Texel Raytracer by Antoni Gual

[The Librarian]

Texel Raytracer

Author: Antoni Gual
Source: petesqbsite
URL: http://www.petesqbsite.com/downloads/graphics.shtml
Version: 2004
Tags: [3d], [raytrace], [poke]

Description:
Pure QB Realtime Raytracer Demo. Translated to/optimized for QB by Antoni Gual agual@eic.ictnet.es. The original was written in C by Texel, a Spanish demo coder [...]

Source Code:

Code: QB64: [Select]

1. 'Pure QB Realtime Raytracer Demo
2. 'Translated to/optimized for QB by Antoni Gual agual@eic.ictnet.es
3. 'The original was written in C by Texel, a Spanish demo coder.
4. 'It will not work in the IDE due to integer overflow errors.
5. 'Compile with QB 4.0 or QB4.5 + ffix. It does 12.5 fps in my P4 1,4.
6. 'The C version (DOS protected mode, DJGPP) does 50 fps :(
7.  
8. DECLARE SUB ffix
9. 'ffix
10. CONST objnum = 4
11.  
12. DIM n AS INTEGER, K AS INTEGER, OBJMIN AS INTEGER, OBJMIN2 AS INTEGER
13. DIM OBJ(objnum) AS INTEGER, l AS INTEGER, posi AS INTEGER, POS2 AS INTEGER
14. DIM s AS INTEGER, t(8200) AS INTEGER, XX AS INTEGER, YY AS INTEGER, XQ AS INTEGER
15. DIM YQ AS INTEGER, mmmm AS INTEGER, xx1 AS INTEGER, yy1 AS INTEGER
16. DIM t2(8200) AS INTEGER, ipos AS INTEGER
17.  
18. DIM A(objnum) AS SINGLE, B(objnum) AS SINGLE, C(objnum) AS SINGLE
19. DIM R(objnum) AS SINGLE
20.  
21. SCREEN 13
22. DEF SEG = &HA000
23. 'Cambiar la paleta a tonos de azul
24. OUT &H3C8, 0 '
25. FOR n = 0 TO 127
26.     OUT &H3C9, 0
27.     OUT &H3C9, INT(n / 4)
28.     OUT &H3C9, INT(n / 2)
29. NEXT
30. FOR n = 0 TO 127
31.     OUT &H3C9, INT(n / 2)
32.     OUT &H3C9, INT(31 + n / 4)
33.     OUT &H3C9, 63
34. NEXT
35. D = 230
36. l = 0
37.    
38. 'four objects
39. OBJ(0) = 0: A(0) = -50 + l: B(0) = 0: C(0) = -100: R(0) = -55 * 55
40. OBJ(1) = 0: A(1) = 50 - l: B(1) = -25: C(1) = -120: R(1) = -55 * 55
41. OBJ(2) = 0: A(2) = 0: B(2) = 500: C(2) = -220: R(2) = -500! * 500
42. OBJ(3) = 1: A(3) = 60: B(3) = -35: C(3) = -30
43.  
44. tt! = TIMER
45. FOR l = 0 TO 199
46.        
47.     A(0) = -50 + l
48.     A(1) = 50 - l
49.     posi = 400
50.     mmmm = -1
51.     'calculamos uno de cada 4 pixels a buffer t()
52.     FOR Y = -40 TO 39 STEP 2
53.         FOR X = -80 TO 79 STEP 2
54.             X0 = X
55.             Y0 = Y
56.             GOSUB raytrace
57.             t(posi) = COL
58.             posi = posi + 1
59.         NEXT
60.     NEXT
61.     posi = 482
62.     POS2 = 0
63.     'calculamos pixels restantes, interpolando si podemos
64.     FOR YQ = 6 TO 43
65.         FOR XQ = 2 TO 77
66.             'interpolar
67.             IF t2(posi) = t2(posi + 1) AND t2(posi) = t2(posi + 80) AND t2(posi) = t2(posi + 81) THEN
68.                 ipos = (YQ * 1280 + (XQ * 4))
69.                 FOR YY = 0 TO 3
70.                     FOR XX = 0 TO 3
71.                         POKE ipos, (YY * (t(posi + 80) * (4 - XX) + t(posi + 81) * XX) + (t(posi) * (4 - XX) + t(posi + 1) * XX) * (4 - YY)) \ 16
72.                         ipos = ipos + 1
73.                     NEXT
74.                     ipos = ipos + 316
75.                 NEXT
76.                 'no interpolar
77.             ELSE
78.                 mmmm = 0
79.                 FOR yy1 = 0 TO 3
80.                     FOR xx1 = 0 TO 3
81.                         IF xx1 OR yy1 THEN
82.                             X0 = (-160 + XQ * 4 + xx1) / 2
83.                             Y0 = (-100 + YQ * 4 + yy1) / 2
84.                             GOSUB raytrace
85.                             POKE (YQ * 4 + yy1) * 320 + XQ * 4 + xx1, COL
86.                         ELSE
87.                             POKE YQ * 1280 + XQ * 4, t(posi)
88.                         END IF
89.                     NEXT
90.                 NEXT
91.             END IF
92.             posi = posi + 1
93.         NEXT
94.         posi = posi + 4
95.     NEXT
96.     IF LEN(INKEY$) THEN EXIT FOR
97. NEXT
98. COLOR 255: PRINT l / (TIMER - tt!)
99. KK$ = INPUT$(1)
100. END
101.  
102. raytrace:
103. Z0 = 0
104. MD = 1 / SQR(X0 * X0 + Y0 * Y0 + D * D)
105. X1 = X0 * MD
106. Y1 = Y0 * MD
107. Z1 = -(D + Z0) * MD
108. K = 0
109. COL = 0
110. OBJMIN = objnum
111. IF mmmm THEN t2(posi) = objnum
112. DO
113.     TMIN = 327680
114.     FOR n = 0 TO 2
115.         IF OBJ(n) = 0 AND (OBJ(n) <> OBJMIN) THEN
116.             A0 = A(n) - X0
117.             B0 = B(n) - Y0
118.             C0 = C(n) - Z0
119.             TB = A0 * X1 + B0 * Y1 + C0 * Z1
120.             RZ = TB * TB - A0 * A0 - B0 * B0 - C0 * C0
121.             IF RZ >= R(n) THEN
122.                 TN = TB - SQR(RZ - R(n))
123.                 IF TN < TMIN AND TN > 0 THEN TMIN = TN: OBJMIN2 = n
124.             END IF
125.         END IF
126.     NEXT
127.     OBJMIN = OBJMIN2
128.     IF TMIN < 327680 AND (OBJ(OBJMIN) = 0) THEN
129.         IF mmmm THEN t2(posi) = t2(posi) * K * objnum * 3 + OBJMIN
130.         X0 = X0 + X1 * TMIN
131.         Y0 = Y0 + Y1 * TMIN
132.         Z0 = Z0 + Z1 * TMIN
133.         NX = X0 - A(OBJMIN)
134.         NY = Y0 - B(OBJMIN)
135.         NZ = Z0 - C(OBJMIN)
136.         CA = 2 * (NX * X1 + NY * Y1 + NZ * Z1) / (NX * NX + NY * NY + NZ * NZ + 1)
137.         X1 = X1 - NX * CA
138.         Y1 = Y1 - NY * CA
139.         Z1 = Z1 - NZ * CA
140.         A2 = A(3) - X0
141.         B2 = B(3) - Y0
142.         C2 = C(3) - Z0
143.         MV = 1 / SQR(A2 * A2 + B2 * B2 + C2 * C2)
144.         A2 = A2 * MV
145.         B2 = B2 * MV
146.         C2 = C2 * MV
147.         s = 0
148.         FOR n = 0 TO 2
149.             IF OBJ(n) = 0 AND NOT s THEN
150.                 A0 = X0 - A(n)
151.                 B0 = Y0 - B(n)
152.                 C0 = Z0 - C(n)
153.                 TB = A2 * A0 + B2 * B0 + C2 * C0
154.                 RZ = TB * TB - A0 * A0 - B0 * B0 - C0 * C0
155.                 IF RZ >= R(n) AND TB < 0 THEN s = -1: IF mmmm THEN t2(posi) = t2(posi) * 32
156.             END IF
157.         NEXT
158.         IF NOT s THEN
159.             IF mmmm THEN t2(posi) = t2(posi) + 1
160.             col2 = X1 * A2 + Y1 * B2 + Z1 * C2
161.             IF col2 < 0 THEN col2 = 0
162.             cc = col2 * col2
163.             col2 = cc * cc
164.             MV = SQR(NX * NX + NY * NY + NZ * NZ)
165.             'IF COL2 < 0 THEN COL2 = 0
166.             col2 = col2 + (NX * A2 + NY * B2 + NZ * C2) / MV
167.             IF col2 < 0 THEN col2 = 0
168.             COL = COL + col2 / ((K + 1) * (K + 1) * 2)
169.             IF COL > 1 THEN COL = 1
170.         END IF
171.         K = K + 1
172.     END IF
173. LOOP WHILE TMIN < 327680 AND K <= 2
174. IF K = 0 THEN COL = 50 ELSE COL = COL * 255
175. RETURN
176.