29 lines
862 B
PHP
29 lines
862 B
PHP
;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
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;; The triangles 3 corner-positions, they may be in any given order.
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;; This is inputs to the subrotine!
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A_X = $EA
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A_Y = $E9
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B_X = $E8
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B_Y = $E7
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C_X = $E6
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C_Y = $E5
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;; Differense in height (after these points have been sorted look in triangle.s for more detail)
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AB = $E4
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BC = $E3
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;; We need some values for Bresenham's line algorithm, see triangle.s and line_down.s
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V_l = $E2 ;16-bit value (uses E3)
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V_r = $E0 ;16-bit value (used E1)
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dy_2_l = $DE ;16-bit value (used DF)
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dy_2_r = $DC ;16-bit value (used DD)
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D_l = $DA ;16-bit value (uses DB)
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D_r = $D8 ;16-bit value (uses D9)
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;; These come from mem.inc
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;; Takes up FF - F5
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X_pos = $FC
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Y_pos = $FB
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byte_to_paint = $FE ; Byte with one 1 that corisponds to a pixel.
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btp_mem_pos = $F9 ; 16-bit value (uses FA), byte to paint memory position
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