win32: create OpenGL context on the GUI thread

This fixes the fullscreen issues on Intel for me. I'm baffled by it and
don't understand why this suddenly works. Intel drivers being shit?
Windows being shit? HWND or HDC being only 97% thread-safe instead of
98%? Me missing something subtle that is not documented anywhere?

Who knows.

Now instead of creating the HDC and OpenGL context on the renderer
thread, they're created on the GUI thread. The renderer thread will
then only call wglMakeCurrent, SwapBuffers, and OpenGL standard
functions.

Probably fixes github issue #968.

1 files changed, 33 insertions, 12 deletions

diff --git a/video/out/gl_w32.c b/video/out/gl_w32.c
index 20d453bf3f..0be8ff0165 100644
--- a/video/out/gl_w32.c
+++ b/video/out/gl_w32.c
@@ -27,6 +27,7 @@
 struct w32_context {
     HGLRC context;
     HDC hdc;
+    int flags;
 };
 
 static bool create_dc(struct MPGLContext *ctx, int flags)
@@ -193,6 +194,21 @@ out:
     return false;
 }
 
+static void create_ctx(void *ptr)
+{
+    struct MPGLContext *ctx = ptr;
+    struct w32_context *w32_ctx = ctx->priv;
+
+    if (!create_dc(ctx, w32_ctx->flags))
+        return;
+
+    if (ctx->requested_gl_version >= MPGL_VER(3, 0))
+        create_context_w32_gl3(ctx);
+    if (!w32_ctx->context)
+        create_context_w32_old(ctx);
+    wglMakeCurrent(w32_ctx->hdc, NULL);
+}
+
 static bool config_window_w32(struct MPGLContext *ctx, int flags)
 {
     struct w32_context *w32_ctx = ctx->priv;
@@ -202,30 +218,35 @@ static bool config_window_w32(struct MPGLContext *ctx, int flags)
     if (w32_ctx->context) // reuse existing context
         return true;
 
-    if (!create_dc(ctx, flags))
-        return false;
+    w32_ctx->flags = flags;
+    vo_w32_run_on_thread(ctx->vo, create_ctx, ctx);
 
-    bool success = false;
-    if (ctx->requested_gl_version >= MPGL_VER(3, 0))
-        success = create_context_w32_gl3(ctx);
-    if (!success)
-        success = create_context_w32_old(ctx);
-    return success;
+    if (w32_ctx->context)
+        wglMakeCurrent(w32_ctx->hdc, w32_ctx->context);
+    return !!w32_ctx->context;
 }
 
-static void releaseGlContext_w32(MPGLContext *ctx)
+static void destroy_gl(void *ptr)
 {
+    struct MPGLContext *ctx = ptr;
     struct w32_context *w32_ctx = ctx->priv;
-    if (w32_ctx->context) {
-        wglMakeCurrent(w32_ctx->hdc, 0);
+    if (w32_ctx->context)
         wglDeleteContext(w32_ctx->context);
-    }
     w32_ctx->context = 0;
     if (w32_ctx->hdc)
         ReleaseDC(vo_w32_hwnd(ctx->vo), w32_ctx->hdc);
     w32_ctx->hdc = NULL;
 }
 
+static void releaseGlContext_w32(MPGLContext *ctx)
+{
+    struct MPGLContext *ctx = ptr;
+    struct w32_context *w32_ctx = ctx->priv;
+    if (w32_ctx->context)
+        wglMakeCurrent(w32_ctx->hdc, 0);
+    vo_w32_run_on_thread(ctx->vo, destroy_gl, ctx);
+}
+
 static void swapGlBuffers_w32(MPGLContext *ctx)
 {
     struct w32_context *w32_ctx = ctx->priv;