mesa: don't ever bind NullBufferObj to glBindBuffer(Base,Range) slots

Reviewed-by: Pierre-Eric Pelloux-Prayer <[email protected]>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4466>

10 files changed, 96 insertions, 90 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
index bb2d8043f18..a200468ac2a 100644
--- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
@@ -1329,7 +1329,7 @@ upload_buffer_surface(struct brw_context *brw,
 {
    struct gl_context *ctx = &brw->ctx;
 
-   if (binding->BufferObject == ctx->Shared->NullBufferObj) {
+   if (!binding->BufferObject) {
       emit_null_surface_state(brw, NULL, out_offset);
    } else {
       ptrdiff_t size = binding->BufferObject->Size - binding->Offset;
diff --git a/src/mesa/drivers/dri/i965/genX_state_upload.c b/src/mesa/drivers/dri/i965/genX_state_upload.c
index a3738e63511..e9d3b614ee3 100644
--- a/src/mesa/drivers/dri/i965/genX_state_upload.c
+++ b/src/mesa/drivers/dri/i965/genX_state_upload.c
@@ -3125,7 +3125,7 @@ genX(upload_push_constant_packets)(struct brw_context *brw)
                const struct gl_buffer_binding *binding =
                   &ctx->UniformBufferBindings[block->Binding];
 
-               if (binding->BufferObject == ctx->Shared->NullBufferObj) {
+               if (!binding->BufferObject) {
                   static unsigned msg_id = 0;
                   _mesa_gl_debugf(ctx, &msg_id, MESA_DEBUG_SOURCE_API,
                                   MESA_DEBUG_TYPE_UNDEFINED,
diff --git a/src/mesa/main/bufferobj.c b/src/mesa/main/bufferobj.c
index 39a620b22e6..4119f3ec92c 100644
--- a/src/mesa/main/bufferobj.c
+++ b/src/mesa/main/bufferobj.c
@@ -872,7 +872,7 @@ _mesa_init_buffer_objects( struct gl_context *ctx )
    for (i = 0; i < MAX_COMBINED_UNIFORM_BUFFERS; i++) {
       _mesa_reference_buffer_object(ctx,
 				    &ctx->UniformBufferBindings[i].BufferObject,
-				    ctx->Shared->NullBufferObj);
+				    NULL);
       ctx->UniformBufferBindings[i].Offset = -1;
       ctx->UniformBufferBindings[i].Size = -1;
    }
@@ -880,7 +880,7 @@ _mesa_init_buffer_objects( struct gl_context *ctx )
    for (i = 0; i < MAX_COMBINED_SHADER_STORAGE_BUFFERS; i++) {
       _mesa_reference_buffer_object(ctx,
                                     &ctx->ShaderStorageBufferBindings[i].BufferObject,
-                                    ctx->Shared->NullBufferObj);
+                                    NULL);
       ctx->ShaderStorageBufferBindings[i].Offset = -1;
       ctx->ShaderStorageBufferBindings[i].Size = -1;
    }
@@ -888,7 +888,7 @@ _mesa_init_buffer_objects( struct gl_context *ctx )
    for (i = 0; i < MAX_COMBINED_ATOMIC_BUFFERS; i++) {
       _mesa_reference_buffer_object(ctx,
 				    &ctx->AtomicBufferBindings[i].BufferObject,
-				    ctx->Shared->NullBufferObj);
+				    NULL);
       ctx->AtomicBufferBindings[i].Offset = 0;
       ctx->AtomicBufferBindings[i].Size = 0;
    }
@@ -1079,10 +1079,9 @@ _mesa_lookup_bufferobj_err(struct gl_context *ctx, GLuint buffer,
  * of an existing buffer object.
  *
  * If the buffer ID refers to an existing buffer object, a pointer
- * to the buffer object is returned.  If the ID is zero, a pointer
- * to the shared NullBufferObj is returned.  If the ID is not zero
- * and does not refer to a valid buffer object, this function
- * returns NULL.
+ * to the buffer object is returned.  If the ID is zero, NULL is returned.
+ * If the ID is not zero and does not refer to a valid buffer object, this
+ * function returns NULL.
  *
  * This function assumes that the caller has already locked the
  * hash table mutex by calling
@@ -1091,9 +1090,12 @@ _mesa_lookup_bufferobj_err(struct gl_context *ctx, GLuint buffer,
 struct gl_buffer_object *
 _mesa_multi_bind_lookup_bufferobj(struct gl_context *ctx,
                                   const GLuint *buffers,
-                                  GLuint index, const char *caller)
+                                  GLuint index, const char *caller,
+                                  bool *error)
 {
-   struct gl_buffer_object *bufObj;
+   struct gl_buffer_object *bufObj = NULL;
+
+   *error = false;
 
    if (buffers[index] != 0) {
       bufObj = _mesa_lookup_bufferobj_locked(ctx, buffers[index]);
@@ -1102,20 +1104,20 @@ _mesa_multi_bind_lookup_bufferobj(struct gl_context *ctx,
          when they don't exist. */
       if (bufObj == &DummyBufferObject)
          bufObj = NULL;
-   } else
-      bufObj = ctx->Shared->NullBufferObj;
 
-   if (!bufObj) {
-      /* The ARB_multi_bind spec says:
-       *
-       *    "An INVALID_OPERATION error is generated if any value
-       *     in <buffers> is not zero or the name of an existing
-       *     buffer object (per binding)."
-       */
-      _mesa_error(ctx, GL_INVALID_OPERATION,
-                  "%s(buffers[%u]=%u is not zero or the name "
-                  "of an existing buffer object)",
-                  caller, index, buffers[index]);
+      if (!bufObj) {
+         /* The ARB_multi_bind spec says:
+          *
+          *    "An INVALID_OPERATION error is generated if any value
+          *     in <buffers> is not zero or the name of an existing
+          *     buffer object (per binding)."
+          */
+         _mesa_error(ctx, GL_INVALID_OPERATION,
+                     "%s(buffers[%u]=%u is not zero or the name "
+                     "of an existing buffer object)",
+                     caller, index, buffers[index]);
+         *error = true;
+      }
    }
 
    return bufObj;
@@ -1255,17 +1257,21 @@ set_buffer_multi_binding(struct gl_context *ctx,
                          gl_buffer_usage usage)
 {
    struct gl_buffer_object *bufObj;
+
    if (binding->BufferObject && binding->BufferObject->Name == buffers[idx])
       bufObj = binding->BufferObject;
-   else
-      bufObj = _mesa_multi_bind_lookup_bufferobj(ctx, buffers, idx, caller);
-
-   if (bufObj) {
-      if (bufObj == ctx->Shared->NullBufferObj)
-         set_buffer_binding(ctx, binding, bufObj, -1, -1, !range, usage);
-      else
-         set_buffer_binding(ctx, binding, bufObj, offset, size, !range, usage);
+   else {
+      bool error;
+      bufObj = _mesa_multi_bind_lookup_bufferobj(ctx, buffers, idx, caller,
+                                                 &error);
+      if (error)
+         return;
    }
+
+   if (!bufObj)
+      set_buffer_binding(ctx, binding, bufObj, -1, -1, !range, usage);
+   else
+      set_buffer_binding(ctx, binding, bufObj, offset, size, !range, usage);
 }
 
 static void
@@ -1367,7 +1373,7 @@ bind_buffer_base_uniform_buffer(struct gl_context *ctx,
 
    _mesa_reference_buffer_object(ctx, &ctx->UniformBuffer, bufObj);
 
-   if (bufObj == ctx->Shared->NullBufferObj)
+   if (!bufObj)
       bind_uniform_buffer(ctx, index, bufObj, -1, -1, GL_TRUE);
    else
       bind_uniform_buffer(ctx, index, bufObj, 0, 0, GL_TRUE);
@@ -1389,7 +1395,7 @@ bind_buffer_base_shader_storage_buffer(struct gl_context *ctx,
 
    _mesa_reference_buffer_object(ctx, &ctx->ShaderStorageBuffer, bufObj);
 
-   if (bufObj == ctx->Shared->NullBufferObj)
+   if (!bufObj)
       bind_shader_storage_buffer(ctx, index, bufObj, -1, -1, GL_TRUE);
    else
       bind_shader_storage_buffer(ctx, index, bufObj, 0, 0, GL_TRUE);
@@ -1411,7 +1417,7 @@ bind_buffer_base_atomic_buffer(struct gl_context *ctx,
 
    _mesa_reference_buffer_object(ctx, &ctx->AtomicBuffer, bufObj);
 
-   if (bufObj == ctx->Shared->NullBufferObj)
+   if (!bufObj)
       bind_atomic_buffer(ctx, index, bufObj, -1, -1, GL_TRUE);
    else
       bind_atomic_buffer(ctx, index, bufObj, 0, 0, GL_TRUE);
@@ -1484,16 +1490,14 @@ delete_buffers(struct gl_context *ctx, GLsizei n, const GLuint *ids)
             if (ctx->TransformFeedback.CurrentObject->Buffers[j] == bufObj) {
                _mesa_bind_buffer_base_transform_feedback(ctx,
                                            ctx->TransformFeedback.CurrentObject,
-                                           j, ctx->Shared->NullBufferObj,
-                                           false);
+                                           j, NULL, false);
             }
          }
 
          /* unbind UBO binding points */
          for (j = 0; j < ctx->Const.MaxUniformBufferBindings; j++) {
             if (ctx->UniformBufferBindings[j].BufferObject == bufObj) {
-               bind_buffer_base_uniform_buffer(ctx, j,
-                                               ctx->Shared->NullBufferObj);
+               bind_buffer_base_uniform_buffer(ctx, j, NULL);
             }
          }
 
@@ -1504,8 +1508,7 @@ delete_buffers(struct gl_context *ctx, GLsizei n, const GLuint *ids)
          /* unbind SSBO binding points */
          for (j = 0; j < ctx->Const.MaxShaderStorageBufferBindings; j++) {
             if (ctx->ShaderStorageBufferBindings[j].BufferObject == bufObj) {
-               bind_buffer_base_shader_storage_buffer(ctx, j,
-                                                    ctx->Shared->NullBufferObj);
+               bind_buffer_base_shader_storage_buffer(ctx, j, NULL);
             }
          }
 
@@ -1516,8 +1519,7 @@ delete_buffers(struct gl_context *ctx, GLsizei n, const GLuint *ids)
          /* unbind Atomci Buffer binding points */
          for (j = 0; j < ctx->Const.MaxAtomicBufferBindings; j++) {
             if (ctx->AtomicBufferBindings[j].BufferObject == bufObj) {
-               bind_buffer_base_atomic_buffer(ctx, j,
-                                              ctx->Shared->NullBufferObj);
+               bind_buffer_base_atomic_buffer(ctx, j, NULL);
             }
          }
 
@@ -3713,7 +3715,7 @@ bind_buffer_range_uniform_buffer(struct gl_context *ctx, GLuint index,
                                  struct gl_buffer_object *bufObj,
                                  GLintptr offset, GLsizeiptr size)
 {
-   if (bufObj == ctx->Shared->NullBufferObj) {
+   if (!bufObj) {
       offset = -1;
       size = -1;
    }
@@ -3756,7 +3758,7 @@ bind_buffer_range_shader_storage_buffer(struct gl_context *ctx,
                                         GLintptr offset,
                                         GLsizeiptr size)
 {
-   if (bufObj == ctx->Shared->NullBufferObj) {
+   if (!bufObj) {
       offset = -1;
       size = -1;
    }
@@ -3798,7 +3800,7 @@ bind_buffer_range_atomic_buffer(struct gl_context *ctx, GLuint index,
                                  struct gl_buffer_object *bufObj,
                                  GLintptr offset, GLsizeiptr size)
 {
-   if (bufObj == ctx->Shared->NullBufferObj) {
+   if (!bufObj) {
       offset = -1;
       size = -1;
    }
@@ -3933,11 +3935,9 @@ error_check_bind_shader_storage_buffers(struct gl_context *ctx,
 static void
 unbind_uniform_buffers(struct gl_context *ctx, GLuint first, GLsizei count)
 {
-   struct gl_buffer_object *bufObj = ctx->Shared->NullBufferObj;
-
    for (int i = 0; i < count; i++)
       set_buffer_binding(ctx, &ctx->UniformBufferBindings[first + i],
-                         bufObj, -1, -1, GL_TRUE, 0);
+                         NULL, -1, -1, GL_TRUE, 0);
 }
 
 /**
@@ -3948,11 +3948,9 @@ static void
 unbind_shader_storage_buffers(struct gl_context *ctx, GLuint first,
                               GLsizei count)
 {
-   struct gl_buffer_object *bufObj = ctx->Shared->NullBufferObj;
-
    for (int i = 0; i < count; i++)
       set_buffer_binding(ctx, &ctx->ShaderStorageBufferBindings[first + i],
-                         bufObj, -1, -1, GL_TRUE, 0);
+                         NULL, -1, -1, GL_TRUE, 0);
 }
 
 static void
@@ -4212,11 +4210,9 @@ unbind_xfb_buffers(struct gl_context *ctx,
                    struct gl_transform_feedback_object *tfObj,
                    GLuint first, GLsizei count)
 {
-   struct gl_buffer_object * const bufObj = ctx->Shared->NullBufferObj;
-
    for (int i = 0; i < count; i++)
       _mesa_set_transform_feedback_binding(ctx, tfObj, first + i,
-                                           bufObj, 0, 0);
+                                           NULL, 0, 0);
 }
 
 static void
@@ -4325,12 +4321,16 @@ bind_xfb_buffers(struct gl_context *ctx,
 
       if (boundBufObj && boundBufObj->Name == buffers[i])
          bufObj = boundBufObj;
-      else
-         bufObj = _mesa_multi_bind_lookup_bufferobj(ctx, buffers, i, caller);
+      else {
+         bool error;
+         bufObj = _mesa_multi_bind_lookup_bufferobj(ctx, buffers, i, caller,
+                                                    &error);
+         if (error)
+            continue;
+      }
 
-      if (bufObj)
-         _mesa_set_transform_feedback_binding(ctx, tfObj, index, bufObj,
-                                              offset, size);
+      _mesa_set_transform_feedback_binding(ctx, tfObj, index, bufObj,
+                                           offset, size);
    }
 
    _mesa_HashUnlockMutex(ctx->Shared->BufferObjects);
@@ -4371,11 +4371,9 @@ error_check_bind_atomic_buffers(struct gl_context *ctx,
 static void
 unbind_atomic_buffers(struct gl_context *ctx, GLuint first, GLsizei count)
 {
-   struct gl_buffer_object * const bufObj = ctx->Shared->NullBufferObj;
-
    for (int i = 0; i < count; i++)
       set_buffer_binding(ctx, &ctx->AtomicBufferBindings[first + i],
-                         bufObj, -1, -1, GL_TRUE, 0);
+                         NULL, -1, -1, GL_TRUE, 0);
 }
 
 static void
@@ -4492,7 +4490,7 @@ bind_buffer_range(GLenum target, GLuint index, GLuint buffer, GLintptr offset,
    }
 
    if (buffer == 0) {
-      bufObj = ctx->Shared->NullBufferObj;
+      bufObj = NULL;
    } else {
       bufObj = _mesa_lookup_bufferobj(ctx, buffer);
       if (!_mesa_handle_bind_buffer_gen(ctx, buffer,
@@ -4590,7 +4588,7 @@ _mesa_BindBufferBase(GLenum target, GLuint index, GLuint buffer)
    }
 
    if (buffer == 0) {
-      bufObj = ctx->Shared->NullBufferObj;
+      bufObj = NULL;
    } else {
       bufObj = _mesa_lookup_bufferobj(ctx, buffer);
       if (!_mesa_handle_bind_buffer_gen(ctx, buffer,
diff --git a/src/mesa/main/bufferobj.h b/src/mesa/main/bufferobj.h
index 588a6a7449b..44ac95f40e9 100644
--- a/src/mesa/main/bufferobj.h
+++ b/src/mesa/main/bufferobj.h
@@ -101,7 +101,8 @@ _mesa_lookup_bufferobj_err(struct gl_context *ctx, GLuint buffer,
 extern struct gl_buffer_object *
 _mesa_multi_bind_lookup_bufferobj(struct gl_context *ctx,
                                   const GLuint *buffers,
-                                  GLuint index, const char *caller);
+                                  GLuint index, const char *caller,
+                                  bool *error);
 
 extern void
 _mesa_initialize_buffer_object(struct gl_context *ctx,
diff --git a/src/mesa/main/get.c b/src/mesa/main/get.c
index f71fd55c814..08315517167 100644
--- a/src/mesa/main/get.c
+++ b/src/mesa/main/get.c
@@ -2531,7 +2531,8 @@ find_value_indexed(const char *func, GLenum pname, GLuint index, union value *v)
          goto invalid_value;
       if (!ctx->Extensions.ARB_uniform_buffer_object)
          goto invalid_enum;
-      v->value_int = ctx->UniformBufferBindings[index].BufferObject->Name;
+      buf = ctx->UniformBufferBindings[index].BufferObject;
+      v->value_int = buf ? buf->Name : 0;
       return TYPE_INT;
 
    case GL_UNIFORM_BUFFER_START:
@@ -2558,7 +2559,8 @@ find_value_indexed(const char *func, GLenum pname, GLuint index, union value *v)
          goto invalid_enum;
       if (index >= ctx->Const.MaxShaderStorageBufferBindings)
          goto invalid_value;
-      v->value_int = ctx->ShaderStorageBufferBindings[index].BufferObject->Name;
+      buf = ctx->ShaderStorageBufferBindings[index].BufferObject;
+      v->value_int = buf ? buf->Name : 0;
       return TYPE_INT;
 
    case GL_SHADER_STORAGE_BUFFER_START:
@@ -2593,7 +2595,8 @@ find_value_indexed(const char *func, GLenum pname, GLuint index, union value *v)
          goto invalid_enum;
       if (index >= ctx->Const.MaxAtomicBufferBindings)
          goto invalid_value;
-      v->value_int = ctx->AtomicBufferBindings[index].BufferObject->Name;
+      buf = ctx->AtomicBufferBindings[index].BufferObject;
+      v->value_int = buf ? buf->Name : 0;
       return TYPE_INT;
 
    case GL_ATOMIC_COUNTER_BUFFER_START:
diff --git a/src/mesa/main/transformfeedback.c b/src/mesa/main/transformfeedback.c
index b9cbe5a309b..315233b2c6b 100644
--- a/src/mesa/main/transformfeedback.c
+++ b/src/mesa/main/transformfeedback.c
@@ -633,7 +633,7 @@ _mesa_validate_buffer_range_xfb(struct gl_context *ctx,
       return false;
    }
 
-   if (size <= 0 && (dsa || bufObj != ctx->Shared->NullBufferObj)) {
+   if (size <= 0 && (dsa || bufObj)) {
       /* OpenGL 4.5 core profile, 6.1, pdf page 82: "An INVALID_VALUE error is
        * generated by BindBufferRange if buffer is non-zero and size is less
        * than or equal to zero."
@@ -709,20 +709,22 @@ lookup_transform_feedback_object_err(struct gl_context *ctx,
  */
 static struct gl_buffer_object *
 lookup_transform_feedback_bufferobj_err(struct gl_context *ctx,
-                                        GLuint buffer, const char* func)
+                                        GLuint buffer, const char* func,
+                                        bool *error)
 {
-   struct gl_buffer_object *bufObj;
+   struct gl_buffer_object *bufObj = NULL;
+
+   *error = false;
 
    /* OpenGL 4.5 core profile, 13.2, pdf page 444: buffer must be zero or the
     * name of an existing buffer object.
     */
-   if (buffer == 0) {
-      bufObj = ctx->Shared->NullBufferObj;
-   } else {
+   if (buffer) {
       bufObj = _mesa_lookup_bufferobj(ctx, buffer);
       if (!bufObj) {
          _mesa_error(ctx, GL_INVALID_VALUE, "%s(invalid buffer=%u)", func,
                      buffer);
+         *error = true;
       }
    }
 
@@ -742,9 +744,11 @@ _mesa_TransformFeedbackBufferBase(GLuint xfb, GLuint index, GLuint buffer)
       return;
    }
 
+   bool error;
    bufObj = lookup_transform_feedback_bufferobj_err(ctx, buffer,
-                                              "glTransformFeedbackBufferBase");
-   if (!bufObj) {
+                                              "glTransformFeedbackBufferBase",
+                                                    &error);
+   if (error) {
       return;
    }
 
@@ -765,9 +769,11 @@ _mesa_TransformFeedbackBufferRange(GLuint xfb, GLuint index, GLuint buffer,
       return;
    }
 
+   bool error;
    bufObj = lookup_transform_feedback_bufferobj_err(ctx, buffer,
-                                              "glTransformFeedbackBufferRange");
-   if (!bufObj) {
+                                              "glTransformFeedbackBufferRange",
+                                                    &error);
+   if (error) {
       return;
    }
 
@@ -793,7 +799,7 @@ bind_buffer_offset(struct gl_context *ctx,
    struct gl_buffer_object *bufObj;
 
    if (buffer == 0) {
-      bufObj = ctx->Shared->NullBufferObj;
+      bufObj = NULL;
    } else {
       bufObj = _mesa_lookup_bufferobj(ctx, buffer);
       if (!no_error && !bufObj) {
diff --git a/src/mesa/main/transformfeedback.h b/src/mesa/main/transformfeedback.h
index 729b790ed6f..c699fcb94f3 100644
--- a/src/mesa/main/transformfeedback.h
+++ b/src/mesa/main/transformfeedback.h
@@ -165,11 +165,11 @@ _mesa_set_transform_feedback_binding(struct gl_context *ctx,
 {
    _mesa_reference_buffer_object(ctx, &tfObj->Buffers[index], bufObj);
 
-   tfObj->BufferNames[index]   = bufObj->Name;
+   tfObj->BufferNames[index]   = bufObj ? bufObj->Name : 0;
    tfObj->Offset[index]        = offset;
    tfObj->RequestedSize[index] = size;
 
-   if (bufObj != ctx->Shared->NullBufferObj)
+   if (bufObj)
       bufObj->UsageHistory |= USAGE_TRANSFORM_FEEDBACK_BUFFER;
 }
 
diff --git a/src/mesa/main/varray.c b/src/mesa/main/varray.c
index f516d0008d6..7fa35879e58 100644
--- a/src/mesa/main/varray.c
+++ b/src/mesa/main/varray.c
@@ -3167,13 +3167,11 @@ vertex_array_vertex_buffers(struct gl_context *ctx,
          else if (binding->BufferObj && binding->BufferObj->Name == buffers[i])
             vbo = binding->BufferObj;
          else {
-            vbo = _mesa_multi_bind_lookup_bufferobj(ctx, buffers, i, func);
-            if (!vbo)
+            bool error;
+            vbo = _mesa_multi_bind_lookup_bufferobj(ctx, buffers, i, func,
+                                                    &error);
+            if (error)
                continue;
-
-            /* TODO: remove this hack */
-            if (vbo == ctx->Shared->NullBufferObj)
-               vbo = NULL;
          }
       } else {
          vbo = NULL;
diff --git a/src/mesa/state_tracker/st_atom_constbuf.c b/src/mesa/state_tracker/st_atom_constbuf.c
index 530e2f2ce2e..c1682544f49 100644
--- a/src/mesa/state_tracker/st_atom_constbuf.c
+++ b/src/mesa/state_tracker/st_atom_constbuf.c
@@ -212,7 +212,7 @@ st_bind_ubos(struct st_context *st, struct gl_program *prog,
          &st->ctx->UniformBufferBindings[prog->sh.UniformBlocks[i]->Binding];
       st_obj = st_buffer_object(binding->BufferObject);
 
-      cb.buffer = st_obj->buffer;
+      cb.buffer = st_obj ? st_obj->buffer : NULL;
 
       if (cb.buffer) {
          cb.buffer_offset = binding->Offset;
diff --git a/src/mesa/state_tracker/st_atom_storagebuf.c b/src/mesa/state_tracker/st_atom_storagebuf.c
index b12c9164464..2c5d4885841 100644
--- a/src/mesa/state_tracker/st_atom_storagebuf.c
+++ b/src/mesa/state_tracker/st_atom_storagebuf.c
@@ -58,7 +58,7 @@ st_bind_ssbos(struct st_context *st, struct gl_program *prog,
             prog->sh.ShaderStorageBlocks[i]->Binding];
       st_obj = st_buffer_object(binding->BufferObject);
 
-      sb->buffer = st_obj->buffer;
+      sb->buffer = st_obj ? st_obj->buffer : NULL;
 
       if (sb->buffer) {
          sb->buffer_offset = binding->Offset;