Block attributes - Revision history

Dummiesman: /* Texture references */

2017-02-20T14:53:14Z

‎Texture references

Midas: Rephrased some things

2016-04-21T14:34:28Z

Rephrased some things

Midas: /* Junction tunnel/railing */

2016-04-21T12:10:03Z

‎Junction tunnel/railing

Midas: /* Slivers */

2014-09-10T15:45:47Z

‎Slivers

Midas: /* Slivers */

2014-09-10T15:40:33Z

‎Slivers

Midas: See http://forum.mm2c.com/viewtopic.php?p=155661#155661

2014-09-08T15:16:55Z

See http://forum.mm2c.com/viewtopic.php?p=155661#155661

Midas at 23:15, 7 February 2014

2014-02-07T23:15:57Z

Midas: /* Junction tunnel/railing */

2014-02-07T23:13:16Z

‎Junction tunnel/railing

Midas: /* Junction tunnel/railing */

2014-02-07T23:11:38Z

‎Junction tunnel/railing

Midas: /* Junction tunnel/railing */

2014-02-07T23:05:45Z

‎Junction tunnel/railing

@@ Line 49: / Line 49: @@
 ===Texture references===
-Most geometry primitives use texture mappings. The textures are identified by attributes of type ''0xa''. The data is just one byte and a padding zero byte. The byte is an eight bit index in the list of materials. In order to be able to use more than 256 textures, the subtype indicates a value to add to the byte to get the real index. This formula can be used to compute the real index, ''n'': ''n'' = ''data'' + (256 * ''subtype'') - 1. The data value 0 in subtype 0 is special, it is used in both SF and London, but the effect is unknown.
+Most geometry primitives use texture mappings. The textures are identified by attributes of type ''0xa''. The data is just one byte and a padding zero byte. The byte is an eight bit index in the list of materials. In order to be able to use more than 256 textures, the subtype indicates a value to add to the byte to get the real index. This formula can be used to compute the real index, ''n'': ''n'' = ''data'' + (256 * ''subtype'') - 1. The data value 0 in subtype 0 is special, it prevents rendering and collision on attributes that use it.
 Several block attributes use more than one texture. In most cases the texture attribute references the first texture in a list. This texture index is referenced to as texture ''n'' and block attributes sometimes uses texture index ''n'', ''n + 1'', ''n + 2'', ''n + 3'' and so on.

@@ Line 339: / Line 339: @@
+  }
-==Tunnels==
+==Tunnels and railings==
-Roads and intersections use two versions of the same attribute (0x9) to create tunnels; subtype 3 indicates that the attribute is used on a road, and no subtype indicates that the attribute is used on an intersection (junction).
+The 0x9 attribute family is used for rendering tunnels and railings in MM2; subtype 3 being used for roads only and subtype 0 for all sorts of blocks (mainly intersections).
-Tunnels use 6 textures, where the first one is defined in the preceding [[#Texture_references|texture attribute]]:
+Tunnels and railings use 6 textures, defined in the preceding [[#Texture_references|texture attribute]]:
 # Left wall
@@ Line 351: / Line 351: @@
 # Ground, facing down
-Attribute 0x48 (junction) ignores wall textures 2 and 4, and instead uses 1 and 5 for all walls.
+Subtype 0 (junction tunnel/railing) ignores wall textures 2 and 4, and instead uses 1 and 5 for all walls.
 ===Road tunnel/railing===
-This version of the tunnel attribute applies to roads. The subtype indicates the size of the attribute (number of shorts). The only common version of this attribute is 0x4b (subtype ''3''), as used in San Francisco and London.
+This type of tunnel attribute applies to roads. The subtype indicates the size of the attribute (number of shorts). The only common version of this attribute is 0x4b (subtype ''3''), as used in San Francisco and London.
 {{Clr}}
   struct RoadTunnel
@@ Line 390: / Line 392: @@
 ===Junction tunnel/railing===
-This version of the tunnel attribute applies to intersections. It uses the same parameters for the appearance of the tunnel as the version for roads. The only difference is that it holds a bit array to indicate which walls are visible, whereas roads always have all walls enabled. The walls indicated in this array are references to vertex pairs in the perimeter list of the PSDL block (in the same order). A wall is visible if its bit is set to ''1''. Often the array is padded with trailing zeros to match the attribute's size, which is defined in the first ''ushort''.
+This type of tunnel attribute can be used for any type of block, but is mainly used for intersections. It uses the same parameters for the appearance of the tunnel as the version for roads. The only difference is that this attribute allows more control over the visibility of the walls. This is done in form of a bit array, each bit referencing to a perimeter point of the PSDL block. For example, if the first bit is set to ''1'', MM2 will render a wall between perimeter point ''n'' and ''0''. If the second bit is set to ''1'', a wall will be rendered between perimeter point ''0'' and ''1'', and so on. Often the array is padded with trailing zeros to match the attribute's size, which is defined in the first ''ushort''.
 {{Clr}}
   struct TunnelJunction
@@ Line 424: / Line 426: @@
       ubyte  height2          // usage unknown
-      short  unknown3         // controls something about the visibiliy of the ceiling (more bits?)
+      short  unknown3         // controls something about the visibility of the ceiling (more bits?)
       ushort[nSize - 4] enabledWalls // Each bit is used to indicate the visibility of a wall
-                                     // (references to the perimeter list)
+                                     // (see description above)
+  }

@@ Line 424: / Line 424: @@
       ubyte  height2          // usage unknown
-      short  unknown3
+      short  unknown3         // controls something about the visibiliy of the ceiling (more bits?)
       ushort[nSize - 4] enabledWalls // Each bit is used to indicate the visibility of a wall
                                      // (references to the perimeter list)
+  }

@@ Line 304: / Line 304: @@
 ===Slivers===
 The ground floor of a building is often partially below street level. To simulate this, there is an attribute that accepts different y-components on the two bottom vertices. This means that the bottom edge of the facade can be slanted so that it follows the street outside the building. The top edge of the sliver is always horizontal, though.
 {{Clr}}
   struct Sliver
@@ Line 317: / Line 321: @@
       ushort right; // Index in the vertex list
+  }
 ===Facades===

@@ Line 304: / Line 304: @@
 ===Slivers===
-The ground floor of a building is often partially below street level. To simulate this, there is an attribute that accepts different y-components on the two bottom vertices. This means that the bottom edge of the facade can be slanted so that it follows the street outside the building. The top edge of the sliver is always horisontal, though.
+The ground floor of a building is often partially below street level. To simulate this, there is an attribute that accepts different y-components on the two bottom vertices. This means that the bottom edge of the facade can be slanted so that it follows the street outside the building. The top edge of the sliver is always horizontal, though.
 {{Clr}}
   struct Sliver
@@ Line 312: / Line 312: @@
       bit[3] subtype = 0x04;
       bit[8] padding = 0x00;
-      ushort top;   // Index in the height list
+      ushort top;          // Index in the height list
-      ushort textureScale; // Value for uniformly scaling the texture
+      ushort textureScale; // Index in the height list
       ushort left;  // Index in the vertex list
       ushort right; // Index in the vertex list
+  }
 ===Facades===

@@ Line 201: / Line 201: @@
 [[Image:Roadcrossing Sidewalk.jpg|thumbnail|350px|Sidewalk strip attribute]]
 A sidewalk strip defines a piece of a sidewalk. The sidewalk is defined by a set of inner and outer vertex indices, repeating a vertex index can be used to ''bend'' a sidewalk around a point as shown in the image. The actual geometry will have an additional point 0.15 units above the inner vertex of each cross section.
 {{Clr}}
   struct SidewalkStrip

@@ Line 118: / Line 118: @@
 The most common roads in an MM2 city are the ones with sidewalks on both sides. These are easily defined using cross-sections of the road. Attribute 0x00 defines cross sections of the particular road segment.
-The vertices in each cross section are organized like this: First comes the vertex defining the position of the outer edge of the left sidewalk, then follows the outer edge of the left road surface, the outer edge of the right road surface and finally the outer edge of the right sidewalk. MM2 automatically renders the vertical sides of the sidewalks and the road surface vertices are expected to be located 15 cm below the sidewalk vertices.
+The vertices in each cross section are organized like this: First comes the vertex defining the position of the outer edge of the left sidewalk, then follows the outer edge of the left road surface, the outer edge of the right road surface and finally the outer edge of the right sidewalk. MM2 automatically renders the vertical sides of the sidewalks and the road surface vertices are expected to be located 0.15 units below the sidewalk vertices.
 This type of roads use three textures. The texture attribute points out texture ''n'', this texture is used to render the road surface. This texture is mirrored along the center line of the road. The sidewalks are rendered using texture ''n'' + 1 and texture ''n'' + 2 is the texture used across the entire road in the lowest ''LOD'', or level of detail, of the road segment.
@@ Line 143: / Line 143: @@
 ===Divided roads===
 [[Image:0x08 Divided road.jpg|thumb|350px]]
-The vertices in each cross section are organized like this: First comes the vertex defining the position of the outer edge of the left sidewalk, then follows the outer edge of the left road surface, the inner edge of the left road surface, the inner edge of the right road surface, the outer edge of the right road surface and finally the outer edge of the right sidewalk. MM2 automatically renders the vertical sides of the sidewalks and the road surface vertices are expected to be located 15 cm below the sidewalk vertices.
+The vertices in each cross section are organized like this: First comes the vertex defining the position of the outer edge of the left sidewalk, then follows the outer edge of the left road surface, the inner edge of the left road surface, the inner edge of the right road surface, the outer edge of the right road surface and finally the outer edge of the right sidewalk. MM2 automatically renders the vertical sides of the sidewalks and the road surface vertices are expected to be located 0.15 units below the sidewalk vertices.
 The road surface and sidewalks are rendered in the same way as the road with sidewalk attributes.
@@ Line 200: / Line 200: @@
 ===Sidewalk strip===
 [[Image:Roadcrossing Sidewalk.jpg|thumbnail|350px|Sidewalk strip attribute]]
-A sidewalk strip defines a piece of a sidewalk. The sidewalk is defined by a set of inner and outer vertex indices, repeating a vertex index can be used to ''bend'' a sidewalk around a point as shown in the image. The actual geometry will have an additional point 15 centimetres above the inner vertex of each cross section.
+A sidewalk strip defines a piece of a sidewalk. The sidewalk is defined by a set of inner and outer vertex indices, repeating a vertex index can be used to ''bend'' a sidewalk around a point as shown in the image. The actual geometry will have an additional point 0.15 units above the inner vertex of each cross section.
 {{Clr}}
   struct SidewalkStrip

@@ Line 381: / Line 381: @@
 ===Junction tunnel/railing===
-This version of the tunnel attribute applies to intersections. It uses the same parameters for the appearance of the tunnel as the version for roads. The only difference is that it holds an array to indicate which walls are visible, whereas roads always have all walls enabled. The walls indicated in this array are references to vertex pairs in the perimeter list of the PSDL block. The length of this attribute is stored in the first ''ushort''.
+This version of the tunnel attribute applies to intersections. It uses the same parameters for the appearance of the tunnel as the version for roads. The only difference is that it holds a bit array to indicate which walls are visible, whereas roads always have all walls enabled. The walls indicated in this array are references to vertex pairs in the perimeter list of the PSDL block (in the same order). The array is usually padded with trailing zeros to match the attribute's size, which is defined in the first ''ushort''.
 {{Clr}}
   struct TunnelJunction