Difference between revisions of "FF7/Field/Walkmesh"

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m (Section 5: Walkmesh (Kero))
 
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=== Section 5: Walkmesh ([[User:Kero|Kero]]) ===
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=== Section 5: Walkmesh ([[User:Kero|Kero]]) ===
  
[[Image:Field Wutai.jpg|thumb|Wutai Walkmesh]]
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<div class="thumb tright"><div class="thumbinner" style="width: 182px">[[File:Field_Wutai.jpg|180px|[[Image:180px-Field_Wutai.jpg]]]]<div class="thumbcaption"><div class="magnify">[[File:Field Wutai.jpg]]</div>Wutai Walkmesh</div></div></div>
  
 
Every every offset is here relative, 00 is at the start of section 5 (after length indicator).
 
Every every offset is here relative, 00 is at the start of section 5 (after length indicator).
  
Section 5 of field files is a stored walkmesh. A walkmesh is a mesh of polygons on which characters move, telling the engine for example how high it is, and using this the character can, for example, cross bridges with the real feeling that in the middle he is at a higher place than on the sides. It has very simple structure.  
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Section 5 of field files is a stored walkmesh. A walkmesh is a mesh of polygons on which characters move, telling the engine for example how high it is, and using this the character can, for example, cross bridges with the real feeling that in the middle he is at a higher place than on the sides. It has very simple structure.
  
{| border="0" cellspacing="1" cellpadding="3" style="background: rgb(0,0,0)" align="center"
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{| class="wikitable"
! style="background:rgb(0,255,0)" align="center" | Offset
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! Offset
! style="background:rgb(0,255,0)" align="center" | Name
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! Name
! style="background:rgb(0,255,0)" align="center" | Data Type
+
! Data Type
! style="background:rgb(0,255,0)" align="center" | Length
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! Length
! style="background:rgb(0,255,0)" align="center" | Description
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! Description
 
|-
 
|-
|style="background:rgb(0,255,0)" | 0x0000
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| 0x0000
|style="background:rgb(0,255,0)" | NoS  
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| NoS
|style="background:rgb(0,255,0)" | DWORD
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| DWORD
|style="background:rgb(0,255,0)" | 0x04
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| 0x04
|style="background:rgb(0,255,0)" | Number of Sectors
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| Number of Sectors
 
|-
 
|-
|style="background:rgb(0,255,0)" | 0x0004
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| 0x0004
|style="background:rgb(0,255,0)" | Sector Pool (SP)
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| Sector Pool (SP)
|style="background:rgb(0,255,0)" | 24 * NoS
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| DWORD
|style="background:rgb(0,255,0)" | DWORD [0x04]
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| 24 * NoS
|style="background:rgb(0,255,0)" | The data pool of Secots
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| The data pool of Secots
 
|-
 
|-
|style="background:rgb(0,255,0)" | 0x0004 + 24 * NoS
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| 0x0004 + 24 * NoS
|style="background:rgb(0,255,0)" | Sector Access Pool (SAP)
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| Sector Access Pool (SAP)
|style="background:rgb(0,255,0)" | WORD[3]
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| WORD[3]
|style="background:rgb(0,255,0)" | 6 * NoS
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| 6 * NoS
|style="background:rgb(0,255,0)" | ID of triangle of each Edge
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| ID of triangle of each Edge
 
|}
 
|}
==== Section 5 Header ====
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 +
==== Section 5 Header ====
  
 
Startofs 0x00 Length 0x04
 
Startofs 0x00 Length 0x04
Line 38: Line 39:
 
The walkmesh information is preceeded by a DWORD (4 bytes) unsigned int, named '''NoS''', short for the Number of Sectors in the walkmesh.
 
The walkmesh information is preceeded by a DWORD (4 bytes) unsigned int, named '''NoS''', short for the Number of Sectors in the walkmesh.
  
==== Sector pool ====
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==== Sector pool ====
  
 
Startofs 0x04 Length NoS*24
 
Startofs 0x04 Length NoS*24
  
 
  typedef struct {
 
  typedef struct {
     short x,z,y,res; // short is a 2 byte signed integer
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     short x,y,z,res; // short is a 2 byte signed integer
 
  } vertex_3s; // 3s == 3 short although there are 4 this is for 32 bit data alignment in PSX
 
  } vertex_3s; // 3s == 3 short although there are 4 this is for 32 bit data alignment in PSX
  
Line 50: Line 51:
 
  } sect_t; // Sector Type
 
  } sect_t; // Sector Type
  
The pool of pool consists of sectors, which are in fact triangles with there vertex position. For each sector you have 3 vertexs (3 vertex_3s). Res and z values are often the same, for z this is expected (think planes of data), more study is needed as to what res might be being used for. The polygons are 'wound' clockwise, likely it is used for determining if a point is in said triangle.
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The pool consists of sectors, which are in fact triangles, each with their vertices position. For each sector there are 3 vertices (3 vertex_3s). Res is always equal to v[0].z (it is just a padding value). The polygons are 'wound' clockwise, this makes determining if a point is within a triangle easier.
  
==== Access pool ====
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==== Access pool ====
  
 
Startofs 0x04 + NoS*24 Length NoS*6
 
Startofs 0x04 + NoS*24 Length NoS*6
Line 62: Line 63:
 
The access pool is an array of access data (ID's of triangles in the Mesh) in the mesh, the ID is the triangle you should be in if you cross that edge.
 
The access pool is an array of access data (ID's of triangles in the Mesh) in the mesh, the ID is the triangle you should be in if you cross that edge.
  
acces1 is for line from vertex 0 to 1
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acces1 is for line from vertex 0 to 1 acces2 is for line from vertex 1 to 2 acces3 is for line from vertex 2 to 0
acces2 is for line from vertex 1 to 2
 
acces3 is for line from vertex 2 to 0
 
  
If the edge value is 0xFFFF, than this edge cannot be crossed (it's blocked). The access pool and sector pool have the same number of entries, thus you use the same index value for both pools of data to access the data for the same triangle. The access data merely informs one that if the PC object crosses this line the object should be in the indentified triangle. FF7 will halt running if you are not in the '''access''' specified triangle.
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If the edge value is 0xFFFF, than this edge cannot be crossed (it's blocked). The access pool and sector pool have the same number of entries, thus you use the same index value for both pools of data to access the data for the same triangle. The access data merely informs one that if the PC object crosses this line the object should be in the indentified triangle. FF7 will halt running if you are not in the '''access''' specified triangle.

Latest revision as of 02:41, 13 July 2019

Section 5: Walkmesh (Kero)

File:180px-Field Wutai.jpg
Field Wutai.jpg
Wutai Walkmesh

Every every offset is here relative, 00 is at the start of section 5 (after length indicator).

Section 5 of field files is a stored walkmesh. A walkmesh is a mesh of polygons on which characters move, telling the engine for example how high it is, and using this the character can, for example, cross bridges with the real feeling that in the middle he is at a higher place than on the sides. It has very simple structure.

Offset Name Data Type Length Description
0x0000 NoS DWORD 0x04 Number of Sectors
0x0004 Sector Pool (SP) DWORD 24 * NoS The data pool of Secots
0x0004 + 24 * NoS Sector Access Pool (SAP) WORD[3] 6 * NoS ID of triangle of each Edge

Section 5 Header

Startofs 0x00 Length 0x04

The walkmesh information is preceeded by a DWORD (4 bytes) unsigned int, named NoS, short for the Number of Sectors in the walkmesh.

Sector pool

Startofs 0x04 Length NoS*24

typedef struct {
   short x,y,z,res;		// short is a 2 byte signed integer
} vertex_3s;			// 3s == 3 short although there are 4 this is for 32 bit data alignment in PSX
typedef struct {
   vertex_3s v[3];		// a triangle has 3 vertices
} sect_t; 			// Sector Type

The pool consists of sectors, which are in fact triangles, each with their vertices position. For each sector there are 3 vertices (3 vertex_3s). Res is always equal to v[0].z (it is just a padding value). The polygons are 'wound' clockwise, this makes determining if a point is within a triangle easier.

Access pool

Startofs 0x04 + NoS*24 Length NoS*6

typedef {
   short acces1,acces2,acces3;
}

The access pool is an array of access data (ID's of triangles in the Mesh) in the mesh, the ID is the triangle you should be in if you cross that edge.

acces1 is for line from vertex 0 to 1 acces2 is for line from vertex 1 to 2 acces3 is for line from vertex 2 to 0

If the edge value is 0xFFFF, than this edge cannot be crossed (it's blocked). The access pool and sector pool have the same number of entries, thus you use the same index value for both pools of data to access the data for the same triangle. The access data merely informs one that if the PC object crosses this line the object should be in the indentified triangle. FF7 will halt running if you are not in the access specified triangle.