terrain: Use QgsTextureMaterial for non shading texture

There is no functional change. With this change, the terrain uses a
material defined by QGIS instead of a default Qt3D. This will make it
easier to customize the shader in the future.

src/3d/terrain/qgsterraintileloader_p.cpp

@@ -25,13 +25,12 @@
 #include "qgsterraintexturegenerator_p.h"
 #include "qgsterraintileentity_p.h"
 #include "qgscoordinatetransform.h"
+#include "qgstexturematerial.h"
 
 #include <Qt3DRender/QTexture>
 #include <Qt3DRender/QTechnique>
 #include <Qt3DRender/QCullFace>
 
-#include <Qt3DExtras/QTextureMaterial>
-
 /// @cond PRIVATE
 
 QgsTerrainTileLoader::QgsTerrainTileLoader( QgsTerrainEntity *terrain, QgsChunkNode *node )
@@ -67,7 +66,7 @@ void QgsTerrainTileLoader::createTextureComponent( QgsTerrainTileEntity *entity,
     }
     else
     {
-      Qt3DExtras::QTextureMaterial *textureMaterial = new Qt3DExtras::QTextureMaterial;
+      QgsTextureMaterial *textureMaterial = new QgsTextureMaterial;
       textureMaterial->setTexture( texture );
       material = textureMaterial;
     }