From 7cc971f6b0011efea0f459948cf98ce2afed0cef Mon Sep 17 00:00:00 2001
From: Mitya Selivanov <automainint@guattari.tech>
Date: Tue, 13 Aug 2024 17:11:14 +0200
Subject: Add Julia set example

---
 examples/julia_set.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 63 insertions(+), 3 deletions(-)

(limited to 'examples/julia_set.c')

diff --git a/examples/julia_set.c b/examples/julia_set.c
index 85a4674..9d12bb8 100755
--- a/examples/julia_set.c
+++ b/examples/julia_set.c
@@ -17,7 +17,7 @@ gcc                                         \
   -Wno-unused-but-set-variable              \
   -Wno-unused-parameter                     \
   -Wno-overlength-strings                   \
-  -O3                                       \
+  -g -O3                                    \
   -fsanitize=undefined,address,leak -mshstk \
   -lX11 -lm                                 \
   -o $BIN $SRC &&                           \
@@ -39,10 +39,70 @@ i32 main(i32 argc, c8 **argv) {
 
   p_init();
 
+  i64 p = 4;
+
+  f64 view_x = 0.;
+  f64 view_y = 0.;
+  f64 view_s = 1.;
+
+  f64 cx     = -.8;
+  f64 cy     = .1;
+  f64 radius = 2.;
+  i64 limit  = 1024;
+
   while (!platform.done) {
-    p_handle_events();
+    p_wait_events();
+
+    if (platform.key_pressed['\n'])
+      p = (p == 1 ? 4 : 1);
+
+    if (platform.key_pressed[KEY_ESCAPE]) {
+      view_x = 0.;
+      view_y = 0.;
+      view_s = 1.;
+    }
+
+    f64 d = platform.key_down[MOD_CTRL] ? .0005 : .01;
+
+    if (platform.key_pressed['q']) cx -= d;
+    if (platform.key_pressed['w']) cx += d;
+    if (platform.key_pressed['a']) cy -= d;
+    if (platform.key_pressed['s']) cy += d;
+
+
+    if (platform.key_down[BUTTON_LEFT]) {
+      view_x += platform.cursor_dx * view_s;
+      view_y += platform.cursor_dy * view_s;
+    }
+
+    view_s += .1 * platform.wheel_dy * view_s;
+
+    for (i32 j = 0; j + p <= platform.frame_height; j += p)
+      for (i32 i = 0; i + p <= platform.frame_width; i += p) {
+        f64 x = .003 * ((i - platform.frame_width  * .5) * view_s - view_x);
+        f64 y = .003 * ((j - platform.frame_height * .5) * view_s - view_y);
+
+        i64 n = 0;
+
+        for (; x * x + y * y < radius * radius && n < limit; ++n) {
+          f64 z = x * x - y * y;
+          y     = 2. * x * y  + cy;
+          x     = z + cx;
+        }
+
+        u32 c;
+
+        if (n == limit)
+          c = 0;
+        else
+          c = 0xffffff - n * 8 - n * 256 * 4;
+
+        for (i32 jj = 0; jj < p; ++jj)
+          for (i32 ii = 0; ii < p; ++ii)
+            platform.pixels[(j + jj) * platform.frame_width + (i + ii)] = c;
+      }
+
     p_render_frame();
-    p_sleep_for(0);
   }
 
   p_cleanup();
-- 
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