Added two-dimensional scrolling API and X11 implementation.

src/input.c

@@ -148,26 +148,10 @@ GLFWAPI void glfwSetMousePos(GLFWwindow window, int xpos, int ypos)
 
 
 //========================================================================
-// Returns the mouse wheel "position" for the specified window
+// Returns the scroll offset for the specified window
 //========================================================================
 
-GLFWAPI int glfwGetMouseWheel(GLFWwindow window)
-{
-    if (!_glfwInitialized)
-    {
-        _glfwSetError(GLFW_NOT_INITIALIZED);
-        return 0;
-    }
-
-    return window->wheelPos;
-}
-
-
-//========================================================================
-// Sets the mouse wheel "position" for the specified window
-//========================================================================
-
-GLFWAPI void glfwSetMouseWheel(GLFWwindow window, int pos)
+GLFWAPI void glfwGetScrollOffset(GLFWwindow window, int* x, int* y)
 {
     if (!_glfwInitialized)
     {
@@ -175,7 +159,11 @@ GLFWAPI void glfwSetMouseWheel(GLFWwindow window, int pos)
         return;
     }
 
-    window->wheelPos = pos;
+    if (x)
+      *x = window->scrollX;
+
+    if (y)
+      *y = window->scrollY;
 }
 
 
@@ -250,10 +238,10 @@ GLFWAPI void glfwSetMousePosCallback(GLFWwindow window, GLFWmouseposfun cbfun)
 
 
 //========================================================================
-// Set callback function for mouse wheel
+// Set callback function for scroll events
 //========================================================================
 
-GLFWAPI void glfwSetMouseWheelCallback(GLFWwindow window, GLFWmousewheelfun cbfun)
+GLFWAPI void glfwSetScrollCallback(GLFWwindow window, GLFWscrollfun cbfun)
 {
     if (!_glfwInitialized)
     {
@@ -262,11 +250,11 @@ GLFWAPI void glfwSetMouseWheelCallback(GLFWwindow window, GLFWmousewheelfun cbfu
     }
 
     // Set callback function
-    window->mouseWheelCallback = cbfun;
+    window->scrollCallback = cbfun;
 
     // Call the callback function to let the application know the current
-    // mouse wheel position
+    // scroll offset
     if (cbfun)
-        cbfun(window, window->wheelPos);
+        cbfun(window, window->scrollX, window->scrollY);
 }
 

src/internal.h

@@ -152,7 +152,7 @@ typedef struct _GLFWwindow
     GLFWwindowiconifyfun windowIconifyCallback;
     GLFWmousebuttonfun   mouseButtonCallback;
     GLFWmouseposfun      mousePosCallback;
-    GLFWmousewheelfun    mouseWheelCallback;
+    GLFWscrollfun        scrollCallback;
     GLFWkeyfun           keyCallback;
     GLFWcharfun          charCallback;
 
@@ -172,7 +172,7 @@ typedef struct _GLFWwindow
     GLboolean stickyMouseButtons;
     GLboolean keyRepeat;
     int       mousePosX, mousePosY;
-    int       wheelPos;
+    int       scrollX, scrollY;
     char      mouseButton[GLFW_MOUSE_BUTTON_LAST + 1];
     char      key[GLFW_KEY_LAST + 1];
 

src/window.c

@@ -91,7 +91,8 @@ void clearInputState(_GLFWwindow* window)
     window->mousePosY = 0;
 
     // Set mouse wheel position to 0
-    window->wheelPos = 0;
+    window->scrollX = 0;
+    window->scrollY = 0;
 
     // The default is to use non sticky keys and mouse buttons
     window->stickyKeys = GL_FALSE;
@@ -163,6 +164,20 @@ void _glfwInputChar(_GLFWwindow* window, int character)
 }
 
 
+//========================================================================
+// Register scroll events
+//========================================================================
+
+void _glfwInputScroll(_GLFWwindow* window, int x, int y)
+{
+    window->scrollX += x;
+    window->scrollY += y;
+
+    if (window->scrollCallback)
+        window->scrollCallback(window, x, y);
+}
+
+
 //========================================================================
 // Register mouse button clicks
 //========================================================================

src/x11/x11_window.c

@@ -41,6 +41,9 @@
 #define _NET_WM_STATE_ADD           1
 #define _NET_WM_STATE_TOGGLE        2
 
+// Additional mouse button names for XButtonEvent
+#define Button6			6
+#define Button7			7
 
 //////////////////////////////////////////////////////////////////////////
 //////                       GLFW internal API                      //////
@@ -1094,17 +1097,15 @@ static void processSingleEvent(void)
             // XFree86 3.3.2 and later translates mouse wheel up/down into
             // mouse button 4 & 5 presses
             else if (event.xbutton.button == Button4)
-            {
-                window->wheelPos++;  // To verify: is this up or down?
-                if (window->mouseWheelCallback)
-                    window->mouseWheelCallback(window, window->wheelPos);
-            }
+                _glfwInputScroll(window, 0, 1);
             else if (event.xbutton.button == Button5)
-            {
-                window->wheelPos--;
-                if (window->mouseWheelCallback)
-                    window->mouseWheelCallback(window, window->wheelPos);
-            }
+                _glfwInputScroll(window, 0, -1);
+
+            else if (event.xbutton.button == Button6)
+                _glfwInputScroll(window, -1, 0);
+            else if (event.xbutton.button == Button7)
+                _glfwInputScroll(window, 1, 0);
+
             break;
         }
 
@@ -1741,8 +1742,15 @@ void _glfwPlatformPollEvents(void)
 {
     _GLFWwindow* window;
 
+    for (window = _glfwLibrary.windowListHead;  window;  window = window->next)
+    {
+        window->scrollX = 0;
+        window->scrollY = 0;
+    }
+
     // Flag that the cursor has not moved
-    if (window = _glfwLibrary.cursorLockWindow)
+    window = _glfwLibrary.cursorLockWindow;
+    if (window)
         window->X11.mouseMoved = GL_FALSE;
 
     // Process all pending events
@@ -1750,7 +1758,8 @@ void _glfwPlatformPollEvents(void)
         processSingleEvent();
 
     // Did we get mouse movement in fully enabled hidden cursor mode?
-    if (window = _glfwLibrary.cursorLockWindow)
+    window = _glfwLibrary.cursorLockWindow;
+    if (window)
     {
         if (window->X11.mouseMoved && window->X11.pointerHidden)
         {