NML:Changes 0.3
Introduction
Between NML 0.2.x and NML 0.3.x (and their corresponding nightlies) the generated NewGRF version by NML changed from v7 to v8. This brings lot of advantages, but requires a few changes to existing NML files. NewGRFs thus will require a minimum OpenTTD version of 1.2.0 (r23166).
Callbacks
NML 0.3 only supports the new style callbacks. Thus all callback_flag properties have been removed as have the callback flag constants *CBF*. For a complete list of affected constants see the related commit
New named constants
A few constants have recently been introduced in both NML 0.2 and 0.3 that make the transition easier. Make sure to use them. For callback "articulated_part" use CB_RESULT_NO_MORE_ARTICULATED_PARTS and/or CB_RESULT_REVERSED_VEHICLE instead of hard-coded 0xFF / 0x80. For callbacks "cargo_subtype_text", "cargo_subtype_display" and "start_stop" use CB_RESULT_NO_TEXT instead of hard-coded 0xFF.
Industry availability
The callback "availability" is no longer available. Use the callback "construction_probability" instead.
Heights
The "snowline_height" variable returns the height in tiles instead of pixels (=tiles*8).
The "nearby_tile_height" variable returns the height in tiles instead of pixels (=tiles*8).
Base costs
Base costs are treated in NewGRF v8 (NML 0.3.x) differently than in NewGRF v7 (NML 0.2.x and earlier). Base costs do NOT influence eachother anymore. You'll need to set all base costs directly and cannot rely anymore that any are set indirectly. See the base costs table which will be influenced.
