The SHIP_ASTEROID (Bank 1) variable - Elite on the BBC Micro and NES

       Name: SHIP_ASTEROID                                           [Show more]
       Type: Variable
   Category: Drawing ships
    Summary: Ship blueprint for an asteroid
  Deep dive: Ship blueprints
    Context: See this variable in context in the source code
 References: This variable is used as follows:
             * Unused copy of XX21 uses SHIP_ASTEROID
             * XX21 uses SHIP_ASTEROID


.SHIP_ASTEROID

 EQUB 0                 ; Max. canisters on demise = 0
 EQUW 80 * 80           ; Targetable area          = 80 * 80

 EQUB LO(SHIP_ASTEROID_EDGES - SHIP_ASTEROID)      ; Edges data offset (low)
 EQUB LO(SHIP_ASTEROID_FACES - SHIP_ASTEROID)      ; Faces data offset (low)

 EQUB 69                ; Max. edge count          = (69 - 1) / 4 = 17
 EQUB 0                 ; Gun vertex               = 0
 EQUB 34                ; Explosion count          = 7, as (4 * n) + 6 = 34
 EQUB 54                ; Number of vertices       = 54 / 6 = 9
 EQUB 21                ; Number of edges          = 21
 EQUW 5                 ; Bounty                   = 5
 EQUB 56                ; Number of faces          = 56 / 4 = 14
 EQUB 50                ; Visibility distance      = 50
 EQUB 60                ; Max. energy              = 60
 EQUB 30                ; Max. speed               = 30

 EQUB HI(SHIP_ASTEROID_EDGES - SHIP_ASTEROID)      ; Edges data offset (high)
 EQUB HI(SHIP_ASTEROID_FACES - SHIP_ASTEROID)      ; Faces data offset (high)

 EQUB 1                 ; Normals are scaled by    = 2^1 = 2
 EQUB %00000000         ; Laser power              = 0
                        ; Missiles                 = 0

.SHIP_ASTEROID_VERTICES

      ;    x,    y,    z, face1, face2, face3, face4, visibility
 VERTEX    0,   80,    0,    15,     15,   15,    15,         31    ; Vertex 0
 VERTEX  -80,  -10,    0,    15,     15,   15,    15,         31    ; Vertex 1
 VERTEX    0,  -80,    0,    15,     15,   15,    15,         31    ; Vertex 2
 VERTEX   70,  -40,    0,    15,     15,   15,    15,         31    ; Vertex 3
 VERTEX   60,   50,    0,     5,      6,   12,    13,         31    ; Vertex 4
 VERTEX   50,    0,   60,    15,     15,   15,    15,         31    ; Vertex 5
 VERTEX  -40,    0,   70,     0,      1,    2,     3,         31    ; Vertex 6
 VERTEX    0,   30,  -75,    15,     15,   15,    15,         31    ; Vertex 7
 VERTEX    0,  -50,  -60,     8,      9,   10,    11,         31    ; Vertex 8

.SHIP_ASTEROID_EDGES

    ; vertex1, vertex2, face1, face2, visibility
 EDGE       0,       1,     2,     7,         31    ; Edge 0
 EDGE       0,       4,     6,    13,         31    ; Edge 1
 EDGE       3,       4,     5,    12,         31    ; Edge 2
 EDGE       2,       3,     4,    11,         31    ; Edge 3
 EDGE       1,       2,     3,    10,         31    ; Edge 4
 EDGE       1,       6,     2,     3,         31    ; Edge 5
 EDGE       2,       6,     1,     3,         31    ; Edge 6
 EDGE       2,       5,     1,     4,         31    ; Edge 7
 EDGE       5,       6,     0,     1,         31    ; Edge 8
 EDGE       0,       5,     0,     6,         31    ; Edge 9
 EDGE       3,       5,     4,     5,         31    ; Edge 10
 EDGE       0,       6,     0,     2,         31    ; Edge 11
 EDGE       4,       5,     5,     6,         31    ; Edge 12
 EDGE       1,       8,     8,    10,         31    ; Edge 13
 EDGE       1,       7,     7,     8,         31    ; Edge 14
 EDGE       0,       7,     7,    13,         31    ; Edge 15
 EDGE       4,       7,    12,    13,         31    ; Edge 16
 EDGE       3,       7,     9,    12,         31    ; Edge 17
 EDGE       3,       8,     9,    11,         31    ; Edge 18
 EDGE       2,       8,    10,    11,         31    ; Edge 19
 EDGE       7,       8,     8,     9,         31    ; Edge 20

.SHIP_ASTEROID_FACES

    ; normal_x, normal_y, normal_z, visibility
 FACE        9,       66,       81,         31    ; Face 0
 FACE        9,      -66,       81,         31    ; Face 1
 FACE      -72,       64,       31,         31    ; Face 2
 FACE      -64,      -73,       47,         31    ; Face 3
 FACE       45,      -79,       65,         31    ; Face 4
 FACE      135,       15,       35,         31    ; Face 5
 FACE       38,       76,       70,         31    ; Face 6
 FACE      -66,       59,      -39,         31    ; Face 7
 FACE      -67,      -15,      -80,         31    ; Face 8
 FACE       66,      -14,      -75,         31    ; Face 9
 FACE      -70,      -80,      -40,         31    ; Face 10
 FACE       58,     -102,      -51,         31    ; Face 11
 FACE       81,        9,      -67,         31    ; Face 12
 FACE       47,       94,      -63,         31    ; Face 13

[X]

Macro EDGE (category: Drawing ships)

Macro definition for adding edges to ship blueprints

[X]

Macro FACE (category: Drawing ships)

Macro definition for adding faces to ship blueprints

[X]

Variable SHIP_ASTEROID (category: Drawing ships)

Ship blueprint for an asteroid

[X]

Label SHIP_ASTEROID_EDGES is local to this routine

[X]

Label SHIP_ASTEROID_FACES is local to this routine

[X]

Macro VERTEX (category: Drawing ships)

Macro definition for adding vertices to ship blueprints

Drawing ships: SHIP_ASTEROID

[NES version, Bank 1]