Cycles: use SPDX license headers

* Replace license text in headers with SPDX identifiers.
* Remove specific license info from outdated readme.txt, instead leave details
  to the source files.
* Add list of SPDX license identifiers used, and corresponding license texts.
* Update copyright dates while we're at it.

Ref D14069, T95597

11 files changed, 22 insertions, 167 deletions

diff --git a/intern/cycles/kernel/bvh/bvh.h b/intern/cycles/kernel/bvh/bvh.h
index 1797bf60720..04ccb7ceff5 100644
--- a/intern/cycles/kernel/bvh/bvh.h
+++ b/intern/cycles/kernel/bvh/bvh.h
@@ -1,18 +1,5 @@
-/*
- * Copyright 2011-2013 Blender Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright 2011-2022 Blender Foundation */
 
 /* BVH
  *
diff --git a/intern/cycles/kernel/bvh/embree.h b/intern/cycles/kernel/bvh/embree.h
index 19c4b9f6f3d..4f7e6435daf 100644
--- a/intern/cycles/kernel/bvh/embree.h
+++ b/intern/cycles/kernel/bvh/embree.h
@@ -1,18 +1,5 @@
-/*
- * Copyright 2018, Blender Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright 2018-2022 Blender Foundation. */
 
 #pragma once
 
diff --git a/intern/cycles/kernel/bvh/local.h b/intern/cycles/kernel/bvh/local.h
index 4ef6deef98d..0d05e09d75f 100644
--- a/intern/cycles/kernel/bvh/local.h
+++ b/intern/cycles/kernel/bvh/local.h
@@ -1,21 +1,6 @@
-/*
+/* SPDX-License-Identifier: Apache-2.0
  * Adapted from code Copyright 2009-2010 NVIDIA Corporation,
- * and code copyright 2009-2012 Intel Corporation
- *
- * Modifications Copyright 2011-2013, Blender Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+ * and code copyright 2009-2012 Intel Corporation */
 
 #if BVH_FEATURE(BVH_HAIR)
 #  define NODE_INTERSECT bvh_node_intersect
diff --git a/intern/cycles/kernel/bvh/metal.h b/intern/cycles/kernel/bvh/metal.h
index 5ab413d9314..04289e259a7 100644
--- a/intern/cycles/kernel/bvh/metal.h
+++ b/intern/cycles/kernel/bvh/metal.h
@@ -1,18 +1,5 @@
-/*
- * Copyright 2021 Blender Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright 2021-2022 Blender Foundation */
 
 struct MetalRTIntersectionPayload {
   RaySelfPrimitives self;
diff --git a/intern/cycles/kernel/bvh/nodes.h b/intern/cycles/kernel/bvh/nodes.h
index 71122085f69..fd475dcd5e9 100644
--- a/intern/cycles/kernel/bvh/nodes.h
+++ b/intern/cycles/kernel/bvh/nodes.h
@@ -1,18 +1,5 @@
-/*
- * Copyright 2011-2016, Blender Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright 2011-2022 Blender Foundation. */
 
 // TODO(sergey): Look into avoid use of full Transform and use 3x3 matrix and
 // 3-vector which might be faster.
diff --git a/intern/cycles/kernel/bvh/shadow_all.h b/intern/cycles/kernel/bvh/shadow_all.h
index 59a7ba63045..a5769e91a28 100644
--- a/intern/cycles/kernel/bvh/shadow_all.h
+++ b/intern/cycles/kernel/bvh/shadow_all.h
@@ -1,21 +1,8 @@
-/*
+/* SPDX-License-Identifier: Apache-2.0
  * Adapted from code Copyright 2009-2010 NVIDIA Corporation,
  * and code copyright 2009-2012 Intel Corporation
  *
- * Modifications Copyright 2011-2013, Blender Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+ * Modifications Copyright 2011-2022 Blender Foundation. */
 
 #if BVH_FEATURE(BVH_HAIR)
 #  define NODE_INTERSECT bvh_node_intersect
diff --git a/intern/cycles/kernel/bvh/traversal.h b/intern/cycles/kernel/bvh/traversal.h
index 17cd357a069..1181d4bfdee 100644
--- a/intern/cycles/kernel/bvh/traversal.h
+++ b/intern/cycles/kernel/bvh/traversal.h
@@ -1,21 +1,8 @@
-/*
+/* SPDX-License-Identifier: Apache-2.0
  * Adapted from code Copyright 2009-2010 NVIDIA Corporation,
  * and code copyright 2009-2012 Intel Corporation
  *
- * Modifications Copyright 2011-2013, Blender Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+ * Modifications Copyright 2011-2022 Blender Foundation. */
 
 #if BVH_FEATURE(BVH_HAIR)
 #  define NODE_INTERSECT bvh_node_intersect
diff --git a/intern/cycles/kernel/bvh/types.h b/intern/cycles/kernel/bvh/types.h
index f16f43333f8..e46d5c668f0 100644
--- a/intern/cycles/kernel/bvh/types.h
+++ b/intern/cycles/kernel/bvh/types.h
@@ -1,18 +1,5 @@
-/*
- * Copyright 2011-2013 Blender Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright 2011-2022 Blender Foundation */
 
 #pragma once
 
diff --git a/intern/cycles/kernel/bvh/util.h b/intern/cycles/kernel/bvh/util.h
index 39c3ecd78c0..1fd3a3f2850 100644
--- a/intern/cycles/kernel/bvh/util.h
+++ b/intern/cycles/kernel/bvh/util.h
@@ -1,18 +1,5 @@
-/*
- * Copyright 2011-2013 Blender Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright 2011-2022 Blender Foundation */
 
 #pragma once
 
diff --git a/intern/cycles/kernel/bvh/volume.h b/intern/cycles/kernel/bvh/volume.h
index 95bba4f071d..d711b3abbf4 100644
--- a/intern/cycles/kernel/bvh/volume.h
+++ b/intern/cycles/kernel/bvh/volume.h
@@ -1,21 +1,8 @@
-/*
+/* SPDX-License-Identifier: Apache-2.0
  * Adapted from code Copyright 2009-2010 NVIDIA Corporation,
  * and code copyright 2009-2012 Intel Corporation
  *
- * Modifications Copyright 2011-2014, Blender Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+ * Modifications Copyright 2011-2022 Blender Foundation. */
 
 #if BVH_FEATURE(BVH_HAIR)
 #  define NODE_INTERSECT bvh_node_intersect
diff --git a/intern/cycles/kernel/bvh/volume_all.h b/intern/cycles/kernel/bvh/volume_all.h
index 9f53e987cf1..a969bae14a1 100644
--- a/intern/cycles/kernel/bvh/volume_all.h
+++ b/intern/cycles/kernel/bvh/volume_all.h
@@ -1,21 +1,8 @@
-/*
+/* SPDX-License-Identifier: Apache-2.0
  * Adapted from code Copyright 2009-2010 NVIDIA Corporation,
  * and code copyright 2009-2012 Intel Corporation
  *
- * Modifications Copyright 2011-2014, Blender Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+ * Modifications Copyright 2011-2022 Blender Foundation. */
 
 #if BVH_FEATURE(BVH_HAIR)
 #  define NODE_INTERSECT bvh_node_intersect