4 files changed, 50 insertions, 0 deletions

diff --git a/src/glut/glx/glut_ext.c b/src/glut/glx/glut_ext.c
index abcb17a911b..ceea4ca15ab 100644
--- a/src/glut/glx/glut_ext.c
+++ b/src/glut/glx/glut_ext.c
@@ -50,4 +50,19 @@ glutExtensionSupported(const char *extension)
   return 0;
 }
 
+
+/* XXX This isn't an official GLUT function, yet */
+void * APIENTRY 
+glutGetProcAddress(const char *procName)
+{
+#if defined(_WIN32)
+  return (void *) wglGetProcAddress((LPCSTR) procName);
+#elif defined(GLX_ARB_get_proc_address)
+  return (void *) glXGetProcAddressARB((const GLubyte *) procName);
+#else
+  return NULL;
+#endif
+}
+
+
 /* ENDCENTRY */
diff --git a/src/glut/glx/glut_init.c b/src/glut/glx/glut_init.c
index dcd423a9417..d814479db0d 100644
--- a/src/glut/glx/glut_init.c
+++ b/src/glut/glx/glut_init.c
@@ -331,6 +331,16 @@ glutInit(int *argcp, char **argv)
     glutInitWindowPosition(__glutInitX, __glutInitY);
   }
   __glutInitTime(&unused);
+
+  /* check if GLUT_FPS env var is set */
+  {
+     const char *fps = getenv("GLUT_FPS");
+     if (fps) {
+        sscanf(fps, "%d", &__glutFPS);
+        if (__glutFPS <= 0)
+           __glutFPS = 5000;  /* 5000 milliseconds */
+     }
+  }
 }
 
 #ifdef _WIN32
diff --git a/src/glut/glx/glut_swap.c b/src/glut/glx/glut_swap.c
index 0864e58d429..cb3f653c72c 100644
--- a/src/glut/glx/glut_swap.c
+++ b/src/glut/glx/glut_swap.c
@@ -5,8 +5,13 @@
    and is provided without guarantee or warrantee expressed or
    implied. This program is -not- in the public domain. */
 
+#include <stdio.h>
 #include "glutint.h"
 
+GLint __glutFPS = 0;
+GLint __glutSwapCount = 0;
+GLint __glutSwapTime = 0;
+
 /* CENTRY */
 void APIENTRY
 glutSwapBuffers(void)
@@ -43,5 +48,20 @@ glutSwapBuffers(void)
      glutPostRedisplay to trigger redraws.  If
      glutPostRedisplay were used, __glutSetWindow would be
      called and a glFinish to throttle buffering would occur. */
+
+  if (__glutFPS) {
+     GLint t = glutGet(GLUT_ELAPSED_TIME);
+     __glutSwapCount++;
+     if (__glutSwapTime == 0)
+        __glutSwapTime = t;
+     else if (t - __glutSwapTime > __glutFPS) {
+        float time = 0.001 * (t - __glutSwapTime);
+        float fps = (float) __glutSwapCount / time;
+        fprintf(stderr, "GLUT: %d frames in %.2f seconds = %.2f FPS\n",
+                __glutSwapCount, time, fps);
+        __glutSwapTime = t;
+        __glutSwapCount = 0;
+     }
+  }
 }
 /* ENDCENTRY */
diff --git a/src/glut/glx/glutint.h b/src/glut/glx/glutint.h
index b0d6c86b7c4..5e06bfc435e 100644
--- a/src/glut/glx/glutint.h
+++ b/src/glut/glx/glutint.h
@@ -798,6 +798,11 @@ extern void __glutDetermineMesaSwapHackSupport(void);
 /* private routines from glut_gameglut.c */
 extern void GLUTAPIENTRYV __glutCloseDownGameMode(void);
 
+/* private variables from glut_swap.c (BrianP) */
+extern GLint __glutFPS;
+extern GLint __glutSwapCount;
+extern GLint __glutSwapTime;
+
 #if defined(_WIN32)
 /* private routines from win32_*.c */
 extern LONG WINAPI __glutWindowProc(HWND win, UINT msg, WPARAM w, LPARAM l);