Now I found the reason for this bug: this happens to all buildings that do not need ground tiles (ie buildings that cover the whole tile) after change of seasons. Then the ground has no image to reduce overhead for the drawing stuff.
New try to patch this:
Index: simview.cc
===================================================================
--- simview.cc (revision 2456)
+++ simview.cc (working copy)
@@ -186,9 +186,12 @@
if(gr && gr->is_visible()) {
const PLAYER_COLOR_VAL transparent = TRANSPARENT25_FLAG|OUTLINE_FLAG| umgebung_t::cursor_overlay_color;
if( gr->get_bild()==IMG_LEER ) {
- if( gr->obj_bei(0) ) {
+ if( gr->hat_wege() ) {
display_img_blend( gr->obj_bei(0)->get_bild(), x, y, transparent, 0, true );
}
+ else {
+ display_img_blend( grund_besch_t::get_ground_tile(0,gr->get_hoehe()), x, y, transparent, 0, true );
+ }
}
else {
display_img_blend( gr->get_bild(), x, y, transparent, 0, true );