adding that file might be good, too

src/libui_sdl/libui/windows/gl.cpp

@@ -0,0 +1,66 @@
+// 31 march 2019
+#include "uipriv_windows.hpp"
+
+struct uiGLContext
+{
+    uiControl* c;
+
+    HWND hwnd;
+    HDC dc;
+    HGLRC rc;
+};
+
+
+uiGLContext* uiGLNewContext(uiControl* c)
+{
+    uiGLContext* ctx;
+
+    ctx = uiNew(uiGLContext);
+
+    ctx->c = c;
+    if (c)
+    {
+        ctx->hwnd = (HWND)c->Handle(c); // welp
+    }
+    else
+    {
+        // windowless context
+        ctx->hwnd = GetDesktopWindow();
+    }
+
+    PIXELFORMATDESCRIPTOR pfd;
+    memset(&pfd, 0, sizeof(pfd));
+    pfd.nSize = sizeof(pfd);
+    pfd.nVersion = 1;
+    pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL;
+    pfd.iPixelType = PFD_TYPE_RGBA;
+    pfd.cColorBits = 24;
+    pfd.cAlphaBits = 8;
+    pfd.cDepthBits = 24;
+    pfd.cStencilBits = 8;
+    pfd.iLayerType = PFD_MAIN_PLANE;
+
+    ctx->dc = GetDC(ctx->hwnd);
+
+    int pixelformat = ChoosePixelFormat(ctx->dc, &pfd);
+    SetPixelFormat(ctx->dc, pixelformat, &pfd);
+
+    ctx->rc = wglCreateContext(ctx->dc);
+}
+
+void uiGLFreeContext(uiGLContext* ctx)
+{
+    wglDeleteContext(ctx->rc);
+    ReleaseDC(ctx->hwnd, ctx->dc);
+    uiFree(ctx);
+}
+
+void uiGLMakeContextCurrent(uiGLContext* ctx)
+{
+    wglMakeCurrent(ctx->dc, ctx->rc);
+}
+
+void *uiGLGetProcAddress(const char* proc)
+{
+    return (void*)wglGetProcAddress(proc);
+}