Add Chromium-only Blender WebEngine parity work

blender-5.2.0/source/blender/gpu/GPU_primitive.hh

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+/* SPDX-FileCopyrightText: 2016 by Mike Erwin. All rights reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup gpu
+ *
+ * GPU geometric primitives
+ */
+
+#pragma once
+
+#include "BLI_assert.h"
+#include "BLI_sys_types.h"
+
+namespace blender {
+
+enum GPUPrimType : int8_t {
+  GPU_PRIM_POINTS,
+  GPU_PRIM_LINES,
+  GPU_PRIM_TRIS,
+  GPU_PRIM_LINE_STRIP,
+  GPU_PRIM_LINE_LOOP, /* GL has this, Vulkan and Metal do not */
+  GPU_PRIM_TRI_STRIP,
+  GPU_PRIM_TRI_FAN, /* Metal API does not support this. */
+
+  /* Metal API does not support ADJ primitive types but
+   * handled via the geometry-shader-alternative path. */
+  GPU_PRIM_LINES_ADJ,
+  GPU_PRIM_TRIS_ADJ,
+  GPU_PRIM_LINE_STRIP_ADJ,
+
+  GPU_PRIM_NONE,
+};
+
+/* what types of primitives does each shader expect? */
+enum GPUPimClass {
+  GPU_PRIM_CLASS_NONE = 0,
+  GPU_PRIM_CLASS_POINT = (1 << 0),
+  GPU_PRIM_CLASS_LINE = (1 << 1),
+  GPU_PRIM_CLASS_SURFACE = (1 << 2),
+  GPU_PRIM_CLASS_ANY = GPU_PRIM_CLASS_POINT | GPU_PRIM_CLASS_LINE | GPU_PRIM_CLASS_SURFACE,
+};
+
+inline int gpu_get_prim_count_from_type(uint vertex_len, GPUPrimType prim_type)
+{
+  /* does vertex_len make sense for this primitive type? */
+  if (vertex_len == 0) {
+    return 0;
+  }
+
+  switch (prim_type) {
+    case GPU_PRIM_POINTS:
+      return vertex_len;
+
+    case GPU_PRIM_LINES:
+      BLI_assert(vertex_len % 2 == 0);
+      return vertex_len / 2;
+
+    case GPU_PRIM_LINE_STRIP:
+      return vertex_len - 1;
+
+    case GPU_PRIM_LINE_LOOP:
+      return vertex_len;
+
+    case GPU_PRIM_LINES_ADJ:
+      BLI_assert(vertex_len % 4 == 0);
+      return vertex_len / 4;
+
+    case GPU_PRIM_LINE_STRIP_ADJ:
+      return vertex_len - 2;
+
+    case GPU_PRIM_TRIS:
+      BLI_assert(vertex_len % 3 == 0);
+      return vertex_len / 3;
+
+    case GPU_PRIM_TRI_STRIP:
+      BLI_assert(vertex_len >= 3);
+      return vertex_len - 2;
+
+    case GPU_PRIM_TRI_FAN:
+      BLI_assert(vertex_len >= 3);
+      return vertex_len - 2;
+
+    case GPU_PRIM_TRIS_ADJ:
+      BLI_assert(vertex_len % 6 == 0);
+      return vertex_len / 6;
+
+    default:
+      BLI_assert_unreachable();
+      return 0;
+  }
+}
+
+inline bool is_restart_compatible(GPUPrimType type)
+{
+  switch (type) {
+    case GPU_PRIM_POINTS:
+    case GPU_PRIM_LINES:
+    case GPU_PRIM_TRIS:
+    case GPU_PRIM_LINES_ADJ:
+    case GPU_PRIM_TRIS_ADJ:
+    case GPU_PRIM_NONE:
+    default: {
+      return false;
+    }
+    case GPU_PRIM_LINE_STRIP:
+    case GPU_PRIM_LINE_LOOP:
+    case GPU_PRIM_TRI_STRIP:
+    case GPU_PRIM_TRI_FAN:
+    case GPU_PRIM_LINE_STRIP_ADJ: {
+      return true;
+    }
+  }
+  return false;
+}
+
+/**
+ * TODO: Improve error checking by validating that the shader is suited for this primitive type.
+ * GPUPrimClass GPU_primtype_class(GPUPrimType);
+ * bool GPU_primtype_belongs_to_class(GPUPrimType, GPUPrimClass);
+ */
+
+}  // namespace blender