ray: remove vestigial ray_threads code

Now that rototiller is generally threaded when a prepare_frame() method is
supplied, and modules/ray has been updated accordingly, discard the now
redundant ray-specific threading code and related stuff.

6 files changed, 1 insertions, 162 deletions

diff --git a/src/modules/ray/Makefile.am b/src/modules/ray/Makefile.am
index 7acfdd8..957b6d1 100644
--- a/src/modules/ray/Makefile.am
+++ b/src/modules/ray/Makefile.am
@@ -1,4 +1,4 @@
 noinst_LIBRARIES = libray.a
-libray_a_SOURCES = ray_3f.h ray.c ray_camera.c ray_camera.h ray_color.h ray_euler.c ray_euler.h ray.h ray_light_emitter.h ray_object.c ray_object.h ray_object_light.h ray_object_plane.h ray_object_point.h ray_object_sphere.h ray_object_type.h ray_ray.h ray_scene.c ray_scene.h ray_surface.h ray_threads.c ray_threads.h
+libray_a_SOURCES = ray_3f.h ray.c ray_camera.c ray_camera.h ray_color.h ray_euler.c ray_euler.h ray.h ray_light_emitter.h ray_object.c ray_object.h ray_object_light.h ray_object_plane.h ray_object_point.h ray_object_sphere.h ray_object_type.h ray_ray.h ray_scene.c ray_scene.h ray_surface.h
 libray_a_CFLAGS = @ROTOTILLER_CFLAGS@ -ffast-math
 libray_a_CPPFLAGS = @ROTOTILLER_CFLAGS@ -I@top_srcdir@/src
diff --git a/src/modules/ray/ray.c b/src/modules/ray/ray.c
index 9847bd9..e79bfaf 100644
--- a/src/modules/ray/ray.c
+++ b/src/modules/ray/ray.c
@@ -9,7 +9,6 @@
 #include "ray_camera.h"
 #include "ray_object.h"
 #include "ray_scene.h"
-#include "ray_threads.h"
 
 /* Copyright (C) 2016-2017 Vito Caputo <vcaputo@pengaru.com> */
 
diff --git a/src/modules/ray/ray_scene.c b/src/modules/ray/ray_scene.c
index b4cddad..e2c7f2c 100644
--- a/src/modules/ray/ray_scene.c
+++ b/src/modules/ray/ray_scene.c
@@ -8,7 +8,6 @@
 #include "ray_object.h"
 #include "ray_ray.h"
 #include "ray_scene.h"
-#include "ray_threads.h"
 
 #define MAX_RECURSION_DEPTH	5
 
@@ -168,19 +167,3 @@ void ray_scene_render_fragment(ray_scene_t *scene, ray_camera_t *camera, fb_frag
 		buf += stride;
 	} while (ray_camera_frame_y_step(&frame));
 }
-
-/* we expect fragments[threads->n_threads + 1], or fragments[1] when threads == NULL */
-void ray_scene_render_fragments(ray_scene_t *scene, ray_camera_t *camera, ray_threads_t *threads, fb_fragment_t *fragments)
-{
-	unsigned	n_threads = threads ? threads->n_threads + 1 : 1;
-	unsigned	i;
-
-	for (i = 1; i < n_threads; i++)
-		ray_thread_fragment_submit(&threads->threads[i - 1], scene, camera, &fragments[i]);
-
-	/* always render the zero fragment in-line */
-	ray_scene_render_fragment(scene, camera, &fragments[0]);
-
-	for (i = 1; i < n_threads; i++)
-		ray_thread_wait_idle(&threads->threads[i - 1]);
-}
diff --git a/src/modules/ray/ray_scene.h b/src/modules/ray/ray_scene.h
index e9781c6..9a31d80 100644
--- a/src/modules/ray/ray_scene.h
+++ b/src/modules/ray/ray_scene.h
@@ -6,7 +6,6 @@
 #include "ray_camera.h"
 #include "ray_color.h"
 #include "ray_ray.h"
-#include "ray_threads.h"
 
 typedef union ray_object_t ray_object_t;
 
@@ -21,7 +20,6 @@ typedef struct ray_scene_t {
 	float		ambient_brightness;
 } ray_scene_t;
 
-void ray_scene_render_fragments(ray_scene_t *scene, ray_camera_t *camera, ray_threads_t *threads, fb_fragment_t *fragments);
 void ray_scene_render_fragment(ray_scene_t *scene, ray_camera_t *camera, fb_fragment_t *fragment);
 
 #endif
diff --git a/src/modules/ray/ray_threads.c b/src/modules/ray/ray_threads.c
deleted file mode 100644
index 2369687..0000000
--- a/src/modules/ray/ray_threads.c
+++ /dev/null
@@ -1,111 +0,0 @@
-#include <pthread.h>
-#include <stdlib.h>
-
-#include "fb.h"
-
-#include "ray_scene.h"
-#include "ray_threads.h"
-
-#define BUSY_WAIT_NUM	1000000000	/* How much to spin before sleeping in pthread_cond_wait() */
-
-/* for now assuming x86 */
-#define cpu_relax() \
-	__asm__ __volatile__ ( "pause\n" : : : "memory")
-
-/* This is a very simple/naive implementation, there's certainly room for improvement.
- *
- * Without the BUSY_WAIT_NUM spinning this approach seems to leave a fairly
- * substantial proportion of CPU idle while waiting for the render thread to
- * complete on my core 2 duo.
- *
- * It's probably just latency in getting the render thread woken when the work
- * is submitted, and since the fragments are split equally the main thread gets
- * a head start and has to wait when it finishes first.  The spinning is just
- * an attempt to avoid going to sleep while the render threads finish, there
- * still needs to be improvement in how the work is submitted.
- *
- * I haven't spent much time on optimizing the raytracer yet.
- */
-
-static void * ray_thread_func(void *_thread)
-{
-	ray_thread_t	*thread = _thread;
-
-	for (;;) {
-		pthread_mutex_lock(&thread->mutex);
-		while (thread->fragment == NULL)
-			pthread_cond_wait(&thread->cond, &thread->mutex);
-
-		ray_scene_render_fragment(thread->scene, thread->camera, thread->fragment);
-		thread->fragment = NULL;
-		pthread_mutex_unlock(&thread->mutex);
-		pthread_cond_signal(&thread->cond);
-	}
-
-	return NULL;
-}
-
-
-void ray_thread_fragment_submit(ray_thread_t *thread, ray_scene_t *scene, ray_camera_t *camera, fb_fragment_t *fragment)
-{
-	pthread_mutex_lock(&thread->mutex);
-	while (thread->fragment != NULL)	/* XXX: never true due to ray_thread_wait_idle() */
-		pthread_cond_wait(&thread->cond, &thread->mutex);
-
-	thread->fragment = fragment;
-	thread->scene = scene;
-	thread->camera = camera;
-
-	pthread_mutex_unlock(&thread->mutex);
-	pthread_cond_signal(&thread->cond);
-}
-
-
-void ray_thread_wait_idle(ray_thread_t *thread)
-{
-	unsigned	n;
-
-	/* Spin before going to sleep, the other thread should not take substantially longer. */
-	for (n = 0; thread->fragment != NULL && n < BUSY_WAIT_NUM; n++)
-		cpu_relax();
-
-	pthread_mutex_lock(&thread->mutex);
-	while (thread->fragment != NULL)
-		pthread_cond_wait(&thread->cond, &thread->mutex);
-	pthread_mutex_unlock(&thread->mutex);
-}
-
-
-ray_threads_t * ray_threads_create(unsigned num)
-{
-	ray_threads_t	*threads;
-	unsigned	i;
-
-	threads = malloc(sizeof(ray_threads_t) + sizeof(ray_thread_t) * num);
-	if (!threads)
-		return NULL;
-
-	for (i = 0; i < num; i++) {
-		pthread_mutex_init(&threads->threads[i].mutex, NULL);
-		pthread_cond_init(&threads->threads[i].cond, NULL);
-		threads->threads[i].fragment = NULL;
-		pthread_create(&threads->threads[i].thread, NULL, ray_thread_func, &threads->threads[i]);
-	}
-	threads->n_threads = num;
-
-	return threads;
-}
-
-
-void ray_threads_destroy(ray_threads_t *threads)
-{
-	unsigned	i;
-
-	for (i = 0; i < threads->n_threads; i++)
-		pthread_cancel(threads->threads[i].thread);
-
-	for (i = 0; i < threads->n_threads; i++)
-		pthread_join(threads->threads[i].thread, NULL);
-
-	free(threads);	
-}
diff --git a/src/modules/ray/ray_threads.h b/src/modules/ray/ray_threads.h
deleted file mode 100644
index b4c601d..0000000
--- a/src/modules/ray/ray_threads.h
+++ /dev/null
@@ -1,30 +0,0 @@
-#ifndef _RAY_THREADS_H
-#define _RAY_THREADS_H
-
-#include <pthread.h>
-
-typedef struct ray_scene_t ray_scene_t;
-typedef struct ray_camera_t ray_camera_t;
-typedef struct fb_fragment_t fb_fragment_t;
-
-typedef struct ray_thread_t {
-	pthread_t	thread;
-	pthread_mutex_t	mutex;
-	pthread_cond_t	cond;
-	ray_scene_t	*scene;
-	ray_camera_t	*camera;
-	fb_fragment_t	*fragment;
-} ray_thread_t;
-
-typedef struct ray_threads_t {
-	unsigned	n_threads;
-	ray_thread_t	threads[];
-} ray_threads_t;
-
-
-ray_threads_t * ray_threads_create(unsigned num);
-void ray_threads_destroy(ray_threads_t *threads);
-
-void ray_thread_fragment_submit(ray_thread_t *thread, ray_scene_t *scene, ray_camera_t *camera, fb_fragment_t *fragment);
-void ray_thread_wait_idle(ray_thread_t *thread);
-#endif