diff --git a/examples/mandelbrot/mandelbrot.ww b/examples/mandelbrot/mandelbrot.ww index da6ba1a2..8b44c40a 100644 --- a/examples/mandelbrot/mandelbrot.ww +++ b/examples/mandelbrot/mandelbrot.ww @@ -1,4 +1,4 @@ -// mandelbrot — ASCII Mandelbrot set, printed via libc. +// mandelbrot — ANSI-color Mandelbrot set, printed via libc. // // What this proves: // 1. ww does f64 arithmetic (mul, add, sub, div) end to end. @@ -7,9 +7,11 @@ // a real .so at runtime — `ldd mandelbrot` shows libc.so.6 as a // NEEDED entry. // -// We use libc's `write` (a thin syscall wrapper) rather than `putchar` -// because the runtime here doesn't call __libc_start_main, so stdio -// state stays uninitialised and putchar's buffer is never flushed. +// Each pixel is a colored space rendered via xterm 256-color background +// escapes (\e[48;5;Nm). We use libc's `write` (a thin syscall wrapper) +// rather than `putchar` because the runtime here doesn't call +// __libc_start_main, so stdio state stays uninitialised and putchar's +// buffer is never flushed. // // Build: see ./Makefile. No cc — pure ww toolchain. @@ -36,14 +38,70 @@ fn iterate(cr: f64, ci: f64) i32 = { return MAXI; }; -// Pick an ASCII glyph by escape iteration count. Inside the set -// (n == MAXI) renders as space — the classic look. -fn shade(n: i32) i32 = { - if (n >= MAXI) { return ' ': i32; }; - let chars: str = " .:-=+*#%@"; - let idx: i32 = (n * chars.len) / MAXI; - if (idx >= chars.len) { idx = chars.len - 1; }; - return chars[idx]: i32; +// Pick an xterm-256 color for an escape count. Inside the set is black; +// outside cycles blue → cyan → green → yellow → red. +fn palette(n: i32) i32 = { + if (n >= MAXI) { return 16; }; // black, inside set + let q: i32 = (n * 12) / MAXI; + if (q == 0) { return 17; }; // dark blue + if (q == 1) { return 18; }; + if (q == 2) { return 19; }; + if (q == 3) { return 21; }; // bright blue + if (q == 4) { return 33; }; + if (q == 5) { return 45; }; + if (q == 6) { return 51; }; // cyan + if (q == 7) { return 50; }; + if (q == 8) { return 46; }; // green + if (q == 9) { return 154; }; + if (q == 10) { return 226; }; // yellow + if (q == 11) { return 208; }; // orange + return 196; // red +}; + +// Write `n` as decimal into buf at off; return new offset. +fn writedec(buf: *u8, off: i32, n: i32) i32 = { + if (n == 0) { buf[off] = '0': u8; return off + 1; }; + let tmp: [4]u8; + let v: i32 = n; + let i: i32 = 0; + for (v > 0) { + tmp[i] = ((v % 10) + 48): u8; + v = v / 10; + i += 1; + }; + let cnt: i32 = i; + let j: i32 = 0; + for (j < cnt) { + i -= 1; + buf[off + j] = tmp[i]; + j += 1; + }; + return off + cnt; +}; + +// Emit "\e[48;5;m " (set background + the pixel) into buf. +fn emitcell(buf: *u8, off: i32, color: i32) i32 = { + buf[off + 0] = 27u8; + buf[off + 1] = '[': u8; + buf[off + 2] = '4': u8; + buf[off + 3] = '8': u8; + buf[off + 4] = ';': u8; + buf[off + 5] = '5': u8; + buf[off + 6] = ';': u8; + let p: i32 = writedec(buf, off + 7, color); + buf[p + 0] = 'm': u8; + buf[p + 1] = ' ': u8; + return p + 2; +}; + +// Emit "\e[0m\n" — restore default colors, end the row. +fn emitendrow(buf: *u8, off: i32) i32 = { + buf[off + 0] = 27u8; + buf[off + 1] = '[': u8; + buf[off + 2] = '0': u8; + buf[off + 3] = 'm': u8; + buf[off + 4] = 10u8; // '\n' + return off + 5; }; export fn main() i32 = { @@ -61,21 +119,23 @@ export fn main() i32 = { let dx: f64 = (xmax - xmin) / (W: f64); let dy: f64 = (ymax - ymin) / (H: f64); - // Compose the picture into a row buffer, then flush per row to - // avoid one libc call per character. - let row: [128]u8; - let y: i32 = 0; + // Each pixel is ~12 bytes (\e[48;5;NNNm ); plus 5 for the reset + // + newline. 2048 bytes per row is comfortably above the worst + // case of W=78. + let row: [2048]u8; + let y: i32 = 0; for (y < H) { - let ci: f64 = ymin + (y: f64) * dy; - let x: i32 = 0; + let ci: f64 = ymin + (y: f64) * dy; + let off: i32 = 0; + let x: i32 = 0; for (x < W) { let cr: f64 = xmin + (x: f64) * dx; let n: i32 = iterate(cr, ci); - row[x] = (shade(n)): u8; + off = emitcell(row.ptr, off, palette(n)); x += 1; }; - row[W] = 10u8; // '\n' - c_write(1, row.ptr: *void, (W + 1): u64); + off = emitendrow(row.ptr, off); + c_write(1, row.ptr: *void, off: u64); y += 1; }; return 0;