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examples: speed up mandelbrot.v by using a constant size thread pool, processing smaller chunks

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This commit is contained in:
Delyan Angelov 2022-05-22 11:11:49 +03:00
parent 50ab2cfd1a
commit 64a686f41f
1 changed files with 73 additions and 29 deletions
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102
examples/gg/mandelbrot.v
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@ -7,6 +7,8 @@ const pwidth = 800
const pheight = 600
const chunk_height = 2 // the image is recalculated in chunks, each chunk processed in a separate thread
const zoom_factor = 1.1
struct ViewRect {
@ -17,22 +19,47 @@ mut:
y_max f64
}
fn (v &ViewRect) width() f64 {
return v.x_max - v.x_min
}
fn (v &ViewRect) height() f64 {
return v.y_max - v.y_min
}
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
pixels &u32 = unsafe { vcalloc(pwidth * pheight * sizeof(u32)) }
npixels &u32 = unsafe { vcalloc(pwidth * pheight * sizeof(u32)) } // all drawing happens here, results are swapped 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]
gx.indigo, gx.violet, gx.black].map(u32(it.abgr8()))
struct MandelChunk {
cview ViewRect
ymin f64
ymax f64
}
fn (mut state AppState) update() {
mut sw := time.new_stopwatch()
mut chunk_channel := chan MandelChunk{cap: state.ntasks}
mut chunk_ready_channel := chan bool{cap: 1000}
mut threads := []thread{cap: state.ntasks}
defer {
chunk_channel.close()
threads.wait()
}
for t in 0 .. state.ntasks {
threads << go state.worker(t, chunk_channel, chunk_ready_channel)
}
//
mut oview := ViewRect{}
mut sw := time.new_stopwatch()
for {
sw.restart()
cview := state.view
@ -40,39 +67,56 @@ fn (mut state AppState) update() {
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)
// schedule chunks, describing the work:
mut nchunks := 0
for start := 0; start < pheight; start += chunk_height {
chunk_channel <- MandelChunk{
cview: cview
ymin: start
ymax: start + chunk_height
}
nchunks++
}
threads.wait()
state.pixels = state.npixels
// wait for all chunks to be processed:
for _ in 0 .. nchunks {
_ := <-chunk_ready_channel
}
// everything is done, swap the buffer pointers
state.pixels, state.npixels = state.npixels, state.pixels
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
fn (mut state AppState) worker(id int, input chan MandelChunk, ready chan bool) {
for {
chunk := <-input or { break }
yscale := chunk.cview.height() / pheight
xscale := chunk.cview.width() / pwidth
for y_pixel := chunk.ymin; y_pixel < chunk.ymax && y_pixel < pheight; y_pixel++ {
y0 := y_pixel * yscale + chunk.cview.y_min
for x_pixel := 0.0; x_pixel < pwidth; x_pixel++ {
x0 := x_pixel * xscale + chunk.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
}
}
unsafe {
state.npixels[int(y_pixel * pwidth) + int(x_pixel)] = colors[iter & 7]
}
}
state.npixels[int(y_pixel) * pwidth + int(x_pixel)] = u32(colors[iter % 8].abgr8())
}
ready <- true
}
}
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])
istream_image.update_pixel_data(state.pixels)
size := gg.window_size()
state.gg.draw_image(0, 0, size.width, size.height, istream_image)
}
@ -110,8 +154,8 @@ fn graphics_frame(mut state AppState) {
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
m_x := (x / size.width) * state.view.width() + state.view.x_min
m_y := (y / size.height) * state.view.height() + state.view.y_min
state.center(m_x, m_y)
}
}
@ -119,8 +163,8 @@ fn graphics_click(x f32, y f32, btn gg.MouseButton, mut state AppState) {
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)
d_x := (f64(state.gg.mouse_dx) / size.width) * state.view.width()
d_y := (f64(state.gg.mouse_dy) / size.height) * state.view.height()
state.view.x_min -= d_x
state.view.x_max -= d_x
state.view.y_min -= d_y
@ -133,8 +177,8 @@ fn graphics_scroll(e &gg.Event, mut state AppState) {
}
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
s_x := state.view.width() / 5
s_y := state.view.height() / 5
// movement
mut d_x, mut d_y := 0.0, 0.0
if code == .enter {