OpenGL: Fix contexts & loaders

src/Nazara/OpenGLRenderer/Wrapper/Context.cpp

@@ -3,8 +3,96 @@
 // For conditions of distribution and use, see copyright notice in Config.hpp
 
 #include <Nazara/OpenGLRenderer/Wrapper/Context.hpp>
+#include <Nazara/Core/Error.hpp>
+#include <Nazara/Core/StringExt.hpp>
+#include <Nazara/OpenGLRenderer/Wrapper/Loader.hpp>
+#include <stdexcept>
 #include <Nazara/OpenGLRenderer/Debug.hpp>
 
 namespace Nz::GL
 {
+	Context::~Context() = default;
+
+	bool Context::Initialize(const ContextParams& params)
+	{
+		if (!Activate())
+		{
+			NazaraError("failed to activate context");
+			return false;
+		}
+
+		const Loader& loader = GetLoader();
+
+		auto LoadSymbol = [&](auto& func, const char* funcName)
+		{
+			func = reinterpret_cast<std::decay_t<decltype(func)>>(loader.LoadFunction(funcName));
+			if (!func && !ImplementFallback(funcName) && !func) //< Not a mistake
+				throw std::runtime_error("failed to load core function " + std::string(funcName));
+		};
+
+		try
+		{
+#define NAZARA_OPENGLRENDERER_FUNC(name, sig) LoadSymbol(name, #name);
+			NAZARA_OPENGLRENDERER_FOREACH_GLES_FUNC(NAZARA_OPENGLRENDERER_FUNC)
+#undef NAZARA_OPENGLRENDERER_FUNC
+		}
+		catch (const std::exception& e)
+		{
+			NazaraError(e.what());
+			return false;
+		}
+
+		// Retrieve OpenGL version
+		auto DecodeDigit = [](char c) -> int
+		{
+			if (c >= '0' && c <= '9')
+				return c - '0';
+			else
+				return -1;
+		};
+
+		std::string_view versionString = reinterpret_cast<const char*>(glGetString(GL_VERSION));
+		if (versionString.size() > 2 && DecodeDigit(versionString[0]) >= 0 && versionString[1] == '.' && DecodeDigit(versionString[2]) >= 0)
+		{
+			m_params.glMajorVersion = DecodeDigit(versionString[0]);
+			m_params.glMinorVersion = DecodeDigit(versionString[2]);
+		}
+		else
+			NazaraWarning("Failed to decode OpenGL version: " + std::string(versionString));
+
+		// Load extensions
+		std::string_view extensionList = reinterpret_cast<const char*>(glGetString(GL_EXTENSIONS));
+		SplitString(extensionList, " ", [&](std::string_view extension)
+		{
+			m_supportedExtensions.emplace(extension);
+			return true;
+		});
+
+		// If we requested an OpenGL ES context but cannot create one, check for some compatibility extensions
+		if (params.type == ContextType::OpenGL_ES && m_params.type != params.type)
+		{
+			if (m_supportedExtensions.count("GL_ARB_ES3_2_compatibility"))
+			{
+				m_params.type = ContextType::OpenGL_ES;
+				m_params.glMajorVersion = 3;
+				m_params.glMinorVersion = 2;
+			}
+			else if (m_supportedExtensions.count("GL_ARB_ES3_1_compatibility"))
+			{
+				m_params.type = ContextType::OpenGL_ES;
+				m_params.glMajorVersion = 3;
+				m_params.glMinorVersion = 1;
+			}
+			else if (m_supportedExtensions.count("GL_ARB_ES3_compatibility"))
+			{
+				m_params.type = ContextType::OpenGL_ES;
+				m_params.glMajorVersion = 3;
+				m_params.glMinorVersion = 0;
+			}
+			else
+				NazaraWarning("desktop support for OpenGL ES is missing, falling back to OpenGL...");
+		}
+
+		return true;
+	}
 }