GPU: Add GC to FBOs and UBOs and centralize all GCs

GPUFrameBuffers were being free when no context was attached or in the
wrong gl context. This make sure this does not happen again.

You can now safely free any gl resource from any thread (well as long as
it's not used anymore!).

1 files changed, 315 insertions, 0 deletions

diff --git a/source/blender/gpu/intern/gpu_context.cpp b/source/blender/gpu/intern/gpu_context.cpp
new file mode 100644
index 00000000000..6a42552c2fd
--- /dev/null
+++ b/source/blender/gpu/intern/gpu_context.cpp
@@ -0,0 +1,315 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2016 by Mike Erwin.
+ * All rights reserved.
+ *
+ * Contributor(s): Blender Foundation, Clément Foucault
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/gpu/intern/gpu_vertex_array_id.cpp
+ *  \ingroup gpu
+ *
+ * Manage GL vertex array IDs in a thread-safe way
+ * Use these instead of glGenBuffers & its friends
+ * - alloc must be called from a thread that is bound
+ *   to the context that will be used for drawing with
+ *   this vao.
+ * - free can be called from any thread
+ */
+
+#include "BLI_assert.h"
+#include "BLI_utildefines.h"
+
+#include "GPU_context.h"
+#include "GPU_framebuffer.h"
+
+#include "gpu_batch_private.h"
+#include "gpu_context_private.h"
+
+#include <vector>
+#include <string.h>
+#include <pthread.h>
+#include <mutex>
+#include <unordered_set>
+
+#if TRUST_NO_ONE
+#if 0
+extern "C" {
+extern int BLI_thread_is_main(void); /* Blender-specific function */
+}
+
+static bool thread_is_main() {
+	/* "main" here means the GL context's thread */
+	return BLI_thread_is_main();
+}
+#endif
+#endif
+
+static std::vector<GLuint> orphaned_buffer_ids;
+static std::vector<GLuint> orphaned_texture_ids;
+
+static std::mutex orphans_mutex;
+
+struct GPUContext {
+	GLuint default_vao;
+	std::unordered_set<GPUBatch *> batches; /* Batches that have VAOs from this context */
+#ifdef DEBUG
+	std::unordered_set<GPUFrameBuffer *> framebuffers; /* Framebuffers that have FBO from this context */
+#endif
+	std::vector<GLuint> orphaned_vertarray_ids;
+	std::vector<GLuint> orphaned_framebuffer_ids;
+	std::mutex orphans_mutex; /* todo: try spinlock instead */
+#if TRUST_NO_ONE
+	pthread_t thread; /* Thread on which this context is active. */
+	bool thread_is_used;
+
+	GPUContext() {
+		thread_is_used = false;
+	}
+#endif
+};
+
+#if defined(_MSC_VER) && (_MSC_VER == 1800)
+#define thread_local __declspec(thread)
+thread_local GPUContext *active_ctx = NULL;
+#else
+static thread_local GPUContext *active_ctx = NULL;
+#endif
+
+static void orphans_add(GPUContext *ctx, std::vector<GLuint> *orphan_list, GLuint id)
+{
+	std::mutex *mutex = (ctx) ? &ctx->orphans_mutex : &orphans_mutex;
+
+	mutex->lock();
+	orphan_list->emplace_back(id);
+	mutex->unlock();
+}
+
+static void orphans_clear(GPUContext *ctx)
+{
+	BLI_assert(ctx); /* need at least an active context */
+	BLI_assert(pthread_equal(pthread_self(), ctx->thread)); /* context has been activated by another thread! */
+
+	ctx->orphans_mutex.lock();
+	if (!ctx->orphaned_vertarray_ids.empty()) {
+		uint orphan_len = (uint)ctx->orphaned_vertarray_ids.size();
+		glDeleteVertexArrays(orphan_len, ctx->orphaned_vertarray_ids.data());
+		ctx->orphaned_vertarray_ids.clear();
+	}
+	if (!ctx->orphaned_framebuffer_ids.empty()) {
+		uint orphan_len = (uint)ctx->orphaned_framebuffer_ids.size();
+		glDeleteFramebuffers(orphan_len, ctx->orphaned_framebuffer_ids.data());
+		ctx->orphaned_framebuffer_ids.clear();
+	}
+
+	ctx->orphans_mutex.unlock();
+
+	orphans_mutex.lock();
+	if (!orphaned_buffer_ids.empty()) {
+		uint orphan_len = (uint)orphaned_buffer_ids.size();
+		glDeleteBuffers(orphan_len, orphaned_buffer_ids.data());
+		orphaned_buffer_ids.clear();
+	}
+	if (!orphaned_texture_ids.empty()) {
+		uint orphan_len = (uint)orphaned_texture_ids.size();
+		glDeleteTextures(orphan_len, orphaned_texture_ids.data());
+		orphaned_texture_ids.clear();
+	}
+	orphans_mutex.unlock();
+}
+
+GPUContext *GPU_context_create(void)
+{
+	/* BLI_assert(thread_is_main()); */
+	GPUContext *ctx = new GPUContext;
+	glGenVertexArrays(1, &ctx->default_vao);
+	GPU_context_active_set(ctx);
+	return ctx;
+}
+
+/* to be called after GPU_context_active_set(ctx_to_destroy) */
+void GPU_context_discard(GPUContext *ctx)
+{
+	/* Make sure no other thread has locked it. */
+	BLI_assert(ctx == active_ctx);
+	BLI_assert(pthread_equal(pthread_self(), ctx->thread));
+	BLI_assert(ctx->orphaned_vertarray_ids.empty());
+	/* For now don't allow GPUFrameBuffers to be reuse in another ctx. */
+	BLI_assert(ctx->framebuffers.empty());
+	/* delete remaining vaos */
+	while (!ctx->batches.empty()) {
+		/* this removes the array entry */
+		GPU_batch_vao_cache_clear(*ctx->batches.begin());
+	}
+	glDeleteVertexArrays(1, &ctx->default_vao);
+	delete ctx;
+	active_ctx = NULL;
+}
+
+/* ctx can be NULL */
+void GPU_context_active_set(GPUContext *ctx)
+{
+#if TRUST_NO_ONE
+	if (active_ctx) {
+		active_ctx->thread_is_used = false;
+	}
+	/* Make sure no other context is already bound to this thread. */
+	if (ctx) {
+		/* Make sure no other thread has locked it. */
+		assert(ctx->thread_is_used == false);
+		ctx->thread = pthread_self();
+		ctx->thread_is_used = true;
+	}
+#endif
+	if (ctx) {
+		orphans_clear(ctx);
+	}
+	active_ctx = ctx;
+}
+
+GPUContext *GPU_context_active_get(void)
+{
+	return active_ctx;
+}
+
+GLuint GPU_vao_default(void)
+{
+	BLI_assert(active_ctx); /* need at least an active context */
+	BLI_assert(pthread_equal(pthread_self(), active_ctx->thread)); /* context has been activated by another thread! */
+	return active_ctx->default_vao;
+}
+
+GLuint GPU_vao_alloc(void)
+{
+	GLuint new_vao_id = 0;
+	orphans_clear(active_ctx);
+	glGenVertexArrays(1, &new_vao_id);
+	return new_vao_id;
+}
+
+GLuint GPU_fbo_alloc(void)
+{
+	GLuint new_fbo_id = 0;
+	orphans_clear(active_ctx);
+	glGenFramebuffers(1, &new_fbo_id);
+	return new_fbo_id;
+}
+
+GLuint GPU_buf_alloc(void)
+{
+	GLuint new_buffer_id = 0;
+	orphans_clear(active_ctx);
+	glGenBuffers(1, &new_buffer_id);
+	return new_buffer_id;
+}
+
+GLuint GPU_tex_alloc(void)
+{
+	GLuint new_texture_id = 0;
+	orphans_clear(active_ctx);
+	glGenTextures(1, &new_texture_id);
+	return new_texture_id;
+}
+
+void GPU_vao_free(GLuint vao_id, GPUContext *ctx)
+{
+	BLI_assert(ctx);
+	if (ctx == active_ctx) {
+		glDeleteVertexArrays(1, &vao_id);
+	}
+	else {
+		orphans_add(ctx, &ctx->orphaned_vertarray_ids, vao_id);
+	}
+}
+
+void GPU_fbo_free(GLuint fbo_id, GPUContext *ctx)
+{
+	BLI_assert(ctx);
+	if (ctx == active_ctx) {
+		glDeleteFramebuffers(1, &fbo_id);
+	}
+	else {
+		orphans_add(ctx, &ctx->orphaned_framebuffer_ids, fbo_id);
+	}
+}
+
+void GPU_buf_free(GLuint buf_id)
+{
+	if (active_ctx) {
+		glDeleteBuffers(1, &buf_id);
+	}
+	else {
+		orphans_add(NULL, &orphaned_buffer_ids, buf_id);
+	}
+}
+
+void GPU_tex_free(GLuint tex_id)
+{
+	if (active_ctx) {
+		glDeleteTextures(1, &tex_id);
+	}
+	else {
+		orphans_add(NULL, &orphaned_texture_ids, tex_id);
+	}
+}
+
+/* GPUBatch & GPUFrameBuffer contains respectively VAO & FBO indices
+ * which are not shared across contexts. So we need to keep track of
+ * ownership. */
+
+void gpu_context_add_batch(GPUContext *ctx, GPUBatch *batch)
+{
+	BLI_assert(ctx);
+	ctx->orphans_mutex.lock();
+	ctx->batches.emplace(batch);
+	ctx->orphans_mutex.unlock();
+}
+
+void gpu_context_remove_batch(GPUContext *ctx, GPUBatch *batch)
+{
+	BLI_assert(ctx);
+	ctx->orphans_mutex.lock();
+	ctx->batches.erase(batch);
+	ctx->orphans_mutex.unlock();
+}
+
+void gpu_context_add_framebuffer(GPUContext *ctx, GPUFrameBuffer *fb)
+{
+#ifdef DEBUG
+	BLI_assert(ctx);
+	ctx->orphans_mutex.lock();
+	ctx->framebuffers.emplace(fb);
+	ctx->orphans_mutex.unlock();
+#else
+	UNUSED_VARS(ctx, fb);
+#endif
+}
+
+void gpu_context_remove_framebuffer(GPUContext *ctx, GPUFrameBuffer *fb)
+{
+#ifdef DEBUG
+	BLI_assert(ctx);
+	ctx->orphans_mutex.lock();
+	ctx->framebuffers.erase(fb);
+	ctx->orphans_mutex.unlock();
+#else
+	UNUSED_VARS(ctx, fb);
+#endif
+}