Add damage presentation and reduce CPU surface latency

Add yasl_cpu_present_damage to submit partial damage rectangles.
Skip commit timers for CPU surfaces to prevent display delay.
Remove frame callback gating in surface_draw_frame when free buffers exist.
Flush the display immediately on CPU present.
Forward tearing option to window specifications.

1 files changed, 5 insertions, 1 deletions

diff --git a/include/yasl/yasl.h b/include/yasl/yasl.h
index 6d2b4f0..15bbe16 100644
--- a/include/yasl/yasl.h
+++ b/include/yasl/yasl.h
@@ -62,7 +62,7 @@ struct yasl_surface_options {
     const char *title;
     int width, height; /**< Required. */
     enum yasl_surface_type type;
-    bool undecorated, fixed_size;
+    bool undecorated, fixed_size, tearing;
     void *userdata;
     /** Called when the window needs drawing while the system blocks the event
      * loop, as during a macOS live resize; draw and present before returning.
@@ -281,8 +281,12 @@ YASL_API uint64_t yasl_time_ns(void);
  * 0xAARRGGBB pixels, rows tightly packed. They persist, and a resize keeps the
  * overlap and zeroes the rest. Valid until the next wait. Present to show them;
  * the system may also show them when it redraws the window. */
+struct yasl_damage {
+    int x, y, width, height;
+};
 YASL_API uint32_t *yasl_cpu_pixels(yasl_surface *surface, int *pixel_width, int *pixel_height);
 YASL_API int yasl_cpu_present(yasl_surface *surface);
+YASL_API int yasl_cpu_present_damage(yasl_surface *surface, const struct yasl_damage *damage, int count);
 
 typedef void (*yasl_gl_proc)(void);
 /** These four may run on a rendering thread; synchronize them with destruction.