[Mesa-dev] [PATCH 11/19] mesa: Add helper functions for looking up multiple buffers

[Fredrik Höglund]

---

v2: Document the difference between _mesa_lookup_bufferobj() and
    _mesa_multi_bind_lookup_bufferobj().

 src/mesa/main/bufferobj.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++
 src/mesa/main/bufferobj.h | 14 ++++++++
 2 files changed, 97 insertions(+)

diff --git a/src/mesa/main/bufferobj.c b/src/mesa/main/bufferobj.c
index 4d53e5c..9a59a5a 100644
--- a/src/mesa/main/bufferobj.c
+++ b/src/mesa/main/bufferobj.c
@@ -975,6 +975,89 @@ _mesa_lookup_bufferobj(struct gl_context *ctx, GLuint buffer)
 }
 
 
+struct gl_buffer_object *
+_mesa_lookup_bufferobj_locked(struct gl_context *ctx, GLuint buffer)
+{
+   return (struct gl_buffer_object *)
+      _mesa_HashLookupLocked(ctx->Shared->BufferObjects, buffer);
+}
+
+
+void
+_mesa_begin_bufferobj_lookups(struct gl_context *ctx)
+{
+   _mesa_HashLockMutex(ctx->Shared->BufferObjects);
+}
+
+
+void
+_mesa_end_bufferobj_lookups(struct gl_context *ctx)
+{
+   _mesa_HashUnlockMutex(ctx->Shared->BufferObjects);
+}
+
+
+/**
+ * Look up a buffer object for a multi-bind function.
+ *
+ * Unlike _mesa_lookup_bufferobj(), this function also takes care
+ * of allocating the buffer object if the buffer ID has not been
+ * used before.  It will also generate a GL error if the ID
+ * is not zero or the name 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.
+ *
+ * This function assumes that the caller has already locked the
+ * hash table mutex by calling _mesa_begin_bufferobj_lookups().
+ */
+struct gl_buffer_object *
+_mesa_multi_bind_lookup_bufferobj(struct gl_context *ctx, GLenum target,
+                                  const GLuint *buffers,
+                                  GLuint index, const char *caller)
+{
+   struct gl_buffer_object *bufObj;
+
+   if (buffers[index] != 0)
+      bufObj = _mesa_lookup_bufferobj_locked(ctx, buffers[index]);
+   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 (unlikely(bufObj == &DummyBufferObject)) {
+      /* If the buffer ID has been generated but never used before,
+       * allocate a buffer object now.
+       */
+      ASSERT(ctx->Driver.NewBufferObject);
+      bufObj = ctx->Driver.NewBufferObject(ctx, buffers[index], target);
+      if (unlikely(!bufObj)) {
+         _mesa_error(ctx, GL_OUT_OF_MEMORY, "%s", caller);
+         return NULL;
+      }
+
+      _mesa_HashInsertLocked(ctx->Shared->BufferObjects,
+                             buffers[index], bufObj);
+   }
+
+   return bufObj;
+}
+
+
 /**
  * If *ptr points to obj, set ptr = the Null/default buffer object.
  * This is a helper for buffer object deletion.
diff --git a/src/mesa/main/bufferobj.h b/src/mesa/main/bufferobj.h
index e1b2a56..1fb5cd4 100644
--- a/src/mesa/main/bufferobj.h
+++ b/src/mesa/main/bufferobj.h
@@ -86,6 +86,20 @@ _mesa_update_default_objects_buffer_objects(struct gl_context *ctx);
 extern struct gl_buffer_object *
 _mesa_lookup_bufferobj(struct gl_context *ctx, GLuint buffer);
 
+extern struct gl_buffer_object *
+_mesa_lookup_bufferobj_locked(struct gl_context *ctx, GLuint buffer);
+
+extern void
+_mesa_begin_bufferobj_lookups(struct gl_context *ctx);
+
+extern void
+_mesa_end_bufferobj_lookups(struct gl_context *ctx);
+
+extern struct gl_buffer_object *
+_mesa_multi_bind_lookup_bufferobj(struct gl_context *ctx, GLenum target,
+                                  const GLuint *buffers,
+                                  GLuint index, const char *caller);
+
 extern void
 _mesa_initialize_buffer_object(struct gl_context *ctx,
                                struct gl_buffer_object *obj,
-- 
1.8.5.3