Commit 3208680f4bf6491463371bff569fe0b78dcbccfd
2023-12-05T19:24:54
lightspeed: adjust star count to screen density
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diff --git a/libc3/window/sdl2/demo/lightspeed.c b/libc3/window/sdl2/demo/lightspeed.c
index 86b6bde..8f08a88 100644
--- a/libc3/window/sdl2/demo/lightspeed.c
+++ b/libc3/window/sdl2/demo/lightspeed.c
@@ -13,18 +13,23 @@
#include <libc3/c3.h>
#include "lightspeed.h"
+#define LIGHTSPEED_STAR_MAX 1024 * 1024
+#define LIGHTSPEED_STAR_PROBABILITY 0.01
+
static void star_init (s_tag *star)
{
f64 x;
f64 y;
f64_random(&x);
f64_random(&y);
- tag_init_map(star, 3);
- tag_init_sym(star->data.map.keys, sym_1("speed"));
- tag_init_f64(star->data.map.values, 0.0);
- tag_init_sym(star->data.map.keys + 1, sym_1("x"));
+ if (star->type != TAG_MAP || star->data.map.count != 3) {
+ tag_map(star, 3);
+ tag_init_sym(star->data.map.keys + 0, sym_1("speed"));
+ tag_init_sym(star->data.map.keys + 1, sym_1("x"));
+ tag_init_sym(star->data.map.keys + 2, sym_1("y"));
+ }
+ tag_init_f64(star->data.map.values + 0, 0.0);
tag_init_f64(star->data.map.values + 1, 2.0 * x - 1.0);
- tag_init_sym(star->data.map.keys + 2, sym_1("y"));
tag_init_f64(star->data.map.values + 2, 2.0 * y - 1.0);
}
@@ -34,6 +39,8 @@ static void star_render (s_tag *star, s_sequence *seq)
f64 *speed;
f64 *x;
f64 *y;
+ if (star->type != TAG_MAP || star->data.map.count < 3)
+ star_init(star);
speed = &star->data.map.values[0].data.f64;
x = &star->data.map.values[1].data.f64;
y = &star->data.map.values[2].data.f64;
@@ -51,10 +58,14 @@ static void star_render (s_tag *star, s_sequence *seq)
bool lightspeed_load (s_sequence *seq, s_window_sdl2 *window)
{
uw i;
+ uw star_count;
(void) window;
- tag_tuple(&seq->tag, LIGHTSPEED_STARS);
+ tag_tuple(&seq->tag, LIGHTSPEED_STAR_MAX);
+ star_count = window->w * window->h * LIGHTSPEED_STAR_PROBABILITY;
+ if (star_count > LIGHTSPEED_STAR_MAX)
+ star_count = LIGHTSPEED_STAR_MAX;
i = 0;
- while (i < LIGHTSPEED_STARS) {
+ while (i < star_count) {
star_init(seq->tag.data.tuple.tag + i);
i++;
}
@@ -65,6 +76,7 @@ bool lightspeed_render (s_sequence *seq, s_window_sdl2 *window,
void *context)
{
uw i;
+ uw star_count;
(void) window;
(void) context;
glDisable(GL_TEXTURE_2D);
@@ -82,8 +94,11 @@ bool lightspeed_render (s_sequence *seq, s_window_sdl2 *window,
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_LINE_SMOOTH);
glBegin(GL_LINES);
+ star_count = window->w * window->h * LIGHTSPEED_STAR_PROBABILITY;
+ if (star_count > LIGHTSPEED_STAR_MAX)
+ star_count = LIGHTSPEED_STAR_MAX;
i = 0;
- while (i < LIGHTSPEED_STARS) {
+ while (i < star_count) {
star_render(seq->tag.data.tuple.tag + i, seq);
i++;
}
diff --git a/libc3/window/sdl2/demo/lightspeed.h b/libc3/window/sdl2/demo/lightspeed.h
index 44b297f..acaaf1b 100644
--- a/libc3/window/sdl2/demo/lightspeed.h
+++ b/libc3/window/sdl2/demo/lightspeed.h
@@ -15,8 +15,6 @@
#include "../types.h"
-#define LIGHTSPEED_STARS 10000
-
bool lightspeed_load (s_sequence *seq, s_window_sdl2 *window);
bool lightspeed_render (s_sequence *seq, s_window_sdl2 *window,
void *context);