OpenGL: disable vsync, atleast under Windows

src/libui_sdl/libui/ui.h

@@ -620,6 +620,7 @@ _UI_EXTERN void *uiGLGetProcAddress(const char* proc);
 _UI_EXTERN int uiGLGetFramebuffer(uiGLContext* ctx);
 _UI_EXTERN float uiGLGetFramebufferScale(uiGLContext* ctx);
 _UI_EXTERN void uiGLSwapBuffers(uiGLContext* ctx);
+_UI_EXTERN void uiGLSetVSync(int sync);
 
 
 _UI_ENUM(uiModifiers) {

src/libui_sdl/libui/unix/gl.c

@@ -193,6 +193,11 @@ void uiGLSwapBuffers(uiGLContext* ctx)
     ctx->backbuffer = ctx->backbuffer ? 0 : 1;
 }
 
+void uiGLSetVSync(int sync)
+{
+	// TODO
+}
+
 void uiGLMakeContextCurrent(uiGLContext* ctx)
 {
 	if (!ctx)

src/libui_sdl/libui/windows/gl.cpp

@@ -3,6 +3,7 @@
 #include "area.hpp"
 
 #include <GL/gl.h>
+#include <GL/glext.h>
 #include <GL/wglext.h>
 
 struct uiGLContext
@@ -159,3 +160,37 @@ float uiGLGetFramebufferScale(uiGLContext* ctx)
     // TODO
     return 1;
 }
+
+void uiGLSetVSync(int sync)
+{
+	static PFNWGLSWAPINTERVALEXTPROC _wglSwapIntervalEXT = NULL;
+	static bool symloaded = false;
+
+	if (!symloaded)
+    {
+        PFNGLGETSTRINGIPROC _glGetStringi = (PFNGLGETSTRINGIPROC)wglGetProcAddress("glGetStringi");
+        if (_glGetStringi == NULL) return;
+
+        GLint numext;
+        glGetIntegerv(GL_NUM_EXTENSIONS, &numext);
+
+        bool hasswapctrl = false;
+        for (GLint i = 0; i < numext; i++)
+        {
+            const char* ext = (const char*)_glGetStringi(GL_EXTENSIONS, i);
+            if (!stricmp(ext, "WGL_EXT_swap_control"))
+            {
+                hasswapctrl = true;
+                break;
+            }
+        }
+
+        if (hasswapctrl)
+            _wglSwapIntervalEXT = (PFNWGLSWAPINTERVALEXTPROC)wglGetProcAddress("wglSwapIntervalEXT");
+
+        symloaded = true;
+    }
+
+    if (_wglSwapIntervalEXT)
+        _wglSwapIntervalEXT(sync);
+}

src/libui_sdl/main.cpp

@@ -2417,6 +2417,7 @@ void CreateMainWindow(bool opengl)
     if (opengl_good)
     {
         uiGLMakeContextCurrent(GLContext);
+        uiGLSetVSync(0); // TODO: make configurable?
         if (!GLScreen_Init()) opengl_good = false;
         if (opengl_good)
         {