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Elite on the BBC Micro

Version analysis of SHIP_VIPER

This code appears in the following versions (click to see it in the source code):

Code variations between these versions are shown below.

Name: SHIP_VIPER Type: Variable Category: Drawing ships Summary: Ship blueprint for a Viper Deep dive: Ship blueprints
.SHIP_VIPER EQUB 0 \ Max. canisters on demise = 0 EQUW 75 * 75 \ Targetable area = 75 * 75 EQUB LO(SHIP_VIPER_EDGES - SHIP_VIPER) \ Edges data offset (low) EQUB LO(SHIP_VIPER_FACES - SHIP_VIPER) \ Faces data offset (low)

Code variation 1 of 2Related to an advanced feature

The advanced versions of Elite have an extra edge count for the ship colour; Vipers are shown in cyan.

Tap on a version to expand it, and tap it again to show to all variations.

Cassette, Flight, Docked, Electron

6502SP, Master

EQUB 77 \ Max. edge count = (77 - 1) / 4 = 19
EQUB 81 \ Max. edge count = (81 - 1) / 4 = 20
 EQUB 0                 \ Gun vertex               = 0
 EQUB 42                \ Explosion count          = 9, as (4 * n) + 6 = 42
 EQUB 90                \ Number of vertices       = 90 / 6 = 15
 EQUB 20                \ Number of edges          = 20
 EQUW 0                 \ Bounty                   = 0
 EQUB 28                \ Number of faces          = 28 / 4 = 7
 EQUB 23                \ Visibility distance      = 23

Code variation 2 of 2Related to a standard feature

The Viper has a different maximum energy in the disc version (100), cassette version (120) and advanced versions (140), so they are easiest to kill in the disc version, harder to kill in the cassette version, and even harder to kill in the advanced versions.

Tap on a version to expand it, and tap it again to show to all variations.

Cassette, Electron

Flight, Docked

6502SP, Master

EQUB 120 \ Max. energy = 120
EQUB 100 \ Max. energy = 100
EQUB 140 \ Max. energy = 140
 EQUB 32                \ Max. speed               = 32
 EQUB HI(SHIP_VIPER_EDGES - SHIP_VIPER)            \ Edges data offset (high)
 EQUB HI(SHIP_VIPER_FACES - SHIP_VIPER)            \ Faces data offset (high)
 EQUB 1                 \ Normals are scaled by    = 2^1 = 2
 EQUB %00010001         \ Laser power              = 2
                        \ Missiles                 = 1

\VERTEX    x,    y,    z, face1, face2, face3, face4, visibility
 VERTEX    0,    0,   72,     1,      2,    3,     4,         31    \ Vertex 0
 VERTEX    0,   16,   24,     0,      1,    2,     2,         30    \ Vertex 1
 VERTEX    0,  -16,   24,     3,      4,    5,     5,         30    \ Vertex 2
 VERTEX   48,    0,  -24,     2,      4,    6,     6,         31    \ Vertex 3
 VERTEX  -48,    0,  -24,     1,      3,    6,     6,         31    \ Vertex 4
 VERTEX   24,  -16,  -24,     4,      5,    6,     6,         30    \ Vertex 5
 VERTEX  -24,  -16,  -24,     5,      3,    6,     6,         30    \ Vertex 6
 VERTEX   24,   16,  -24,     0,      2,    6,     6,         31    \ Vertex 7
 VERTEX  -24,   16,  -24,     0,      1,    6,     6,         31    \ Vertex 8
 VERTEX  -32,    0,  -24,     6,      6,    6,     6,         19    \ Vertex 9
 VERTEX   32,    0,  -24,     6,      6,    6,     6,         19    \ Vertex 10
 VERTEX    8,    8,  -24,     6,      6,    6,     6,         19    \ Vertex 11
 VERTEX   -8,    8,  -24,     6,      6,    6,     6,         19    \ Vertex 12
 VERTEX   -8,   -8,  -24,     6,      6,    6,     6,         18    \ Vertex 13
 VERTEX    8,   -8,  -24,     6,      6,    6,     6,         18    \ Vertex 14

.SHIP_VIPER_EDGES

\EDGE vertex1, vertex2, face1, face2, visibility
 EDGE       0,       3,     2,     4,         31    \ Edge 0
 EDGE       0,       1,     1,     2,         30    \ Edge 1
 EDGE       0,       2,     3,     4,         30    \ Edge 2
 EDGE       0,       4,     1,     3,         31    \ Edge 3
 EDGE       1,       7,     0,     2,         30    \ Edge 4
 EDGE       1,       8,     0,     1,         30    \ Edge 5
 EDGE       2,       5,     4,     5,         30    \ Edge 6
 EDGE       2,       6,     3,     5,         30    \ Edge 7
 EDGE       7,       8,     0,     6,         31    \ Edge 8
 EDGE       5,       6,     5,     6,         30    \ Edge 9
 EDGE       4,       8,     1,     6,         31    \ Edge 10
 EDGE       4,       6,     3,     6,         30    \ Edge 11
 EDGE       3,       7,     2,     6,         31    \ Edge 12
 EDGE       3,       5,     6,     4,         30    \ Edge 13
 EDGE       9,      12,     6,     6,         19    \ Edge 14
 EDGE       9,      13,     6,     6,         18    \ Edge 15
 EDGE      10,      11,     6,     6,         19    \ Edge 16
 EDGE      10,      14,     6,     6,         18    \ Edge 17
 EDGE      11,      14,     6,     6,         16    \ Edge 18
 EDGE      12,      13,     6,     6,         16    \ Edge 19

.SHIP_VIPER_FACES

\FACE normal_x, normal_y, normal_z, visibility
 FACE        0,       32,        0,         31    \ Face 0
 FACE      -22,       33,       11,         31    \ Face 1
 FACE       22,       33,       11,         31    \ Face 2
 FACE      -22,      -33,       11,         31    \ Face 3
 FACE       22,      -33,       11,         31    \ Face 4
 FACE        0,      -32,        0,         31    \ Face 5
 FACE        0,        0,      -48,         31    \ Face 6

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