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b3dacc2613
There's no "standard" coordinate system, so the choice is arbitrary. However, an examination of the Transporter mesh in Elite revealed that the mesh was designed for a left-handed coordinate system. We can compensate for that trivially in the Elite visualizer, but we might as well match what they're doing. (The only change required in the code is a couple of sign changes on the Z coordinate, and an update to the rotation matrix.) This also downsizes Matrix44 to Matrix33, exposes the rotation mode enum, and adds a left-handed ZYX rotation mode. This does mean that meshes that put the front at +Z will show their backsides initially, since we're now oriented as if we're flying the ships rather than facing them. I considered adding a 180-degree Y rotation (with a tweak to the rotation matrix handedness to correct the first rotation axis) to have them facing by default, but figured that might be confusing since +Z is supposed to be away. Anybody who really wants it to be the other way can trivially flip the coordinates in their visualizer (negate xc/zc). The Z coordinates in the visualization test project were flipped so that the design is still facing the viewer at rotation (0,0,0).
62 lines
1.7 KiB
ArmAsm
62 lines
1.7 KiB
ArmAsm
; Copyright 2020 faddenSoft. All Rights Reserved.
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; See the LICENSE.txt file for distribution terms (Apache 2.0).
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;
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; Assembler: Merlin 32
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; Cube with a decoration on the front (should look like a "7").
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; Defined in a left-handed coordinate system (+Z away from viewer).
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org $1000
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lda vertices
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lda edges
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lda faces
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rts
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; List of vertices (X,Y,Z).
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vertices
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dfb -32,32,-32 ;0
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dfb -32,-32,-32 ;1
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dfb 32,-32,-32 ;2
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dfb 32,32,-32 ;3
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dfb -32,32,32 ;4
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dfb -32,-32,32 ;5
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dfb 32,-32,32 ;6
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dfb 32,32,32 ;7
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; Put a decoration on the front face.
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dfb -20,-20,-32 ;8
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dfb 20,20,-32 ;9
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dfb 10,20,-32 ;10
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dfb $80
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; List of edges (vertex0, vertex1, face0, face1).
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edges
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dfb 0,1, 0,5 ;0
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dfb 1,2, 0,3 ;1
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dfb 2,3, 0,4 ;2
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dfb 3,0, 0,2 ;3
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dfb 4,5, 1,5 ;4
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dfb 5,6, 1,3 ;5
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dfb 6,7, 1,4 ;6
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dfb 7,4, 1,2 ;7
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dfb 0,4, 2,5 ;8
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dfb 1,5, 3,5 ;9
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dfb 2,6, 3,4 ;10
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dfb 3,7, 2,4 ;11
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dfb 8,9, 0,0 ;12
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dfb 9,10, 0,0 ;13
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dfb $80
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; List of faces (surface normal X,Y,Z).
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faces
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dfb 0,0,-1 ;0 front
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dfb 0,0,1 ;1 back
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dfb 0,1,0 ;2 top
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dfb 0,-1,0 ;3 bottom
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dfb 1,0,0 ;4 right
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dfb -1,0,0 ;5 left
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dfb $80
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