[brlcad-devel] Bare bones renderer

[Vasco Alexandre da Silva Costa]

Hello,
I've been trying to make a really simple bare bones rendering loop in C
without branches, recursion, etc that we can try to parallelize later.

For now I managed to do this for the ray generation part (patch attached).
Still need to work on the ray traversal and color computation proper.

Regards,

-- 
Vasco Alexandre da Silva Costa
PhD Student at Department of Information Systems and Computer Science
Instituto Superior Técnico/University of Lisbon, Portugal

Index: src/rt/do.c
===================================================================
--- src/rt/do.c	(revision 65157)
+++ src/rt/do.c	(working copy)
@@ -542,6 +542,89 @@
 }
 
 
+void
+my_pixel(int cpu, int pixelnum)
+{
+    struct application a;
+    vect_t point;		/* Ref point on eye or view plane */
+    vect_t colorsum = {(fastf_t)0.0, (fastf_t)0.0, (fastf_t)0.0};
+
+
+    /* Obtain fresh copy of global application struct */
+    a = APP;				/* struct copy */
+    a.a_resource = &resource[cpu];
+
+    a.a_y = (int)(pixelnum/width);
+    a.a_x = (int)(pixelnum - (a.a_y * width));
+
+    /* our starting point, used for non-jitter */
+    VJOIN2 (point, viewbase_model, a.a_x, dx_model, a.a_y, dy_model);
+
+    /* not tracing the corners of a prism by default */
+    a.a_pixelext=(struct pixel_ext *)NULL;
+
+    /* LOOP BELOW IS UNROLLED ONE SAMPLE SINCE THAT'S THE COMMON CASE.
+     *
+     * XXX - If you edit the unrolled or non-unrolled section, be sure
+     * to edit the other section.
+     */
+    /* not hypersampling, so just do it */
+
+    VMOVE(a.a_ray.r_pt, point);
+    VMOVE(a.a_ray.r_dir, APP.a_ray.r_dir);
+    
+    a.a_level = 0;		/* recursion level */
+    a.a_purpose = "main ray";
+    (void)rt_shootray(&a);
+    VADD2(colorsum, colorsum, a.a_color);
+
+    view_pixel(&a);
+    return;
+}
+
+void
+my_run(int a, int b)
+{
+    size_t cpu = 0;
+    int per_processor_chunk = 0;	/* how many pixels to do at once */
+
+    int cur_pixel;			/* current pixel number, 0..last_pixel */
+    int last_pixel;			/* last pixel number */
+
+    int pixelnum;
+
+    cur_pixel = a;
+    last_pixel = b;
+
+    /*
+     * SERIAL case -- one CPU does all the work.
+     */
+    npsw = 1;
+
+    /* The more CPUs at work, the bigger the bites we take */
+    if (per_processor_chunk <= 0) per_processor_chunk = npsw;
+
+    RT_CK_RESOURCE(&resource[cpu]);
+
+    bu_semaphore_acquire(RT_SEM_WORKER);
+
+    for (pixelnum = cur_pixel; pixelnum <= last_pixel; pixelnum++) {
+        my_pixel(cpu, pixelnum);
+    }
+
+    bu_semaphore_release(RT_SEM_WORKER);
+
+    /* Tally up the statistics */
+    for (cpu=0; cpu < npsw; cpu++) {
+	if (resource[cpu].re_magic != RESOURCE_MAGIC) {
+	    bu_log("ERROR: CPU %d resources corrupted, statistics bad\n", cpu);
+	    continue;
+	}
+	rt_add_res_stats(APP.a_rt_i, &resource[cpu]);
+    }
+    return;
+}
+
 /**
  * Do all the actual work to run a frame.
  *
@@ -810,7 +893,7 @@
      * It may prove desirable to do this in chunks
      */
     rt_prep_timer();
-
+#if 0
     if (incr_mode) {
 	for (incr_level = 1; incr_level <= incr_nlevel; incr_level++) {
 	    if (incr_level > 1)
@@ -835,6 +918,15 @@
 	pix_start = 0;
 	pix_end = (int)(height*width - 1);
     }
+#endif
+    printf("pix_start: %d, pix_end: %d\n", pix_start, pix_end);
+    my_run(pix_start, pix_end);
+
+    /* Reset values to full size, for next frame (if any) */
+    pix_start = 0;
+    pix_end = (int)(height*width - 1);
+    /**/
+    
     utime = rt_get_timer(&times, &wallclock);
 
     /*

------------------------------------------------------------------------------

_______________________________________________
BRL-CAD Developer mailing list
brlcad-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/brlcad-devel