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The '''lights''' section in Metroid Prime areas defines several different types of lights: local ambient, directional, spot, and custom. Every light type has the same structure in the file; however, different types are utilized in different ways by the engine. This particular light format can be found in Metroid Prime 1 and 2.
The '''lights''' section in Metroid Prime areas defines several different types of lights: local ambient, directional, spot, and custom. Every light type has the same structure in the file; however, different types are utilized in different ways by the engine.


{{research|minor|Lights are mostly figured out; the remaining unknowns are very likely unused, because the game's code never accesses them or passes them to the main light class, but it would be good to have some double-checking.}}
{{research|minor|Lights are mostly figured out; the remaining unknowns are very likely unused, because the game's code never accesses them or passes them to the main light class, but it would be good to have some double-checking. There's also more unknowns in the Prime 3 lights format that probably -are- used.}}


__TOC__
__TOC__
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==Format==
==Format==


The header for the light section is extremely simple and consists of the magic value <code>0xBABEDEAD</code>. It's then followed by two arrays of lights, each preceded by a light count.
The lights section has a very brief header consisting of the magic value <code>0xBABEDEAD</code>. It's then followed by a number of '''light layers'''. Each light layer consists of a count value, then an array of lights. Each layer represents a separate set of lights; actors can choose with set they're lit with through an object property in LightParameters. The number of light layers is static, but it varies from game to game; Prime 1 and 2 can have up to two light layers, while Prime 3 can have four.


===Light===
=== Metroid Prime 1/2 ===


Each light is a 0x41-byte struct. Note that the same structure is used for every light type, but not every value is used by every type; in fact, some of them aren't used by any of them.
Each light is a 0x41-byte struct. Note that the same structure is used for every light type, but not every value is used by every type; in fact, some of them aren't used by any of them.
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| 0x4
| 0x4
| float3
| float3
| '''Light Color'''
| '''Color'''
|  
| There is no alpha component.
|-
|-
| 0x10
| 0x10
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| 0x28
| 0x28
| float
| float
| '''Multiplier'''
| '''Brightness'''
| Color multiplier for local ambient, used to calculate attenuation coefficients for spot/custom
| Multiplied by color for local ambient, used to calculate distance attenuation coefficients for spot/custom
|-
|-
| 0x2C
| 0x2C
| float
| float
| '''Spot Cutoff'''
| '''Spot Cutoff'''
|  
| Used to calculate angle attenuation coefficients for spotlights
|-
|-
| 0x30
| 0x30
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|-
|-
| 0x34
| 0x34
| byte
| bool
| {{unknown|'''Unknown'''}}
| {{unknown|'''Unknown'''}}
| Possibly unused
| Possibly unused
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|-
|-
| 0x41
| 0x41
| colspan=3 {{unknown|End of light}}
|}
=== Metroid Prime 3 ===
Prime 3's light format is very similar, but there's a number of new fields introduced (most of which are currently unknown).
{| class="wikitable"
! Offset
! Type
! Description
! Notes
|-
| 0x0
| long
| '''Light Type'''
|
|-
| 0x4
| float4
| '''Color'''
| This color ''does'' have an alpha component, unlike Prime 1 lights.
|-
| 0x14
| float3
| '''Position'''
|
|-
| 0x20
| float3
| '''Direction'''
|
|-
| 0x2C
| float3
| '''Codirection'''
| The light's up vector
|-
| 0x38
| float
| '''Brightness'''
| Multiplied by color for local ambient, used to calculate distance attenuation coefficients for spot/custom
|-
| 0x3C
| float
| '''Spot Cutoff'''
| Used to calculate angle attenuation coefficients for spotlights
|-
| 0x40
| float
| {{unknown|'''Unknown'''}}
|
|-
| 0x44
| bool
| {{unknown|'''Unknown'''}}
|
|-
| 0x45
| float
| {{unknown|'''Unknown'''}}
|
|-
| 0x49
| u32
| '''Falloff Type'''
|
|-
| 0x4D
| float
| {{unknown|'''Unknown'''}}
|
|-
| 0x51
| float
| {{unknown|'''Unknown'''}}
|
|-
| 0x55
| float
| {{unknown|'''Unknown'''}}
|
|-
| 0x59
| float
| {{unknown|'''Unknown'''}}
|
|-
| 0x5D
| float
| {{unknown|'''Unknown'''}}
|
|-
| 0x61
| u32
| {{unknown|'''Unknown'''}}
|
|-
| 0x65
| colspan=3 {{unknown|End of light}}
| colspan=3 {{unknown|End of light}}
|}
|}
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Each falloff type will set one distance attenuation coefficient, with the other two set to 0. For each type:
Each falloff type will set one distance attenuation coefficient, with the other two set to 0. For each type:


* 0: '''Constant''': Coefficient A is set to <code>2.0 / Multiplier</code>
* 0: '''Constant''': Coefficient A is set to <code>2.0 / Brightness</code>
* 1: '''Linear''': Coefficient B is set to <code>250 / Multiplier</code>
* 1: '''Linear''': Coefficient B is set to <code>250 / Brightness</code>
* 2: '''Quadratic''': Coefficient C is set to <code>25000 / Multiplier</code>
* 2: '''Quadratic''': Coefficient C is set to <code>25000 / Brightness</code>


[[Category:File Formats]]
[[Category:File Formats]]
[[Category:Metroid Prime]]
[[Category:Metroid Prime]]
[[Category:Metroid Prime 2: Echoes]]
[[Category:Metroid Prime 2: Echoes]]
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