GPUUniformBuf: GL backend isolation

This is in preparation of vulkan backend. We move all opengl
functionnalities behind an abstract class.

This also cleansup the "dynamic" ubo create and rename it to
`GPU_uniformbuf_from_list()`

Contains, no functional change.

Part of T68990 Vulkan support.

12 files changed, 360 insertions, 119 deletions

diff --git a/source/blender/gpu/CMakeLists.txt b/source/blender/gpu/CMakeLists.txt
index 3b867429acc..b319a9d91a3 100644
--- a/source/blender/gpu/CMakeLists.txt
+++ b/source/blender/gpu/CMakeLists.txt
@@ -95,6 +95,7 @@ set(SRC
   opengl/gl_shader.cc
   opengl/gl_shader_interface.cc
   opengl/gl_state.cc
+  opengl/gl_uniform_buffer.cc
   opengl/gl_vertex_array.cc
 
   GPU_attr_binding.h
@@ -142,6 +143,7 @@ set(SRC
   intern/gpu_shader_private.hh
   intern/gpu_shader_interface.hh
   intern/gpu_state_private.hh
+  intern/gpu_uniform_buffer_private.hh
   intern/gpu_vertex_format_private.h
 
   opengl/gl_backend.hh
@@ -151,6 +153,7 @@ set(SRC
   opengl/gl_shader.hh
   opengl/gl_shader_interface.hh
   opengl/gl_state.hh
+  opengl/gl_uniform_buffer.hh
   opengl/gl_vertex_array.hh
 )
 
diff --git a/source/blender/gpu/GPU_uniform_buffer.h b/source/blender/gpu/GPU_uniform_buffer.h
index 2f3ce61bce0..2026522f2d5 100644
--- a/source/blender/gpu/GPU_uniform_buffer.h
+++ b/source/blender/gpu/GPU_uniform_buffer.h
@@ -29,10 +29,13 @@ extern "C" {
 
 struct ListBase;
 
-typedef struct GPUUniformBuf GPUUniformBuf;
+/** Opaque pointer */
+typedef struct GPUUniformBuf {
+  void *dummy;
+} GPUUniformBuf;
 
 GPUUniformBuf *GPU_uniformbuf_create_ex(size_t size, const void *data, const char *name);
-GPUUniformBuf *GPU_uniformbuf_dynamic_create(struct ListBase *inputs, const char *name);
+GPUUniformBuf *GPU_uniformbuf_create_from_list(struct ListBase *inputs, const char *name);
 
 #define GPU_uniformbuf_create(size) GPU_uniformbuf_create_ex(size, NULL, __func__);
 
diff --git a/source/blender/gpu/intern/gpu_backend.hh b/source/blender/gpu/intern/gpu_backend.hh
index 6ab0e32a754..f63f3cead2b 100644
--- a/source/blender/gpu/intern/gpu_backend.hh
+++ b/source/blender/gpu/intern/gpu_backend.hh
@@ -25,14 +25,16 @@
 
 #pragma once
 
-#include "gpu_batch_private.hh"
-#include "gpu_context_private.hh"
-#include "gpu_drawlist_private.hh"
-#include "gpu_shader_private.hh"
+struct GPUContext;
 
 namespace blender {
 namespace gpu {
 
+class Batch;
+class DrawList;
+class Shader;
+class UniformBuf;
+
 class GPUBackend {
  public:
   virtual ~GPUBackend(){};
@@ -46,6 +48,7 @@ class GPUBackend {
   // virtual FrameBuffer *framebuffer_alloc(void) = 0;
   virtual Shader *shader_alloc(const char *name) = 0;
   // virtual Texture *texture_alloc(void) = 0;
+  virtual UniformBuf *uniformbuf_alloc(int size, const char *name) = 0;
 };
 
 }  // namespace gpu
diff --git a/source/blender/gpu/intern/gpu_material.c b/source/blender/gpu/intern/gpu_material.c
index 95fb0aa56fc..a0432b78a7e 100644
--- a/source/blender/gpu/intern/gpu_material.c
+++ b/source/blender/gpu/intern/gpu_material.c
@@ -237,7 +237,7 @@ void GPU_material_uniform_buffer_create(GPUMaterial *material, ListBase *inputs)
 #else
   const char *name = NULL;
 #endif
-  material->ubo = GPU_uniformbuf_dynamic_create(inputs, name);
+  material->ubo = GPU_uniformbuf_create_from_list(inputs, name);
 }
 
 /* Eevee Subsurface scattering. */
diff --git a/source/blender/gpu/intern/gpu_uniform_buffer.cc b/source/blender/gpu/intern/gpu_uniform_buffer.cc
index 76459dcf9f0..905d7a4adb3 100644
--- a/source/blender/gpu/intern/gpu_uniform_buffer.cc
+++ b/source/blender/gpu/intern/gpu_uniform_buffer.cc
@@ -13,7 +13,7 @@
  * 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) 2005 Blender Foundation.
+ * The Original Code is Copyright (C) 2020 Blender Foundation.
  * All rights reserved.
  */
 
@@ -27,64 +27,46 @@
 #include "BLI_blenlib.h"
 #include "BLI_math_base.h"
 
-#include "gpu_context_private.hh"
+#include "gpu_backend.hh"
 #include "gpu_node_graph.h"
 
-#include "GPU_extensions.h"
-#include "GPU_glew.h"
 #include "GPU_material.h"
+
+#include "GPU_extensions.h"
+
 #include "GPU_uniform_buffer.h"
+#include "gpu_uniform_buffer_private.hh"
 
-typedef struct GPUUniformBuf {
-  /** Data size in bytes. */
-  int size;
-  /** GL handle for UBO. */
-  GLuint bindcode;
-  /** Current binding point. */
-  int bindpoint;
-  /** Continuous memory block to copy to GPU. Is own by the GPUUniformBuf. */
-  void *data;
-
-#ifndef NDEBUG
-  char name[64];
-#endif
-} GPUUniformBuf;
+/* -------------------------------------------------------------------- */
+/** \name Creation & Deletion
+ * \{ */
 
-GPUUniformBuf *GPU_uniformbuf_create_ex(size_t size, const void *data, const char *name)
+namespace blender::gpu {
+
+UniformBuf::UniformBuf(size_t size, const char *name)
 {
   /* Make sure that UBO is padded to size of vec4 */
   BLI_assert((size % 16) == 0);
+  BLI_assert(size <= GPU_max_ubo_size());
 
-  if (size > GPU_max_ubo_size()) {
-    fprintf(stderr, "GPUUniformBuf: UBO too big. %s", name);
-    return NULL;
-  }
-
-  GPUUniformBuf *ubo = (GPUUniformBuf *)MEM_mallocN(sizeof(GPUUniformBuf), __func__);
-  ubo->size = size;
-  ubo->data = NULL;
-  ubo->bindcode = 0;
-  ubo->bindpoint = -1;
+  size_in_bytes_ = size;
 
-#ifndef NDEBUG
-  BLI_strncpy(ubo->name, name, sizeof(ubo->name));
-#endif
-
-  /* Direct init. */
-  if (data != NULL) {
-    GPU_uniformbuf_update(ubo, data);
-  }
-
-  return ubo;
+  BLI_strncpy(name_, name, sizeof(name_));
 }
 
-void GPU_uniformbuf_free(GPUUniformBuf *ubo)
+UniformBuf::~UniformBuf()
 {
-  MEM_SAFE_FREE(ubo->data);
-  GPU_buf_free(ubo->bindcode);
-  MEM_freeN(ubo);
+  MEM_SAFE_FREE(data_);
 }
 
+}  // namespace blender::gpu
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Uniform buffer from GPUInput list
+ * \{ */
+
 /**
  * We need to pad some data types (vec3) on the C side
  * To match the GPU expected memory block alignment.
@@ -117,10 +99,10 @@ static int inputs_cmp(const void *a, const void *b)
  * Make sure we respect the expected alignment of UBOs.
  * mat4, vec4, pad vec3 as vec4, then vec2, then floats.
  */
-static void gpu_uniformbuffer_inputs_sort(ListBase *inputs)
+static void buffer_from_list_inputs_sort(ListBase *inputs)
 {
-/* Only support up to this type, if you want to extend it, make sure the
- * padding logic is correct for the new types. */
+/* Only support up to this type, if you want to extend it, make sure tstatic void
+ * inputs_sobuffer_size_compute *inputs) padding logic is correct for the new types. */
 #define MAX_UBO_GPU_TYPE GPU_MAT4
 
   /* Order them as mat4, vec4, vec3, vec2, float. */
@@ -179,23 +161,9 @@ static void gpu_uniformbuffer_inputs_sort(ListBase *inputs)
 #undef MAX_UBO_GPU_TYPE
 }
 
-/**
- * Create dynamic UBO from parameters
- * Return NULL if failed to create or if \param inputs: is empty.
- *
- * \param inputs: ListBase of #BLI_genericNodeN(#GPUInput).
- */
-GPUUniformBuf *GPU_uniformbuf_dynamic_create(ListBase *inputs, const char *name)
+static inline size_t buffer_size_from_list(ListBase *inputs)
 {
-  /* There is no point on creating an UBO if there is no arguments. */
-  if (BLI_listbase_is_empty(inputs)) {
-    return NULL;
-  }
-  /* Make sure we comply to the ubo alignment requirements. */
-  gpu_uniformbuffer_inputs_sort(inputs);
-
   size_t buffer_size = 0;
-
   LISTBASE_FOREACH (LinkData *, link, inputs) {
     const eGPUType gputype = get_padded_gpu_type(link);
     buffer_size += gputype * sizeof(float);
@@ -203,8 +171,12 @@ GPUUniformBuf *GPU_uniformbuf_dynamic_create(ListBase *inputs, const char *name)
   /* Round up to size of vec4. (Opengl Requirement) */
   size_t alignment = sizeof(float[4]);
   buffer_size = divide_ceil_u(buffer_size, alignment) * alignment;
-  void *data = MEM_mallocN(buffer_size, __func__);
 
+  return buffer_size;
+}
+
+static inline void buffer_fill_from_list(void *data, ListBase *inputs)
+{
   /* Now that we know the total ubo size we can start populating it. */
   float *offset = (float *)data;
   LISTBASE_FOREACH (LinkData *, link, inputs) {
@@ -212,71 +184,73 @@ GPUUniformBuf *GPU_uniformbuf_dynamic_create(ListBase *inputs, const char *name)
     memcpy(offset, input->vec, input->type * sizeof(float));
     offset += get_padded_gpu_type(link);
   }
-
-  /* Pass data as NULL for late init. */
-  GPUUniformBuf *ubo = GPU_uniformbuf_create_ex(buffer_size, NULL, name);
-  /* Data will be update just before binding. */
-  ubo->data = data;
-  return ubo;
 }
 
-static void gpu_uniformbuffer_init(GPUUniformBuf *ubo)
-{
-  BLI_assert(ubo->bindcode == 0);
-  ubo->bindcode = GPU_buf_alloc();
+/** \} */
 
-  if (ubo->bindcode == 0) {
-    fprintf(stderr, "GPUUniformBuf: UBO create failed");
-    BLI_assert(0);
-    return;
-  }
+/* -------------------------------------------------------------------- */
+/** \name C-API
+ * \{ */
 
-  glBindBuffer(GL_UNIFORM_BUFFER, ubo->bindcode);
-  glBufferData(GL_UNIFORM_BUFFER, ubo->size, NULL, GL_DYNAMIC_DRAW);
-}
+using namespace blender::gpu;
 
-void GPU_uniformbuf_update(GPUUniformBuf *ubo, const void *data)
+GPUUniformBuf *GPU_uniformbuf_create_ex(size_t size, const void *data, const char *name)
 {
-  if (ubo->bindcode == 0) {
-    gpu_uniformbuffer_init(ubo);
+  UniformBuf *ubo = GPUBackend::get()->uniformbuf_alloc(size, name);
+  /* Direct init. */
+  if (data != NULL) {
+    ubo->update(data);
   }
-
-  glBindBuffer(GL_UNIFORM_BUFFER, ubo->bindcode);
-  glBufferSubData(GL_UNIFORM_BUFFER, 0, ubo->size, data);
-  glBindBuffer(GL_UNIFORM_BUFFER, 0);
+  return reinterpret_cast<GPUUniformBuf *>(ubo);
 }
 
-void GPU_uniformbuf_bind(GPUUniformBuf *ubo, int number)
+/**
+ * Create UBO from inputs list.
+ * Return NULL if failed to create or if \param inputs: is empty.
+ *
+ * \param inputs: ListBase of #BLI_genericNodeN(#GPUInput).
+ */
+GPUUniformBuf *GPU_uniformbuf_create_from_list(ListBase *inputs, const char *name)
 {
-  if (number >= GPU_max_ubo_binds()) {
-    fprintf(stderr, "GPUUniformBuf: UBO too big.");
-    return;
+  /* There is no point on creating an UBO if there is no arguments. */
+  if (BLI_listbase_is_empty(inputs)) {
+    return NULL;
   }
 
-  if (ubo->bindcode == 0) {
-    gpu_uniformbuffer_init(ubo);
-  }
+  buffer_from_list_inputs_sort(inputs);
+  size_t buffer_size = buffer_size_from_list(inputs);
+  void *data = MEM_mallocN(buffer_size, __func__);
+  buffer_fill_from_list(data, inputs);
 
-  if (ubo->data != NULL) {
-    GPU_uniformbuf_update(ubo, ubo->data);
-    MEM_SAFE_FREE(ubo->data);
-  }
+  UniformBuf *ubo = GPUBackend::get()->uniformbuf_alloc(buffer_size, name);
+  /* Defer data upload. */
+  ubo->attach_data(data);
+  return reinterpret_cast<GPUUniformBuf *>(ubo);
+}
+
+void GPU_uniformbuf_free(GPUUniformBuf *ubo)
+{
+  delete reinterpret_cast<UniformBuf *>(ubo);
+}
+
+void GPU_uniformbuf_update(GPUUniformBuf *ubo, const void *data)
+{
+  reinterpret_cast<UniformBuf *>(ubo)->update(data);
+}
 
-  glBindBufferBase(GL_UNIFORM_BUFFER, number, ubo->bindcode);
-  ubo->bindpoint = number;
+void GPU_uniformbuf_bind(GPUUniformBuf *ubo, int slot)
+{
+  reinterpret_cast<UniformBuf *>(ubo)->bind(slot);
 }
 
 void GPU_uniformbuf_unbind(GPUUniformBuf *ubo)
 {
-#ifndef NDEBUG
-  glBindBufferBase(GL_UNIFORM_BUFFER, ubo->bindpoint, 0);
-#endif
-  ubo->bindpoint = 0;
+  reinterpret_cast<UniformBuf *>(ubo)->unbind();
 }
 
 void GPU_uniformbuf_unbind_all(void)
 {
-  for (int i = 0; i < GPU_max_ubo_binds(); i++) {
-    glBindBufferBase(GL_UNIFORM_BUFFER, i, 0);
-  }
+  /* FIXME */
 }
+
+/** \} */
diff --git a/source/blender/gpu/intern/gpu_uniform_buffer_private.hh b/source/blender/gpu/intern/gpu_uniform_buffer_private.hh
new file mode 100644
index 00000000000..069a3b1c80c
--- /dev/null
+++ b/source/blender/gpu/intern/gpu_uniform_buffer_private.hh
@@ -0,0 +1,65 @@
+/*
+ * 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.
+ *
+ * Copyright 2020, Blender Foundation.
+ */
+
+/** \file
+ * \ingroup gpu
+ */
+
+#pragma once
+
+#include "BLI_sys_types.h"
+
+namespace blender {
+namespace gpu {
+
+#ifdef DEBUG
+#  define DEBUG_NAME_LEN 8
+#else
+#  define DEBUG_NAME_LEN 64
+#endif
+
+class UniformBuf {
+ protected:
+  /** Data size in bytes. */
+  size_t size_in_bytes_;
+  /** Continuous memory block to copy to GPU. This data is owned by the UniformBuf. */
+  void *data_ = NULL;
+  /** Debugging name */
+  char name_[DEBUG_NAME_LEN];
+
+ public:
+  UniformBuf(size_t size, const char *name);
+  virtual ~UniformBuf();
+
+  virtual void update(const void *data) = 0;
+  virtual void bind(int slot) = 0;
+  virtual void unbind(void) = 0;
+
+  /** Used to defer data upload at drawing time.
+   * This is useful if the thread has no context bound.
+   * This transfers ownership to this UniformBuf. */
+  void attach_data(void *data)
+  {
+    data_ = data;
+  }
+};
+
+#undef DEBUG_NAME_LEN
+
+}  // namespace gpu
+}  // namespace blender
diff --git a/source/blender/gpu/opengl/gl_backend.hh b/source/blender/gpu/opengl/gl_backend.hh
index 63a14af6612..0234c1a3f63 100644
--- a/source/blender/gpu/opengl/gl_backend.hh
+++ b/source/blender/gpu/opengl/gl_backend.hh
@@ -31,6 +31,7 @@
 #include "gl_context.hh"
 #include "gl_drawlist.hh"
 #include "gl_shader.hh"
+#include "gl_uniform_buffer.hh"
 
 namespace blender {
 namespace gpu {
@@ -40,6 +41,11 @@ class GLBackend : public GPUBackend {
   GLSharedOrphanLists shared_orphan_list_;
 
  public:
+  static GLBackend *get(void)
+  {
+    return static_cast<GLBackend *>(GPUBackend::get());
+  }
+
   GPUContext *context_alloc(void *ghost_window)
   {
     return new GLContext(ghost_window, shared_orphan_list_);
@@ -60,6 +66,11 @@ class GLBackend : public GPUBackend {
     return new GLShader(name);
   };
 
+  UniformBuf *uniformbuf_alloc(int size, const char *name)
+  {
+    return new GLUniformBuf(size, name);
+  };
+
   /* TODO remove */
   void buf_free(GLuint buf_id);
   void tex_free(GLuint tex_id);
diff --git a/source/blender/gpu/opengl/gl_batch.hh b/source/blender/gpu/opengl/gl_batch.hh
index 9a7767d679d..9399148c68d 100644
--- a/source/blender/gpu/opengl/gl_batch.hh
+++ b/source/blender/gpu/opengl/gl_batch.hh
@@ -35,6 +35,7 @@
 namespace blender {
 namespace gpu {
 
+class GLContext;
 class GLShaderInterface;
 
 #define GPU_VAO_STATIC_LEN 3
@@ -45,7 +46,7 @@ class GLShaderInterface;
 class GLVaoCache {
  private:
   /** Context for which the vao_cache_ was generated. */
-  struct GLContext *context_ = NULL;
+  GLContext *context_ = NULL;
   /** Last interface this batch was drawn with. */
   GLShaderInterface *interface_ = NULL;
   /** Cached vao for the last interface. */
diff --git a/source/blender/gpu/opengl/gl_context.hh b/source/blender/gpu/opengl/gl_context.hh
index 0b762c939f1..ee8189255ca 100644
--- a/source/blender/gpu/opengl/gl_context.hh
+++ b/source/blender/gpu/opengl/gl_context.hh
@@ -32,13 +32,13 @@
 
 #include "glew-mx.h"
 
-#include "gl_batch.hh"
-
 #include <mutex>
 
 namespace blender {
 namespace gpu {
 
+class GLVaoCache;
+
 class GLSharedOrphanLists {
  public:
   /** Mutex for the bellow structures. */
@@ -51,7 +51,7 @@ class GLSharedOrphanLists {
   void orphans_clear(void);
 };
 
-struct GLContext : public GPUContext {
+class GLContext : public GPUContext {
   /* TODO(fclem) these needs to become private. */
  public:
   /** Default VAO for procedural draw calls. */
diff --git a/source/blender/gpu/opengl/gl_shader.cc b/source/blender/gpu/opengl/gl_shader.cc
index 93ed7a408c6..b2cca2ef45e 100644
--- a/source/blender/gpu/opengl/gl_shader.cc
+++ b/source/blender/gpu/opengl/gl_shader.cc
@@ -49,7 +49,7 @@ GLShader::GLShader(const char *name) : Shader(name)
 #ifndef __APPLE__
   if ((G.debug & G_DEBUG_GPU) && (GLEW_VERSION_4_3 || GLEW_KHR_debug)) {
     char sh_name[64];
-    BLI_snprintf(sh_name, sizeof(sh_name), "ShaderProgram-%s", name);
+    SNPRINTF(sh_name, "ShaderProgram-%s", name);
     glObjectLabel(GL_PROGRAM, shader_program_, -1, sh_name);
   }
 #endif
diff --git a/source/blender/gpu/opengl/gl_uniform_buffer.cc b/source/blender/gpu/opengl/gl_uniform_buffer.cc
new file mode 100644
index 00000000000..5115034639c
--- /dev/null
+++ b/source/blender/gpu/opengl/gl_uniform_buffer.cc
@@ -0,0 +1,126 @@
+/*
+ * 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_extensions.h"
+
+#include "gpu_backend.hh"
+#include "gpu_context_private.hh"
+
+#include "gl_backend.hh"
+#include "gl_uniform_buffer.hh"
+
+namespace blender::gpu {
+
+/* -------------------------------------------------------------------- */
+/** \name Creation & Deletion
+ * \{ */
+
+GLUniformBuf::GLUniformBuf(size_t size, const char *name) : UniformBuf(size, name)
+{
+  /* Do not create ubo GL buffer here to allow allocation from any thread. */
+}
+
+GLUniformBuf::~GLUniformBuf()
+{
+  GLBackend::get()->buf_free(ubo_id_);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Data upload / update
+ * \{ */
+
+void GLUniformBuf::init(void)
+{
+  BLI_assert(GPU_context_active_get());
+
+  glGenBuffers(1, &ubo_id_);
+  glBindBuffer(GL_UNIFORM_BUFFER, ubo_id_);
+  glBufferData(GL_UNIFORM_BUFFER, size_in_bytes_, NULL, GL_DYNAMIC_DRAW);
+
+#ifndef __APPLE__
+  if ((G.debug & G_DEBUG_GPU) && (GLEW_VERSION_4_3 || GLEW_KHR_debug)) {
+    char sh_name[64];
+    SNPRINTF(sh_name, "UBO-%s", name_);
+    glObjectLabel(GL_BUFFER, ubo_id_, -1, sh_name);
+  }
+#endif
+}
+
+void GLUniformBuf::update(const void *data)
+{
+  if (ubo_id_ == 0) {
+    this->init();
+  }
+  glBindBuffer(GL_UNIFORM_BUFFER, ubo_id_);
+  glBufferSubData(GL_UNIFORM_BUFFER, 0, size_in_bytes_, data);
+  glBindBuffer(GL_UNIFORM_BUFFER, 0);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Usage
+ * \{ */
+
+void GLUniformBuf::bind(int slot)
+{
+  if (slot >= GPU_max_ubo_binds()) {
+    fprintf(stderr,
+            "Error: Trying to bind \"%s\" ubo to slot %d which is above the reported limit of %d.",
+            name_,
+            slot,
+            GPU_max_ubo_binds());
+    return;
+  }
+
+  if (ubo_id_ == 0) {
+    this->init();
+  }
+
+  if (data_ != NULL) {
+    this->update(data_);
+    MEM_SAFE_FREE(data_);
+  }
+
+  slot_ = slot;
+  glBindBufferBase(GL_UNIFORM_BUFFER, slot_, ubo_id_);
+}
+
+void GLUniformBuf::unbind(void)
+{
+#ifdef DEBUG
+  /* NOTE: This only unbinds the last bound slot. */
+  glBindBufferBase(GL_UNIFORM_BUFFER, slot_, 0);
+#endif
+  slot_ = 0;
+}
+
+/** \} */
+
+}  // namespace blender::gpu
\ No newline at end of file
diff --git a/source/blender/gpu/opengl/gl_uniform_buffer.hh b/source/blender/gpu/opengl/gl_uniform_buffer.hh
new file mode 100644
index 00000000000..9b904cb34ee
--- /dev/null
+++ b/source/blender/gpu/opengl/gl_uniform_buffer.hh
@@ -0,0 +1,55 @@
+/*
+ * 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_uniform_buffer_private.hh"
+
+#include "glew-mx.h"
+
+namespace blender {
+namespace gpu {
+
+class GLUniformBuf : public UniformBuf {
+ private:
+  int slot_ = -1;
+  GLuint ubo_id_ = 0;
+
+ public:
+  GLUniformBuf(size_t size, const char *name);
+  ~GLUniformBuf();
+
+  void update(const void *data) override;
+  void bind(int slot) override;
+  void unbind(void) override;
+
+ private:
+  void init(void);
+
+  MEM_CXX_CLASS_ALLOC_FUNCS("GLUniformBuf");
+};
+
+}  // namespace gpu
+}  // namespace blender