GPU/GL: Add StorageBuf implementation

Almost 1:1 identical to UniformBuf implementation.

5 files changed, 207 insertions, 0 deletions

diff --git a/source/blender/gpu/opengl/gl_backend.cc b/source/blender/gpu/opengl/gl_backend.cc
index 9885b16966b..fe730ba3c05 100644
--- a/source/blender/gpu/opengl/gl_backend.cc
+++ b/source/blender/gpu/opengl/gl_backend.cc
@@ -426,6 +426,8 @@ GLint GLContext::max_cubemap_size = 0;
 GLint GLContext::max_texture_3d_size = 0;
 GLint GLContext::max_ubo_binds = 0;
 GLint GLContext::max_ubo_size = 0;
+GLint GLContext::max_ssbo_binds = 0;
+GLint GLContext::max_ssbo_size = 0;
 
 /** Extensions. */
 
@@ -493,7 +495,9 @@ void GLBackend::capabilities_init()
   glGetIntegerv(GL_MAX_3D_TEXTURE_SIZE, &GLContext::max_texture_3d_size);
   glGetIntegerv(GL_MAX_CUBE_MAP_TEXTURE_SIZE, &GLContext::max_cubemap_size);
   glGetIntegerv(GL_MAX_FRAGMENT_UNIFORM_BLOCKS, &GLContext::max_ubo_binds);
+  glGetIntegerv(GL_MAX_FRAGMENT_SHADER_STORAGE_BLOCKS, &GLContext::max_ssbo_binds);
   glGetIntegerv(GL_MAX_UNIFORM_BLOCK_SIZE, &GLContext::max_ubo_size);
+  glGetIntegerv(GL_MAX_SHADER_STORAGE_BLOCK_SIZE, &GLContext::max_ssbo_size);
   GLContext::base_instance_support = GLEW_ARB_base_instance;
   GLContext::clear_texture_support = GLEW_ARB_clear_texture;
   GLContext::copy_image_support = GLEW_ARB_copy_image;
diff --git a/source/blender/gpu/opengl/gl_backend.hh b/source/blender/gpu/opengl/gl_backend.hh
index 9d637d7b6af..d7edd162f33 100644
--- a/source/blender/gpu/opengl/gl_backend.hh
+++ b/source/blender/gpu/opengl/gl_backend.hh
@@ -19,6 +19,7 @@
 #include "gl_index_buffer.hh"
 #include "gl_query.hh"
 #include "gl_shader.hh"
+#include "gl_storage_buffer.hh"
 #include "gl_texture.hh"
 #include "gl_uniform_buffer.hh"
 #include "gl_vertex_buffer.hh"
@@ -101,6 +102,11 @@ class GLBackend : public GPUBackend {
     return new GLUniformBuf(size, name);
   };
 
+  StorageBuf *storagebuf_alloc(int size, GPUUsageType usage, const char *name) override
+  {
+    return new GLStorageBuf(size, usage, name);
+  };
+
   VertBuf *vertbuf_alloc() override
   {
     return new GLVertBuf();
diff --git a/source/blender/gpu/opengl/gl_context.hh b/source/blender/gpu/opengl/gl_context.hh
index 369b667cbcc..54ef1b69e22 100644
--- a/source/blender/gpu/opengl/gl_context.hh
+++ b/source/blender/gpu/opengl/gl_context.hh
@@ -45,6 +45,8 @@ class GLContext : public Context {
   static GLint max_texture_3d_size;
   static GLint max_ubo_size;
   static GLint max_ubo_binds;
+  static GLint max_ssbo_size;
+  static GLint max_ssbo_binds;
 
   /** Extensions. */
 
diff --git a/source/blender/gpu/opengl/gl_storage_buffer.cc b/source/blender/gpu/opengl/gl_storage_buffer.cc
new file mode 100644
index 00000000000..c24f9841a09
--- /dev/null
+++ b/source/blender/gpu/opengl/gl_storage_buffer.cc
@@ -0,0 +1,133 @@
+/*
+ * 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) 2020 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup gpu
+ */
+
+#include "BKE_global.h"
+
+#include "BLI_string.h"
+
+#include "gpu_backend.hh"
+#include "gpu_context_private.hh"
+
+#include "gl_backend.hh"
+#include "gl_debug.hh"
+#include "gl_storage_buffer.hh"
+#include "gl_vertex_buffer.hh"
+
+namespace blender::gpu {
+
+/* -------------------------------------------------------------------- */
+/** \name Creation & Deletion
+ * \{ */
+
+GLStorageBuf::GLStorageBuf(size_t size, GPUUsageType usage, const char *name)
+    : StorageBuf(size, name)
+{
+  usage_ = usage;
+  /* Do not create ubo GL buffer here to allow allocation from any thread. */
+  BLI_assert(size <= GLContext::max_ssbo_size);
+}
+
+GLStorageBuf::~GLStorageBuf()
+{
+  GLContext::buf_free(ssbo_id_);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Data upload / update
+ * \{ */
+
+void GLStorageBuf::init()
+{
+  BLI_assert(GLContext::get());
+
+  glGenBuffers(1, &ssbo_id_);
+  glBindBuffer(GL_SHADER_STORAGE_BUFFER, ssbo_id_);
+  glBufferData(GL_SHADER_STORAGE_BUFFER, size_in_bytes_, nullptr, to_gl(this->usage_));
+
+  debug::object_label(GL_SHADER_STORAGE_BUFFER, ssbo_id_, name_);
+}
+
+void GLStorageBuf::update(const void *data)
+{
+  if (ssbo_id_ == 0) {
+    this->init();
+  }
+  glBindBuffer(GL_SHADER_STORAGE_BUFFER, ssbo_id_);
+  glBufferSubData(GL_SHADER_STORAGE_BUFFER, 0, size_in_bytes_, data);
+  glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Usage
+ * \{ */
+
+void GLStorageBuf::bind(int slot)
+{
+  if (slot >= GLContext::max_ssbo_binds) {
+    fprintf(
+        stderr,
+        "Error: Trying to bind \"%s\" ssbo to slot %d which is above the reported limit of %d.",
+        name_,
+        slot,
+        GLContext::max_ssbo_binds);
+    return;
+  }
+
+  if (ssbo_id_ == 0) {
+    this->init();
+  }
+
+  if (data_ != nullptr) {
+    this->update(data_);
+    MEM_SAFE_FREE(data_);
+  }
+
+  slot_ = slot;
+  glBindBufferBase(GL_SHADER_STORAGE_BUFFER, slot_, ssbo_id_);
+
+#ifdef DEBUG
+  BLI_assert(slot < 16);
+  /* TODO */
+  // GLContext::get()->bound_ssbo_slots |= 1 << slot;
+#endif
+}
+
+void GLStorageBuf::unbind()
+{
+#ifdef DEBUG
+  /* NOTE: This only unbinds the last bound slot. */
+  glBindBufferBase(GL_SHADER_STORAGE_BUFFER, slot_, 0);
+  /* Hope that the context did not change. */
+  /* TODO */
+  // GLContext::get()->bound_ssbo_slots &= ~(1 << slot_);
+#endif
+  slot_ = 0;
+}
+
+/** \} */
+
+}  // namespace blender::gpu
diff --git a/source/blender/gpu/opengl/gl_storage_buffer.hh b/source/blender/gpu/opengl/gl_storage_buffer.hh
new file mode 100644
index 00000000000..3280db4e521
--- /dev/null
+++ b/source/blender/gpu/opengl/gl_storage_buffer.hh
@@ -0,0 +1,62 @@
+/*
+ * 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) 2020 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup gpu
+ */
+
+#pragma once
+
+#include "MEM_guardedalloc.h"
+
+#include "gpu_storage_buffer_private.hh"
+
+#include "glew-mx.h"
+
+namespace blender {
+namespace gpu {
+
+/**
+ * Implementation of Storage Buffers using OpenGL.
+ */
+class GLStorageBuf : public StorageBuf {
+ private:
+  /** Slot to which this UBO is currently bound. -1 if not bound. */
+  int slot_ = -1;
+  /** OpenGL Object handle. */
+  GLuint ssbo_id_ = 0;
+  /** Usage type. */
+  GPUUsageType usage_;
+
+ public:
+  GLStorageBuf(size_t size, GPUUsageType usage, const char *name);
+  ~GLStorageBuf();
+
+  void update(const void *data) override;
+  void bind(int slot) override;
+  void unbind() override;
+
+ private:
+  void init();
+
+  MEM_CXX_CLASS_ALLOC_FUNCS("GLStorageBuf");
+};
+
+}  // namespace gpu
+}  // namespace blender