Implement swapInterval for EGL on GLX

src/libANGLE/renderer/gl/glx/DisplayGLX.cpp

@@ -236,6 +236,7 @@ egl::ConfigSet DisplayGLX::generateConfigs() const
 
     // GLX_EXT_texture_from_pixmap is required for the "bind to rgb(a)" attributes
     bool hasTextureFromPixmap = mGLX.hasExtension("GLX_EXT_texture_from_pixmap");
+    bool hasSwapControl = mGLX.hasExtension("GLX_EXT_swap_control");
 
     int attribList[] =
     {
@@ -332,9 +333,17 @@ egl::ConfigSet DisplayGLX::generateConfigs() const
             (glxDrawable & GLX_PBUFFER_BIT ? EGL_PBUFFER_BIT : 0) |
             (glxDrawable & GLX_PIXMAP_BIT ? EGL_PIXMAP_BIT : 0);
 
-        // In GLX_EXT_swap_control querying these is done on a GLXWindow so we just set a default value.
-        config.maxSwapInterval = 1;
-        config.minSwapInterval = 1;
+        if (hasSwapControl)
+        {
+            // In GLX_EXT_swap_control querying these is done on a GLXWindow so we just set a default value.
+            config.minSwapInterval = 0;
+            config.maxSwapInterval = 4;
+        }
+        else
+        {
+            config.minSwapInterval = 1;
+            config.maxSwapInterval = 1;
+        }
         // TODO(cwallez) wildly guessing these formats, another TODO says they should be removed anyway
         config.renderTargetFormat = GL_RGBA8;
         config.depthStencilFormat = GL_DEPTH24_STENCIL8;

src/libANGLE/renderer/gl/glx/FunctionsGLX.cpp

@@ -50,7 +50,8 @@ struct FunctionsGLX::GLXFunctionTable
         createPbufferPtr(nullptr),
         destroyPbufferPtr(nullptr),
         queryDrawablePtr(nullptr),
-        createContextAttribsARBPtr(nullptr)
+        createContextAttribsARBPtr(nullptr),
+        swapIntervalEXTPtr(nullptr)
     {
     }
 
@@ -79,6 +80,9 @@ struct FunctionsGLX::GLXFunctionTable
 
     // GLX_ARB_create_context
     PFNGLXCREATECONTEXTATTRIBSARBPROC createContextAttribsARBPtr;
+
+    // GLX_EXT_swap_control
+    PFNGLXSWAPINTERVALEXTPROC swapIntervalEXTPtr;
 };
 
 FunctionsGLX::FunctionsGLX()
@@ -191,6 +195,14 @@ bool FunctionsGLX::initialize(Display *xDisplay, int screen, std::string *errorS
     {
         mFnPtrs->createContextAttribsARBPtr = nullptr;
     }
+    if (hasExtension("GLX_EXT_swap_control"))
+    {
+        GET_PROC_OR_ERROR(&mFnPtrs->swapIntervalEXTPtr, "glXSwapIntervalEXT");
+    }
+    else
+    {
+        mFnPtrs->swapIntervalEXTPtr = nullptr;
+    }
 
 #undef GET_PROC_OR_ERROR
 
@@ -315,4 +327,9 @@ glx::Context FunctionsGLX::createContextAttribsARB(glx::FBConfig config, glx::Co
     return reinterpret_cast<glx::Context>(ctx);
 }
 
+void FunctionsGLX::swapIntervalEXT(glx::Drawable drawable, int intervals) const
+{
+    mFnPtrs->swapIntervalEXTPtr(mXDisplay, drawable, intervals);
+}
+
 }

src/libANGLE/renderer/gl/glx/FunctionsGLX.h

@@ -62,6 +62,9 @@ class FunctionsGLX
     // GLX_ARB_create_context
     glx::Context createContextAttribsARB(glx::FBConfig config, glx::Context shareContext, Bool direct, const int *attribList) const;
 
+    // GLX_EXT_swap_control
+    void swapIntervalEXT(glx::Drawable drawable, int interval) const;
+
   private:
     // So as to isolate GLX from angle we do not include angleutils.h and cannot
     // use angle::NonCopyable so we replicated it here instead.

src/libANGLE/renderer/gl/glx/WindowSurfaceGLX.cpp

@@ -26,7 +26,8 @@ WindowSurfaceGLX::WindowSurfaceGLX(const FunctionsGLX &glx, const DisplayGLX &gl
       mGLXDisplay(glxDisplay),
       mContext(context),
       mFBConfig(fbConfig),
-      mGLXWindow(0)
+      mGLXWindow(0),
+      mMaxSwapInterval(1)
 {
 }
 
@@ -87,6 +88,11 @@ egl::Error WindowSurfaceGLX::initialize()
                             0, visualInfo->depth, InputOutput, visual, attributeMask, &attributes);
     mGLXWindow = mGLX.createWindow(mFBConfig, mWindow, nullptr);
 
+    if (mGLX.hasExtension("GLX_EXT_swap_control"))
+    {
+        mGLX.queryDrawable(mGLXWindow, GLX_MAX_SWAP_INTERVAL_EXT, &mMaxSwapInterval);
+    }
+
     XMapWindow(mDisplay, mWindow);
     XFlush(mDisplay);
 
@@ -141,7 +147,12 @@ egl::Error WindowSurfaceGLX::releaseTexImage(EGLint buffer)
 
 void WindowSurfaceGLX::setSwapInterval(EGLint interval)
 {
-    // TODO(cwallez) WGL has this, implement it
+    if (mGLX.hasExtension("GLX_EXT_swap_control"))
+    {
+        // TODO(cwallez) error checking?
+        const int realInterval = std::min(interval, static_cast<int>(mMaxSwapInterval));
+        mGLX.swapIntervalEXT(mGLXWindow, realInterval);
+    }
 }
 
 EGLint WindowSurfaceGLX::getWidth() const

src/libANGLE/renderer/gl/glx/WindowSurfaceGLX.h

@@ -50,6 +50,7 @@ class WindowSurfaceGLX : public SurfaceGL
     glx::Context mContext;
     glx::FBConfig mFBConfig;
     glx::Window mGLXWindow;
+    unsigned int mMaxSwapInterval;
 };
 
 }

src/libANGLE/renderer/gl/glx/platform_glx.h

@@ -145,6 +145,10 @@
 #define GLX_AUX7_EXT 0x20E9
 #define GLX_AUX8_EXT 0x20EA
 #define GLX_AUX9_EXT 0x20EB
+
+// GLX_EXT_swap_control
+#define GLX_SWAP_INTERVAL_EXT 0x20F1
+#define GLX_MAX_SWAP_INTERVAL_EXT 0x20F2
 #endif // !defined(ANGLE_SKIP_GLX_DEFINES)
 
 // GLX typedefs depend on the X headers