Fix loading OpenGL library on Windows

On loading GL symbols we are using SDL_GL_GetProcAddress(), which only valid if we previously loaded OpenGL library with SDL_GL_LoadLibrary(). We cannot use mod_LoadModule() here, otherwise finding symbols will fail.

Author: winterheart

Descent3/descent.h

@@ -128,7 +128,9 @@
 #ifndef _DESCENT_H
 #define _DESCENT_H
 
-#include <stdlib.h>
+#include <cstdlib>
+#include <filesystem>
+
 #include "application.h"
 
 // The name of this product
@@ -181,6 +183,9 @@ extern bool Descent_overrided_intro;
 // The "root" directory of the D3 file tree
 extern char Base_directory[];
 
+// Variable to preserve current path. TODO: redundant?
+extern std::filesystem::path orig_pwd;
+
 //	---------------------------------------------------------------------------
 //	Globals
 

Descent3/sdlmain.cpp

@@ -25,10 +25,11 @@
 
 #include <cstdlib>
 #include <cstring>
-#include <csignal>
+#include <filesystem>
 
 #ifndef WIN32
 #include <unistd.h>
+#include <csignal>
 #endif
 
 #include <SDL.h>
@@ -50,7 +51,7 @@ extern bool ddio_mouseGrabbed;
 const char *DMFCGetString(int d);
 // void *x = (void *) DMFCGetString;   // just force a reference to dmfc.so ...
 
-char *__orig_pwd = NULL;
+std::filesystem::path orig_pwd;
 
 bool linux_permit_gamma = false;
 
@@ -361,10 +362,11 @@ int PASCAL WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR szCmdLine, int nC
   GatherArgs(szCmdLine);
 #else
 int main(int argc, char *argv[]) {
-  __orig_pwd = getcwd(NULL, 0);
   GatherArgs(argv);
 #endif
 
+  orig_pwd = std::filesystem::current_path();
+
   /* Setup the logging system */
   InitLog();
 

renderer/HardwareOpenGL.cpp

@@ -16,11 +16,17 @@
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include "byteswap.h"
+#include <algorithm>
+#include <cstdlib>
+#include <cstdio>
+#include <cstring>
+#include <SDL.h>
+
 #if defined(WIN32)
 #include <windows.h>
 #endif
 
+#include "byteswap.h"
 #include "pserror.h"
 #include "mono.h"
 #include "3d.h"
@@ -33,15 +39,9 @@
 #include "mem.h"
 #include "config.h"
 #include "rtperformance.h"
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
 #include "HardwareInternal.h"
 #include "../Descent3/args.h"
-#include "lnxscreenmode.h"
-#include <SDL.h>
-
-#include <NewBitmap.h>
+#include "NewBitmap.h"
 
 #define DECLARE_OPENGL
 #include "dyna_gl.h"
@@ -50,8 +50,6 @@
 #include "win/arb_extensions.h"
 #endif
 
-#include <algorithm>
-
 int FindArg(const char *);
 void rend_SetLightingState(light_state state);
 
@@ -66,9 +64,6 @@ extern uint8_t Renderer_initted;
 renderer_type Renderer_type = RENDERER_OPENGL;
 int WindowGL = 0;
 
-extern matrix Unscaled_matrix;
-extern vector View_position;
-
 #ifndef GL_UNSIGNED_SHORT_5_5_5_1
 #define GL_UNSIGNED_SHORT_5_5_5_1 0x8034
 #endif
@@ -452,16 +447,17 @@ int opengl_Setup(oeApplication *app, int *width, int *height) {
     if (!(OpenGLDLLHandle)) {
       // rcg07072000 last ditch effort...
 #ifdef __LINUX__
-      OpenGLDLLHandle = LoadOpenGLDLL("libGL.so.1");
+      strcpy(gl_library, "libGL.so.1");
 #else
-      OpenGLDLLHandle = LoadOpenGLDLL("opengl32.dll");
+      strcpy(gl_library, "opengl32.dll");
 #endif
+      OpenGLDLLHandle = LoadOpenGLDLL(gl_library);
       if (!(OpenGLDLLHandle)) {
         success = false;
       }
     } // if
 
-    if (success == false) {
+    if (!success) {
       char buffer[512];
       snprintf(buffer, sizeof(buffer), "Failed to load library [%s].\n", gl_library);
       fprintf(stderr, "%s", buffer);

renderer/dyna_gl.h

@@ -18,12 +18,15 @@
 
 #pragma once
 
+#include <filesystem>
+
 #if defined(WIN32)
-#include <GL/gl.h>
+#include <gl/GL.h>
 #else
-#include "SDL_opengl.h"
+#include <SDL_opengl.h>
 #endif
 
+#include "descent.h"
 #include "module.h"
 
 #if defined(WIN32)
@@ -220,14 +223,14 @@ static module OpenGLDLLInst;
 static void *__SDL_mod_GetSymbol(const char *funcStr) {
   void *retVal = NULL;
 
-  mprintf(0, "Looking up GL function [%s]...", funcStr);
+  mprintf(0, "Looking up GL function [%s]... ", funcStr);
 
   retVal = SDL_GL_GetProcAddress(funcStr);
 
   if (retVal == NULL)
     fprintf(stderr, " Could not find GL symbol [%s]!\n\n", funcStr);
   else {
-    mprintf(0, "Found at (%p).", retVal);
+    mprintf(0, "Found at (%p).\n", retVal);
   } // else
 
   return (retVal);
@@ -237,19 +240,16 @@ static void *__SDL_mod_GetSymbol(const char *funcStr) {
 #define mod_GetSymbol(x, funcStr, y) __SDL_mod_GetSymbol(funcStr)
 /****************** WARNING: NASTY HACK! ***********************/
 
-
-#ifdef __LINUX__
-extern char *__orig_pwd;
 extern char loadedLibrary[_MAX_PATH];
-#endif
+
 module *LoadOpenGLDLL(const char *dllname) {
   mprintf(0, "Loading OpenGL dll...\n");
-#ifdef __LINUX__
-  char *tmp = getcwd(NULL, 0);
-  chdir(__orig_pwd);
-  int rc = SDL_GL_LoadLibrary(dllname[0] ? dllname : NULL);
-  chdir(tmp);
-  free(tmp);
+
+  std::filesystem::path tmp = std::filesystem::current_path();
+  std::filesystem::current_path(orig_pwd);
+  int rc = SDL_GL_LoadLibrary(dllname[0] ? dllname : nullptr);
+  std::filesystem::current_path(tmp);
+
   if (rc < 0) {
     const char *sdlErr = SDL_GetError();
     mprintf(0, "OpenGL: Couldn't open library [%s].\n", dllname[0] ? dllname : "system default");
@@ -259,13 +259,6 @@ module *LoadOpenGLDLL(const char *dllname) {
 
   strcpy(loadedLibrary, dllname);
 
-#else
-  if (!mod_LoadModule(&OpenGLDLLInst, dllname, MODF_LAZY | MODF_GLOBAL)) {
-    int err = mod_GetLastError();
-    mprintf(0, "Couldn't open module called %s\n", dllname);
-    return NULL;
-  }
-#endif
 
   dglAlphaFunc = (glAlphaFunc_fp)mod_GetSymbol(&OpenGLDLLInst, "glAlphaFunc", 255);
   if (!dglAlphaFunc)