Adding SGI Video Sync support.

src/celengine/glcontext.cpp

@@ -109,6 +109,9 @@ void GLContext::init(const vector<string>& ignoreExt)
             fpNV = fp::initNV();
         fragmentProc = fpNV;
     }
+
+    // Initialize GLX_SGI_video_sync blindly. At most, it will be null.
+    InitExtension("GLX_SGI_video_sync");
 }
 
 

src/celengine/glext.cpp

@@ -130,6 +130,11 @@ glx::PFNGLBLENDEQUATIONEXTPROC glx::glBlendEquationEXT;
 glx::PFNWGLSWAPINTERVALEXTPROC glx::wglSwapIntervalEXT;
 glx::PFNWGLGETSWAPINTERVALEXTPROC glx::wglGetSwapIntervalEXT;
 
+// GLX_SGI_video_sync command function pointers
+glx::PFNGLXGETVIDEOSYNCSGIPROC glx::glXGetVideoSyncSGI;
+glx::PFNGLXWAITVIDEOSYNCSGIPROC glx::glXWaitVideoSyncSGI;
+glx::PFNGLXGETREFRESHRATESGIPROC glx::glXGetRefreshRateSGI;
+
 // ARB_vertex_program function pointers
 glx::PFNGLBINDPROGRAMARBPROC glx::glBindProgramARB;
 glx::PFNGLDELETEPROGRAMSARBPROC glx::glDeleteProgramsARB;
@@ -650,6 +655,14 @@ static void InitExt_EXT_swap_control()
 }
 
 
+static void InitExt_GLX_SGI_video_sync()
+{
+    glx::glXGetVideoSyncSGI = (glx::PFNGLXGETVIDEOSYNCSGIPROC) GET_GL_PROC_ADDRESS("glXGetVideoSyncSGI");
+    glx::glXWaitVideoSyncSGI = (glx::PFNGLXWAITVIDEOSYNCSGIPROC) GET_GL_PROC_ADDRESS("glXWaitVideoSyncSGI");
+    glx::glXGetRefreshRateSGI = (glx::PFNGLXGETREFRESHRATESGIPROC) GET_GL_PROC_ADDRESS("glXGetRefreshRateSGI");
+}
+
+
 static void InitExt_NV_fragment_program()
 {
 #if defined(GET_GL_PROC_ADDRESS)
@@ -840,6 +853,9 @@ void InitExtension(const char* ext)
         InitExt_ARB_vertex_shader();
     else if (!strcmp(ext, "WGL_EXT_swap_control"))
         InitExt_EXT_swap_control();
+    else if (!strcmp(ext, "GLX_SGI_video_sync"))
+        InitExt_GLX_SGI_video_sync();
+
 }
 
 

src/celengine/glext.h

@@ -1275,6 +1275,19 @@ namespace glx
 #endif
 
 
+/* SGI Video Sync from glxext.h, for refresh-rate syncing. */
+namespace glx
+{
+    typedef int ( * PFNGLXGETVIDEOSYNCSGIPROC) (unsigned int *count);
+    typedef int ( * PFNGLXWAITVIDEOSYNCSGIPROC) (int divisor, int remainder, unsigned int *count);
+    typedef int ( * PFNGLXGETREFRESHRATESGIPROC) (unsigned int *);
+
+    extern PFNGLXGETVIDEOSYNCSGIPROC glXGetVideoSyncSGI;
+    extern PFNGLXWAITVIDEOSYNCSGIPROC glXWaitVideoSyncSGI;
+    extern PFNGLXGETREFRESHRATESGIPROC glXGetRefreshRateSGI;
+};
+
+
 extern void InitExtension(const char* ext);
 extern bool ExtensionSupported(const char *ext);
 

src/celengine/render.cpp

@@ -203,7 +203,8 @@ Renderer::Renderer() :
     distanceLimit(1.0e6f),
     minFeatureSize(MinFeatureSizeForLabel),
     locationFilter(~0u),
-    colorTemp(NULL)
+    colorTemp(NULL),
+    videoSync(false)
 {
     starVertexBuffer = new StarVertexBuffer(2048);
     pointStarVertexBuffer = new PointStarVertexBuffer(2048);
@@ -821,6 +822,17 @@ Renderer::setStarColorTable(const ColorTemperatureTable* ct)
 }
 
 
+bool Renderer::getVideoSync() const
+{
+    return videoSync;
+}
+
+void Renderer::setVideoSync(bool sync)
+{
+    videoSync = sync;
+}
+
+
 float Renderer::getAmbientLightLevel() const
 {
     return ambientLightLevel;
@@ -1980,6 +1992,13 @@ void Renderer::render(const Observer& observer,
         cout << "glError: " << (char*) gluErrorString(errCode) << '\n';
     }
 #endif
+
+    if (videoSync && glx::glXWaitVideoSyncSGI != NULL)
+    {
+        unsigned int count;
+        glx::glXGetVideoSyncSGI(&count);
+        glx::glXWaitVideoSyncSGI(2, (count+1) & 1, &count);
+    }
 }
 
 

src/celengine/render.h

@@ -140,6 +140,8 @@ class Renderer
     void setScreenDpi(int);
     const ColorTemperatureTable* getStarColorTable() const;
     void setStarColorTable(const ColorTemperatureTable*);
+    bool getVideoSync() const;
+    void setVideoSync(bool);
 
     bool getFragmentShaderEnabled() const;
     void setFragmentShaderEnabled(bool);
@@ -543,6 +545,8 @@ class Renderer
     const ColorTemperatureTable* colorTemp;
     
     Selection highlightObject;
+
+    bool videoSync;
 };
 
 #endif // _RENDER_H_