Web framerate calibration; Julia Set example update

1 files changed, 56 insertions, 28 deletions

diff --git a/reduced_system_layer.c b/reduced_system_layer.c
index 4043f58..219d360 100644
--- a/reduced_system_layer.c
+++ b/reduced_system_layer.c
@@ -196,27 +196,35 @@ i32 main(i32 argc, c8 **argv);
 #endif
 
 #ifndef MIN_PIXEL_SIZE
-#define MIN_PIXEL_SIZE 1
+#define MIN_PIXEL_SIZE (1.0)
 #endif
 
 #ifndef MAX_PIXEL_SIZE
-#define MAX_PIXEL_SIZE 16
+#define MAX_PIXEL_SIZE (16.0)
+#endif
+
+#ifndef PIXEL_SIZE_DELTA
+#define PIXEL_SIZE_DELTA (0.1)
 #endif
 
 #ifndef DEFAULT_PIXEL_SIZE
-#define DEFAULT_PIXEL_SIZE 3
+#define DEFAULT_PIXEL_SIZE (3.0)
 #endif
 
 #ifndef MIN_FRAME_DURATION
-#define MIN_FRAME_DURATION 9
+#define MIN_FRAME_DURATION 8
 #endif
 
 #ifndef MAX_FRAME_DURATION
-#if defined(__wasm__)
-#define MAX_FRAME_DURATION 83
-#else
-#define MAX_FRAME_DURATION 41
+#define MAX_FRAME_DURATION 34
 #endif
+
+#ifndef NUM_FRAMES_AVERAGED
+#define NUM_FRAMES_AVERAGED 400
+#endif
+
+#ifndef AVERAGE_FRAME_BIAS
+#define AVERAGE_FRAME_BIAS (0.00)
 #endif
 
 #ifndef NUM_SOUND_CHANNELS
@@ -519,7 +527,7 @@ typedef struct {
   c8 *title;
   i32 frame_width;
   i32 frame_height;
-  i32 pixel_size;
+  f64 pixel_size;
   b8  exact_resolution;
   b8  graceful_exit;
 
@@ -610,9 +618,11 @@ Platform g_platform = {0};
 static i64 _sound_clock_time  = 0;
 static i64 _sound_clock_carry = 0;
 static i64 _sound_position    = 0;
+static i64 _frame_index        = 0;
 
 static f32 _sound_ring        [MAX_NUM_SOUND_FRAMES]   = {0};
 static u8  _drop_files_buffer [DROP_FILES_BUFFER_SIZE] = {0};
+static i64 _frame_duration    [NUM_FRAMES_AVERAGED]     = {0};
 
 void p_event_loop(void) {
   p_init();
@@ -719,7 +729,7 @@ i8 utf8_write(c32 c, c8 *buffer) {
   return 0;
 }
 
-u32 rgb_u32_from_f32_(vec3_f32 c) {
+static u32 rgb_u32_from_f32_(vec3_f32 c) {
   i32 ir = (i32) floor(c.x * 255. + .5);
   i32 ig = (i32) floor(c.y * 255. + .5);
   i32 ib = (i32) floor(c.z * 255. + .5);
@@ -731,6 +741,22 @@ u32 rgb_u32_from_f32_(vec3_f32 c) {
   return (r << 16) | (g << 8) | b;
 }
 
+static i64 average_frame_duration_(i64 duration) {
+  _frame_duration[_frame_index] = duration;
+  _frame_index = (_frame_index + 1) % NUM_FRAMES_AVERAGED;
+
+  i64 durs[NUM_FRAMES_AVERAGED + 1];
+  for (i64 i = 0; i < NUM_FRAMES_AVERAGED; ++i)
+    durs[i] = _frame_duration[i];
+
+  //  FIXME: Use better sorting algorithm.
+  for (i64 i = 0; i < (i64) NUM_FRAMES_AVERAGED; ++i)
+    for (i64 j = i + 1; j < NUM_FRAMES_AVERAGED; ++j)
+      if (durs[i] < durs[j]) { i64 t = durs[i]; durs[i] = durs[j]; durs[j] = t; }
+
+  return durs[(i64) ((NUM_FRAMES_AVERAGED - 1) * AVERAGE_FRAME_BIAS)];
+}
+
 static i64 sound_samples_elapsed_(void) {
   if (_sound_clock_time == 0) {
     _sound_clock_time  = p_time();
@@ -1396,6 +1422,9 @@ static b8 sub_str_eq_(c8 *a, c8 *b, i64 len) {
 }
 
 void p_init(void) {
+  for (i64 i = 0; i < NUM_FRAMES_AVERAGED; ++i)
+    _frame_duration[i] = (MIN_FRAME_DURATION + MAX_FRAME_DURATION) / 2;
+
   _display = XOpenDisplay(NULL);
 
   if (_display == NULL) {
@@ -2078,13 +2107,11 @@ i32 p_handle_events(void) {
   i32 width  = _image.width;
   i32 height = _image.height;
 
-  if (g_platform.pixel_size <= 0)
-    g_platform.pixel_size = DEFAULT_PIXEL_SIZE;
-
-  if (g_platform.pixel_size <= MIN_PIXEL_SIZE)
-    g_platform.pixel_size = MIN_PIXEL_SIZE;
+  if (g_platform.pixel_size <= 0.)             g_platform.pixel_size = DEFAULT_PIXEL_SIZE;
+  if (g_platform.pixel_size <  MIN_PIXEL_SIZE) g_platform.pixel_size = MIN_PIXEL_SIZE;
+  if (g_platform.pixel_size >  MAX_PIXEL_SIZE) g_platform.pixel_size = MAX_PIXEL_SIZE;
 
-  if (g_platform.pixel_size > 1) {
+  if (g_platform.pixel_size > 1.) {
     width  = (i32) floor(((f64) _image.width)  / g_platform.pixel_size + .5);
     height = (i32) floor(((f64) _image.height) / g_platform.pixel_size + .5);
   }
@@ -2143,12 +2170,12 @@ void p_render_frame(void) {
   XFlush(_display);
 
   if (!g_platform.exact_resolution) {
-    i64 frame_duration = p_time() - _frame_time;
+    i64 frame_duration = average_frame_duration_(p_time() - _frame_time);
 
     if (g_platform.pixel_size < MAX_PIXEL_SIZE && frame_duration > MAX_FRAME_DURATION)
-      ++g_platform.pixel_size;
+      g_platform.pixel_size += PIXEL_SIZE_DELTA * (frame_duration - MAX_FRAME_DURATION);
     else if (g_platform.pixel_size > MIN_PIXEL_SIZE && frame_duration < MIN_FRAME_DURATION)
-      --g_platform.pixel_size;
+      g_platform.pixel_size -= PIXEL_SIZE_DELTA * (MIN_FRAME_DURATION - frame_duration);
   }
 }
 
@@ -2227,6 +2254,9 @@ void p_init(void) {
 
   g_platform.done = 1;
 
+  for (i64 i = 0; i < NUM_FRAMES_AVERAGED; ++i)
+    _frame_duration[i] = (MIN_FRAME_DURATION + MAX_FRAME_DURATION) / 2;
+
   _sound_read = (MAX_NUM_SOUND_FRAMES + ((-SOUND_AVAIL_MIN) % MAX_NUM_SOUND_FRAMES)) % MAX_NUM_SOUND_FRAMES;
 }
 
@@ -2491,13 +2521,11 @@ __attribute__((export_name("js_frame"))) void js_frame(i32 frame_width, i32 fram
   i32 width  = _frame_width;
   i32 height = _frame_height;
 
-  if (g_platform.pixel_size <= 0)
-    g_platform.pixel_size = DEFAULT_PIXEL_SIZE;
-
-  if (g_platform.pixel_size <= MIN_PIXEL_SIZE)
-    g_platform.pixel_size = MIN_PIXEL_SIZE;
+  if (g_platform.pixel_size <= 0.)             g_platform.pixel_size = DEFAULT_PIXEL_SIZE;
+  if (g_platform.pixel_size <  MIN_PIXEL_SIZE) g_platform.pixel_size = MIN_PIXEL_SIZE;
+  if (g_platform.pixel_size >  MAX_PIXEL_SIZE) g_platform.pixel_size = MAX_PIXEL_SIZE;
 
-  if (g_platform.pixel_size > 1) {
+  if (g_platform.pixel_size > 1.) {
     width  = (i32) floor(((f64) _frame_width)  / g_platform.pixel_size + .5);
     height = (i32) floor(((f64) _frame_height) / g_platform.pixel_size + .5);
   }
@@ -2534,12 +2562,12 @@ __attribute__((export_name("js_frame"))) void js_frame(i32 frame_width, i32 fram
   _sound_read = (_sound_read + num_samples * NUM_SOUND_CHANNELS) % MAX_NUM_SOUND_FRAMES;
 
   if (!g_platform.exact_resolution && do_render) {
-    i64 frame_duration = p_time() - frame_time;
+    i64 frame_duration = average_frame_duration_(p_time() - frame_time);
 
     if (g_platform.pixel_size < MAX_PIXEL_SIZE && frame_duration > MAX_FRAME_DURATION)
-      ++g_platform.pixel_size;
+      g_platform.pixel_size += PIXEL_SIZE_DELTA * (frame_duration - MAX_FRAME_DURATION);
     else if (g_platform.pixel_size > MIN_PIXEL_SIZE && frame_duration < MIN_FRAME_DURATION)
-      --g_platform.pixel_size;
+      g_platform.pixel_size -= PIXEL_SIZE_DELTA * (MIN_FRAME_DURATION - frame_duration);
   }
 }