v/examples/gg/mandelbrot.v

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import gg
import gx
import runtime
import time
const pwidth = 800
const pheight = 600
const zoom_factor = 1.1
struct ViewRect {
mut:
x_min f64
x_max f64
y_min f64
y_max f64
}
struct AppState {
mut:
gg &gg.Context = 0
iidx int
pixels []u32 = []u32{len: pwidth * pheight}
npixels []u32 = []u32{len: pwidth * pheight} // all drawing happens here, results are copied at the end
view ViewRect = ViewRect{-2.7610033817025625, 1.1788897130338223, -1.824584023871934, 2.1153096311072788}
ntasks int = runtime.nr_jobs()
}
const colors = [gx.black, gx.blue, gx.red, gx.green, gx.yellow, gx.orange, gx.purple, gx.white,
gx.indigo, gx.violet, gx.black]
fn (mut state AppState) update() {
mut sw := time.new_stopwatch()
mut oview := ViewRect{}
for {
sw.restart()
cview := state.view
if oview == cview {
time.sleep(5 * time.millisecond)
continue
}
sheight := pheight / state.ntasks
mut threads := []thread{}
for start := 0; start < pheight; start += sheight {
threads << go state.recalc_lines(cview, start, start + sheight)
}
threads.wait()
state.pixels = state.npixels
println('$state.ntasks threads; $sw.elapsed().milliseconds() ms / frame')
oview = cview
}
}
fn (mut state AppState) recalc_lines(cview ViewRect, ymin f64, ymax f64) {
for y_pixel := ymin; y_pixel < ymax && y_pixel < pheight; y_pixel++ {
y0 := (y_pixel / pheight) * (cview.y_max - cview.y_min) + cview.y_min
for x_pixel := 0.0; x_pixel < pwidth; x_pixel++ {
x0 := (x_pixel / pwidth) * (cview.x_max - cview.x_min) + cview.x_min
mut x, mut y := x0, y0
mut iter := 0
for ; iter < 80; iter++ {
x, y = x * x - y * y + x0, 2 * x * y + y0
if x * x + y * y > 4 {
break
}
}
state.npixels[int(y_pixel) * pwidth + int(x_pixel)] = u32(colors[iter % 8].abgr8())
}
}
}
fn (mut state AppState) draw() {
mut istream_image := state.gg.get_cached_image_by_idx(state.iidx)
istream_image.update_pixel_data(&state.pixels[0])
size := gg.window_size()
state.gg.draw_image(0, 0, size.width, size.height, istream_image)
}
fn (mut state AppState) zoom(zoom_factor f64) {
c_x, c_y := (state.view.x_max + state.view.x_min) / 2, (state.view.y_max + state.view.y_min) / 2
d_x, d_y := c_x - state.view.x_min, c_y - state.view.y_min
state.view.x_min = c_x - zoom_factor * d_x
state.view.x_max = c_x + zoom_factor * d_x
state.view.y_min = c_y - zoom_factor * d_y
state.view.y_max = c_y + zoom_factor * d_y
}
fn (mut state AppState) center(s_x f64, s_y f64) {
c_x, c_y := (state.view.x_max + state.view.x_min) / 2, (state.view.y_max + state.view.y_min) / 2
d_x, d_y := c_x - state.view.x_min, c_y - state.view.y_min
state.view.x_min = s_x - d_x
state.view.x_max = s_x + d_x
state.view.y_min = s_y - d_y
state.view.y_max = s_y + d_y
}
// gg callbacks:
fn graphics_init(mut state AppState) {
state.iidx = state.gg.new_streaming_image(pwidth, pheight, 4, pixel_format: .rgba8)
}
fn graphics_frame(mut state AppState) {
state.gg.begin()
state.draw()
state.gg.end()
}
fn graphics_click(x f32, y f32, btn gg.MouseButton, mut state AppState) {
if btn == .right {
size := gg.window_size()
m_x := (x / size.width) * (state.view.x_max - state.view.x_min) + state.view.x_min
m_y := (y / size.height) * (state.view.y_max - state.view.y_min) + state.view.y_min
state.center(m_x, m_y)
}
}
fn graphics_move(x f32, y f32, mut state AppState) {
if state.gg.mouse_buttons.has(.left) {
size := gg.window_size()
d_x := (f64(state.gg.mouse_dx) / size.width) * (state.view.x_max - state.view.x_min)
d_y := (f64(state.gg.mouse_dy) / size.height) * (state.view.y_max - state.view.y_min)
state.view.x_min -= d_x
state.view.x_max -= d_x
state.view.y_min -= d_y
state.view.y_max -= d_y
}
}
fn graphics_scroll(e &gg.Event, mut state AppState) {
state.zoom(if e.scroll_y < 0 { zoom_factor } else { 1 / zoom_factor })
}
fn graphics_keydown(code gg.KeyCode, mod gg.Modifier, mut state AppState) {
s_x := (state.view.x_max - state.view.x_min) / 5
s_y := (state.view.y_max - state.view.y_min) / 5
// movement
mut d_x, mut d_y := 0.0, 0.0
if code == .enter {
println('> $state.view.x_min | $state.view.x_max | $state.view.y_min | $state.view.y_max')
}
if state.gg.pressed_keys[int(gg.KeyCode.left)] {
d_x -= s_x
}
if state.gg.pressed_keys[int(gg.KeyCode.right)] {
d_x += s_x
}
if state.gg.pressed_keys[int(gg.KeyCode.up)] {
d_y -= s_y
}
if state.gg.pressed_keys[int(gg.KeyCode.down)] {
d_y += s_y
}
state.view.x_min += d_x
state.view.x_max += d_x
state.view.y_min += d_y
state.view.y_max += d_y
// zoom in/out
if state.gg.pressed_keys[int(gg.KeyCode.left_bracket)]
|| state.gg.pressed_keys[int(gg.KeyCode.z)] {
state.zoom(1 / zoom_factor)
return
}
if state.gg.pressed_keys[int(gg.KeyCode.right_bracket)]
|| state.gg.pressed_keys[int(gg.KeyCode.x)] {
state.zoom(zoom_factor)
return
}
}
[console]
fn main() {
mut state := &AppState{}
state.gg = gg.new_context(
width: 800
height: 600
create_window: true
window_title: 'The Mandelbrot Set'
init_fn: graphics_init
frame_fn: graphics_frame
click_fn: graphics_click
move_fn: graphics_move
keydown_fn: graphics_keydown
scroll_fn: graphics_scroll
user_data: state
)
go state.update()
state.gg.run()
}