_TITLE "RayTrace" 'b+ trans from JB to QB64 2022-02-26

CONST scrw = 1024, scrh = 680

SCREEN _NEWIMAGE(scrw, scrh, 32)

_SCREENMOVE 150, 40

READ spheres

DIM c(spheres, 3), r(spheres), q(spheres), cl(4) AS _UNSIGNED LONG

w = scrw / 2

h = scrh / 2

s = 0

cl(1) = _RGB32(120, 65, 45) ' shaddow

cl(2) = _RGB32(0, 0, 100)

cl(3) = _RGB32(255, 255, 0)

cl(4) = _RGB32(0, 0, 200)

FOR k = 1 TO spheres

    READ a, b, c, d

    c(k, 1) = a

    c(k, 2) = b

    c(k, 3) = c

    r = d

    r(k) = r

    q(k) = r * r

NEXT k



FOR i = 1 TO scrh

    FOR j = 0 TO scrw - 1

        x = 0.3: y = -0.5: z = 0: ba = 3

        dx = j - w: dy = h - i: dz = (scrh / 480) * 600

        dd = dx * dx + dy * dy + dz * dz

        DO

            n = (y >= 0 OR dy <= 0) '* -1  <<< Makes $1000 for knowing where to tap the hammer

            IF n = 0 THEN s = (y / dy) * -1

            FOR k = 1 TO spheres

                px = c(k, 1) - x: py = c(k, 2) - y: pz = c(k, 3) - z

                pp = px * px + py * py + pz * pz

                sc = px * dx + py * dy + pz * dz

                IF sc > 0 THEN

                    bb = sc * sc / dd

                    aa = q(k) - pp + bb

                    IF aa > 0 THEN

                        sc = (SQR(bb) - SQR(aa)) / SQR(dd)

                        IF sc < s OR n < 0 THEN n = k: s = sc

                    END IF

                END IF

            NEXT k

            IF n < 0 THEN

                PSET (j, scrh - i), _RGB32(128 * (scrh - i) / scrh + 128 * (dy * dy / dd), 128 * (scrh - i) / scrh + 128 * (dy * dy / dd), 200 + 55 * (dy * dy / dd))

                EXIT DO

            ELSE

                dx = dx * s: dy = dy * s: dz = dz * s: dd = dd * s * s

                x = x + dx: y = y + dy: z = z + dz

                IF n <> 0 THEN

                    nx = x - c(n, 1): ny = y - c(n, 2): nz = z - c(n, 3)

                    nn = nx * nx + ny * ny + nz * nz

                    l = 2 * (dx * nx + dy * ny + dz * nz) / nn

                    dx = dx - nx * l: dy = dy - ny * l: dz = dz - nz * l

                ELSE

                    FOR k = 1 TO spheres

                        u = c(k, 1) - x

                        v = c(k, 3) - z

                        IF u * u + v * v <= q(k) THEN ba = 1: EXIT FOR

                    NEXT k

                    IF (x - INT(x) > .5) = (z - INT(z) > .5) THEN

                        PSET (j, scrh - i), cl(ba)

                    ELSE

                        PSET (j, scrh - i), cl(ba + 1)

                    END IF

                    EXIT DO

                END IF

            END IF

        LOOP

    NEXT j

NEXT i

SLEEP



DATA 6

DATA -0.3,-0.8,3,0.6

DATA 0.9,-1.4,3.5,0.35

DATA 0.7,-0.45,2.5,0.4

DATA -0.5,-0.3,1.5,0.15

DATA 1.0,-0.2,1.5,0.1

DATA -0.1,-0.2,1.25,0.2