267 lines
9.3 KiB
QBasic
267 lines
9.3 KiB
QBasic
'default integer type
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DEFINT A-Z
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'screen mode 13h
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SCREEN 13
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'set palette
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'. . . and make an gradiant green palette
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OUT &H3C8, 0 ' tell port whole palette is coming (otherwise # of color)
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FOR i = 0 TO 255
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OUT &H3C9, 10 'red
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OUT &H3C9, INT(i / 4) 'green
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OUT &H3C9, 50 'blue
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NEXT i
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'define program constants
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'CONST SCRX = 320 unused
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'CONST SCRY = 200
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'CONST CLRS = 255
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CONST HLFX = 160
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CONST HLFY = 100
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CONST PI = 3.141592654#
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CONST FACES = 11
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CONST SHAPES = 0
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'trig lookup-tables
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DIM sine(255) AS SINGLE: DIM cosine(255) AS SINGLE
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FOR i = 0 TO 255
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sine(i) = SIN(i * PI / 128)
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cosine(i) = COS(i * PI / 128)
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NEXT i
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'data types:
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'integer vector (for initial shape data)
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TYPE vec3it
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x AS INTEGER
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y AS INTEGER
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z AS INTEGER
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END TYPE
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'real vector
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TYPE vec3t
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x AS SINGLE
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y AS SINGLE
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z AS SINGLE
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END TYPE
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'a face
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TYPE face3t
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'object vertices
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ov1 AS vec3it
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ov2 AS vec3it
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ov3 AS vec3it
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'world verteces
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wv1 AS vec3t
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wv2 AS vec3t
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wv3 AS vec3t
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END TYPE
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'an object
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TYPE objt
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p AS vec3t 'position
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r AS vec3it 'rotation
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END TYPE
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'a pixel point
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TYPE vec2it
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x AS INTEGER
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y AS INTEGER
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END TYPE
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'a triangle on-screen
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TYPE face2t
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v1 AS vec2it
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v2 AS vec2it
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v3 AS vec2it
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END TYPE
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'make a 12-polygon shape
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DIM shape(0 TO SHAPES, 0 TO FACES) AS face3t 'holds shape's form (obj spc)
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DIM obj(0 TO SHAPES) AS objt 'holds shape's pos (wrld spc)
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'make the viewer
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DIM pov AS objt
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'make a variable to hold mapped 2d drawing data
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DIM tri AS face2t
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'load the shape's data
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'base (-y)
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DATA -10,-10,-10, -10,-10,10, 10,-10,-10
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DATA -10,-10,10, 10,-10,10, 10,-10,-10
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'front (-z)
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DATA -10,-10,-10, 10,-10,-10, -10,10,-10
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DATA -10,10,-10, 10,-10,-10, 10,10,-10
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'left (-x)
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DATA -10,-10,-10, -10,10,-10, -10,-10,10
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DATA -10,-10,10, -10,10,-10, -10,10,10
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'top (+y)
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DATA 10,10,10, -10,10,-10, 10,10,-10
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DATA 10,10,10, -10,10,10, -10,10,-10
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'back (+z)
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DATA 10,10,10, 10,-10,10, -10,10,10
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DATA -10,10,10, 10,-10,10, -10,-10,10
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'right (+x)
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DATA 10,10,10, 10,10,-10, 10,-10,10
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DATA 10,-10,10, 10,10,-10, 10,-10,-10
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FOR i = 0 TO FACES
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READ shape(0, i).ov1.x 'read first vertex position
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READ shape(0, i).ov1.y
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READ shape(0, i).ov1.z
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READ shape(0, i).ov2.x 'read second vertex position
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READ shape(0, i).ov2.y
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READ shape(0, i).ov2.z
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READ shape(0, i).ov3.x 'read third vertex position
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READ shape(0, i).ov3.y
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READ shape(0, i).ov3.z
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NEXT i
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'read shape's starting position
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'imput strating pov position
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pov.p.x = 20
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pov.p.y = 30
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pov.p.z = -70
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DO
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'draw the shapes
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FOR j = 0 TO SHAPES 'go through @ shape
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FOR i = 0 TO FACES 'go through @ face
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obj(j).r.y = (obj(j).r.y + 1) MOD 256
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'transform @ point from object to world space
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rx = obj(j).r.x 'extra 2-letter vars are for
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ry = obj(j).r.y 'simplification only
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rz = obj(j).r.z
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vx = shape(j, i).ov1.x
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vy = shape(j, i).ov1.y
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vz = shape(j, i).ov1.z
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shape(j, i).wv1.x = ((vx * cosine(ry) - vz * sine(ry)) - pov.p.x)' * sine(pov.r.y)
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shape(j, i).wv1.y = vy - pov.p.y
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shape(j, i).wv1.z = ((vx * sine(ry) + vz * cosine(ry)) - pov.p.z)' * cosine(pov.r.y)
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vx = shape(j, i).ov2.x
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vy = shape(j, i).ov2.y
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vz = shape(j, i).ov2.z
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shape(j, i).wv2.x = ((vx * cosine(ry) - vz * sine(ry)) - pov.p.x)' * sine(pov.r.y)
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shape(j, i).wv2.y = vy - pov.p.y
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shape(j, i).wv2.z = ((vx * sine(ry) + vz * cosine(ry)) - pov.p.z)' * cosine(pov.r.y)
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vx = shape(j, i).ov3.x
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vy = shape(j, i).ov3.y
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vz = shape(j, i).ov3.z
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shape(j, i).wv3.x = ((vx * cosine(ry) - vz * sine(ry)) - pov.p.x)' * sine(pov.r.y)
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shape(j, i).wv3.y = vy - pov.p.y
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shape(j, i).wv3.z = ((vx * sine(ry) + vz * cosine(ry)) - pov.p.z)' * cosine(pov.r.y)
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'map the world-space coords into a 2d triangle
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tri.v1.x = HLFX + (shape(j, i).wv1.x / shape(j, i).wv1.z * HLFX)
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tri.v1.y = HLFY - (shape(j, i).wv1.y / shape(j, i).wv1.z * HLFY)
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tri.v2.x = HLFX + (shape(j, i).wv2.x / shape(j, i).wv2.z * HLFX)
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tri.v2.y = HLFY - (shape(j, i).wv2.y / shape(j, i).wv2.z * HLFY)
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tri.v3.x = HLFX + (shape(j, i).wv3.x / shape(j, i).wv3.z * HLFX)
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tri.v3.y = HLFY - (shape(j, i).wv3.y / shape(j, i).wv3.z * HLFY)
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'check if clockwise (backface culling)
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x1 = tri.v2.x - tri.v1.x 'make (x1, y1) & (x2, y2)
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x2 = tri.v3.x - tri.v1.x 'normalized
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y1 = tri.v2.y - tri.v1.y
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y2 = tri.v3.y - tri.v1.y
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IF x1 * y2 < x2 * y1 THEN
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'order the vertices top-bottom
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IF tri.v1.y > tri.v2.y THEN
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tmp = tri.v1.y
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tri.v1.y = tri.v2.y
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tri.v2.y = tmp
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tmp = tri.v1.x
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tri.v1.x = tri.v2.x
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tri.v2.x = tmp
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END IF
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IF tri.v1.y > tri.v3.y THEN
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tmp = tri.v1.y
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tri.v1.y = tri.v3.y
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tri.v3.y = tmp
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tmp = tri.v1.x
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tri.v1.x = tri.v3.x
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tri.v3.x = tmp
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END IF
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IF tri.v2.y > tri.v3.y THEN
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tmp = tri.v2.y
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tri.v2.y = tri.v3.y
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tri.v3.y = tmp
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tmp = tri.v2.x
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tri.v2.x = tri.v3.x
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tri.v3.x = tmp
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END IF
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'find the color of the face
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colr = 255 - shape(j, i).wv1.z
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''fill in the 2d triangle
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'dx = tri.v3.x - tri.v1.x
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'dy = tri.v3.y - tri.v1.y
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'dx1 = tri.v2.x - tri.v1.x
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'dy1 = tri.v2.y - tri.v1.y
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'dx1 = tri.v3.x - tri.v2.x
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'dy1 = tri.v3.y - tri.v2.y
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'
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'sdx = SGN(dx) 'sign of dy is always positive
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'sdx1 = SGN(dx1) 'since they've been sorted top to
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'sdx2 = SGN(dx2) 'bottom: sdy = 1; ady = dy
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'
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'adx = ABS(dx)
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'adx1 = ABS(dx1)
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'adx2 = ABS(dx2)
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'
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'px = tri.v1.x
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'px1 = tri.v1.x
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'x = 0
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'x1 = 0
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'x2 = 0
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'IF dy > adx THEN 'the line is tall
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' FOR h = 0 TO dy
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' x = x + adx
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' IF x > dy THEN px = px + sdx: x = x - dy
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' NEXT h
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'ELSE 'the line is wide
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'END IF
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'wireframe
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IF colr >= 0 AND colr <= 255 THEN
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LINE (tri.v1.x, tri.v1.y)-(tri.v2.x, tri.v2.y), colr
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LINE (tri.v2.x, tri.v2.y)-(tri.v3.x, tri.v3.y), colr
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LINE (tri.v3.x, tri.v3.y)-(tri.v1.x, tri.v1.y), colr
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END IF
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END IF 'end backface cull
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NEXT i
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NEXT j
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a$ = INKEY$
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SELECT CASE a$
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CASE CHR$(27)
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SYSTEM
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CASE CHR$(13)
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SYSTEM
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CASE "w" 'forward
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pov.p.z = pov.p.z + 1
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CASE "s" 'back
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pov.p.z = pov.p.z - 1
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CASE "a" 'strafe left
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pov.p.x = pov.p.x - 1
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CASE "d" 'strafe right
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pov.p.x = pov.p.x + 1
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CASE "e" 'jump
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pov.p.y = pov.p.y + 1
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CASE "c" 'crouch
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pov.p.y = pov.p.y - 1
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CASE "f" 'yaw left
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pov.r.y = pov.r.y + 1
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CASE "h" 'yaw right
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pov.r.y = pov.r.y - 1
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CASE "e" 'roll left
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pov.r.z = pov.r.z + 1
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CASE "t" 'roll right
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pov.r.z = pov.r.z - 1
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CASE "r" 'pitch forward
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pov.r.x = pov.r.x - 1
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CASE "f" 'pitch backward
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pov.r.x = pov.r.x + 1
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END SELECT
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t! = TIMER: DO: LOOP UNTIL TIMER > t! + .01
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CLS
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LOOP
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