From 7f4ca56af8d543c1dbf7b8ce12c3d7c6f2ce05d6 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Wed, 18 Sep 2019 18:51:09 -0700
Subject: [PATCH] Qt: Fix shader loading while thread not running (fixes #1528)

---
 src/platform/qt/DisplayGL.cpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/platform/qt/DisplayGL.cpp b/src/platform/qt/DisplayGL.cpp
index 175ddc042..af0dac717 100644
--- a/src/platform/qt/DisplayGL.cpp
+++ b/src/platform/qt/DisplayGL.cpp
@@ -296,7 +296,6 @@ PainterGL::PainterGL(QWindow* surface, QOpenGLContext* parent, int forceVersion)
 		m_shader.preprocessShader = static_cast<void*>(&reinterpret_cast<mGLES2Context*>(m_backend)->initialShader);
 	}
 #endif
-	m_gl->doneCurrent();
 
 	m_backend->user = this;
 	m_backend->filter = false;
@@ -517,6 +516,12 @@ void PainterGL::setShaders(struct VDir* dir) {
 		return;
 	}
 #ifdef BUILD_GLES2
+	if (!m_started) {
+		m_gl->makeCurrent(m_surface);
+#if defined(_WIN32) && defined(USE_EPOXY)
+		epoxy_handle_external_wglMakeCurrent();
+#endif
+	}
 	if (m_shader.passes) {
 		mGLES2ShaderDetach(reinterpret_cast<mGLES2Context*>(m_backend));
 		mGLES2ShaderFree(&m_shader);
@@ -524,6 +529,8 @@ void PainterGL::setShaders(struct VDir* dir) {
 	mGLES2ShaderLoad(&m_shader, dir);
 	if (m_started) {
 		mGLES2ShaderAttach(reinterpret_cast<mGLES2Context*>(m_backend), static_cast<mGLES2Shader*>(m_shader.passes), m_shader.nPasses);
+	} else {
+		m_gl->doneCurrent();
 	}
 #endif
 }