Only set shadow texture size if configured by the user in the SDFormat file (#642)

Signed-off-by: Addisu Z. Taddese <addisu@openrobotics.org>

Author: Addisu Z. Taddese

src/plugins/minimal_scene/MinimalScene.cc

@@ -762,11 +762,12 @@ std::string GzRenderer::Initialize(RenderThreadRhi &_rhi)
     scene->SetSkyEnabled(true);
   }
 
-  if (!scene->SetShadowTextureSize(rendering::LightType::DIRECTIONAL,
-      this->directionalLightTextureSize))
+  if (this->directionalLightTextureSize.has_value() &&
+    !scene->SetShadowTextureSize(rendering::LightType::DIRECTIONAL,
+      *this->directionalLightTextureSize))
   {
     gzerr << "Unable to set directional light shadow <texture_size> to '"
-          << this->directionalLightTextureSize
+          << *this->directionalLightTextureSize
           << "'. Using default texture size of "
           << scene->ShadowTextureSize(rendering::LightType::DIRECTIONAL)
           << std::endl;

src/plugins/minimal_scene/MinimalScene.hh

@@ -20,6 +20,7 @@
 
 #include <string>
 #include <memory>
+#include <optional>
 
 #include <gz/common/KeyEvent.hh>
 #include <gz/common/MouseEvent.hh>
@@ -240,7 +241,7 @@ namespace gz::gui::plugins
     public: bool skyEnable = false;
 
     /// \brief Shadow texture size for directional light
-    public: unsigned int directionalLightTextureSize = 2048u;
+    public: std::optional<unsigned int> directionalLightTextureSize;
 
     /// \brief Horizontal FOV of the camera;
     public: math::Angle cameraHFOV = math::Angle(M_PI * 0.5);