VISI (MREA Section) - Revision history

imported>Jackoalan at 03:31, 28 June 2018

2018-06-28T03:31:45Z

← Older revision		Revision as of 03:31, 28 June 2018
Line 19:		Line 19:
	\|-		\|-
	\| bool		\| bool
	\| ~~Unknown 1~~		\| Has Actors
	\|		\| If set, the game will resolve script entity IDs for the PVS lookup
	\|-		\|-
	\| bool		\| bool

imported>Jackoalan at 19:24, 9 April 2017

2017-04-09T19:24:27Z

← Older revision		Revision as of 19:24, 9 April 2017
Line 32:		Line 32:
	\| u32		\| u32
	\| Light count		\| Light count
	\| ~~Number~~ of area lights encoded in octree leaves.		\| Total number of area lights encoded in octree leaves.
	\|-		\|-
	\| u32		\| u32
	\| ~~Unknown 3~~		\| 2nd Layer Light Count
	\|		\| Lights within total that are in the 2nd BABEDEAD layer.
	\|-		\|-
	\| u32		\| u32
Line 56:		Line 56:
	\| u8[lightVisibilityNodeCount][leafSize]		\| u8[lightVisibilityNodeCount][leafSize]
	\| Light visibility node array		\| Light visibility node array
	\| Array of [[#Leaf Nodes\|leaf node data]] indicating visibility of other objects from light's perspective.		\| Array of [[#Leaf Nodes\|leaf node data]] indicating visibility of other objects from light's perspective. 2nd layer lights are listed first.
	\|-		\|-
	\| float[2][3]		\| float[2][3]
Line 114:		Line 114:
	in-order of the first MREA sections. Next are bits relating the scripted entities in the VISI entities table.		in-order of the first MREA sections. Next are bits relating the scripted entities in the VISI entities table.

	Finally are the bits relating lights in order of the BABEDEAD section of the MREA. Each light encodes 2-bits apiece,		Finally are the bits relating lights in order of the BABEDEAD section of the MREA. The 2nd layer lights are related first. Each light encodes 2-bits apiece,
	with the following enum represented:		with the following enum represented:

imported>Jackoalan: /* Layout */

2017-02-26T18:11:49Z

Layout

← Older revision		Revision as of 18:11, 26 February 2017
Line 60:		Line 60:
	\| float[2][3]		\| float[2][3]
	\| Octree AABB		\| Octree AABB
	\| Total bounds subdivided by octree. '''Note:''' the coordinates of the AABB are in local area space (I.e. inverse-transformed with the matrix in the MREA header).		\| Total bounds subdivided by octree. '''Note:''' the coordinates of the AABB are in local area space (i.e. inverse-transformed with the matrix in the MREA header).
	\|-		\|-
	\| u32		\| u32

imported>Jackoalan: /* Layout */

2017-02-26T18:11:02Z

Layout

← Older revision		Revision as of 18:11, 26 February 2017
Line 60:		Line 60:
	\| float[2][3]		\| float[2][3]
	\| Octree AABB		\| Octree AABB
	\| Total bounds subdivided by octree.		\| Total bounds subdivided by octree. '''Note:''' the coordinates of the AABB are in local area space (I.e. inverse-transformed with the matrix in the MREA header).
	\|-		\|-
	\| u32		\| u32

imported>Jackoalan: /* Layout */

2017-02-26T18:02:10Z

Layout

← Older revision		Revision as of 18:02, 26 February 2017
Line 63:		Line 63:
	\|-		\|-
	\| u32		\| u32
	\| Total visibility ~~bit~~ count		\| Total visibility object count
	\| Number of ~~bits~~ per-leaf that indicate visibility from the selected octree region (static + entities + lights).		\| Number of objects per-leaf that indicate visibility from the selected octree region (static + entities + lights).
	\|-		\|-
	\| u32		\| u32
	\| Total light ~~bit~~ count		\| Total light object count
	\| Number of ~~bits after visibility bits~~ that ~~indicate in-bounds/out-of-bounds state of each light~~.		\| Number of objects within total that are lights.
	\|-		\|-
	\| u32		\| u32

imported>Jackoalan: /* Leaf Nodes */

2017-02-26T06:27:44Z

Leaf Nodes

@@ Line 113: / Line 113: @@
 The bits are arranged from LSB to MSB per-byte. First are the bits relating static MREA geometry
 in-order of the first MREA sections. Next are bits relating the scripted entities in the VISI entities table.
-Finally are the bits relating lights in order of the BABEDEAD section of the MREA. Following these is another
-set of bits for each light indicating if it's in-bounds of the octree or not.
+Finally are the bits relating lights in order of the BABEDEAD section of the MREA. Each light encodes 2-bits apiece,

imported>Jackoalan: /* Leaf Nodes */

2017-02-26T06:00:29Z

Leaf Nodes

← Older revision		Revision as of 06:00, 26 February 2017
Line 112:		Line 112:
	Instead of child pointers, leaf nodes contain byte-packed bits indicating visibility.		Instead of child pointers, leaf nodes contain byte-packed bits indicating visibility.
	The bits are arranged from LSB to MSB per-byte. First are the bits relating static MREA geometry		The bits are arranged from LSB to MSB per-byte. First are the bits relating static MREA geometry
	in-order of the first MREA ~~section~~. Next are bits relating the scripted entities in the VISI entities table.		in-order of the first MREA sections. Next are bits relating the scripted entities in the VISI entities table.
	Finally are the bits relating lights in order of the BABEDEAD section of the MREA. Following these is another		Finally are the bits relating lights in order of the BABEDEAD section of the MREA. Following these is another
	set of bits for each light indicating if it's in-bounds of the octree or not.		set of bits for each light indicating if it's in-bounds of the octree or not.

imported>Jackoalan: /* Octree Nodes */

2017-02-26T05:59:52Z

Octree Nodes

← Older revision		Revision as of 05:59, 26 February 2017
Line 81:		Line 81:
	=== Octree Nodes ===		=== Octree Nodes ===

	The octree data is arranged in a Z-major depth-first hierarchy embedded with variable-length pointers to skip over		The octree data is arranged in a Z-major, depth-first hierarchy embedded with variable-length pointers to skip over
	children, permitting rapid child selection. Each node of the octree starts with a 1-byte header		children, permitting rapid child selection. Each node of the octree starts with a 1-byte header
	of classification bits. If at least one subdivide bit is set, the node is a branch and contains 1-7 pointers, addressed		of classification bits. If at least one subdivide bit is set, the node is a branch and contains 1-7 pointers, addressed

imported>Jackoalan: Created page with "Within MREA resources, the '''VISI section''' stores a PVS indexed into an octree. This PVS..."

2017-02-26T05:56:19Z

Created page with "Within MREA resources, the '''VISI section''' stores a PVS indexed into an octree. This PVS..."

New page

Within [[MREA (File Format)|MREA]] resources, the '''VISI section''' stores a [[wikipedia:Potentially_visible_set|PVS]]
indexed into an [[wikipedia:Octree|octree]]. This PVS is used to determine visibility/occlusion between cubic sections of
the area and models, scripting entities, and lights in the scene.

=== Layout ===

{| class="wikitable"
! Data Type
! Description
! Notes
|-
| FourCC
| <code>VISI</code> magic
|
|-
| u32
| VISI Version
| 0x2 in ''Metroid Prime''.
|-
| bool
| Unknown 1
|
|-
| bool
| Unknown 2
|
|-
| u32
| Feature count
| Number of static MREA meshes + script entities encoded in octree.
|-
| u32
| Light count
| Number of area lights encoded in octree leaves.
|-
| u32
| Unknown 3
|
|-
| u32
| Entity count
| Number of script entities encoded in octree.
|-
| u32
| Leaf size
| Size of octree leaf node in bytes.
|-
| u32
| Light visibility node count
| Count of leaf nodes from light perspectives (matches light count).
|-
| u32[entityCount]
| Entity array
| Array of entity IDs mapping the octree bits to the lower 16-bits of the SCLY editor IDs.
|-
| u8[lightVisibilityNodeCount][leafSize]
| Light visibility node array
| Array of [[#Leaf Nodes|leaf node data]] indicating visibility of other objects from light's perspective.
|-
| float[2][3]
| Octree AABB
| Total bounds subdivided by octree.
|-
| u32
| Total visibility bit count
| Number of bits per-leaf that indicate visibility from the selected octree region (static + entities + lights).
|-
| u32
| Total light bit count
| Number of bits after visibility bits that indicate in-bounds/out-of-bounds state of each light.
|-
| u32
| Octree length
| Size of octree in bytes.
|-
| u8[octreeLength]
| Octree data
| Byte-packed PVS octree data described below.
|}

=== Octree Nodes ===

The octree data is arranged in a Z-major depth-first hierarchy embedded with variable-length pointers to skip over
children, permitting rapid child selection. Each node of the octree starts with a 1-byte header
of classification bits. If at least one subdivide bit is set, the node is a branch and contains 1-7 pointers, addressed
relative to the position after the pointers. One subdivision will have 1 pointer, two subdivisions will have 3 pointers,
and three subdivisions will have 7 pointers. The first child pointer is implied to be 0x0. Pointer data type is specified
in the header (8, 16, or 24 bits).

{| class="wikitable"
! Bit (from LSB)
! Description
|-
| 0
| Branch Subdivide X
|-
| 1
| Branch Subdivide Y
|-
| 2
| Branch Subdivide Z
|-
| 3-4
| Node type <ol><li>Out of bounds (not used)</li><li>End of hierarchy (indicates nothing is visible)</li><li>Regular node (followed by branch pointers or leaf bits)</li></ol>
|-
| 5-6
| Branch pointer type <ol start=0><li>16-bit pointers</li><li>8-bit pointers</li><li>24-bit pointers</li></ol>
|}

=== Leaf Nodes ===

Instead of child pointers, leaf nodes contain byte-packed bits indicating visibility.
The bits are arranged from LSB to MSB per-byte. First are the bits relating static MREA geometry
in-order of the first MREA section. Next are bits relating the scripted entities in the VISI entities table.
Finally are the bits relating lights in order of the BABEDEAD section of the MREA. Following these is another
set of bits for each light indicating if it's in-bounds of the octree or not.