Adapt default stepping values to Vera resolution

derive_stepping.rs

@@ -0,0 +1,45 @@
+// ***********************************
+// Change here for new values
+// ***********************************
+
+// Coordinate of upper left corner in complex plane
+const X_UPPER_LEFT: f64 = -2.0;
+const Y_UPPER_LEFT: f64 = 1.0 + 1.0/8.0 + 1.0/64.0 + 1.0/256.0;
+// Coordinate of lower right corner in complex plane
+const X_LOWER_RIGHT: f64 = 1.0;
+const Y_LOWER_RIGHT: f64 = -Y_UPPER_LEFT;
+// Resolution in X and Y direction
+const PIXELS_X: f64 = 320.0;
+const PIXELS_Y: f64 = 240.0;
+// Accuracy in bytes after the comma
+const NUM_FIXED_BYTES: u16 = 4;
+
+fn print_mandel_fixed_point(f_in: f64) {
+    let mut f: f64 = f_in;
+    let num_bits = (NUM_FIXED_BYTES - 1) * 8;
+    let mut bit_count = 0;
+    let mut res: u64 = 0;
+
+    while bit_count < num_bits {
+        f = f.fract();
+        res <<= 1;
+        if f >= 0.5 {
+            res = res | 1;
+        }
+
+        f = f * 2.0;
+        bit_count += 1;
+    }
+
+    println!("{:06x}", res);
+}
+
+fn main() {
+    let stepping_x: f64 = (X_LOWER_RIGHT - X_UPPER_LEFT) / PIXELS_X;
+    let stepping_y: f64 = (Y_UPPER_LEFT - Y_LOWER_RIGHT) / PIXELS_Y;
+
+    println!("Stepping X:");
+    print_mandel_fixed_point(stepping_x);
+    println!("Stepping Y:");
+    print_mandel_fixed_point(stepping_y);
+}

main.a

@@ -51,7 +51,7 @@ STEP_X
 
 ; Y offset to move in complex plane for next line of picture
 STEP_Y
-!byte 1, $5C, $8F, $02, $00
+!byte 1, $11, $71, $02, $00
 
 ; real part of upper left point of picture
 INIT_REAL
@@ -139,7 +139,7 @@ DEFAULT_STEP_X
 
 ; Y offset to move in complex plane for next line of default picture
 DEFAULT_STEP_Y
-!byte 1, $5C, $8F, $02, $00
+!byte 1, $11, $71, $02, $00
 
 ; real part of upper left point of default picture
 DEFAULT_INIT_REAL