix, // Direct3D
+			NazaraRendererPrefix "NazaraMantleRenderer"   NazaraRendererDebugSuffix, // Mantle
+			NazaraRendererPrefix "NazaraMetalRenderer"    NazaraRendererDebugSuffix, // Metal
+			NazaraRendererPrefix "NazaraOpenGLRenderer"   NazaraRendererDebugSuffix, // OpenGL
+			NazaraRendererPrefix "NazaraVulkanRenderer"   NazaraRendererDebugSuffix, // Vulkan
+
+			nullptr // Unknown
+		};
+	}
+
+	Renderer::Renderer(Config config) :
 	ModuleBase("Renderer", this)
 	{
 		struct RendererImplementations
@@ -40,8 +53,12 @@ namespace Nz
 		};
 		std::vector<RendererImplementations> implementations;
 
-		auto RegisterImpl = [&](std::filesystem::path fileName, auto ComputeScore)
+		auto RegisterImpl = [&](RenderAPI api, auto ComputeScore)
 		{
+			const char* rendererName = s_rendererPaths[UnderlyingCast(api)];
+			assert(rendererName);
+
+			std::filesystem::path fileName(rendererName);
 			fileName.replace_extension(NAZARA_DYNLIB_EXTENSION);
 
 			int score = ComputeScore();
@@ -49,12 +66,12 @@ namespace Nz
 			{
 				auto& impl = implementations.emplace_back();
 				impl.fileName = std::move(fileName);
-				impl.score = score;
+				impl.score = (config.preferredAPI == api) ? std::numeric_limits<int>::max() : score;
 			}
 		};
 
-		RegisterImpl(NazaraRendererPrefix "NazaraOpenGLRenderer" NazaraRendererDebugSuffix, [] { return 50; });
-		RegisterImpl(NazaraRendererPrefix "NazaraVulkanRenderer" NazaraRendererDebugSuffix, [] { return 100; });
+		RegisterImpl(RenderAPI::OpenGL, [] { return 50; });
+		RegisterImpl(RenderAPI::Vulkan, [] { return 100; });
 
 		std::sort(implementations.begin(), implementations.end(), [](const auto& lhs, const auto& rhs) { return lhs.score > rhs.score; });