Revert "Fix T93350: Cycles renders shows black during rendering huge resolutions"

This reverts commit 5e37f70307bdacedd0f7da65f8b385bc1426f21d.

It is leading to freezing of the entire desktop for a few seconds when stopping
3D viewport rendering on my Linux / NVIDIA system.

1 files changed, 222 insertions, 498 deletions

diff --git a/intern/cycles/blender/display_driver.cpp b/intern/cycles/blender/display_driver.cpp
index d902edc4695..abf421983b3 100644
--- a/intern/cycles/blender/display_driver.cpp
+++ b/intern/cycles/blender/display_driver.cpp
@@ -273,299 +273,11 @@ uint BlenderDisplaySpaceShader::get_shader_program()
 }
 
 /* --------------------------------------------------------------------
- * DrawTile.
- */
-
-/* Higher level representation of a texture from the graphics library. */
-class GLTexture {
- public:
-  /* Global counter for all allocated OpenGL textures used by instances of this class. */
-  static inline std::atomic<int> num_used = 0;
-
-  GLTexture() = default;
-
-  ~GLTexture()
-  {
-    assert(gl_id == 0);
-  }
-
-  GLTexture(const GLTexture &other) = delete;
-  GLTexture &operator=(GLTexture &other) = delete;
-
-  GLTexture(GLTexture &&other) noexcept
-      : gl_id(other.gl_id), width(other.width), height(other.height)
-  {
-    other.reset();
-  }
-
-  GLTexture &operator=(GLTexture &&other)
-  {
-    if (this == &other) {
-      return *this;
-    }
-
-    gl_id = other.gl_id;
-    width = other.width;
-    height = other.height;
-
-    other.reset();
-
-    return *this;
-  }
-
-  bool gl_resources_ensure()
-  {
-    if (gl_id) {
-      return true;
-    }
-
-    /* Create texture. */
-    glGenTextures(1, &gl_id);
-    if (!gl_id) {
-      LOG(ERROR) << "Error creating texture.";
-      return false;
-    }
-
-    /* Configure the texture. */
-    glActiveTexture(GL_TEXTURE0);
-    glBindTexture(GL_TEXTURE_2D, gl_id);
-
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
-
-    /* Clamp to edge so that precision issues when zoomed out (which forces linear interpolation)
-     * does not cause unwanted repetition. */
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-
-    glBindTexture(GL_TEXTURE_2D, 0);
-
-    ++num_used;
-
-    return true;
-  }
-
-  void gl_resources_destroy()
-  {
-    if (!gl_id) {
-      return;
-    }
-
-    glDeleteTextures(1, &gl_id);
-
-    reset();
-
-    --num_used;
-  }
-
-  /* OpenGL resource IDs of the texture.
-   *
-   * NOTE: Allocated on the render engine's context. */
-  uint gl_id = 0;
-
-  /* Dimensions of the texture in pixels. */
-  int width = 0;
-  int height = 0;
-
- protected:
-  void reset()
-  {
-    gl_id = 0;
-    width = 0;
-    height = 0;
-  }
-};
-
-/* Higher level representation of a Pixel Buffer Object (PBO) from the graphics library. */
-class GLPixelBufferObject {
- public:
-  /* Global counter for all allocated OpenGL PBOs used by instances of this class. */
-  static inline std::atomic<int> num_used = 0;
-
-  GLPixelBufferObject() = default;
-
-  ~GLPixelBufferObject()
-  {
-    assert(gl_id == 0);
-  }
-
-  GLPixelBufferObject(const GLPixelBufferObject &other) = delete;
-  GLPixelBufferObject &operator=(GLPixelBufferObject &other) = delete;
-
-  GLPixelBufferObject(GLPixelBufferObject &&other) noexcept
-      : gl_id(other.gl_id), width(other.width), height(other.height)
-  {
-    other.reset();
-  }
-
-  GLPixelBufferObject &operator=(GLPixelBufferObject &&other)
-  {
-    if (this == &other) {
-      return *this;
-    }
-
-    gl_id = other.gl_id;
-    width = other.width;
-    height = other.height;
-
-    other.reset();
-
-    return *this;
-  }
-
-  bool gl_resources_ensure()
-  {
-    if (gl_id) {
-      return true;
-    }
-
-    glGenBuffers(1, &gl_id);
-    if (!gl_id) {
-      LOG(ERROR) << "Error creating texture pixel buffer object.";
-      return false;
-    }
-
-    ++num_used;
-
-    return true;
-  }
-
-  void gl_resources_destroy()
-  {
-    if (!gl_id) {
-      return;
-    }
-
-    glDeleteBuffers(1, &gl_id);
-
-    reset();
-
-    --num_used;
-  }
-
-  /* OpenGL resource IDs of the PBO.
-   *
-   * NOTE: Allocated on the render engine's context. */
-  uint gl_id = 0;
-
-  /* Dimensions of the PBO. */
-  int width = 0;
-  int height = 0;
-
- protected:
-  void reset()
-  {
-    gl_id = 0;
-    width = 0;
-    height = 0;
-  }
-};
-
-class DrawTile {
- public:
-  DrawTile() = default;
-  ~DrawTile() = default;
-
-  DrawTile(const DrawTile &other) = delete;
-  DrawTile &operator=(const DrawTile &other) = delete;
-
-  DrawTile(DrawTile &&other) noexcept = default;
-
-  DrawTile &operator=(DrawTile &&other) = default;
-
-  bool gl_resources_ensure()
-  {
-    if (!texture.gl_resources_ensure()) {
-      gl_resources_destroy();
-      return false;
-    }
-
-    if (!gl_vertex_buffer) {
-      glGenBuffers(1, &gl_vertex_buffer);
-      if (!gl_vertex_buffer) {
-        LOG(ERROR) << "Error allocating tile VBO.";
-        gl_resources_destroy();
-        return false;
-      }
-    }
-
-    return true;
-  }
-
-  void gl_resources_destroy()
-  {
-    texture.gl_resources_destroy();
-
-    if (gl_vertex_buffer) {
-      glDeleteBuffers(1, &gl_vertex_buffer);
-      gl_vertex_buffer = 0;
-    }
-  }
-
-  inline bool ready_to_draw() const
-  {
-    return texture.gl_id != 0;
-  }
-
-  /* Texture which contains pixels of the tile. */
-  GLTexture texture;
-
-  /* Display parameters the texture of this tile has been updated for. */
-  BlenderDisplayDriver::Params params;
-
-  /* OpenGL resources needed for drawing. */
-  uint gl_vertex_buffer = 0;
-};
-
-class DrawTileAndPBO {
- public:
-  bool gl_resources_ensure()
-  {
-    if (!tile.gl_resources_ensure() || !buffer_object.gl_resources_ensure()) {
-      gl_resources_destroy();
-      return false;
-    }
-
-    return true;
-  }
-
-  void gl_resources_destroy()
-  {
-    tile.gl_resources_destroy();
-    buffer_object.gl_resources_destroy();
-  }
-
-  DrawTile tile;
-  GLPixelBufferObject buffer_object;
-};
-
-/* --------------------------------------------------------------------
  * BlenderDisplayDriver.
  */
 
-struct BlenderDisplayDriver::Tiles {
-  /* Resources of a tile which is being currently rendered. */
-  DrawTileAndPBO current_tile;
-
-  /* All tiles which rendering is finished and which content will not be changed. */
-  struct {
-    vector<DrawTile> tiles;
-
-    void gl_resources_destroy_and_clear()
-    {
-      for (DrawTile &tile : tiles) {
-        tile.gl_resources_destroy();
-      }
-
-      tiles.clear();
-    }
-  } finished_tiles;
-};
-
 BlenderDisplayDriver::BlenderDisplayDriver(BL::RenderEngine &b_engine, BL::Scene &b_scene)
-    : b_engine_(b_engine),
-      display_shader_(BlenderDisplayShader::create(b_engine, b_scene)),
-      tiles_(make_unique<Tiles>())
+    : b_engine_(b_engine), display_shader_(BlenderDisplayShader::create(b_engine, b_scene))
 {
   /* Create context while on the main thread. */
   gl_context_create();
@@ -580,21 +292,6 @@ BlenderDisplayDriver::~BlenderDisplayDriver()
  * Update procedure.
  */
 
-void BlenderDisplayDriver::next_tile_begin()
-{
-  if (!tiles_->current_tile.tile.ready_to_draw()) {
-    LOG(ERROR)
-        << "Unexpectedly moving to the next tile without any data provided for current tile.";
-    return;
-  }
-
-  /* Moving to the next tile without giving render data for the current tile is not an expected
-   * situation. */
-  DCHECK(!need_clear_);
-
-  tiles_->finished_tiles.tiles.emplace_back(std::move(tiles_->current_tile.tile));
-}
-
 bool BlenderDisplayDriver::update_begin(const Params &params,
                                         int texture_width,
                                         int texture_height)
@@ -615,33 +312,24 @@ bool BlenderDisplayDriver::update_begin(const Params &params,
     glWaitSync((GLsync)gl_render_sync_, 0, GL_TIMEOUT_IGNORED);
   }
 
-  DrawTile &current_tile = tiles_->current_tile.tile;
-  GLPixelBufferObject &current_tile_buffer_object = tiles_->current_tile.buffer_object;
-
-  /* Clear storage of all finished tiles when display clear is requested.
-   * Do it when new tile data is provided to handle the display clear flag in a single place.
-   * It also makes the logic reliable from the whether drawing did happen or not point of view. */
-  if (need_clear_) {
-    tiles_->finished_tiles.gl_resources_destroy_and_clear();
-    need_clear_ = false;
-  }
-
-  if (!tiles_->current_tile.gl_resources_ensure()) {
-    tiles_->current_tile.gl_resources_destroy();
+  if (!gl_texture_resources_ensure()) {
     gl_context_disable();
     return false;
   }
 
   /* Update texture dimensions if needed. */
-  if (current_tile.texture.width != texture_width ||
-      current_tile.texture.height != texture_height) {
+  if (texture_.width != texture_width || texture_.height != texture_height) {
     glActiveTexture(GL_TEXTURE0);
-    glBindTexture(GL_TEXTURE_2D, current_tile.texture.gl_id);
+    glBindTexture(GL_TEXTURE_2D, texture_.gl_id);
     glTexImage2D(
         GL_TEXTURE_2D, 0, GL_RGBA16F, texture_width, texture_height, 0, GL_RGBA, GL_HALF_FLOAT, 0);
-    current_tile.texture.width = texture_width;
-    current_tile.texture.height = texture_height;
+    texture_.width = texture_width;
+    texture_.height = texture_height;
     glBindTexture(GL_TEXTURE_2D, 0);
+
+    /* Texture did change, and no pixel storage was provided. Tag for an explicit zeroing out to
+     * avoid undefined content. */
+    texture_.need_clear = true;
   }
 
   /* Update PBO dimensions if needed.
@@ -653,58 +341,29 @@ bool BlenderDisplayDriver::update_begin(const Params &params,
    * sending too much data to GPU when resolution divider is not 1. */
   /* TODO(sergey): Investigate whether keeping the PBO exact size of the texture makes non-interop
    * mode faster. */
-  const int buffer_width = params.size.x;
-  const int buffer_height = params.size.y;
-  if (current_tile_buffer_object.width != buffer_width ||
-      current_tile_buffer_object.height != buffer_height) {
+  const int buffer_width = params.full_size.x;
+  const int buffer_height = params.full_size.y;
+  if (texture_.buffer_width != buffer_width || texture_.buffer_height != buffer_height) {
     const size_t size_in_bytes = sizeof(half4) * buffer_width * buffer_height;
-    glBindBuffer(GL_PIXEL_UNPACK_BUFFER, current_tile_buffer_object.gl_id);
+    glBindBuffer(GL_PIXEL_UNPACK_BUFFER, texture_.gl_pbo_id);
     glBufferData(GL_PIXEL_UNPACK_BUFFER, size_in_bytes, 0, GL_DYNAMIC_DRAW);
     glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
 
-    current_tile_buffer_object.width = buffer_width;
-    current_tile_buffer_object.height = buffer_height;
+    texture_.buffer_width = buffer_width;
+    texture_.buffer_height = buffer_height;
   }
 
-  /* Store an updated parameters of the current tile.
-   * In theory it is only needed once per update of the tile, but doing it on every update is
-   * the easiest and is not expensive. */
-  tiles_->current_tile.tile.params = params;
-
-  return true;
-}
-
-static void update_tile_texture_pixels(const DrawTileAndPBO &tile)
-{
-  const GLTexture &texture = tile.tile.texture;
-
-  DCHECK_NE(tile.buffer_object.gl_id, 0);
+  /* New content will be provided to the texture in one way or another, so mark this in a
+   * centralized place. */
+  texture_.need_update = true;
 
-  glActiveTexture(GL_TEXTURE0);
-  glBindTexture(GL_TEXTURE_2D, texture.gl_id);
-  glBindBuffer(GL_PIXEL_UNPACK_BUFFER, tile.buffer_object.gl_id);
-
-  glTexSubImage2D(
-      GL_TEXTURE_2D, 0, 0, 0, texture.width, texture.height, GL_RGBA, GL_HALF_FLOAT, 0);
+  texture_.params = params;
 
-  glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
-  glBindTexture(GL_TEXTURE_2D, 0);
+  return true;
 }
 
 void BlenderDisplayDriver::update_end()
 {
-  /* Unpack the PBO into the texture as soon as the new content is provided.
-   *
-   * This allows to ensure that the unpacking happens while resources like graphics interop (which
-   * lifetime is outside of control of the display driver) are still valid, as well as allows to
-   * move the tile from being current to finished immediately after this call.
-   *
-   * One concern with this approach is that if the update happens more often than drawing then
-   * doing the unpack here occupies GPU transfer for no good reason. However, the render scheduler
-   * takes care of ensuring updates don't happen that often. In regular applications redraw will
-   * happen much more often than this update. */
-  update_tile_texture_pixels(tiles_->current_tile);
-
   gl_upload_sync_ = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
   glFlush();
 
@@ -717,11 +376,7 @@ void BlenderDisplayDriver::update_end()
 
 half4 *BlenderDisplayDriver::map_texture_buffer()
 {
-  const uint pbo_gl_id = tiles_->current_tile.buffer_object.gl_id;
-
-  DCHECK_NE(pbo_gl_id, 0);
-
-  glBindBuffer(GL_PIXEL_UNPACK_BUFFER, pbo_gl_id);
+  glBindBuffer(GL_PIXEL_UNPACK_BUFFER, texture_.gl_pbo_id);
 
   half4 *mapped_rgba_pixels = reinterpret_cast<half4 *>(
       glMapBuffer(GL_PIXEL_UNPACK_BUFFER, GL_WRITE_ONLY));
@@ -729,6 +384,15 @@ half4 *BlenderDisplayDriver::map_texture_buffer()
     LOG(ERROR) << "Error mapping BlenderDisplayDriver pixel buffer object.";
   }
 
+  if (texture_.need_clear) {
+    const int64_t texture_width = texture_.width;
+    const int64_t texture_height = texture_.height;
+    memset(reinterpret_cast<void *>(mapped_rgba_pixels),
+           0,
+           texture_width * texture_height * sizeof(half4));
+    texture_.need_clear = false;
+  }
+
   return mapped_rgba_pixels;
 }
 
@@ -747,9 +411,12 @@ BlenderDisplayDriver::GraphicsInterop BlenderDisplayDriver::graphics_interop_get
 {
   GraphicsInterop interop_dst;
 
-  interop_dst.buffer_width = tiles_->current_tile.buffer_object.width;
-  interop_dst.buffer_height = tiles_->current_tile.buffer_object.height;
-  interop_dst.opengl_pbo_id = tiles_->current_tile.buffer_object.gl_id;
+  interop_dst.buffer_width = texture_.buffer_width;
+  interop_dst.buffer_height = texture_.buffer_height;
+  interop_dst.opengl_pbo_id = texture_.gl_pbo_id;
+
+  interop_dst.need_clear = texture_.need_clear;
+  texture_.need_clear = false;
 
   return interop_dst;
 }
@@ -770,7 +437,7 @@ void BlenderDisplayDriver::graphics_interop_deactivate()
 
 void BlenderDisplayDriver::clear()
 {
-  need_clear_ = true;
+  texture_.need_clear = true;
 }
 
 void BlenderDisplayDriver::set_zoom(float zoom_x, float zoom_y)
@@ -778,78 +445,42 @@ void BlenderDisplayDriver::set_zoom(float zoom_x, float zoom_y)
   zoom_ = make_float2(zoom_x, zoom_y);
 }
 
-/* Update vertex buffer with new coordinates of vertex positions and texture coordinates.
- * This buffer is used to render texture in the viewport.
- *
- * NOTE: The buffer needs to be bound. */
-static void vertex_buffer_update(const DisplayDriver::Params &params)
+void BlenderDisplayDriver::draw(const Params &params)
 {
-  const int x = params.full_offset.x;
-  const int y = params.full_offset.y;
-
-  const int width = params.size.x;
-  const int height = params.size.y;
-
-  /* Invalidate old contents - avoids stalling if the buffer is still waiting in queue to be
-   * rendered. */
-  glBufferData(GL_ARRAY_BUFFER, 16 * sizeof(float), NULL, GL_STREAM_DRAW);
+  /* See do_update_begin() for why no locking is required here. */
+  const bool transparent = true;  // TODO(sergey): Derive this from Film.
 
-  float *vpointer = reinterpret_cast<float *>(glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY));
-  if (!vpointer) {
+  if (!gl_draw_resources_ensure()) {
     return;
   }
 
-  vpointer[0] = 0.0f;
-  vpointer[1] = 0.0f;
-  vpointer[2] = x;
-  vpointer[3] = y;
-
-  vpointer[4] = 1.0f;
-  vpointer[5] = 0.0f;
-  vpointer[6] = x + width;
-  vpointer[7] = y;
-
-  vpointer[8] = 1.0f;
-  vpointer[9] = 1.0f;
-  vpointer[10] = x + width;
-  vpointer[11] = y + height;
-
-  vpointer[12] = 0.0f;
-  vpointer[13] = 1.0f;
-  vpointer[14] = x;
-  vpointer[15] = y + height;
-
-  glUnmapBuffer(GL_ARRAY_BUFFER);
-}
+  if (use_gl_context_) {
+    gl_context_mutex_.lock();
+  }
 
-static void draw_tile(const float2 &zoom,
-                      const int texcoord_attribute,
-                      const int position_attribute,
-                      const DrawTile &draw_tile)
-{
-  if (!draw_tile.ready_to_draw()) {
+  if (texture_.need_clear) {
+    /* Texture is requested to be cleared and was not yet cleared.
+     *
+     * Do early return which should be equivalent of drawing all-zero texture.
+     * Watch out for the lock though so that the clear happening during update is properly
+     * synchronized here. */
+    gl_context_mutex_.unlock();
     return;
   }
 
-  const GLTexture &texture = draw_tile.texture;
-
-  DCHECK_NE(texture.gl_id, 0);
-  DCHECK_NE(draw_tile.gl_vertex_buffer, 0);
+  if (gl_upload_sync_) {
+    glWaitSync((GLsync)gl_upload_sync_, 0, GL_TIMEOUT_IGNORED);
+  }
 
-  glBindBuffer(GL_ARRAY_BUFFER, draw_tile.gl_vertex_buffer);
+  if (transparent) {
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+  }
 
-  /* Draw at the parameters for which the texture has been updated for. This allows to always draw
-   * texture during bordered-rendered camera view without flickering. The validness of the display
-   * parameters for a texture is guaranteed by the initial "clear" state which makes drawing to
-   * have an early output.
-   *
-   * Such approach can cause some extra "jelly" effect during panning, but it is not more jelly
-   * than overlay of selected objects. Also, it's possible to redraw texture at an intersection of
-   * the texture draw parameters and the latest updated draw parameters (although, complexity of
-   * doing it might not worth it. */
-  vertex_buffer_update(draw_tile.params);
+  display_shader_->bind(params.full_size.x, params.full_size.y);
 
-  glBindTexture(GL_TEXTURE_2D, texture.gl_id);
+  glActiveTexture(GL_TEXTURE0);
+  glBindTexture(GL_TEXTURE_2D, texture_.gl_id);
 
   /* Trick to keep sharp rendering without jagged edges on all GPUs.
    *
@@ -859,93 +490,53 @@ static void draw_tile(const float2 &zoom,
    *
    * Use explicit MIN assignment to make sure the driver does not have an undefined behavior at
    * the zoom level 1. The MAG filter is always NEAREST. */
-  const float zoomed_width = draw_tile.params.size.x * zoom.x;
-  const float zoomed_height = draw_tile.params.size.y * zoom.y;
-  if (texture.width != draw_tile.params.size.x || texture.height != draw_tile.params.size.y) {
+  const float zoomed_width = params.size.x * zoom_.x;
+  const float zoomed_height = params.size.y * zoom_.y;
+  if (texture_.width != params.size.x || texture_.height != params.size.y) {
     /* Resolution divider is different from 1, force nearest interpolation. */
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   }
-  else if (zoomed_width - draw_tile.params.size.x > 0.5f ||
-           zoomed_height - draw_tile.params.size.y > 0.5f) {
+  else if (zoomed_width - params.size.x > 0.5f || zoomed_height - params.size.y > 0.5f) {
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   }
   else {
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   }
 
-  glVertexAttribPointer(
-      texcoord_attribute, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (const GLvoid *)0);
-  glVertexAttribPointer(position_attribute,
-                        2,
-                        GL_FLOAT,
-                        GL_FALSE,
-                        4 * sizeof(float),
-                        (const GLvoid *)(sizeof(float) * 2));
-
-  glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
-}
+  glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer_);
 
-void BlenderDisplayDriver::draw(const Params &params)
-{
-  /* See do_update_begin() for why no locking is required here. */
-  const bool transparent = true;  // TODO(sergey): Derive this from Film.
-
-  if (use_gl_context_) {
-    gl_context_mutex_.lock();
-  }
+  texture_update_if_needed();
+  vertex_buffer_update(params);
 
-  if (need_clear_) {
-    /* Texture is requested to be cleared and was not yet cleared.
-     *
-     * Do early return which should be equivalent of drawing all-zero texture.
-     * Watch out for the lock though so that the clear happening during update is properly
-     * synchronized here. */
-    if (use_gl_context_) {
-      gl_context_mutex_.unlock();
-    }
-    return;
-  }
-
-  if (gl_upload_sync_) {
-    glWaitSync((GLsync)gl_upload_sync_, 0, GL_TIMEOUT_IGNORED);
-  }
-
-  if (transparent) {
-    glEnable(GL_BLEND);
-    glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
-  }
-
-  glActiveTexture(GL_TEXTURE0);
-
-  /* NOTE: THe VAO is to be allocated on the drawing context as it is not shared across contects.
-   * Simplest is to allocate it on every redraw so that it is possible to destroy it from a
-   * correct context. */
+  /* TODO(sergey): Does it make sense/possible to cache/reuse the VAO? */
   GLuint vertex_array_object;
   glGenVertexArrays(1, &vertex_array_object);
   glBindVertexArray(vertex_array_object);
 
-  display_shader_->bind(params.full_size.x, params.full_size.y);
-
   const int texcoord_attribute = display_shader_->get_tex_coord_attrib_location();
   const int position_attribute = display_shader_->get_position_attrib_location();
 
   glEnableVertexAttribArray(texcoord_attribute);
   glEnableVertexAttribArray(position_attribute);
 
-  draw_tile(zoom_, texcoord_attribute, position_attribute, tiles_->current_tile.tile);
-
-  for (const DrawTile &tile : tiles_->finished_tiles.tiles) {
-    draw_tile(zoom_, texcoord_attribute, position_attribute, tile);
-  }
+  glVertexAttribPointer(
+      texcoord_attribute, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (const GLvoid *)0);
+  glVertexAttribPointer(position_attribute,
+                        2,
+                        GL_FLOAT,
+                        GL_FALSE,
+                        4 * sizeof(float),
+                        (const GLvoid *)(sizeof(float) * 2));
 
-  display_shader_->unbind();
+  glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 
-  glBindTexture(GL_TEXTURE_2D, 0);
-  glBindVertexArray(0);
   glBindBuffer(GL_ARRAY_BUFFER, 0);
+  glBindTexture(GL_TEXTURE_2D, 0);
 
   glDeleteVertexArrays(1, &vertex_array_object);
 
+  display_shader_->unbind();
+
   if (transparent) {
     glDisable(GL_BLEND);
   }
@@ -953,11 +544,6 @@ void BlenderDisplayDriver::draw(const Params &params)
   gl_render_sync_ = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
   glFlush();
 
-  if (VLOG_IS_ON(5)) {
-    VLOG(5) << "Number of textures: " << GLTexture::num_used;
-    VLOG(5) << "Number of PBOs: " << GLPixelBufferObject::num_used;
-  }
-
   if (use_gl_context_) {
     gl_context_mutex_.unlock();
   }
@@ -1032,16 +618,154 @@ void BlenderDisplayDriver::gl_context_dispose()
   }
 }
 
+bool BlenderDisplayDriver::gl_draw_resources_ensure()
+{
+  if (!texture_.gl_id) {
+    /* If there is no texture allocated, there is nothing to draw. Inform the draw call that it can
+     * can not continue. Note that this is not an unrecoverable error, so once the texture is known
+     * we will come back here and create all the GPU resources needed for draw. */
+    return false;
+  }
+
+  if (gl_draw_resource_creation_attempted_) {
+    return gl_draw_resources_created_;
+  }
+  gl_draw_resource_creation_attempted_ = true;
+
+  if (!vertex_buffer_) {
+    glGenBuffers(1, &vertex_buffer_);
+    if (!vertex_buffer_) {
+      LOG(ERROR) << "Error creating vertex buffer.";
+      return false;
+    }
+  }
+
+  gl_draw_resources_created_ = true;
+
+  return true;
+}
+
 void BlenderDisplayDriver::gl_resources_destroy()
 {
   gl_context_enable();
 
-  tiles_->current_tile.gl_resources_destroy();
-  tiles_->finished_tiles.gl_resources_destroy_and_clear();
+  if (vertex_buffer_ != 0) {
+    glDeleteBuffers(1, &vertex_buffer_);
+  }
+
+  if (texture_.gl_pbo_id) {
+    glDeleteBuffers(1, &texture_.gl_pbo_id);
+    texture_.gl_pbo_id = 0;
+  }
+
+  if (texture_.gl_id) {
+    glDeleteTextures(1, &texture_.gl_id);
+    texture_.gl_id = 0;
+  }
 
   gl_context_disable();
 
   gl_context_dispose();
 }
 
+bool BlenderDisplayDriver::gl_texture_resources_ensure()
+{
+  if (texture_.creation_attempted) {
+    return texture_.is_created;
+  }
+  texture_.creation_attempted = true;
+
+  DCHECK(!texture_.gl_id);
+  DCHECK(!texture_.gl_pbo_id);
+
+  /* Create texture. */
+  glGenTextures(1, &texture_.gl_id);
+  if (!texture_.gl_id) {
+    LOG(ERROR) << "Error creating texture.";
+    return false;
+  }
+
+  /* Configure the texture. */
+  glActiveTexture(GL_TEXTURE0);
+  glBindTexture(GL_TEXTURE_2D, texture_.gl_id);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  glBindTexture(GL_TEXTURE_2D, 0);
+
+  /* Create PBO for the texture. */
+  glGenBuffers(1, &texture_.gl_pbo_id);
+  if (!texture_.gl_pbo_id) {
+    LOG(ERROR) << "Error creating texture pixel buffer object.";
+    return false;
+  }
+
+  /* Creation finished with a success. */
+  texture_.is_created = true;
+
+  return true;
+}
+
+void BlenderDisplayDriver::texture_update_if_needed()
+{
+  if (!texture_.need_update) {
+    return;
+  }
+
+  glBindBuffer(GL_PIXEL_UNPACK_BUFFER, texture_.gl_pbo_id);
+  glTexSubImage2D(
+      GL_TEXTURE_2D, 0, 0, 0, texture_.width, texture_.height, GL_RGBA, GL_HALF_FLOAT, 0);
+  glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
+
+  texture_.need_update = false;
+}
+
+void BlenderDisplayDriver::vertex_buffer_update(const Params & /*params*/)
+{
+  /* Draw at the parameters for which the texture has been updated for. This allows to always draw
+   * texture during bordered-rendered camera view without flickering. The validness of the display
+   * parameters for a texture is guaranteed by the initial "clear" state which makes drawing to
+   * have an early output.
+   *
+   * Such approach can cause some extra "jelly" effect during panning, but it is not more jelly
+   * than overlay of selected objects. Also, it's possible to redraw texture at an intersection of
+   * the texture draw parameters and the latest updated draw parameters (although, complexity of
+   * doing it might not worth it. */
+  const int x = texture_.params.full_offset.x;
+  const int y = texture_.params.full_offset.y;
+
+  const int width = texture_.params.size.x;
+  const int height = texture_.params.size.y;
+
+  /* Invalidate old contents - avoids stalling if the buffer is still waiting in queue to be
+   * rendered. */
+  glBufferData(GL_ARRAY_BUFFER, 16 * sizeof(float), NULL, GL_STREAM_DRAW);
+
+  float *vpointer = reinterpret_cast<float *>(glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY));
+  if (!vpointer) {
+    return;
+  }
+
+  vpointer[0] = 0.0f;
+  vpointer[1] = 0.0f;
+  vpointer[2] = x;
+  vpointer[3] = y;
+
+  vpointer[4] = 1.0f;
+  vpointer[5] = 0.0f;
+  vpointer[6] = x + width;
+  vpointer[7] = y;
+
+  vpointer[8] = 1.0f;
+  vpointer[9] = 1.0f;
+  vpointer[10] = x + width;
+  vpointer[11] = y + height;
+
+  vpointer[12] = 0.0f;
+  vpointer[13] = 1.0f;
+  vpointer[14] = x;
+  vpointer[15] = y + height;
+
+  glUnmapBuffer(GL_ARRAY_BUFFER);
+}
+
 CCL_NAMESPACE_END