mirror of
https://github.com/irmen/prog8.git
synced 2024-07-05 22:29:04 +00:00
466 lines
14 KiB
Lua
466 lines
14 KiB
Lua
; Monochrome Bitmap pixel graphics routines for the Virtual Machine
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; Using the full-screen 640x480 and 320x240 screen modes, but just black/white.
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;
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; NOTE: For sake of speed, NO BOUNDS CHECKING is performed in most routines!
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; You'll have to make sure yourself that you're not writing outside of bitmap boundaries!
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monogfx {
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%option ignore_unused
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; read-only control variables:
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uword width = 0
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uword height = 0
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bool dont_stipple_flag = true ; set to false to enable stippling mode
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sub lores() {
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; enable 320*240 bitmap mode
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sys.gfx_enable(0)
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width = 320
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height = 240
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clear_screen(0)
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}
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sub hires() {
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; enable 640*480 bitmap mode
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sys.gfx_enable(1)
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width = 640
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height = 480
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clear_screen(0)
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}
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sub textmode() {
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; back to normal text mode
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}
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sub clear_screen(ubyte color) {
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stipple(false)
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if color
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color=255
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sys.gfx_clear(color)
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}
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sub stipple(bool enable) {
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dont_stipple_flag = not enable
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}
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sub rect(uword xx, uword yy, uword rwidth, uword rheight, bool draw) {
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if rwidth==0 or rheight==0
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return
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horizontal_line(xx, yy, rwidth, draw)
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if rheight==1
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return
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horizontal_line(xx, yy+rheight-1, rwidth, draw)
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vertical_line(xx, yy+1, rheight-2, draw)
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if rwidth==1
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return
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vertical_line(xx+rwidth-1, yy+1, rheight-2, draw)
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}
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sub fillrect(uword xx, uword yy, uword rwidth, uword rheight, bool draw) {
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; Draw a filled rectangle of the given size and color.
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; To fill the whole screen, use clear_screen(color) instead - it is much faster.
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if rwidth==0
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return
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repeat rheight {
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horizontal_line(xx, yy, rwidth, draw)
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yy++
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}
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}
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sub horizontal_line(uword xx, uword yy, uword length, bool draw) {
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uword xpos
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for xpos in xx to xx+length-1
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plot(xpos, yy, draw)
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}
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sub safe_horizontal_line(uword xx, uword yy, uword length, bool draw) {
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; does bounds checking and clipping
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if msb(yy)&$80!=0 or yy>=height
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return
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if msb(xx)&$80!=0 {
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length += xx
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xx = 0
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}
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if xx>=width
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return
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if xx+length>width
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length = width-xx
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if length>width
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return
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horizontal_line(xx, yy, length, draw)
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}
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sub vertical_line(uword xx, uword yy, uword lheight, bool draw) {
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uword ypos
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for ypos in yy to yy+lheight-1
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plot(xx, ypos, draw)
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}
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sub line(uword @zp x1, uword @zp y1, uword @zp x2, uword @zp y2, bool draw) {
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; Bresenham algorithm.
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; This code special-cases various quadrant loops to allow simple ++ and -- operations.
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if y1>y2 {
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; make sure dy is always positive to have only 4 instead of 8 special cases
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cx16.r0 = x1
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x1 = x2
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x2 = cx16.r0
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cx16.r0 = y1
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y1 = y2
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y2 = cx16.r0
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}
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word @zp dx = (x2 as word)-x1
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word @zp dy = (y2 as word)-y1
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if dx==0 {
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vertical_line(x1, y1, abs(dy) as uword +1, draw)
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return
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}
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if dy==0 {
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if x1>x2
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x1=x2
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horizontal_line(x1, y1, abs(dx) as uword +1, draw)
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return
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}
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word @zp d = 0
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cx16.r1L = true ; 'positive_ix'
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if dx < 0 {
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dx = -dx
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cx16.r1L = false
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}
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word @zp dx2 = dx*2
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word @zp dy2 = dy*2
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cx16.r14 = x1 ; internal plot X
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if dx >= dy {
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if cx16.r1L {
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repeat {
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plot(cx16.r14, y1, draw)
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if cx16.r14==x2
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return
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cx16.r14++
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d += dy2
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if d > dx {
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y1++
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d -= dx2
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}
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}
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} else {
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repeat {
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plot(cx16.r14, y1, draw)
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if cx16.r14==x2
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return
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cx16.r14--
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d += dy2
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if d > dx {
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y1++
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d -= dx2
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}
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}
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}
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}
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else {
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if cx16.r1L {
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repeat {
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plot(cx16.r14, y1, draw)
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if y1 == y2
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return
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y1++
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d += dx2
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if d > dy {
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cx16.r14++
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d -= dy2
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}
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}
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} else {
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repeat {
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plot(cx16.r14, y1, draw)
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if y1 == y2
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return
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y1++
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d += dx2
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if d > dy {
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cx16.r14--
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d -= dy2
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}
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}
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}
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}
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}
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sub circle(uword @zp xcenter, uword @zp ycenter, ubyte radius, bool draw) {
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; Warning: NO BOUNDS CHECKS. Make sure circle fits in the screen.
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; Midpoint algorithm.
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if radius==0
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return
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ubyte @zp xx = radius
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ubyte @zp yy = 0
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word @zp decisionOver2 = (1 as word)-xx
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; R14 = internal plot X
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; R15 = internal plot Y
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while xx>=yy {
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cx16.r14 = xcenter + xx
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cx16.r15 = ycenter + yy
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plotq()
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cx16.r14 = xcenter - xx
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plotq()
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cx16.r14 = xcenter + xx
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cx16.r15 = ycenter - yy
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plotq()
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cx16.r14 = xcenter - xx
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plotq()
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cx16.r14 = xcenter + yy
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cx16.r15 = ycenter + xx
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plotq()
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cx16.r14 = xcenter - yy
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plotq()
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cx16.r14 = xcenter + yy
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cx16.r15 = ycenter - xx
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plotq()
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cx16.r14 = xcenter - yy
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plotq()
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yy++
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if decisionOver2>=0 {
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xx--
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decisionOver2 -= xx*$0002
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}
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decisionOver2 += yy*$0002
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decisionOver2++
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}
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sub plotq() {
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; cx16.r14 = x, cx16.r15 = y, draw=draw
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plot(cx16.r14, cx16.r15, draw)
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}
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}
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sub safe_circle(uword @zp xcenter, uword @zp ycenter, ubyte radius, bool draw) {
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; Does bounds checking and clipping.
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; Midpoint algorithm.
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if radius==0
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return
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ubyte @zp xx = radius
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ubyte @zp yy = 0
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word @zp decisionOver2 = (1 as word)-xx
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; R14 = internal plot X
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; R15 = internal plot Y
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while xx>=yy {
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cx16.r14 = xcenter + xx
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cx16.r15 = ycenter + yy
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plotq()
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cx16.r14 = xcenter - xx
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plotq()
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cx16.r14 = xcenter + xx
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cx16.r15 = ycenter - yy
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plotq()
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cx16.r14 = xcenter - xx
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plotq()
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cx16.r14 = xcenter + yy
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cx16.r15 = ycenter + xx
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plotq()
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cx16.r14 = xcenter - yy
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plotq()
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cx16.r14 = xcenter + yy
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cx16.r15 = ycenter - xx
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plotq()
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cx16.r14 = xcenter - yy
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plotq()
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yy++
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if decisionOver2>=0 {
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xx--
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decisionOver2 -= xx*$0002
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}
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decisionOver2 += yy*$0002
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decisionOver2++
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}
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sub plotq() {
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; cx16.r14 = x, cx16.r15 = y, draw=draw
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safe_plot(cx16.r14, cx16.r15, draw)
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}
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}
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sub disc(uword @zp xcenter, uword @zp ycenter, ubyte @zp radius, bool draw) {
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; Warning: NO BOUNDS CHECKS. Make sure circle fits in the screen.
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; Midpoint algorithm, filled
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if radius==0
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return
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ubyte @zp yy = 0
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word @zp decisionOver2 = (1 as word)-radius
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while radius>=yy {
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horizontal_line(xcenter-radius, ycenter+yy, radius*$0002+1, draw)
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horizontal_line(xcenter-radius, ycenter-yy, radius*$0002+1, draw)
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horizontal_line(xcenter-yy, ycenter+radius, yy*$0002+1, draw)
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horizontal_line(xcenter-yy, ycenter-radius, yy*$0002+1, draw)
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yy++
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if decisionOver2>=0 {
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radius--
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decisionOver2 -= radius*$0002
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}
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decisionOver2 += yy*$0002
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decisionOver2++
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}
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}
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sub safe_disc(uword @zp xcenter, uword @zp ycenter, ubyte @zp radius, bool draw) {
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; Warning: NO BOUNDS CHECKS. Make sure circle fits in the screen.
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; Midpoint algorithm, filled
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if radius==0
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return
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ubyte @zp yy = 0
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word @zp decisionOver2 = (1 as word)-radius
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while radius>=yy {
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safe_horizontal_line(xcenter-radius, ycenter+yy, radius*$0002+1, draw)
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safe_horizontal_line(xcenter-radius, ycenter-yy, radius*$0002+1, draw)
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safe_horizontal_line(xcenter-yy, ycenter+radius, yy*$0002+1, draw)
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safe_horizontal_line(xcenter-yy, ycenter-radius, yy*$0002+1, draw)
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yy++
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if decisionOver2>=0 {
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radius--
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decisionOver2 -= radius*$0002
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}
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decisionOver2 += yy*$0002
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decisionOver2++
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}
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}
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sub plot(uword @zp xx, uword @zp yy, bool @zp draw) {
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if draw {
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if dont_stipple_flag
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sys.gfx_plot(xx, yy, 255)
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else {
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if (xx ^ yy)&1
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sys.gfx_plot(xx, yy, 255)
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else
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sys.gfx_plot(xx, yy, 0)
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}
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}
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else
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sys.gfx_plot(xx, yy, 0)
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}
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sub safe_plot(uword xx, uword yy, bool draw) {
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; A plot that does bounds checks to see if the pixel is inside the screen.
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if msb(xx)&$80!=0 or msb(yy)&$80!=0
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return
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if xx >= width or yy >= height
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return
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plot(xx, yy, draw)
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}
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sub pget(uword @zp xx, uword yy) -> ubyte {
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return sys.gfx_getpixel(xx, yy)
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}
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sub fill(uword x, uword y, bool draw) {
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; Non-recursive scanline flood fill.
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; based loosely on code found here https://www.codeproject.com/Articles/6017/QuickFill-An-efficient-flood-fill-algorithm
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; with the fixes applied to the seedfill_4 routine as mentioned in the comments.
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const ubyte MAXDEPTH = 64
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word @zp xx = x as word
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word @zp yy = y as word
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word[MAXDEPTH] @split @shared stack_xl
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word[MAXDEPTH] @split @shared stack_xr
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word[MAXDEPTH] @split @shared stack_y
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byte[MAXDEPTH] @shared stack_dy
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cx16.r12L = 0 ; stack pointer
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word x1
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word x2
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byte dy
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cx16.r10L = draw as ubyte
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sub push_stack(word sxl, word sxr, word sy, byte sdy) {
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if cx16.r12L==MAXDEPTH
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return
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cx16.r0s = sy+sdy
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if cx16.r0s>=0 and cx16.r0s<=height-1 {
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stack_xl[cx16.r12L] = sxl
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stack_xr[cx16.r12L] = sxr
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stack_y[cx16.r12L] = sy
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stack_dy[cx16.r12L] = sdy
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cx16.r12L++
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}
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}
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sub pop_stack() {
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cx16.r12L--
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x1 = stack_xl[cx16.r12L]
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x2 = stack_xr[cx16.r12L]
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yy = stack_y[cx16.r12L]
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dy = stack_dy[cx16.r12L]
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yy+=dy
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}
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cx16.r11L = pget(xx as uword, yy as uword) ; old_color
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if cx16.r11L == cx16.r10L
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return
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if xx<0 or xx>width-1 or yy<0 or yy>height-1
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return
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push_stack(xx, xx, yy, 1)
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push_stack(xx, xx, yy + 1, -1)
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word left = 0
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while cx16.r12L {
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pop_stack()
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xx = x1
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while xx >= 0 {
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if pget(xx as uword, yy as uword) != cx16.r11L
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break
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xx--
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}
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if x1!=xx
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horizontal_line(xx as uword+1, yy as uword, x1-xx as uword, cx16.r10L)
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else
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goto skip
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left = xx + 1
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if left < x1
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push_stack(left, x1 - 1, yy, -dy)
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xx = x1 + 1
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do {
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cx16.r9 = xx
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while xx <= width-1 {
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if pget(xx as uword, yy as uword) != cx16.r11L
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break
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xx++
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}
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if cx16.r9!=xx
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horizontal_line(cx16.r9, yy as uword, (xx as uword)-cx16.r9, cx16.r10L)
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push_stack(left, xx - 1, yy, dy)
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if xx > x2 + 1
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push_stack(x2 + 1, xx - 1, yy, -dy)
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skip:
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xx++
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while xx <= x2 {
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if pget(xx as uword, yy as uword) == cx16.r11L
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break
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xx++
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}
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left = xx
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} until xx>x2
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}
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}
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sub text_charset(ubyte charset) {
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; -- select the text charset to use with the text() routine
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; the charset number is the same as for the cx16.screen_set_charset() ROM function.
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; 1 = ISO charset, 2 = PETSCII uppercase+graphs, 3= PETSCII uppercase+lowercase.
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; TODO vm bitmap charset
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}
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sub text(uword @zp xx, uword yy, bool draw, uword sctextptr) {
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; -- Write some text at the given pixel position. The text string must be in screencode encoding (not petscii!).
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; You must also have called text_charset() first to select and prepare the character set to use.
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; TODO vm bitmap charset
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}
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}
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