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Ad an extra pixel of lookup to reduce streaking
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@dschmenk
dschmenk committed Dec 7, 2024
1 parent 6ae6a34 commit 8ded05f
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Showing 2 changed files with 98 additions and 66 deletions.
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164 changes: 98 additions & 66 deletions src/dhgr.tk/utils/dhgrrgb.pla
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Original file line number Diff line number Diff line change
Expand Up @@ -55,82 +55,102 @@ def dist(x1, y1, z1, x2, y2, z2)#2
return xx:[0], xx:[1]
end

def rgbPix(r, g, b, nr, ng, nb, x, y)#0
def rgbPix(r0, g0, b0, r1, g1, b1, r2, g2, b2, x)#1
var errptr
var pr, pg, pb
var lr, lg, lb
var pr1, pg1, pb1
var pr2, pg2, pb2
var pr3, pg3, pb3
var lr0, lg0, lb0
var lr1, lg1, lb1
var lr2, lg2, lb2
var er, eg, eb
var cr, cg, cb, cx
byte i
res[t_i32] pd, cd, nd
res[t_i32] pd, d0, d1, d2

// Error propogation
errptr = rgbErr + x * 3 * 2
// Previous 3/4 chroma cycle
i = ((x - 1) & 3) * 3
pr1 = ntscCycle[i+RED]
pg1 = ntscCycle[i+GRN]
pb1 = ntscCycle[i+BLU]
i = ((x - 2) & 3) * 3
pr2 = pr1 + ntscCycle[i+RED]
pg2 = pg1 + ntscCycle[i+GRN]
pb2 = pb1 + ntscCycle[i+BLU]
i = ((x - 3) & 3) * 3
pr3 = pr2 + ntscCycle[i+RED]
pg3 = pg2 + ntscCycle[i+GRN]
pb3 = pb2 + ntscCycle[i+BLU]
// Current chroma cycle
i = (x & 3) * 3
cr = pr3 + ntscChroma[i+RED]
cg = pg3 + ntscChroma[i+GRN]
cb = pb3 + ntscChroma[i+BLU]
if errDiv
r = r + errptr=>[RED] / errDiv
g = g + errptr=>[GRN] / errDiv
b = b + errptr=>[BLU] / errDiv
r0 = r0 + errptr=>[RED] / errDiv
g0 = g0 + errptr=>[GRN] / errDiv
b0 = b0 + errptr=>[BLU] / errDiv
fin
pr = 0
pg = 0
pb = 0
// Previous 3/4 chroma cycle
for cx = x - 1 downto x - 3
i = (cx & 3) * 3
pr = pr + ntscCycle[i+RED]
pg = pg + ntscCycle[i+GRN]
pb = pb + ntscCycle[i+BLU]
next
pd:[0], pd:[1] = dist(r, g, b, pr, pg, pb)
// Look ahead in chroma cycle for possible better match for next RGB pixel
i = ((x + 1) & 3) * 3
lr = pr - ntscCycle[i+RED] + ntscChroma[i+RED]
lg = pg - ntscCycle[i+GRN] + ntscChroma[i+GRN]
lb = pb - ntscCycle[i+BLU] + ntscChroma[i+BLU]
lr1 = pr2 + ntscChroma[i+RED]
lg1 = pg2 + ntscChroma[i+GRN]
lb1 = pb2 + ntscChroma[i+BLU]
if errDiv
r1 = r1 + (errptr=>[3+RED] + r0 - lr1) / errDiv
g1 = g1 + (errptr=>[3+GRN] + g0 - lg1) / errDiv
b1 = b1 + (errptr=>[3+BLU] + b0 - lb1) / errDiv
fin
// Look ahead in chroma cycle for possible better match for after next RGB pixel
i = ((x + 2) & 3) * 3
lr2 = pr1 + ntscChroma[i+RED]
lg2 = pg1 + ntscChroma[i+GRN]
lb2 = pb1 + ntscChroma[i+BLU]
if errDiv
nr = nr + (errptr=>[3+RED] + r - lr) / errDiv
ng = ng + (errptr=>[3+GRN] + g - lg) / errDiv
nb = nb + (errptr=>[3+BLU] + b - lb) / errDiv
r2 = r2 + (errptr=>[3+RED] + r1 - lr2) / errDiv
g2 = g2 + (errptr=>[3+GRN] + g1 - lg2) / errDiv
b2 = b2 + (errptr=>[3+BLU] + b1 - lb2) / errDiv
fin
nd:[0], nd:[1] = dist(nr, ng, nb, lr, lg, lb)
// Current 1/4 chroma color
i = (x & 3) * 3
cr = pr + ntscChroma[i+RED]
cg = pg + ntscChroma[i+GRN]
cb = pb + ntscChroma[i+BLU]
cd:[0], cd:[1] = dist(r, g, b, cr, cg, cb)
load32(@cd)
if islt32(@pd) and islt32(@nd)
// Calc match if current pixel is zero
pd:[0], pd:[1] = dist(r0, g0, b0, pr3, pg3, pb3)
// Calc match if next pixel is one
d2:[0], d2:[1] = dist(r2, g2, b2, lr2, lg2, lb2)
// Calc match if after next pixel is one
d1:[0], d1:[1] = dist(r1, g1, b1, lr1, lg1, lb1)
// Calc match if current pixel is one
d0:[0], d0:[1] = dist(r0, g0, b0, cr, cg, cb)
i = (x & 3) * 3
load32(@d0)
if islt32(@pd) and islt32(@d1) and islt32(@d2)
// RGB better matched with current 1/4 chroma color
nr = r - cr
ng = g - cg
nb = b - cb
er = r0 - cr
eg = g0 - cg
eb = b0 - cb
ntscCycle[i+RED] = ntscChroma[i+RED]
ntscCycle[i+GRN] = ntscChroma[i+GRN]
ntscCycle[i+BLU] = ntscChroma[i+BLU]
dhgrSet(x, y)
i = 1
else
// RGB closer to black
nr = r - pr
ng = g - pg
nb = b - pb
er = r0 - pr3
eg = g0 - pg3
eb = b0 - pb3
ntscCycle[i+RED] = 0
ntscCycle[i+GRN] = 0
ntscCycle[i+BLU] = 0
i = 0
fin
// Propogate error down and forward
errptr=>[RED] = nr
errptr=>[GRN] = ng
errptr=>[BLU] = nb
errptr=>[RED] = er
errptr=>[GRN] = eg
errptr=>[BLU] = eb
errptr = errptr + 6
errptr=>[RED] = nr + errptr=>[RED]
errptr=>[GRN] = ng + errptr=>[GRN]
errptr=>[BLU] = nb + errptr=>[BLU]
// Map dark grey to light grey
if (x & 3) == 3 and dcgrGetPixel(x >> 2, y) == 5
dhgrOp(OP_SRC)
dcgrColor(10)
dcgrPixel(x >> 2, y)
fin
errptr=>[RED] = er + errptr=>[RED]
errptr=>[GRN] = eg + errptr=>[GRN]
errptr=>[BLU] = eb + errptr=>[BLU]
return i
end

def rgbInit#0
Expand All @@ -151,8 +171,8 @@ def rgbInit#0
fin
dhgrMode(DHGR_COLOR_MODE)
// Init error propogation array
rgbErr = heapalloc(561 * 3 * 2)
memset(rgberr, 0, 561 * 3 * 2)
rgbErr = heapalloc(563 * 3 * 2)
memset(rgberr, 0, 563 * 3 * 2)
rgberr=>[RED] = -1
rgberr=>[GRN] = -1
rgberr=>[BLU] = -1
Expand All @@ -164,30 +184,42 @@ def rgbExit#0
end

def rgbImportExport(rgbfile, dhgrfile)#0
byte refnum, r, g, b, nxtr, nxtg, nxtb
byte refnum, r0, g0, b0, r1, g1, b1, r2, g2, b2
var i, j
var rgbScanline, rgbptr

refnum = fileio:open(rgbfile)
if refnum
rgbScanline = heapalloc(560 * 3)
rgbScanline = heapalloc(563 * 3)
memset(rgbScanline, 0, 563 * 3)
if rgbScanline
rgbInit
for j = 0 to 191
fileio:read(refnum, rgbScanline, 560 * 3)
rgbptr = rgbScanline
nxtr = gamma[rgbptr->RED]
nxtg = gamma[rgbptr->GRN]
nxtb = gamma[rgbptr->BLU]
r1 = gamma[rgbptr->RED]
g1 = gamma[rgbptr->GRN]
b1 = gamma[rgbptr->BLU]
rgbptr = rgbptr + 3
r2 = gamma[rgbptr->RED]
g2 = gamma[rgbptr->GRN]
b2 = gamma[rgbptr->BLU]
for i = 0 to 559
r = nxtr
g = nxtg
b = nxtb
r0, g0, b0 = r1, g1, b1
r1, g1, b1 = r2, g2, b2
rgbptr = rgbptr + 3
nxtr = gamma[rgbptr->RED]
nxtg = gamma[rgbptr->GRN]
nxtb = gamma[rgbptr->BLU]
rgbPix(r, g, b, nxtr, nxtg, nxtb, i, j)
r2 = gamma[rgbptr->RED]
g2 = gamma[rgbptr->GRN]
b2 = gamma[rgbptr->BLU]
if rgbPix(r0, g0, b0, r1, g1, b1, r2, g2, b2, i)
dhgrSet(i, j)
fin
// Map dark grey to light grey
if (i & 3) == 3 and dcgrGetPixel(i >> 2, j) == 5
dhgrOp(OP_SRC)
dcgrColor(10)
dcgrPixel(i >> 2, j)
fin
next
if ^$C000 == $83
break
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