Reorganize source files into logical subdirectories

Co-authored-by: Hirek193 <23196899+Hirek193@users.noreply.github.com>

rendering/screenshot.cpp

@@ -0,0 +1,67 @@
+#include "stdafx.h"
+#include "screenshot.h"
+#include "Globals.h"
+#include "Logs.h"
+#include <png.h>
+
+void screenshot_manager::screenshot_save_thread( char *img, int w, int h )
+{
+	png_image png;
+	memset(&png, 0, sizeof(png_image));
+	png.version = PNG_IMAGE_VERSION;
+    png.width = w;
+    png.height = h;
+
+    int stride;
+    if (Global.gfx_usegles)
+    {
+        png.format = PNG_FORMAT_RGBA;
+        stride = -w * 4;
+
+        for (int y = 0; y < h; y++)
+            for (int x = 0; x < w; x++)
+                img[(y * w + x) * 4 + 3] = 0xFF;
+    }
+    else
+    {
+        png.format = PNG_FORMAT_RGB;
+        stride = -w * 3;
+    }
+
+	char datetime[64];
+	time_t timer;
+	struct tm* tm_info;
+	time(&timer);
+	tm_info = localtime(&timer);
+	strftime(datetime, 64, "%Y-%m-%d_%H-%M-%S", tm_info);
+
+	uint64_t perf;
+#ifdef _WIN32
+	QueryPerformanceCounter((LARGE_INTEGER*)&perf);
+#elif __unix__
+	timespec ts;
+	clock_gettime(CLOCK_REALTIME, &ts);
+	perf = ts.tv_nsec;
+#endif
+
+	std::string filename = Global.screenshot_dir + "/" + std::string(datetime) +
+	                       "_" + std::to_string(perf) + ".png";
+
+    if (png_image_write_to_file(&png, filename.c_str(), 0, img, stride, nullptr) == 1)
+		WriteLog("saved " + filename);
+	else
+		WriteLog("failed to save " + filename);
+
+	delete[] img;
+}
+
+void screenshot_manager::make_screenshot()
+{
+    char *img = new char[Global.fb_size.x * Global.fb_size.y * 4];
+    glReadPixels(0, 0, Global.fb_size.x, Global.fb_size.y, Global.gfx_usegles ? GL_RGBA : GL_RGB, GL_UNSIGNED_BYTE, (GLvoid*)img);
+	//m7t: use pbo
+	
+    std::thread t(screenshot_save_thread, img, Global.fb_size.x, Global.fb_size.y);
+	t.detach();
+}
+