Fixed mandelbrot

bench/programs_rust/hello-rust/src/main.rs

@@ -3,7 +3,7 @@
 
 use core::{
     arch::asm,
-    ops::{Add, Mul},
+    ops::{Add, Mul, Sub},
 };
 
 use fpga_lib::{
@@ -18,11 +18,72 @@ pub const ITERATIONS: usize = 100;
 pub const ASPECT_RATIO: f32 = WIDTH as f32 / HEIGHT as f32;
 
 #[derive(Clone, Copy)]
-struct Complex(Float, Float);
+struct Complex(Q3x29, Q3x29);
 
+#[derive(Clone, Copy)]
+struct Q3x29(i32);
+
+impl From<f32> for Q3x29
+{
+    fn from(x: f32) -> Q3x29
+    {
+        const SCALE: f32 = 16.0;
+        const MAX_Q28_4: f32 = (u32::MAX as f32) / SCALE;
+
+        let clamped = x.clamp(0.0, MAX_Q28_4);
+        let scaled = clamped * SCALE;
+
+        Q3x29(scaled as i32)
+    }
+}
+
+impl From<f64> for Q3x29
+{
+    fn from(x: f64) -> Q3x29
+    {
+        const SCALE: f64 = 16.0;
+        const MAX_Q28_4: f64 = (u32::MAX as f64) / SCALE;
+
+        let clamped = x.clamp(0.0, MAX_Q28_4);
+        let scaled = clamped * SCALE;
+
+        Q3x29(scaled as i32)
+    }
+}
+
+impl Add for Q3x29
+{
+    type Output = Q3x29;
+
+    fn add(self, rhs: Self) -> Self::Output
+    {
+        Q3x29(self.0 + rhs.0)
+    }
+}
+
+impl Sub for Q3x29
+{
+    type Output = Q3x29;
+
+    fn sub(self, rhs: Self) -> Self::Output
+    {
+        Q3x29(self.0 - rhs.0)
+    }
+}
+
+impl Mul for Q3x29
+{
+    type Output = Q3x29;
+
+    fn mul(self, rhs: Self) -> Self::Output
+    {
+        let prod: i64 = self.0 as i64 * rhs.0 as i64;
+        Q3x29(((prod >> 28) & 0xFFFFFFFF) as i32)
+    }
+}
 impl Complex
 {
-    pub fn sq_mag(&self) -> Float
+    pub fn sq_mag(&self) -> Q3x29
     {
         self.0 * self.0 + self.1 * self.1
     }
@@ -63,49 +124,42 @@ pub extern "C" fn main() -> !
         for i in 0..(ITERATIONS - 1)
         {
             let val = ((i as Float / ITERATIONS as Float) * 255.) as u8;
-            tab[i] = Color::from_rgb(val, val, val);
+            //tab[i] = Color::from_rgb(val, val, val);
+            tab[i] = Color(val);
         }
 
         tab
     };
 
-    let width = 2.;
+    let zoom_int = 1;
+    let zoom = Q3x29::from(1. / zoom_int as f32);
     for x in 0..WIDTH
     {
         for y in 0..HEIGHT
         {
+            // -0.761574,-0.0847596)
             let pos = Complex(
-                map(
+                Q3x29((x as i32 - WIDTH as i32 / 2) * (0x1FFFFFFF / WIDTH as i32)) * zoom
-                    x as Float,
+                    - Q3x29::from(0.761574),
-                    0.,
+                Q3x29((y as i32 - HEIGHT as i32 / 2) * (0x1FFFFFFF / WIDTH as i32)) * zoom
-                    WIDTH as Float,
+                    - Q3x29::from(0.0847596),
-                    -width * ASPECT_RATIO * 0.5,
-                    width * ASPECT_RATIO * 0.5,
-                ) - 0.5,
-                map(y as Float, 0., HEIGHT as Float, -width * 0.5, width * 0.5),
             );
             let mut acc = pos;
             let mut iter = 0;
 
-            // Optimisations
-            let p = ((pos.0 - 0.25) * (pos.0 - 0.25)) + pos.1 * pos.1;
-            if (pos.0 < libm::sqrtf(p) - 2. * p + 0.25)
-                || (pos.0 + 1.) * (pos.0 + 1.) + pos.1 * pos.1 < 1. / 16.
-            {
-                iter = ITERATIONS - 1;
-            }
-            else
-            {
             for i in 0..ITERATIONS
             {
-                    acc = acc * acc + pos;
+                //acc = acc * acc + pos;
-                    if acc.sq_mag() > 1.
+                acc = Complex(
+                    pos.0 + acc.0 * acc.0 - acc.1 * acc.1,
+                    pos.1 + Q3x29::from(2.) * acc.1 * acc.0,
+                );
+                if acc.sq_mag().0 > Q3x29::from(3.8).0
                 {
                     iter = i;
                     break;
                 }
             }
-            }
 
             unsafe {
                 VGA::write_pixel_unsafe(x as u16, y as u16, color_lut[iter]);