%import textio %import syslib %import conv %import math %import verafx ; TODO add all other Elite's ships, show their name, advance to next ship on keypress main { sub start() { uword anglex uword angley uword anglez void cx16.screen_mode($80, false) cx16.GRAPH_init(0) cx16.GRAPH_set_colors(13, 6, 6) cx16.GRAPH_clear() print_ship_name() repeat { matrix_math.rotate_vertices(msb(anglex), msb(angley), msb(anglez)) verafx.clear(0, 320*10, 0, 320*(220/4)) ; cx16.GRAPH_set_colors(0, 0, 0) ; cx16.GRAPH_draw_rect(32, 10, 256, 220, 0, true) cx16.GRAPH_set_colors(1, 0, 0) draw_lines_hiddenremoval() ; draw_lines() anglex += 317 angley -= 505 anglez += 452 ; test_stack.test() } } sub print_ship_name() { cx16.r0 = 32 cx16.r1 = 8 ubyte c for c in "ship: " cx16.GRAPH_put_next_char(c) for c in shipdata.shipName cx16.GRAPH_put_next_char(c) cx16.r0 += 16 print_number_gfx(shipdata.totalNumberOfPoints) for c in " vertices, " cx16.GRAPH_put_next_char(c) print_number_gfx(shipdata.totalNumberOfEdges) for c in " edges, " cx16.GRAPH_put_next_char(c) print_number_gfx(shipdata.totalNumberOfFaces) for c in " faces" cx16.GRAPH_put_next_char(c) } sub print_number_gfx(ubyte num) { uword num_str = conv.str_ub(num) do { cx16.GRAPH_put_next_char(@(num_str)) num_str++ } until @(num_str)==0 } const uword screen_width = 320 const ubyte screen_height = 240 sub draw_lines() { ; simple routine that draw all edges, exactly once, but no hidden line removal. ubyte @zp i for i in shipdata.totalNumberOfEdges -1 downto 0 { ubyte @zp vFrom = shipdata.edgesFrom[i] ubyte @zp vTo = shipdata.edgesTo[i] word persp1 = 200 + matrix_math.rotatedz[vFrom]/256 word persp2 = 200 + matrix_math.rotatedz[vTo]/256 cx16.GRAPH_draw_line(matrix_math.rotatedx[vFrom] / persp1 + screen_width/2 as uword, matrix_math.rotatedy[vFrom] / persp1 + screen_height/2 as uword, matrix_math.rotatedx[vTo] / persp2 + screen_width/2 as uword, matrix_math.rotatedy[vTo] / persp2 + screen_height/2 as uword) } } sub draw_lines_hiddenremoval() { ; complex drawing routine that draws the ship model based on its faces, ; where it uses the surface normals to determine visibility. sys.memset(edgestodraw, shipdata.totalNumberOfEdges, 1) ubyte @zp edgeIdx = 0 ubyte @zp pointIdx = 0 ubyte faceNumber for faceNumber in shipdata.totalNumberOfFaces -1 downto 0 { if matrix_math.facing_away(pointIdx) { ; don't draw this face, fast-forward over the edges and points edgeIdx += 3 ; every face hast at least 3 edges while shipdata.facesEdges[edgeIdx]!=255 { edgeIdx++ } edgeIdx++ pointIdx += 3 ; every face has at least 3 points while shipdata.facesPoints[pointIdx]!=255 { pointIdx++ } pointIdx++ } else { ; draw this face ubyte @zp e1 = shipdata.facesEdges[edgeIdx] edgeIdx ++ ubyte @zp e2 = shipdata.facesEdges[edgeIdx] edgeIdx ++ ubyte @zp e3 = shipdata.facesEdges[edgeIdx] edgeIdx ++ if edgestodraw[e1] draw_edge(e1) if edgestodraw[e2] draw_edge(e2) while e3!=255 { if edgestodraw[e3] draw_edge(e3) e3 = shipdata.facesEdges[edgeIdx] edgeIdx ++ } ; skip the rest of the facesPoints, we don't need them here anymore pointIdx += 3 ; every face has at least 3 points while shipdata.facesPoints[pointIdx]!=255 { pointIdx++ } pointIdx++ } } } bool[shipdata.totalNumberOfEdges] edgestodraw sub draw_edge(ubyte edgeidx) { edgestodraw[edgeidx] = false ubyte vFrom = shipdata.edgesFrom[edgeidx] ubyte vTo = shipdata.edgesTo[edgeidx] word persp1 = 170 + matrix_math.rotatedz[vFrom]/256 word persp2 = 170 + matrix_math.rotatedz[vTo]/256 cx16.GRAPH_draw_line(matrix_math.rotatedx[vFrom] / persp1 + screen_width/2 as uword, matrix_math.rotatedy[vFrom] / persp1 + screen_height/2 as uword, matrix_math.rotatedx[vTo] / persp2 + screen_width/2 as uword, matrix_math.rotatedy[vTo] / persp2 + screen_height/2 as uword) } } matrix_math { %option verafxmuls ; accellerate all word-multiplications in this block using Vera FX hardware muls ; storage for rotated coordinates word[shipdata.totalNumberOfPoints] @split rotatedx word[shipdata.totalNumberOfPoints] @split rotatedy word[shipdata.totalNumberOfPoints] @split rotatedz sub rotate_vertices(ubyte ax, ubyte ay, ubyte az) { ; rotate around origin (0,0,0) ; set up the 3d rotation matrix values word wcosa = math.cos8(ax) word wsina = math.sin8(ax) word wcosb = math.cos8(ay) word wsinb = math.sin8(ay) word wcosc = math.cos8(az) word wsinc = math.sin8(az) word wcosa_sinb = wcosa*wsinb / 128 word wsina_sinb = wsina*wsinb / 128 word Axx = wcosa*wcosb / 128 word Axy = (wcosa_sinb*wsinc - wsina*wcosc) / 128 word Axz = (wcosa_sinb*wcosc + wsina*wsinc) / 128 word Ayx = wsina*wcosb / 128 word Ayy = (wsina_sinb*wsinc + wcosa*wcosc) / 128 word Ayz = (wsina_sinb*wcosc - wcosa*wsinc) / 128 word Azx = -wsinb word Azy = wcosb*wsinc / 128 word Azz = wcosb*wcosc / 128 ubyte @zp i for i in 0 to shipdata.totalNumberOfPoints-1 { ; don't normalize by dividing by 128, instead keep some precision for perspective calc later rotatedx[i] = Axx*shipdata.xcoor[i] + Axy*shipdata.ycoor[i] + Axz*shipdata.zcoor[i] rotatedy[i] = Ayx*shipdata.xcoor[i] + Ayy*shipdata.ycoor[i] + Ayz*shipdata.zcoor[i] rotatedz[i] = Azx*shipdata.xcoor[i] + Azy*shipdata.ycoor[i] + Azz*shipdata.zcoor[i] } } sub facing_away(ubyte edgePointsIdx) -> bool { ; simplistic visibility determination by checking the Z component of the surface normal ; TODO: actually take the line of sight vector into account ubyte p1 = shipdata.facesPoints[edgePointsIdx] edgePointsIdx++ ubyte p2 = shipdata.facesPoints[edgePointsIdx] edgePointsIdx++ ubyte p3 = shipdata.facesPoints[edgePointsIdx] word p1x = rotatedx[p1] / 128 word p1y = rotatedy[p1] / 128 word p2x = rotatedx[p2] / 128 word p2y = rotatedy[p2] / 128 word p3x = rotatedx[p3] / 128 word p3y = rotatedy[p3] / 128 return (p2x-p3x)*(p1y-p3y) - (p2y-p3y)*(p1x-p3x) > 0 } } shipdata { ; Ship model data converted from BBC Elite's Cobra MK 3 ; downloaded from http://www.elitehomepage.org/archive/index.htm const ubyte totalNumberOfEdges = 51 const ubyte totalNumberOfFaces = 22 const ubyte totalNumberOfPoints = 34 str shipName = "cobra-mk3" ; vertices word[totalNumberOfPoints] @split xcoor = [ 32,-32,0,-120,120,-88,88,128,-128,0,-32,32,-36,-8,8,36,36,8,-8,-36,-1,-1,-80,-80,-88,80,88,80,1,1,1,1,-1,-1 ] word[totalNumberOfPoints] @split ycoor = [ 0,0,26,-3,-3,16,16,-8,-8,26,-24,-24,8,12,12,8,-12,-16,-16,-12,-1,-1,-6,6,0,6,0,-6,-1,-1,1,1,1,1 ] word[totalNumberOfPoints] @split zcoor = [ 76,76,24,-8,-8,-40,-40,-40,-40,-40,-40,-40,-40,-40,-40,-40,-40,-40,-40,-40,76,90,-40,-40,-40,-40,-40,-40,76,90,76,90,76,90 ] ; edges and faces ubyte[totalNumberOfEdges] edgesFrom = [ 0,1,0,10,1,0,2,0,4,0,4,7,2,1,1,3,8,3,2,5,6,5,6,16,15,14,14,18,13,12,12,26,25,25,22,23,22,20,28,21,20,28,29,30,31,30,32,20,21,20,20 ] ubyte[totalNumberOfEdges] edgesTo = [ 1,2,2,11,10,11,6,6,6,4,7,11,5,5,3,5,10,8,9,9,9,8,7,17,16,15,17,19,18,13,19,27,26,27,23,24,24,28,29,29,21,30,31,31,33,32,33,32,33,33,29 ] ubyte[] facesPoints = [ 0,1,2 ,255, 11,10,1,0 ,255, 0,2,6 ,255, 6,4,0 ,255, 4,7,11,0 ,255, 5,2,1 ,255, 1,3,5 ,255, 10,8,3,1 ,255, 9,2,5 ,255, 9,6,2 ,255, 3,8,5 ,255, 4,6,7 ,255, 5,8,10,11,7,6,9 ,255, 17,16,15,14 ,255, 19,18,13,12 ,255, 27,26,25 ,255, 22,23,24 ,255, 20,28,29,21 ,255, 30,28,29,31 ,255, 33,31,30,32 ,255, 20,32,33,21 ,255, 29,31,33,20 ,255 ] ubyte[] facesEdges = [ 0,1,2 ,255, 3,4,0,5 ,255, 2,6,7 ,255, 8,9,7 ,255, 10,11,5,9 ,255, 12,1,13 ,255, 14,15,13 ,255, 16,17,14,4 ,255, 18,12,19 ,255, 20,6,18 ,255, 17,21,15 ,255, 8,22,10 ,255, 21,16,3,11,22,20,19 ,255, 23,24,25,26 ,255, 27,28,29,30 ,255, 31,32,33 ,255, 34,35,36 ,255, 37,38,39,40 ,255, 41,38,42,43 ,255, 44,43,45,46 ,255, 47,46,48,40 ,255, 42,44,49,50 ,255 ] }