mirror of
https://github.com/irmen/prog8.git
synced 2024-12-24 16:29:21 +00:00
fix bresenham line
This commit is contained in:
Irmen de Jong
parent
fac2a2d7cb
commit
fffe36e358
@ -14,6 +14,12 @@ import kotlin.math.pow
|
||||
/*
|
||||
todo add more expression optimizations
|
||||
|
||||
x + x -> x << 1 (for words... for bytes too?)
|
||||
x + x + x + x -> x << 2 (for words... for bytes too?)
|
||||
x + x + x -> ???? x*3 ??? words/bytes?
|
||||
x - x -> 0
|
||||
|
||||
|
||||
Investigate what optimizations binaryen has, also see https://egorbo.com/peephole-optimizations.html
|
||||
|
||||
*/
|
||||
|
||||
@ -1,77 +1,96 @@
|
||||
%import c64lib
|
||||
%import c64utils
|
||||
%zeropage basicsafe
|
||||
|
||||
; bitmap pixel graphics module for the C64
|
||||
; only black/white monchrome for now
|
||||
|
||||
main {
|
||||
; you could put this code at $4000 which is after the bitmap screen in memory ($2000-$3fff),
|
||||
; this leaves more space for user program code.
|
||||
|
||||
graphics {
|
||||
const uword bitmap_address = $2000
|
||||
|
||||
|
||||
sub start() {
|
||||
|
||||
sub enable_bitmap_mode() {
|
||||
; enable bitmap screen, erase it and set colors to black/white.
|
||||
c64.SCROLY |= %00100000
|
||||
c64.VMCSB = (c64.VMCSB & %11110000) | %00001000 ; $2000-$3fff
|
||||
memset(bitmap_address, 320*200/8, 0)
|
||||
c64scr.clear_screen($10, 0)
|
||||
|
||||
lines()
|
||||
circles()
|
||||
forever {
|
||||
}
|
||||
c64scr.clear_screen($10, 0) ; pixel color $1 (white) backround $0 (black)
|
||||
}
|
||||
|
||||
|
||||
|
||||
sub circles() {
|
||||
ubyte xx
|
||||
for xx in 3 to 7 {
|
||||
circle(xx*50-100, 10+xx*16, (xx+6)*4)
|
||||
disc(xx*50-100, 10+xx*16, (xx+6)*2)
|
||||
}
|
||||
}
|
||||
|
||||
sub lines() {
|
||||
ubyte ix
|
||||
for ix in 1 to 15 {
|
||||
line(10, 10, ix*4, 50) ; TODO fix lines of lenghts > 128
|
||||
}
|
||||
}
|
||||
|
||||
sub line(ubyte x1, ubyte y1, ubyte x2, ubyte y2) {
|
||||
sub line(uword x1, ubyte y1, uword x2, ubyte y2) {
|
||||
; Bresenham algorithm
|
||||
byte d = 0
|
||||
ubyte dx = abs(x2 - x1)
|
||||
ubyte dy = abs(y2 - y1)
|
||||
ubyte dx2 = 2 * dx
|
||||
ubyte dy2 = 2 * dy
|
||||
word ix = sgn(x2 as byte - x1 as byte)
|
||||
word iy = sgn(y2 as byte - y1 as byte)
|
||||
word dx
|
||||
word dy
|
||||
byte ix = 1
|
||||
byte iy = 1
|
||||
if x2>x1 {
|
||||
dx = x2-x1
|
||||
} else {
|
||||
ix = -1
|
||||
dx = x1-x2
|
||||
}
|
||||
if y2>y1 {
|
||||
dy = y2-y1
|
||||
} else {
|
||||
iy = -1
|
||||
dy = y1-y2
|
||||
}
|
||||
word dx2 = 2 * dx
|
||||
word dy2 = 2 * dy
|
||||
word d = 0
|
||||
plotx = x1
|
||||
|
||||
if dx >= dy {
|
||||
forever {
|
||||
plot(y1)
|
||||
if plotx==x2
|
||||
return
|
||||
plotx += ix
|
||||
d += dy2
|
||||
if d > dx {
|
||||
y1 += iy
|
||||
d -= dx2
|
||||
if ix<0 {
|
||||
forever {
|
||||
graphics.plot(y1)
|
||||
if plotx==x2
|
||||
return
|
||||
plotx--
|
||||
d += dy2
|
||||
if d > dx {
|
||||
y1 += iy
|
||||
d -= dx2
|
||||
}
|
||||
}
|
||||
} else {
|
||||
forever {
|
||||
graphics.plot(y1)
|
||||
if plotx==x2
|
||||
return
|
||||
plotx++
|
||||
d += dy2
|
||||
if d > dx {
|
||||
y1 += iy
|
||||
d -= dx2
|
||||
}
|
||||
}
|
||||
}
|
||||
} else {
|
||||
forever {
|
||||
plot(y1)
|
||||
if y1 == y2
|
||||
return
|
||||
y1 += iy
|
||||
d += dx2
|
||||
if d > dy {
|
||||
plotx += ix
|
||||
d -= dy2
|
||||
if iy<0 {
|
||||
forever {
|
||||
plot(y1)
|
||||
if y1 == y2
|
||||
return
|
||||
y1--
|
||||
d += dx2
|
||||
if d > dy {
|
||||
plotx += ix as word
|
||||
d -= dy2
|
||||
}
|
||||
}
|
||||
} else {
|
||||
forever {
|
||||
plot(y1)
|
||||
if y1 == y2
|
||||
return
|
||||
y1++
|
||||
d += dx2
|
||||
if d > dy {
|
||||
plotx += ix as word
|
||||
d -= dy2
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
@ -149,6 +168,13 @@ main {
|
||||
}
|
||||
|
||||
|
||||
; here is the non-asm code for the plot routine below:
|
||||
; sub plot_nonasm(uword px, ubyte py) {
|
||||
; ubyte[] ormask = [128, 64, 32, 16, 8, 4, 2, 1]
|
||||
; uword addr = bitmap_address + 320*(py>>3) + (py & 7) + (px & %0000000111111000)
|
||||
; @(addr) |= ormask[lsb(px) & 7]
|
||||
; }
|
||||
|
||||
uword plotx ; 0..319
|
||||
|
||||
asmsub plot(ubyte ploty @A) { ; plotx is 16 bits 0 to 319... doesn't fit in a register
|
||||
@ -219,13 +245,6 @@ _y_lookup_lo
|
||||
}}
|
||||
}
|
||||
|
||||
; here is the non-asm code for the same plot routine:
|
||||
; sub plot_nonasm(uword px, ubyte py) {
|
||||
; ubyte[] ormask = [128, 64, 32, 16, 8, 4, 2, 1]
|
||||
; uword addr = bitmap_address + 320*(py>>3) + (py & 7) + (px & %0000000111111000)
|
||||
; @(addr) |= ormask[lsb(px) & 7]
|
||||
; }
|
||||
|
||||
}
|
||||
|
||||
|
||||
35
examples/line-circle-gfx.p8
Normal file
35
examples/line-circle-gfx.p8
Normal file
@ -0,0 +1,35 @@
|
||||
%import c64lib
|
||||
%import c64graphics
|
||||
%zeropage basicsafe
|
||||
|
||||
|
||||
main {
|
||||
|
||||
sub start() {
|
||||
graphics.enable_bitmap_mode()
|
||||
draw_lines()
|
||||
draw_circles()
|
||||
forever {
|
||||
}
|
||||
}
|
||||
|
||||
sub draw_circles() {
|
||||
ubyte xx
|
||||
for xx in 3 to 7 {
|
||||
graphics.circle(xx*50-100, 10+xx*16, (xx+6)*4)
|
||||
graphics.disc(xx*50-100, 10+xx*16, (xx+6)*2)
|
||||
}
|
||||
}
|
||||
|
||||
sub draw_lines() {
|
||||
ubyte i
|
||||
for i in 0 to 255 step 4 {
|
||||
; uword x1 = (320-256)/2 + sin8u(i)
|
||||
uword x1 = ((320-256)/2 as uword) + sin8u(i) ; TODO fix the need for a cast here
|
||||
uword y1 = (200-128)/2 + cos8u(i)/2
|
||||
uword x2 = ((320-64)/2 as uword) + sin8u(i)/4 ; TODO fix the need for a cast here
|
||||
uword y2 = (200-64)/2 + cos8u(i)/4
|
||||
graphics.line(x1, lsb(y1), x2, lsb(y2))
|
||||
}
|
||||
}
|
||||
}
|
||||
@ -64,7 +64,8 @@ main {
|
||||
}
|
||||
|
||||
sub line(ubyte x1, ubyte y1, ubyte x2, ubyte y2) {
|
||||
; Bresenham algorithm
|
||||
; Bresenham algorithm, not very optimized to keep clear code.
|
||||
; For a better optimized version have a look in the graphics.p8 module.
|
||||
byte d = 0
|
||||
ubyte dx = abs(x2 - x1)
|
||||
ubyte dy = abs(y2 - y1)
|
||||
Loading…
Reference in New Issue
Block a user