Add thread.Pool with example in demo.odin; Update linalg to support handness changes for projection matrices

core/thread/thread_pool.odin

@@ -0,0 +1,147 @@
+package thread
+
+import "intrinsics"
+import "core:sync"
+import "core:mem"
+
+Task_Status :: enum i32 {
+	Ready,
+	Busy,
+	Waiting,
+	Term,
+}
+
+Task_Proc :: #type proc(task: ^Task);
+
+Task :: struct {
+	procedure: Task_Proc,
+	data: rawptr,
+	user_index: int,
+}
+
+Task_Id :: distinct i32;
+INVALID_TASK_ID :: Task_Id(-1);
+
+
+Pool :: struct {
+	allocator:             mem.Allocator,
+	mutex:                 sync.Mutex,
+	sem_available:         sync.Semaphore,
+	processing_task_count: int, // atomic
+	is_running:            bool,
+
+	threads: []^Thread,
+
+	tasks: [dynamic]Task,
+}
+
+pool_init :: proc(pool: ^Pool, thread_count: int, allocator := context.allocator) {
+	worker_thread_internal :: proc(t: ^Thread) {
+		pool := (^Pool)(t.data);
+
+		for pool.is_running {
+			sync.semaphore_wait_for(&pool.sem_available);
+
+			if task, ok := pool_try_and_pop_task(pool); ok {
+				pool_do_work(pool, &task);
+			}
+		}
+
+		sync.semaphore_post(&pool.sem_available, 1);
+	}
+
+
+	context.allocator = allocator;
+	pool.allocator = allocator;
+	pool.tasks = make([dynamic]Task);
+	pool.threads = make([]^Thread, thread_count);
+
+	sync.mutex_init(&pool.mutex);
+	sync.semaphore_init(&pool.sem_available);
+	pool.is_running = true;
+
+	for _, i in pool.threads {
+		t := create(worker_thread_internal);
+		t.user_index = i;
+		t.data = pool;
+		pool.threads[i] = t;
+	}
+}
+
+pool_destroy :: proc(pool: ^Pool) {
+	delete(pool.tasks);
+	delete(pool.threads, pool.allocator);
+
+	sync.mutex_destroy(&pool.mutex);
+	sync.semaphore_destroy(&pool.sem_available);
+}
+
+pool_start :: proc(pool: ^Pool) {
+	for t in pool.threads {
+		start(t);
+	}
+}
+
+pool_join :: proc(pool: ^Pool) {
+	pool.is_running = false;
+
+	sync.semaphore_post(&pool.sem_available, len(pool.threads));
+
+	yield();
+
+	for t in pool.threads {
+		join(t);
+	}
+}
+
+pool_add_task :: proc(pool: ^Pool, procedure: Task_Proc, data: rawptr, user_index: int = 0) {
+	sync.mutex_lock(&pool.mutex);
+	defer sync.mutex_unlock(&pool.mutex);
+
+	task: Task;
+	task.procedure = procedure;
+	task.data = data;
+	task.user_index = user_index;
+
+	append(&pool.tasks, task);
+	sync.semaphore_post(&pool.sem_available, 1);
+}
+
+pool_try_and_pop_task :: proc(pool: ^Pool) -> (task: Task, got_task: bool = false) {
+	if sync.mutex_try_lock(&pool.mutex) {
+		if len(pool.tasks) != 0 {
+			intrinsics.atomic_add(&pool.processing_task_count, 1);
+			task = pool.tasks[0];
+			got_task = true;
+			ordered_remove(&pool.tasks, 0);
+		}
+		sync.mutex_unlock(&pool.mutex);
+	}
+	return;
+}
+
+
+pool_do_work :: proc(pool: ^Pool, task: ^Task) {
+	task.procedure(task);
+	intrinsics.atomic_sub(&pool.processing_task_count, 1);
+}
+
+
+pool_wait_and_process :: proc(pool: ^Pool) {
+	for len(pool.tasks) != 0 || intrinsics.atomic_load(&pool.processing_task_count) != 0 {
+		if task, ok := pool_try_and_pop_task(pool); ok {
+			pool_do_work(pool, &task);
+		}
+
+		// Safety kick
+		if len(pool.tasks) != 0 && intrinsics.atomic_load(&pool.processing_task_count) == 0 {
+			sync.mutex_lock(&pool.mutex);
+			sync.semaphore_post(&pool.sem_available, len(pool.tasks));
+			sync.mutex_unlock(&pool.mutex);
+		}
+
+		yield();
+	}
+
+	pool_join(pool);
+}