add 'u_lightDir' to main shader

src/graphics/render/WorldRenderer.cpp

@@ -166,6 +166,7 @@ void WorldRenderer::setupWorldShader(
     shader->uniform1f("u_fogFactor", fogFactor);
     shader->uniform1f("u_fogCurve", settings.graphics.fogCurve.get());
     shader->uniform1f("u_dayTime", level->getWorld()->getInfo().daytime);
+    shader->uniform2f("u_lightDir", skybox->getLightDir());
     shader->uniform3f("u_cameraPos", camera.position);
     shader->uniform1i("u_cubemap", 1);