1 files changed, 176 insertions, 0 deletions
diff --git a/source/blender/draw/intern/shaders/common_subdiv_lib.glsl b/source/blender/draw/intern/shaders/common_subdiv_lib.glsl
new file mode 100644
index 00000000000..005561964b8
--- /dev/null
+++ b/source/blender/draw/intern/shaders/common_subdiv_lib.glsl
@@ -0,0 +1,176 @@
+
+layout(local_size_x = 64, local_size_y = 1, local_size_z = 1) in;
+
+/* Uniform block for #DRWSubivUboStorage. */
+layout(std140) uniform shader_data
+{
+  /* Offsets in the buffers data where the source and destination data start. */
+  int src_offset;
+  int dst_offset;
+
+  /* Parameters for the DRWPatchMap. */
+  int min_patch_face;
+  int max_patch_face;
+  int max_depth;
+  int patches_are_triangular;
+
+  /* Coarse topology information. */
+  int coarse_poly_count;
+  uint edge_loose_offset;
+
+  /* Subdiv topology information. */
+  uint num_subdiv_loops;
+
+  /* Subdivision settings. */
+  bool optimal_display;
+
+  /* Sculpt data. */
+  bool has_sculpt_mask;
+
+  /* Masks for the extra coarse face data. */
+  uint coarse_face_select_mask;
+  uint coarse_face_smooth_mask;
+  uint coarse_face_active_mask;
+  uint coarse_face_loopstart_mask;
+
+  /* Total number of elements to process. */
+  uint total_dispatch_size;
+};
+
+uint get_global_invocation_index()
+{
+  uint invocations_per_row = gl_WorkGroupSize.x * gl_NumWorkGroups.x;
+  return gl_GlobalInvocationID.x + gl_GlobalInvocationID.y * invocations_per_row;
+}
+
+/* Structure for #CompressedPatchCoord. */
+struct BlenderPatchCoord {
+  int patch_index;
+  uint encoded_uv;
+};
+
+vec2 decode_uv(uint encoded_uv)
+{
+  float u = float((encoded_uv >> 16) & 0xFFFFu) / 65535.0;
+  float v = float(encoded_uv & 0xFFFFu) / 65535.0;
+  return vec2(u, v);
+}
+
+/* This structure is a carbon copy of OpenSubDiv's PatchTable::PatchHandle. */
+struct PatchHandle {
+  int array_index;
+  int patch_index;
+  int vertex_index;
+};
+
+/* This structure is a carbon copy of OpenSubDiv's PatchCoord. */
+struct PatchCoord {
+  int array_index;
+  int patch_index;
+  int vertex_index;
+  float u;
+  float v;
+};
+
+/* This structure is a carbon copy of OpenSubDiv's PatchCoord.QuadNode.
+ * Each child is a bitfield. */
+struct QuadNode {
+  uvec4 child;
+};
+
+bool is_set(uint i)
+{
+  /* QuadNode.Child.isSet is the first bit of the bitfield. */
+  return (i & 0x1u) != 0;
+}
+
+bool is_leaf(uint i)
+{
+  /* QuadNode.Child.isLeaf is the second bit of the bitfield. */
+  return (i & 0x2u) != 0;
+}
+
+uint get_index(uint i)
+{
+  /* QuadNode.Child.index is made of the remaining bits. */
+  return (i >> 2) & 0x3FFFFFFFu;
+}
+
+/* Duplicate of #PosNorLoop from the mesh extract CPU code.
+ * We do not use a vec3 for the position as it will be padded to a vec4 which is incompatible with
+ * the format.  */
+struct PosNorLoop {
+  float x, y, z;
+  /* TODO(kevindietrich) : figure how to compress properly as GLSL does not have char/short types,
+   * bit operations get tricky. */
+  float nx, ny, nz;
+  float flag;
+};
+
+vec3 get_vertex_pos(PosNorLoop vertex_data)
+{
+  return vec3(vertex_data.x, vertex_data.y, vertex_data.z);
+}
+
+vec3 get_vertex_nor(PosNorLoop vertex_data)
+{
+  return vec3(vertex_data.nx, vertex_data.ny, vertex_data.nz);
+}
+
+void set_vertex_pos(inout PosNorLoop vertex_data, vec3 pos)
+{
+  vertex_data.x = pos.x;
+  vertex_data.y = pos.y;
+  vertex_data.z = pos.z;
+}
+
+void set_vertex_nor(inout PosNorLoop vertex_data, vec3 nor, uint flag)
+{
+  vertex_data.nx = nor.x;
+  vertex_data.ny = nor.y;
+  vertex_data.nz = nor.z;
+  vertex_data.flag = float(flag);
+}
+
+/* Set the vertex normal but preserve the existing flag. This is for when we compute manually the
+ * vertex normals when we cannot use the limit surface, in which case the flag and the normal are
+ * set by two separate compute pass. */
+void set_vertex_nor(inout PosNorLoop vertex_data, vec3 nor)
+{
+  set_vertex_nor(vertex_data, nor, 0);
+}
+
+#define ORIGINDEX_NONE -1
+
+#ifdef SUBDIV_POLYGON_OFFSET
+layout(std430, binding = 0) readonly buffer inputSubdivPolygonOffset
+{
+  uint subdiv_polygon_offset[];
+};
+
+/* Given the index of the subdivision quad, return the index of the corresponding coarse polygon.
+ * This uses subdiv_polygon_offset and since it is a growing list of offsets, we can use binary
+ * search to locate the right index. */
+uint coarse_polygon_index_from_subdiv_quad_index(uint subdiv_quad_index, uint coarse_poly_count)
+{
+  uint first = 0;
+  uint last = coarse_poly_count;
+
+  while (first != last) {
+    uint middle = (first + last) / 2;
+
+    if (subdiv_polygon_offset[middle] < subdiv_quad_index) {
+      first = middle + 1;
+    }
+    else {
+      last = middle;
+    }
+  }
+
+  if (subdiv_polygon_offset[first] == subdiv_quad_index) {
+    return first;
+  }
+
+  return first - 1;
+}
+#endif