EEVEE-Next: Cryptomatte render passes.

This change adds cryptomatte render passes to EEVEE-Next. Due to the upcoming viewport
compositor we also improved cryptomatte so it will be real-time. This also allows viewing
the cryptomatte passes in the viewport directly.

{F13482749}

A surface shader would store any active cryptomatte layer to a texture. Object hash is stored
as R, Asset hash as G and Material hash as B. Hashes are only calculated when the cryptomatte
layer is active to reduce any unneeded work.

During film accumulation the hashes are separated and stored in a texture array that matches
the cryptomatte standard. For the real-time use case sorting is skipped. For final rendering
the samples are sorted and normalized.

NOTE: Eventually we should also do sample normalization in the viewport in order to extract the correct
mask when using the viewport compositor.

Reviewed By: fclem

Maniphest Tasks: T99390

Differential Revision: https://developer.blender.org/D15753

3 files changed, 67 insertions, 40 deletions

diff --git a/source/blender/blenkernel/BKE_cryptomatte.h b/source/blender/blenkernel/BKE_cryptomatte.h
index 56049ecf405..b2024f09278 100644
--- a/source/blender/blenkernel/BKE_cryptomatte.h
+++ b/source/blender/blenkernel/BKE_cryptomatte.h
@@ -25,6 +25,8 @@ struct CryptomatteSession *BKE_cryptomatte_init(void);
 struct CryptomatteSession *BKE_cryptomatte_init_from_render_result(
     const struct RenderResult *render_result);
 struct CryptomatteSession *BKE_cryptomatte_init_from_scene(const struct Scene *scene);
+struct CryptomatteSession *BKE_cryptomatte_init_from_view_layer(
+    const struct ViewLayer *view_layer);
 void BKE_cryptomatte_free(struct CryptomatteSession *session);
 void BKE_cryptomatte_add_layer(struct CryptomatteSession *session, const char *layer_name);
 
diff --git a/source/blender/blenkernel/BKE_cryptomatte.hh b/source/blender/blenkernel/BKE_cryptomatte.hh
index cd3f8dc9f58..dd08f7b5c4f 100644
--- a/source/blender/blenkernel/BKE_cryptomatte.hh
+++ b/source/blender/blenkernel/BKE_cryptomatte.hh
@@ -12,6 +12,7 @@
 
 #include "BKE_cryptomatte.h"
 
+#include "BLI_hash_mm3.h"
 #include "BLI_map.hh"
 #include "BLI_string_ref.hh"
 
@@ -54,10 +55,14 @@ struct CryptomatteHash {
   uint32_t hash;
 
   CryptomatteHash(uint32_t hash);
-  CryptomatteHash(const char *name, int name_len);
-  static CryptomatteHash from_hex_encoded(blender::StringRef hex_encoded);
+  CryptomatteHash(const char *name, int name_len)
+  {
+    hash = BLI_hash_mm3((const unsigned char *)name, name_len, 0);
+  }
 
+  static CryptomatteHash from_hex_encoded(blender::StringRef hex_encoded);
   std::string hex_encoded() const;
+
   /**
    * Convert a cryptomatte hash to a float.
    *
@@ -70,7 +75,20 @@ struct CryptomatteHash {
    *
    * Note that this conversion assumes to be running on a L-endian system.
    */
-  float float_encoded() const;
+  float float_encoded() const
+  {
+    uint32_t mantissa = hash & ((1 << 23) - 1);
+    uint32_t exponent = (hash >> 23) & ((1 << 8) - 1);
+    exponent = MAX2(exponent, (uint32_t)1);
+    exponent = MIN2(exponent, (uint32_t)254);
+    exponent = exponent << 23;
+    uint32_t sign = (hash >> 31);
+    sign = sign << 31;
+    uint32_t float_bits = sign | exponent | mantissa;
+    float f;
+    memcpy(&f, &float_bits, sizeof(uint32_t));
+    return f;
+  }
 };
 
 struct CryptomatteLayer {
@@ -107,6 +125,8 @@ struct CryptomatteStampDataCallbackData {
 
 const blender::Vector<std::string> &BKE_cryptomatte_layer_names_get(
     const CryptomatteSession &session);
+CryptomatteLayer *BKE_cryptomatte_layer_get(CryptomatteSession &session,
+                                            const StringRef layer_name);
 
 struct CryptomatteSessionDeleter {
   void operator()(CryptomatteSession *session)
diff --git a/source/blender/blenkernel/intern/cryptomatte.cc b/source/blender/blenkernel/intern/cryptomatte.cc
index 102bda0f2b6..72204f6624e 100644
--- a/source/blender/blenkernel/intern/cryptomatte.cc
+++ b/source/blender/blenkernel/intern/cryptomatte.cc
@@ -41,7 +41,9 @@ struct CryptomatteSession {
   CryptomatteSession() = default;
   CryptomatteSession(const Main *bmain);
   CryptomatteSession(StampData *stamp_data);
+  CryptomatteSession(const ViewLayer *view_layer);
   CryptomatteSession(const Scene *scene);
+  void init(const ViewLayer *view_layer);
 
   blender::bke::cryptomatte::CryptomatteLayer &add_layer(std::string layer_name);
   std::optional<std::string> operator[](float encoded_hash) const;
@@ -54,13 +56,15 @@ struct CryptomatteSession {
 CryptomatteSession::CryptomatteSession(const Main *bmain)
 {
   if (!BLI_listbase_is_empty(&bmain->objects)) {
-    blender::bke::cryptomatte::CryptomatteLayer &objects = add_layer("CryptoObject");
+    blender::bke::cryptomatte::CryptomatteLayer &objects = add_layer(
+        RE_PASSNAME_CRYPTOMATTE_OBJECT);
     LISTBASE_FOREACH (ID *, id, &bmain->objects) {
       objects.add_ID(*id);
     }
   }
   if (!BLI_listbase_is_empty(&bmain->materials)) {
-    blender::bke::cryptomatte::CryptomatteLayer &materials = add_layer("CryptoMaterial");
+    blender::bke::cryptomatte::CryptomatteLayer &materials = add_layer(
+        RE_PASSNAME_CRYPTOMATTE_MATERIAL);
     LISTBASE_FOREACH (ID *, id, &bmain->materials) {
       materials.add_ID(*id);
     }
@@ -83,24 +87,34 @@ CryptomatteSession::CryptomatteSession(StampData *stamp_data)
       false);
 }
 
+CryptomatteSession::CryptomatteSession(const ViewLayer *view_layer)
+{
+  init(view_layer);
+}
+
 CryptomatteSession::CryptomatteSession(const Scene *scene)
 {
-  LISTBASE_FOREACH (ViewLayer *, view_layer, &scene->view_layers) {
-    eViewLayerCryptomatteFlags cryptoflags = static_cast<eViewLayerCryptomatteFlags>(
-        view_layer->cryptomatte_flag & VIEW_LAYER_CRYPTOMATTE_ALL);
-    if (cryptoflags == 0) {
-      cryptoflags = static_cast<eViewLayerCryptomatteFlags>(VIEW_LAYER_CRYPTOMATTE_ALL);
-    }
+  LISTBASE_FOREACH (const ViewLayer *, view_layer, &scene->view_layers) {
+    init(view_layer);
+  }
+}
 
-    if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_OBJECT) {
-      add_layer(blender::StringRefNull(view_layer->name) + ".CryptoObject");
-    }
-    if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_ASSET) {
-      add_layer(blender::StringRefNull(view_layer->name) + ".CryptoAsset");
-    }
-    if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_MATERIAL) {
-      add_layer(blender::StringRefNull(view_layer->name) + ".CryptoMaterial");
-    }
+void CryptomatteSession::init(const ViewLayer *view_layer)
+{
+  eViewLayerCryptomatteFlags cryptoflags = static_cast<eViewLayerCryptomatteFlags>(
+      view_layer->cryptomatte_flag & VIEW_LAYER_CRYPTOMATTE_ALL);
+  if (cryptoflags == 0) {
+    cryptoflags = static_cast<eViewLayerCryptomatteFlags>(VIEW_LAYER_CRYPTOMATTE_ALL);
+  }
+
+  if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_OBJECT) {
+    add_layer(blender::StringRefNull(view_layer->name) + "." + RE_PASSNAME_CRYPTOMATTE_OBJECT);
+  }
+  if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_ASSET) {
+    add_layer(blender::StringRefNull(view_layer->name) + "." + RE_PASSNAME_CRYPTOMATTE_ASSET);
+  }
+  if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_MATERIAL) {
+    add_layer(blender::StringRefNull(view_layer->name) + "." + RE_PASSNAME_CRYPTOMATTE_MATERIAL);
   }
 }
 
@@ -142,6 +156,12 @@ struct CryptomatteSession *BKE_cryptomatte_init_from_scene(const struct Scene *s
   return session;
 }
 
+struct CryptomatteSession *BKE_cryptomatte_init_from_view_layer(const struct ViewLayer *view_layer)
+{
+  CryptomatteSession *session = new CryptomatteSession(view_layer);
+  return session;
+}
+
 void BKE_cryptomatte_add_layer(struct CryptomatteSession *session, const char *layer_name)
 {
   session->add_layer(layer_name);
@@ -485,11 +505,6 @@ CryptomatteHash::CryptomatteHash(uint32_t hash) : hash(hash)
 {
 }
 
-CryptomatteHash::CryptomatteHash(const char *name, const int name_len)
-{
-  hash = BLI_hash_mm3((const unsigned char *)name, name_len, 0);
-}
-
 CryptomatteHash CryptomatteHash::from_hex_encoded(blender::StringRef hex_encoded)
 {
   CryptomatteHash result(0);
@@ -504,21 +519,6 @@ std::string CryptomatteHash::hex_encoded() const
   return encoded.str();
 }
 
-float CryptomatteHash::float_encoded() const
-{
-  uint32_t mantissa = hash & ((1 << 23) - 1);
-  uint32_t exponent = (hash >> 23) & ((1 << 8) - 1);
-  exponent = MAX2(exponent, (uint32_t)1);
-  exponent = MIN2(exponent, (uint32_t)254);
-  exponent = exponent << 23;
-  uint32_t sign = (hash >> 31);
-  sign = sign << 31;
-  uint32_t float_bits = sign | exponent | mantissa;
-  float f;
-  memcpy(&f, &float_bits, sizeof(uint32_t));
-  return f;
-}
-
 std::unique_ptr<CryptomatteLayer> CryptomatteLayer::read_from_manifest(
     blender::StringRefNull manifest)
 {
@@ -625,4 +625,9 @@ const blender::Vector<std::string> &BKE_cryptomatte_layer_names_get(
   return session.layer_names;
 }
 
+CryptomatteLayer *BKE_cryptomatte_layer_get(CryptomatteSession &session, StringRef layer_name)
+{
+  return session.layers.lookup_ptr(layer_name);
+}
+
 }  // namespace blender::bke::cryptomatte