1 files changed, 347 insertions, 0 deletions
diff --git a/source/blender/gpu/intern/gpu_context.cc b/source/blender/gpu/intern/gpu_context.cc
new file mode 100644
index 00000000000..0b9104e5349
--- /dev/null
+++ b/source/blender/gpu/intern/gpu_context.cc
@@ -0,0 +1,347 @@
+/*
+ * 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.
+ */
+
+/** \file
+ * \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 "gpu_matrix_private.h"
+
+#include <mutex>
+#include <pthread.h>
+#include <string.h>
+#include <unordered_set>
+#include <vector>
+
+#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;
+  GLuint default_framebuffer;
+  GPUFrameBuffer *current_fbo;
+  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
+  struct GPUMatrixState *matrix_state;
+  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;
+#endif
+
+  GPUContext()
+  {
+#if TRUST_NO_ONE
+    thread_is_used = false;
+#endif
+    current_fbo = 0;
+  }
+};
+
+static thread_local GPUContext *active_ctx = NULL;
+
+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)
+{
+  /* need at least an active context */
+  BLI_assert(ctx);
+
+  /* context has been activated by another thread! */
+  BLI_assert(pthread_equal(pthread_self(), ctx->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(GLuint default_framebuffer)
+{
+  /* BLI_assert(thread_is_main()); */
+  GPUContext *ctx = new GPUContext;
+  glGenVertexArrays(1, &ctx->default_vao);
+  ctx->default_framebuffer = default_framebuffer;
+  ctx->matrix_state = GPU_matrix_state_create();
+  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());
+#ifdef DEBUG
+  /* For now don't allow GPUFrameBuffers to be reuse in another ctx. */
+  BLI_assert(ctx->framebuffers.empty());
+#endif
+  /* delete remaining vaos */
+  while (!ctx->batches.empty()) {
+    /* this removes the array entry */
+    GPU_batch_vao_cache_clear(*ctx->batches.begin());
+  }
+  GPU_matrix_state_discard(ctx->matrix_state);
+  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_framebuffer_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_framebuffer;
+}
+
+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
+}
+
+void gpu_context_active_framebuffer_set(GPUContext *ctx, GPUFrameBuffer *fb)
+{
+  ctx->current_fbo = fb;
+}
+
+GPUFrameBuffer *gpu_context_active_framebuffer_get(GPUContext *ctx)
+{
+  return ctx->current_fbo;
+}
+
+struct GPUMatrixState *gpu_context_active_matrix_state_get()
+{
+  BLI_assert(active_ctx);
+  return active_ctx->matrix_state;
+}