1 files changed, 87 insertions, 0 deletions
diff --git a/source/blender/draw/intern/draw_command_shared.hh b/source/blender/draw/intern/draw_command_shared.hh
new file mode 100644
index 00000000000..9fbbe23f0ce
--- /dev/null
+++ b/source/blender/draw/intern/draw_command_shared.hh
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2022 Blender Foundation. */
+
+/** \file
+ * \ingroup draw
+ */
+
+#ifndef GPU_SHADER
+#  include "BLI_span.hh"
+#  include "GPU_shader_shared_utils.h"
+
+namespace blender::draw::command {
+
+struct RecordingState;
+
+#endif
+
+/* -------------------------------------------------------------------- */
+/** \name Multi Draw
+ * \{ */
+
+/**
+ * A DrawGroup allow to split the command stream into batch-able chunks of commands with
+ * the same render state.
+ */
+struct DrawGroup {
+  /** Index of next #DrawGroup from the same header. */
+  uint next;
+
+  /** Index of the first instances after sorting. */
+  uint start;
+  /** Total number of instances (including inverted facing). Needed to issue the draw call. */
+  uint len;
+  /** Number of non inverted scaling instances in this Group. */
+  uint front_facing_len;
+
+  /** #GPUBatch values to be copied to #DrawCommand after sorting (if not overridden). */
+  int vertex_len;
+  int vertex_first;
+  int base_index;
+
+  /** Atomic counters used during command sorting. */
+  uint total_counter;
+
+#ifndef GPU_SHADER
+  /* NOTE: Union just to make sure the struct has always the same size on all platform. */
+  union {
+    struct {
+      /** For debug printing only. */
+      uint front_proto_len;
+      uint back_proto_len;
+      /** Needed to create the correct draw call. */
+      GPUBatch *gpu_batch;
+    };
+    struct {
+#endif
+      uint front_facing_counter;
+      uint back_facing_counter;
+      uint _pad0, _pad1;
+#ifndef GPU_SHADER
+    };
+  };
+#endif
+};
+BLI_STATIC_ASSERT_ALIGN(DrawGroup, 16)
+
+/**
+ * Representation of a future draw call inside a DrawGroup. This #DrawPrototype is then
+ * converted into #DrawCommand on GPU after visibility and compaction. Multiple
+ * #DrawPrototype might get merged into the same final #DrawCommand.
+ */
+struct DrawPrototype {
+  /* Reference to parent DrawGroup to get the GPUBatch vertex / instance count. */
+  uint group_id;
+  /* Resource handle associated with this call. Also reference visibility. */
+  uint resource_handle;
+  /* Number of instances. */
+  uint instance_len;
+  uint _pad0;
+};
+BLI_STATIC_ASSERT_ALIGN(DrawPrototype, 16)
+
+/** \} */
+
+#ifndef GPU_SHADER
+};  // namespace blender::draw::command
+#endif