Raster bars
Display bars of color, moving up and down across the screen for horizontal raster bars, or left and right across the screen for vertical raster bars, making the raster bars move as stated by swaying side-to-side the respective way if possible.
- Task
Use multiple colors in succession and carefully make a gradient between the colors (if possible) to achieve an effect of metallic-looking horizontal bars.
Horizontal and/or vertical raster bars are acceptable.
Ada
with Ada.Numerics.Elementary_Functions;
with SDL.Video.Windows.Makers;
with SDL.Video.Renderers.Makers;
with SDL.Video.Palettes;
with SDL.Events.Events;
procedure Raster_Bars is
Width : constant := 1200;
Height : constant := 600;
Window : SDL.Video.Windows.Window;
Renderer : SDL.Video.Renderers.Renderer;
function Check_Quit return Boolean is
use type SDL.Events.Event_Types;
Event : SDL.Events.Events.Events;
begin
while SDL.Events.Events.Poll (Event) loop
if Event.Common.Event_Type = SDL.Events.Quit then
return True;
end if;
end loop;
return False;
end Check_Quit;
procedure Draw_Raster_Bar (Y : Integer) is
use SDL.Video.Palettes;
use SDL.C;
Cc : Colour_Component;
begin
for I in 0 .. 10 loop
Cc := Colour_Component (50 + 20 * I);
Renderer.Set_Draw_Colour ((Cc, Cc, Cc, 255));
Renderer.Draw (Line => ((0, C.int (Y + I)),
(Width, C.int (Y + I))));
end loop;
end Draw_Raster_Bar;
procedure Draw_Raster_Bar_V (X : Integer) is
use SDL.Video.Palettes;
use SDL.C;
Cc : Colour_Component;
begin
for I in 0 .. 10 loop
Cc := Colour_Component (250 - 20 * I);
Renderer.Set_Draw_Colour ((Cc, Cc, Cc, 255));
Renderer.Draw (Line => ((C.int (X + I), 0),
(C.int (X + I), Height)));
end loop;
end Draw_Raster_Bar_V;
procedure Raster_Bars is
use Ada.Numerics.Elementary_Functions;
Xc : constant Integer := 800;
Yc : constant Integer := 200;
XA : constant Float := 40.0;
YA : constant Float := 30.0;
N : Float := 0.0;
begin
loop
Renderer.Set_Draw_Colour ((0, 0, 0, 255));
Renderer.Fill (Rectangle => (0, 0, Width, Height));
Draw_Raster_Bar (Yc + Integer (YA * Sin (N + 00.0, 360.0)));
Draw_Raster_Bar (Yc + Integer (YA * Sin (N + 25.0, 360.0)));
Draw_Raster_Bar (Yc + Integer (YA * Sin (N + 50.0, 360.0)));
Draw_Raster_Bar (Yc + Integer (YA * Sin (N + 75.0, 360.0)));
Draw_Raster_Bar_V (Xc + Integer (XA * Sin (0.6 * N + 00.0, 360.0)));
Draw_Raster_Bar_V (Xc + Integer (XA * Sin (0.6 * N + 90.0, 360.0)));
Draw_Raster_Bar_V (Xc + Integer (XA * Sin (0.6 * N + 180.0, 360.0)));
Window.Update_Surface;
if Check_Quit then
exit;
end if;
delay 0.010;
N := N + 4.0;
end loop;
end Raster_Bars;
begin
if not SDL.Initialise (Flags => SDL.Enable_Screen) then
return;
end if;
SDL.Video.Windows.Makers.Create (Win => Window,
Title => "Raster bar",
Position => SDL.Natural_Coordinates'(X => 10, Y => 10),
Size => SDL.Positive_Sizes'(Width, Height),
Flags => 0);
SDL.Video.Renderers.Makers.Create (Renderer, Window.Get_Surface);
Raster_Bars;
Window.Finalize;
SDL.Finalise;
end Raster_Bars;
FreeBASIC
#define PI 4 * Atn(1)
Const SCREEN_WIDTH = 320
Const SCREEN_HEIGHT = 200
Sub ShowBar(y0 As Integer, r As Integer, c0 As Integer)
Dim As Integer y, c
For y = -r To r
c = c0 - 31 * Abs(y) \ r
Line (0, y + y0)-(SCREEN_WIDTH - 1, y + y0), c
Next y
End Sub
Screenres SCREEN_WIDTH, SCREEN_HEIGHT, 8
Windowtitle "Raster Bars in FreeBASIC"
Dim As Double angulo = 0
Dim As Integer n, y
Dim As Double fase
For n = 0 To 255
Palette n, Rgb(n * 4, (7 * n \ 8) * 4, 0)
Next n
Do
Screenlock
Cls
For n = 1 To 8
fase = n * 0.4
y = 80 * Sin(angulo + fase)
ShowBar(y + 100, 2 * n, 255 - (n * 32))
Next n
angulo += 0.04
If angulo >= 2 * PI Then angulo -= 2 * PI
Screenunlock
Sleep 10, 1
Loop Until Inkey <> ""
Go
This uses Go's 'image' packages in its standard library to create an animated GIF.
After each 20 frames, it switches between horizontal and vertical bars and repeats the whole process 10 times.
WARNING: If you have problems with flashing images, either switch to a longer delay than 150ms between 'sways' or don't run it at all.
Although the .gif works fine in Firefox it might not do so in EOG due to optimizations made during its creation. If so, then the following ImageMagick command should fix it:
$ convert raster_bars.gif -coalesce raster_bars2.gif $ eog raster_bars2.gif
package main
import (
"image"
"image/color"
"image/gif"
"log"
"os"
)
var (
c0 = color.RGBA{166, 124, 0, 255}
c1 = color.RGBA{191, 155, 48, 255}
c2 = color.RGBA{255, 191, 0, 255}
c3 = color.RGBA{255, 207, 64, 255}
c4 = color.RGBA{255, 220, 115, 255}
)
var palette = []color.Color{c0, c1, c2, c3, c4}
func hline(img *image.Paletted, x1, y, x2 int, ci uint8) {
for ; x1 <= x2; x1++ {
img.SetColorIndex(x1, y, ci)
}
}
func vline(img *image.Paletted, x, y1, y2 int, ci uint8) {
for ; y1 <= y2; y1++ {
img.SetColorIndex(x, y1, ci)
}
}
func drawHbar(img *image.Paletted, x1, y1, x2, y2 int, ci uint8) {
for ; y1 <= y2; y1++ {
hline(img, x1, y1, x2, ci)
}
}
func drawVbar(img *image.Paletted, x1, y1, x2, y2 int, ci uint8) {
for ; x1 <= x2; x1++ {
vline(img, x1, y1, y2, ci)
}
}
func main() {
const nframes = 40
const delay = 15 // 150ms
width, height := 500, 500
anim := gif.GIF{LoopCount: 9} // repeats 9 + 1 times
rect := image.Rect(0, 0, width, height)
for f := 0; f < nframes; f++ {
img := image.NewPaletted(rect, palette)
c := uint8(f % 2)
if f < nframes/2 {
for y := 0; y < height; y += 20 {
drawHbar(img, 0, y, width, y+19, c)
c++
if c == 5 {
c = 0
}
}
} else {
for x := 0; x < width; x += 20 {
drawVbar(img, x, 0, x+19, height, c)
c++
if c == 5 {
c = 0
}
}
}
anim.Delay = append(anim.Delay, delay)
anim.Image = append(anim.Image, img)
}
file, err := os.Create("raster_bars.gif")
if err != nil {
log.Fatal(err)
}
defer file.Close()
if err2 := gif.EncodeAll(file, &anim); err != nil {
log.Fatal(err2)
}
}
Julia
using Colors, Cairo, Gtk
const can = GtkCanvas()
const win = GtkWindow(can, "Raster Bar Demo", 500, 500)
const pallete_index = [1]
const horizontal = [true]
const palette = [ # colors from the Go example
colorant"rgba(166, 124, 0, 1.0)",
colorant"rgba(191, 155, 48, 1.0)",
colorant"rgba(255, 191, 0, 1.0)",
colorant"rgba(255, 207, 64, 1.0)",
colorant"rgba(255, 220, 115, 1.0)",
]
function line(ctx, x1, y1, x2, y2, colr, width=1)
set_source(ctx, colr)
set_line_width(ctx, width)
move_to(ctx, x1, y1)
line_to(ctx, x2, y2)
stroke(ctx)
end
hline(ctx, x1, y, x2, c) = line(ctx, x1, y, x2, y, c)
hbar(ctx, x1, y1, x2, y2, c) = foreach(y -> hline(ctx, x1, y, x2, c), y1:y2)
vline(ctx, x, y1, y2, c) = line(ctx, x, y1, x, y2, c)
vbar(ctx, x1, y1, x2, y2, c) = foreach(x -> vline(ctx, x, y1, y2, c), x1:x2)
draw(can) do widget
ctx = Gtk.getgc(can)
height, width = Gtk.height(can), Gtk.width(can)
if horizontal[1]
for i in 1:3:height
hbar(ctx, 0, i, width, i + 3, palette[pallete_index[1]])
pallete_index[1] = mod1(pallete_index[1] + 1, 5)
end
else
for i in 1:3:width
vbar(ctx, i, 0, i + 3, height, palette[pallete_index[1]])
pallete_index[1] = mod1(pallete_index[1] + 1, 5)
end
end
end
set_gtk_property!(can, :expand, true)
for i in 1:typemax(Int)
sleep(0.1)
draw(can)
showall(win)
pallete_index[1] = mod1(pallete_index[1] + 2, 5)
if i % 30 == 29
horizontal[1] = !horizontal[1]
end
end
Nim
import gintro/[gobject, glib, gdk, gtk, gio, cairo]
const Palette = [[166.0, 124.0, 0.0],
[191.0, 155.0, 48.0],
[255.0, 191.0, 0.0],
[255.0, 207.0, 64.0],
[255.0, 220.0, 115.0]]
type
# Description of the simulation.
Simulation = ref object
area: DrawingArea
horizontal: bool
paletteIndex: Natural
count: int
Color = array[3, float]
#---------------------------------------------------------------------------------------------------
proc newSimulation(area: DrawingArea): Simulation {.noInit.} =
## Allocate and initialize the simulation object.
Simulation(area: area, horizontal: true, paletteIndex: 0, count: 0)
#---------------------------------------------------------------------------------------------------
proc bar(ctx: cairo.Context; x1, y1, x2, y2: int; c: Color) =
## Draw a bar.
ctx.setSource(c)
ctx.rectangle(x1.toFloat, y1.toFloat, (x2 - x1 + 1).toFloat, (y2 - y1 + 1).toFloat)
ctx.fill()
#---------------------------------------------------------------------------------------------------
proc draw(sim: Simulation; ctx: cairo.Context) =
## Draw the bars.
let width = sim.area.window.width()
let height = sim.area.window.height()
if sim.horizontal:
for i in countup(0, height - 4, 3):
ctx.bar(0, i, width - 1, i + 3, Palette[sim.paletteIndex])
sim.paletteIndex = (sim.paletteIndex + 1) mod 5
else:
for i in countup(0, width - 4, 3):
ctx.bar(i, 0, i + 3, height - 1, Palette[sim.paletteIndex])
sim.paletteIndex = (sim.paletteIndex + 1) mod 5
#---------------------------------------------------------------------------------------------------
proc update(sim: Simulation): gboolean =
## Update the simulation state.
sim.draw(sim.area.window.cairoCreate())
sim.area.showAll()
sim.paletteIndex = (sim.paletteIndex + 2) mod 5
inc sim.count
if sim.count mod 30 == 29:
sim.horizontal = not sim.horizontal
result = gboolean(1)
#---------------------------------------------------------------------------------------------------
proc activate(app: Application) =
## Activate the application.
let window = app.newApplicationWindow()
window.setSizeRequest(500, 500)
window.setTitle("Raster Bar Demo")
let area = newDrawingArea()
window.add(area)
let sim = newSimulation(area)
timeoutAdd(50, update, sim)
window.showAll()
#———————————————————————————————————————————————————————————————————————————————————————————————————
let app = newApplication(Application, "Rosetta.rasterbars")
discard app.connect("activate", activate)
discard app.run()
Phix
Some grey bars that vaguely shimmer as they march up the screen... (did not turn out quite as well as hoped)
-- demo\rosetta\Raster_bars.exw with javascript_semantics constant title = "Raster bars", N = 10, nColours = floor(255/N) integer offset = 0, clast = nColours include pGUI.e Ihandle dlg, canvas cdCanvas cddbuffer, cdcanvas function colour(integer i) integer g = i*N return cdEncodeColorAlpha(g, g, g, 255) end function function redraw_cb(Ihandle /*ih*/, integer /*posx*/, /*posy*/) cdCanvasActivate(cddbuffer) cdCanvasSetBackground(cddbuffer, colour(clast)) cdCanvasClear(cddbuffer) integer {width, height} = IupGetIntInt(canvas, "DRAWSIZE"), h = floor(height/(nColours-1)), y = height+offset cdCanvasSetInteriorStyle(cddbuffer, CD_SOLID) for i=2 to nColours do integer c = clast+i-1 if c>nColours then c -= nColours end if cdCanvasSetForeground(cddbuffer, colour(c)) cdCanvasBox(cddbuffer, 0, width, y-h, y) y -= h end for cdCanvasFlush(cddbuffer) offset += 1 if offset>=h then offset = 0 clast += 1 if clast>nColours then clast = 1 end if end if return IUP_DEFAULT end function function map_cb(Ihandle ih) cdcanvas = cdCreateCanvas(CD_IUP, ih) cddbuffer = cdCreateCanvas(CD_DBUFFER, cdcanvas) return IUP_DEFAULT end function function unmap_cb(Ihandle /*ih*/) cdKillCanvas(cddbuffer) cdKillCanvas(cdcanvas) return IUP_DEFAULT end function function timer_cb(Ihandle /*ih*/) IupRedraw(dlg) return IUP_DEFAULT end function procedure main() IupOpen() canvas = IupCanvas("RASTERSIZE=600x400") IupSetCallbacks(canvas, {"MAP_CB", Icallback("map_cb"), "UNMAP_CB", Icallback("unmap_cb"), "ACTION", Icallback("redraw_cb")}) dlg = IupDialog(canvas,`TITLE="%s"`, {title}) Ihandle hTimer = IupTimer(Icallback("timer_cb"), 10) IupShow(dlg) IupSetAttribute(canvas, "RASTERSIZE", NULL) if platform()!=JS then IupMainLoop() IupClose() end if end procedure main()
Raku
(formerly Perl 6)
As there is no reference implementation, and rather sketchy task instructions, this may or may not fulfill the original task authors intent.
Not really sure what is meant by "swaying", perhaps this will suffice.
Generate random colored bars and display them. (They ended up looking more plastic than metallic; ah well.)
- Use Up / Down arrows to change the scroll speed.
- Use Left / Right arrows to adjust the gap between the raster bars.
- Use Pg Up / Pg Dn to adjust raster bar height.
- Use Z / X to change the angle of the raster bars.
- Use Space bar to pause / resume scrolling.
- Use Left Ctrl to toggle the scroll direction.
- Press R to toggle Randomize on / off.
- If Randomize is active, adjust the randomize delay with < / >
- Press S to toggle Swaying on / off.
- If Swaying is active, adjust the period with D / F
- Press Q to exit.
unit sub MAIN (
Int :b(:$bar-height) is copy = 60; #= Height of the individual "Raster bars", minimum 32 (pixels)
Int :d(:$dir) is copy = -1; #= Scroll direction: -1 is "up" 1 is "down"
Int :s(:$step) is copy = 4; #= Scroll speed (pixels per step
Int :g(:$gap) is copy = $bar-height + 50; #= Gap between bars (pixels)
Int :a(:$angle) is copy = 0; #= Angle to orient bars off horizontal (-60 to 60 degrees)
Int :sw(:$sway) is copy = 0; #= Swaying on / off
Real :r(:$rnd) is copy = 0; #= Delay between randomize events
);
say q:to/END/;
Use Up / Down arrows to change the scroll speed.
Use Left / Right arrows to adjust the gap between the raster bars.
Use Pg Up / Pg Dn to adjust raster bar height.
Use Z / X to change the angle of the raster bars.
Use Space bar to pause / resume scrolling.
Use Left Ctrl to toggle the scroll direction.
Press R to toggle Randomize on / off.
If Randomize is active, adjust the randomize delay with < / >
Press S to toggle Swaying on / off.
If Swaying is active, adjust the period with D / F
Press Q to exit.
END
use SDL2::Raw;
use Cairo;
my $width = 800;
my $height = 800;
SDL_Init(VIDEO);
my $window = SDL_CreateWindow(
'Raster Bars - Raku',
SDL_WINDOWPOS_CENTERED_MASK,
SDL_WINDOWPOS_CENTERED_MASK,
$width, $height, RESIZABLE
);
my $render = SDL_CreateRenderer($window, -1, ACCELERATED +| PRESENTVSYNC);
my @bars = (^128).map: { gen-bar( rand xx 3 ) };
my $event = SDL_Event.new;
enum KEY_CODES (
K_UP => 82,
K_DOWN => 81,
K_LEFT => 80,
K_RIGHT => 79,
K_SPACE => 44,
K_PGUP => 75,
K_PGDN => 78,
K_LCTRL => 224,
K_Z => 29,
K_X => 27,
K_Q => 20,
K_R => 21,
K_S => 22,
K_D => 7,
K_F => 9,
K_LT => 54,
K_GT => 55,
);
my $port = +@bars * $gap;
my $y = $dir > 0 ?? $height - $port !! $height ;
my $now = now;
my $period = 2;
main: loop {
handle-event($event) while SDL_PollEvent($event);
randomize if $rnd and now - $now > $rnd;
if $dir > 0 {
$y = $height - $port if $y > 0 - ceiling $height / cos(π * $angle / 180).abs
} else {
$y = 0 - ceiling $height / cos(π * $angle / 180).abs if $y < $height - $port
}
$y = $step * $dir + $y;
$angle = (((now * $period) % τ).sin * 35).Int if $sway;
for ^@bars {
my $offset = $sway ?? $gap !! ceiling $gap / cos(π * $angle / 180).abs;
SDL_RenderCopyEx( $render, @bars[$_], Nil,
SDL_Rect.new( -($width*4), $y + $offset * $_, $width * 10, $bar-height),
$angle.Num, SDL_Point.new(:x((4.5*$width).Int),:y($y + $offset * $_)), 0
)
}
SDL_RenderPresent($render);
SDL_RenderClear($render);
print fps;
}
put '';
SDL_Quit();
sub gen-bar (@color) {
my $bar = Cairo::Image.create( Cairo::FORMAT_ARGB32, 1, 128 );
given Cairo::Context.new($bar) {
my Cairo::Pattern::Gradient::Linear $lpat .= create(0.0, 0.0, 0.0, 128.0);
$lpat.add_color_stop_rgba( 1, |(@color »*» .3), 1);
$lpat.add_color_stop_rgba( .2, |(@color), 1);
$lpat.add_color_stop_rgba(.75, |(@color), 1);
$lpat.add_color_stop_rgba( 0, |(@color »+» .5), 1);
.rectangle(0, 0, 1, 128);
.pattern($lpat);
.fill;
$lpat.destroy;
}
my $bar_texture = SDL_CreateTexture(
$render, %PIXELFORMAT<ARGB8888>,
STATIC, 1, 128
);
SDL_UpdateTexture(
$bar_texture,
SDL_Rect.new(:x(0), :y(0), :w(1), :h(128)),
$bar.data, $bar.stride // 1
);
$bar_texture
}
sub handle-event ($event) {
my $casted_event = SDL_CastEvent($event);
given $casted_event {
when *.type == QUIT { last main }
when *.type == KEYDOWN {
if KEY_CODES(.scancode) -> $comm {
given $comm {
when 'K_UP' { $step += 1 }
when 'K_DOWN' { $step -= 1 if $step > 1 }
when 'K_LEFT' { $gap = $gap < 32 ?? $gap !! $gap - 1; $port = +@bars * $gap; }
when 'K_RIGHT' { $gap++; $port += +@bars; }
when 'K_PGUP' { $bar-height += 2 }
when 'K_PGDN' { $bar-height = $bar-height >= 34 ?? $bar-height - 2 !! $bar-height }
when 'K_SPACE' { $step = $step ?? 0 !! 1 }
when 'K_LCTRL' { $dir *= -1 }
when 'K_Z' { $angle = $angle > -45 ?? $angle - 5 !! $angle }
when 'K_X' { $angle = $angle < 45 ?? $angle + 5 !! $angle }
when 'K_R' { $rnd = $rnd ?? 0 !! 1 }
when 'K_S' { $sway xor= 1 }
when 'K_F' { $period += .1 }
when 'K_D' { $period = $period - .1 max .1; }
when 'K_GT' { $rnd += .2 }
when 'K_LT' { $rnd = $rnd > .2 ?? $rnd -.2 !! .2 }
when 'K_Q' { last main }
}
} #else { say .scancode, "\n" }
}
when *.type == WINDOWEVENT {
if .event == RESIZED {
$width = .data1;
$height = .data2 + $bar-height;
}
}
}
}
sub randomize {
$dir = (-1,1).pick;
$step = (4..8).pick;
$bar-height = (32..200).pick;
$gap = $bar-height + (1..100).pick;
$angle = (-45, *+5 ... 45).pick;
$port = +@bars * $gap;
if $dir > 0 {
$y = $height - $port;
} else {
$y = 0 - ceiling ($height max $width) / cos(π * $angle / 180).abs;
}
$now = now;
}
sub fps {
state $fps-frames = 0;
state $fps-now = now;
state $fps = '';
$fps-frames++;
if now - $fps-now >= 1 {
$fps = [~] "\b" x 40, ' ' x 20, "\b" x 20 ,
sprintf "FPS: %5.2f ", ($fps-frames / (now - $fps-now)).round(.01);
$fps-frames = 0;
$fps-now = now;
}
$fps
}
Screenshot still of typical run: (offsite .png image)
(Small) Moving gif of swaying bars: (offsite .gif image)
Rust
extern crate minifb;
use std::iter::repeat;
use minifb::{Key, Window, WindowOptions};
const WIDTH: usize = 640;
const HEIGHT: usize = 360;
struct Bar {
color: [f32; 3],
height: u32,
position: f32,
speed: f32,
}
impl Bar {
fn draw_column(&self, column_buffer: &mut [u32]) {
let start_row = (self.position.round() as i32).clamp(0, HEIGHT as i32) as usize;
let end_row = (start_row + self.height as usize).clamp(0, HEIGHT);
column_buffer[start_row..end_row].iter_mut().enumerate()
.for_each(|(row_index, color)| {
*color = self.row_color(row_index as i32);
});
}
fn row_color(&self, y: i32) -> u32 {
let yy = y as f32 / (self.height - 1) as f32;
let yy = 1.0 - 2.0 * (yy - 0.5).abs();
let r = (25.0 + yy.powf((2.0 - 2.0 * self.color[0]).exp()) * 230.0).round() as u8;
let g = (25.0 + yy.powf((2.0 - 2.0 * self.color[1]).exp()) * 230.0).round() as u8;
let b = (25.0 + yy.powf((2.0 - 2.0 * self.color[2]).exp()) * 230.0).round() as u8;
u32::from_be_bytes([255, r, g, b])
}
fn update_position(&mut self) {
self.position += self.speed;
if let Some(position) = self.bounce_position() {
self.position = position;
self.speed = -self.speed;
}
}
fn bounce_position(&self) -> Option<f32> {
if self.speed > 0.0 {
let limit = (HEIGHT as i32 - self.height as i32) as f32;
(self.position >= limit).then(|| limit - (self.position - limit))
} else {
(self.position <= 0.0).then(|| -self.position)
}
}
}
fn main() {
let mut window = Window::new(
"Raster Bars",
WIDTH,
HEIGHT,
WindowOptions::default(),
)
.unwrap_or_else(|e| {
panic!("{}", e);
});
// Limit to max ~60 fps update rate
window.limit_update_rate(Some(std::time::Duration::from_micros(16600)));
let mut bars = Vec::new();
bars.push(Bar { color: [1.0, 1.0, 0.0], height: 20, position: 0.0, speed: 3.1 });
bars.push(Bar { color: [1.0, 0.0, 0.0], height: 25, position: 0.0, speed: 0.2 });
bars.push(Bar { color: [0.0, 1.0, 0.0], height: 7, position: 0.0, speed: 0.4 });
bars.push(Bar { color: [0.0, 0.0, 1.0], height: 30, position: 0.0, speed: 1.0 });
while window.is_open() && !window.is_key_down(Key::Escape) {
let mut column_buffer = vec![0x_00_00_00_u32; HEIGHT];
for bar in &mut bars {
bar.draw_column(&mut column_buffer);
bar.update_position();
}
let buffer: Vec<u32> = column_buffer.iter()
.flat_map(|&row_color| repeat(row_color).take(WIDTH))
.collect();
window
.update_with_buffer(&buffer, WIDTH, HEIGHT)
.unwrap();
}
}
Wren
Unlike the Go example, repeats indefinitely until the window is closed.
As DOME has no facility to create an animated .gif file, the moving image is displayed but not saved.
import "dome" for Window
import "graphics" for Canvas, Color
var c0 = Color.rgb(166, 124, 0, 255)
var c1 = Color.rgb(191, 155, 48, 255)
var c2 = Color.rgb(255, 191, 0, 255)
var c3 = Color.rgb(255, 207, 64, 255)
var c4 = Color.rgb(255, 220, 115, 255)
var Palette = [c0, c1, c2, c3, c4]
class RasterBars {
construct new(width, height) {
Window.resize(width, height)
Canvas.resize(width, height)
Window.title = "Raster bars"
_width = width
_height = height
}
init() {
_f = 0
_nframes = 320
_draw = false
_c = false
}
hline(x1, y, x2, ci) {
while (x1 <= x2) {
Canvas.pset(x1, y, Palette[ci])
x1 = x1 + 1
}
}
vline(x, y1, y2, ci) {
while (y1 <= y2) {
Canvas.pset(x, y1, Palette[ci])
y1 = y1 + 1
}
}
drawHBar(x1, y1, x2, y2, ci) {
while (y1 <= y2) {
hline(x1, y1, x2, ci)
y1 = y1 + 1
}
}
drawVBar(x1, y1, x2, y2, ci) {
while (x1 <= x2) {
vline(x1, y1, y2, ci)
x1 = x1 + 1
}
}
update() {
_f = _f + 1
if (_f % 8 == 0) {
_draw = true
_c = !_c
} else {
_draw = false
}
if (_f == _nframes) _f = 0
}
draw(alpha) {
if (!_draw) return
var c = _c ? 0 : 1
if (_f < _nframes / 2) {
var y = 0
while (y < _height) {
drawHBar(0, y, _width, y+19, c)
c = (c < 4) ? c + 1 : 0
y = y + 20
}
} else {
var x = 0
while (x < _width) {
drawVBar(x, 0, x+19, _height, c)
c = (c < 4) ? c + 1 : 0
x = x + 20
}
}
}
}
var Game = RasterBars.new(500, 500)
X86 Assembly
256 byte executable. Translation of XPL0. Output is the same.
page 240, 132 ;minimize annoying page headers
;Assemble with:
; tasm
; tlink /t
.model tiny
.code
.486
org 100h
;MS-DOS loads .com files with registers set this way:
; ax=0, bx=0, cx=00FFh, dx=cs, si=0100h, di=-2, bp=09xx, sp=-2, es=ds=cs=ss
;The direction flag (d) is clear (incrementing).
start:
if 0 ;if debug then must initialize registers
mov cx, 00FFh
mov dx, cs
mov si, 0100h
mov di, -2
mov bp, 0955h
endif
mov al,13h ;call BIOS to set graphic mode 13h
int 10h ; 320x200 with 256 colors (ah = 0)
;Set up color registers with sequential shades of red and green (gives yellow,
; gold, copper, brown, etc.). Since the hardware only allows 64 levels of
; intensity, the shades are not continuous. Code from SHR's YEW2 demo program.
yew10: mov al,cl ;cx is assumed set to 00ffh by loader
mov dx,03c8h ;select color register ffh down thru 01h
out dx,al
inc dx ;point to corresponding RGB registers
out dx,al ;set red intensity
aam ;set green intensity to 7/8 of red value
org $-1 ;ah <- al/8; al <- rem
db 8 ;(values other than 0a work just fine)
mov al,cl
sub al,ah
out dx,al
xor ax,ax ;set blue intensity to 0
out dx,al
loop yew10 ;loop for 255 color registers (ff-01)
fninit ;initialize math coprocessor (FPU)
fldz ;push (load) 0.0 onto FPU stack
fstp angle ; Angle:= 0.;
; - - - - - - - - - - - - - - - Main Loop - - - - - - - - - - - - - - - - - - -
ras60:
;WaitForVSync
mov dx, 03dah
wait10: in al, dx ;wait for vertical retrace to go away
and al, 08h
jne short wait10
wait20: in al, dx ;wait for vertical retrace
and al, 08h
je short wait20
;Erase buffer
mov di, offset buffer
mov cx, 200*320/2
xor ax, ax
rep stosw ;es:[di++]:= ax; cx--
; for N:= 2 to 9 do
mov dx, 2 ;dx = N
mov N, dx
ras70:
;Phase:= float(N)*0.4;
fild N ;can't use dx here; must be memory loc
fld n4
fmul
fstp phase
;Y:= fix(80.*Sin(Angle+Phase));
fld n80
fld angle
fld phase
fadd
fsin ;return the sine in one instruction!
fmul
push ax
mov bp, sp
fistp word ptr [bp]
pop ax
;ShowBar(Y+100, 2*N, 64*((3&N)+1)-1);
add ax, 100
mov sbY0, ax
imul ax, dx, 2
mov sbR, ax
mov ax, dx
and ax, 3
inc ax
shl ax, 6
dec ax
mov sbC0, ax
call ShowBar
inc N
mov dx, N
cmp dx, 9
jle short ras70
;Copy buffer to video RAM
mov cx, 320*200/2
mov si, offset buffer
xor di, di
push 0A000h
pop es
rep movsw ;es:[di++] <- ds:[si++]; cx--
push cs
pop es
; Angle:= Angle + 0.04;
fld angle
fld n04
fadd
fstp angle
mov ah, 1 ;a keystroke terminates the program
int 16h
je ras60 ;loop back if no keystroke
mov ah, 0 ;eat the keystroke
int 16h ; so it isn't echoed on the display
mov ax, 0003h ;restore the normal text display mode
int 10h
ret
;-------------------------------------------------------------------------------
ShowBar:
; proc ShowBar(Y0, R, C0); \Display cylindrical rod with its center
; int Y0, R, C0; \ at Y0, radius R, and center color C0
; for Y:= -R to +R do
mov ax, sbR
mov bp, ax ;bp = 'for' loop limit
neg ax
mov si, ax ;si = 'for' loop control variable
sb40:
;C:= C0 - 31*abs(Y)/R; \(looks better than a circular surface)
mov ax, si
sb45: neg ax
jl short sb45
imul ax, 31
cwd
idiv sbR
neg ax
add ax, sbC0
;Line(319, Y+Y0, C); \draw horizontal line from left to right
mov cx, 320
mov di, si
add di, sbY0
imul di, 320
add di, offset buffer
rep stosb ;es:[di++]:= al; cx--
inc si
cmp si, bp
jle short sb40
ret
n4 dd 0.4 ;single precision 'float' constants
n04 dd 0.04
n80 dd 80.0
N dw ?
angle dd ?
phase dd ?
sbY0 dw ?
sbR dw ?
sbC0 dw ?
buffer db 320*200 dup(?) ;stack starts above this at top of 64K
end start
XPL0
proc ShowBar(Y0, R, C0); \Display a cylindrical rod with its center
int Y0, R, C0; \ at Y0, radius R, and center color C0
int Y, C;
for Y:= -R to +R do
[C:= C0 - 31*abs(Y)/R; \(looks better than circular surface)
Move(0, Y+Y0); \start line at left side of screen
Line(319, Y+Y0, C); \draw horizontal line to right side
];
int N, Y;
real Angle, Phase;
[SetVid($13); \set 320x200x8 graphics
for N:= 0 to 255 do \set palette colors to
SetPalette(N, N<<2, (7*N/8)<<2, 0); \ copper, brass, and gold
Angle:= 0.;
repeat WaitForVSync; \regulate speed
Clear; \erase screen
for N:= 2 to 9 do
[Phase:= float(N)*0.4;
Y:= fix(80.*Sin(Angle+Phase));
ShowBar(Y+100, 2*N, 64*((3&N)+1)-1);
];
Angle:= Angle + 0.04;
until KeyHit;
]