Fix Cycles viewport render not updating when tweaking displacement shader.

This was disabled to avoid updating the geometry every time when the
material includes displacement, because there was no way to distinguish
between surface shader and displacement updates.

As a solution, we now compute an MD5 hash of the nodes linked to the
displacement socket, and only update the mesh if that changes.

Differential Revision: https://developer.blender.org/D3018

1 files changed, 2 insertions, 2 deletions

diff --git a/intern/cycles/render/mesh.cpp b/intern/cycles/render/mesh.cpp
index 4bf5b60a737..5bcb47deb65 100644
--- a/intern/cycles/render/mesh.cpp
+++ b/intern/cycles/render/mesh.cpp
@@ -1964,7 +1964,7 @@ void MeshManager::device_update(Device *device, DeviceScene *dscene, Scene *scen
 	/* Update normals. */
 	foreach(Mesh *mesh, scene->meshes) {
 		foreach(Shader *shader, mesh->used_shaders) {
-			if(shader->need_update_attributes)
+			if(shader->need_update_mesh)
 				mesh->need_update = true;
 		}
 
@@ -2104,7 +2104,7 @@ void MeshManager::device_update(Device *device, DeviceScene *dscene, Scene *scen
 	        << summary.full_report();
 
 	foreach(Shader *shader, scene->shaders) {
-		shader->need_update_attributes = false;
+		shader->need_update_mesh = false;
 	}
 
 	Scene::MotionType need_motion = scene->need_motion();