gs-effect: Replace OBS cached file loading with custom one

The normal OBS behavior is to cache files that are loaded from disk, however this is not the behavior we want at all, as it can miss file updates as it never checks the disk for an updated file.

So instead of relying on OBS, this implements the file reading and effect creation without the cache. If a cache is necessary, it would not be the job of this class.

source/gs-effect.cpp

@@ -19,6 +19,9 @@
 
 #include "gs-effect.hpp"
 #include <stdexcept>
+#include <fstream>
+#include <iostream>
+#include <vector>
 
 // OBS
 #ifdef _MSC_VER
@@ -30,10 +33,13 @@
 #pragma warning(pop)
 #endif
 
+//#define OBS_LOAD_EFFECT_FILE
+
 gs::effect::effect() : m_effect(nullptr) {}
 
 gs::effect::effect(std::string file)
 {
+#ifdef OBS_LOAD_EFFECT_FILE
 	obs_enter_graphics();
 	char* errorMessage = nullptr;
 	m_effect           = gs_effect_create_from_file(file.c_str(), &errorMessage);
@@ -47,6 +53,39 @@ gs::effect::effect(std::string file)
 		throw std::runtime_error(error);
 	}
 	obs_leave_graphics();
+#else
+	std::ifstream filestream = std::ifstream(file, std::ios::binary);
+	if (!filestream.is_open()) {
+		throw std::runtime_error("Failed to open file.");
+	}
+
+	filestream.ignore(std::numeric_limits<std::streamsize>::max());
+	std::streamsize length = filestream.gcount();
+	filestream.clear(); //  Since ignore will have set eof.
+	filestream.seekg(0, std::ios_base::beg);
+
+	if (length > 256 * 1024 * 1024) {
+		throw std::runtime_error("Shader too large (>256mb)");
+	}
+
+	std::vector<char> shader_buf(length+1);
+	filestream.read(shader_buf.data(), length);
+	const char* buf = shader_buf.data();
+
+	obs_enter_graphics();
+	char* errorMessage = nullptr;
+	m_effect           = gs_effect_create(shader_buf.data(), file.c_str(), &errorMessage);
+	if (!m_effect || errorMessage) {
+		std::string error = "Generic Error";
+		if (errorMessage) {
+			error = std::string(errorMessage);
+			bfree((void*)errorMessage);
+		}
+		obs_leave_graphics();
+		throw std::runtime_error(error);
+	}
+	obs_leave_graphics();
+#endif
 }
 
 gs::effect::effect(std::string code, std::string name)