Difference between revisions of "Callback: Industry availability"
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This callback is intended for limiting your type as a whole, so you can't access any industry-specific variables, just the global ones. A good example for the use of this callback is a nuclear power plant that isn't allowed to appear before 1970. |
This callback is intended for limiting your type as a whole, so you can't access any industry-specific variables, just the global ones. A good example for the use of this callback is a nuclear power plant that isn't allowed to appear before 1970. |
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| − | {{ |
+ | {{grfTill|7}} For GRF version 7 and below the callback should return zero to make your type available, or any nonzero value to disable it. |
| − | {{ |
+ | {{grfFrom|8}} For GRF version 8 and above the callback should return one of these values: |
:{| |- |
:{| |- |
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|0000 || Disallow construction |
|0000 || Disallow construction |
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| − | |0001..00FF|| Allow construction, and use the returned value as probability for appearance on the map. (Instead of using [[Action0/Industries#Probability_in_random_game_.2817.29.2C_Probability_during_gameplay_.2818.29|property 18]].) |
+ | |0001..00FF|| Allow construction, and use the returned value as probability for appearance on the map. (Instead of using [[Action0/Industries#Probability_in_random_game_.2817.29.2C_Probability_during_gameplay_.2818.29|property 17 or 18]].) |
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| − | |0100|| Allow construction; use the appearance probability from [[Action0/Industries#Probability_in_random_game_.2817.29.2C_Probability_during_gameplay_.2818.29|property 18]] |
+ | |0100|| Allow construction; use the appearance probability from [[Action0/Industries#Probability_in_random_game_.2817.29.2C_Probability_during_gameplay_.2818.29|property 17 resp. 18]]. |
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Latest revision as of 13:25, 1 April 2012
Industry availability (22)
Called when TTDPatch needs to know if a given industry type is available.
This callback is intended for limiting your type as a whole, so you can't access any industry-specific variables, just the global ones. A good example for the use of this callback is a nuclear power plant that isn't allowed to appear before 1970.
GRFv≤7 For GRF version 7 and below the callback should return zero to make your type available, or any nonzero value to disable it.
GRFv≥8 For GRF version 8 and above the callback should return one of these values:
0000 Disallow construction 0001..00FF Allow construction, and use the returned value as probability for appearance on the map. (Instead of using property 17 or 18.) 0100 Allow construction; use the appearance probability from property 17 resp. 18.
During this callback, variable 18 (extra callback info 2) can contain the following values:
| Variable 18 | Meaning |
|---|---|
| 0 | TTD is generating a map and needs to know if your type can appear. |
| 1 | TTD decided to build a new random industry during regular gameplay and needs to know if it can choose your type. |
| 2 | The user tries to build/prospect for your industry via the new industry window. TTD needs to know if the player is allowed to do this. |
