Merge lp:~widelands-dev/widelands/bug-1638394-render-road into lp:widelands

[xxx-deleted]

Fix a crash with rendering roads in previously visible areas:
If the owner of the starting field of the road is not visible, the owner of the end field of the road is used to determine the road texture in RoadProgram::add_road.

If the owner of the starting field of the road is not visible, the owner of the end field of the road is used to determine the road texture in RoadProgram::add_road.

[GunChleoc (gunchleoc)]

LGTM :)

@bunnybot merge

review: Approve

[bunnybot (widelandsofficial)]

Continuous integration builds have changed state:

Travis build 1598. State: passed. Details: https://travis-ci.org/widelands/widelands/builds/175444991.
Appveyor build 1436. State: failed. Details: https://ci.appveyor.com/project/widelands-dev/widelands/build/_widelands_dev_widelands_bug_1638394_render_road-1436.

=== modified file 'src/graphic/gl/road_program.cc'
--- src/graphic/gl/road_program.cc	2016-10-24 20:07:22 +0000
+++ src/graphic/gl/road_program.cc	2016-11-13 08:26:42 +0000
@@ -72,12 +72,17 @@
 	const float road_thickness_x = (-delta_y / vector_length) * kRoadThicknessInPixels * scale;
 	const float road_thickness_y = (delta_x / vector_length) * kRoadThicknessInPixels * scale;
 
-	assert(start.owner != nullptr);
+	assert(start.owner != nullptr || end.owner != nullptr);
+
+	Widelands::Player* visible_owner = start.owner;
+	if (start.owner == nullptr) {
+		visible_owner = end.owner;
+	}
+
 	const Image& texture =
-	   road_type == Widelands::RoadType::kNormal ?
-	      start.owner->tribe().road_textures().get_normal_texture(
-	         start.geometric_coords, direction) :
-	      start.owner->tribe().road_textures().get_busy_texture(start.geometric_coords, direction);
+		road_type == Widelands::RoadType::kNormal ?
+			visible_owner->tribe().road_textures().get_normal_texture(start.geometric_coords, direction) :
+			visible_owner->tribe().road_textures().get_busy_texture(start.geometric_coords, direction);
 	if (*gl_texture == 0) {
 		*gl_texture = texture.blit_data().texture_id;
 	}