Multithread & pixelmap

mas/fractals/mandel/src/main.rs

@@ -4,6 +4,7 @@ mod render;
 use sdl2::pixels::Color;
 use sdl2::event::Event;
 use sdl2::keyboard::Keycode;
+use std::thread;
 
 fn main() {
     /*
@@ -13,6 +14,8 @@ fn main() {
     println!("{} {}", width, height);
     */
     //let (width, height) = (640, 480);
+
+    // config stuff
     let (width, height) = (1600, 900);
     let (mut dx, mut dy) = (1.0, 0.0);
     let (mut zx, mut zy) = (2.8, 2.0); 
@@ -20,6 +23,11 @@ fn main() {
     let (zoom_out, zoom_in) = (1.1, 0.9);
     let depth = 1000;
 
+    // Sectors for multithreading
+    let threads = 4;
+    let (w_sector_size, h_sector_size) = (width/threads, height/threads);
+
+    // create window
     let (window, ctx, _vid_sys) = render::create_window("Mandelbrot set", width, height);
 
     let mut canvas = window.into_canvas().build().unwrap();
@@ -74,14 +82,22 @@ fn main() {
         }
 
         if render_new {
-            println!("Rendering...");
-            mandel::mandelbrot(&mut canvas, width, height, depth, zx, zy, dx, dy);
-            canvas.present();
-            render_new = false;
+            let mut maps = Vec::new();
+            for thread_id in 0..threads {
+                thread::spawn(move || { // do cool threads for performance
+                    let mut pixmap = render::prerender_mandelbrot(
+                        width, height, depth, 
+                        zx, zy, dx, dy, 
+                        thread_id, threads, w_sector_size, h_sector_size);
+                    maps.push(pixmap);
+                });
+            }
 
-            println!("Post mandel render");
+            for pixmap in maps.iter() {
+                // do render
+            }
+            render_new = false;
         }
-
     }
     //::std::thread::sleep(Duration::new(0, 1_000_000_000u32 / 60));
 }

mas/fractals/mandel/src/mandel.rs

@@ -1,4 +1,5 @@
 use crate::render::set_pixel;
+use crate::render::PixelMap;
 use sdl2::pixels::Color;
 use sdl2::render::Canvas;
 
@@ -10,7 +11,7 @@ pub fn get_col(i: u32, max_iter: u32) -> Color {
     }
 }
 
-pub fn mandelbrot(canvas: &mut Canvas<sdl2::video::Window>, w: u32, h: u32, depth: u32, xzoom: f32, yzoom: f32, xoffset: f32, yoffset: f32) {
+pub fn mandelbrot(pixmap: &mut PixelMap, w: u32, h: u32, depth: u32, xzoom: f32, yzoom: f32, xoffset: f32, yoffset: f32) {
 
     /*
     for each pixel (Px, Py) on the screen do
@@ -35,7 +36,7 @@ pub fn mandelbrot(canvas: &mut Canvas<sdl2::video::Window>, w: u32, h: u32, dept
         for dy in 0..h {
             let y0 = ((dy as f32) / (h as f32)) * (yzoom) - (1.0 + yoffset);
 
-        let (mut x, mut y) = (0.0, 0.0);
+            let (mut x, mut y) = (0.0, 0.0);
             let mut i: u32 = 0;
             
             while i < depth && x*x + y*y <= 4.0 {
@@ -45,7 +46,7 @@ pub fn mandelbrot(canvas: &mut Canvas<sdl2::video::Window>, w: u32, h: u32, dept
                 i += 1;
             }
             let col = get_col(i, depth);
-            set_pixel(canvas, dx as i32, dy as i32, col);
+            pixmap.set_pixel(dx as u32, dy as u32, col);
         }
     }
 }

mas/fractals/mandel/src/render.rs

@@ -1,7 +1,11 @@
 extern crate sdl2;
+
 use sdl2::pixels::Color;
 use sdl2::rect::Rect;
 use sdl2::render::Canvas;
+
+use crate::mandel::mandelbrot;
+//use std::time::Duration;
 //use sdl2::ttf::Font;
 
 pub fn create_window(title: &str, width: u32, height: u32) 
@@ -17,6 +21,32 @@ pub fn create_window(title: &str, width: u32, height: u32)
     return (window, ctx, vid_sys);
 }
 
+pub struct PixelMap {
+    pub offset_cols: u32,
+    pub offset_rows: u32,
+    pub cols: u32,
+    pub rows: u32,
+    pub data: Vec<Color>
+}
+
+impl PixelMap {
+    fn new(cols: u32, rows: u32, offset_cols: u32, offset_rows: u32) -> PixelMap {
+        PixelMap {
+            offset_cols: offset_cols,
+            offset_rows: offset_rows,
+            cols: cols,
+            rows: rows,
+            data: vec![Color::RGB(0,0,0); (cols as usize)*(rows as usize)]
+        }
+    }
+
+    pub fn set_pixel(&mut self, x: u32, y: u32, color: Color) {
+        // A[c, r] = a[r*rows + c]
+        // for a vec of U^(cols*rows)
+        self.data[((self.rows * y) + x) as usize] = color;
+    }
+}
+
 /*
 pub fn text(x: u32, y: u32, text: &str, font_path: &str) {
     let ttf_context = sdl2::ttf::init();
@@ -35,3 +65,12 @@ pub fn set_pixel(canvas: &mut Canvas<sdl2::video::Window>, x: i32, y: i32, color
     canvas.set_draw_color(color);
     canvas.fill_rect(Rect::new(x, y, 1, 1));
 }
+
+pub fn prerender_mandelbrot(w: u32, h: u32, depth: u32, xzoom: f32, yzoom: f32, xoffset: f32, yoffset: f32, thread_id: u32, threads: u32, w_sector_size: u32, h_sector_size: u32) -> PixelMap {
+    println!("Rendering...");
+    let mut pixmap = PixelMap::new(w, h, thread_id * w_sector_size, thread_id * h_sector_size);
+    mandelbrot(&mut pixmap, w, h, depth, xzoom, yzoom, xoffset, yoffset);
+    println!("Post mandel render");
+
+    return pixmap;
+}