double the amount of spp for tiled path singlepass if the denoiser is…

… used

export/config.py

@@ -187,7 +187,7 @@ def _convert_final_engine(scene, definitions, config):
 
             definitions["tilepath.sampling.aa.size"] = tile.path_sampling_aa_size
             definitions["tile.size"] = tile.size
-            definitions["tile.multipass.enable"] = tile.multipass_enable
+            definitions["tile.multipass.enable"] = tile.multipass_enable or utils.use_two_tiled_passes(scene)
             thresh = tile.multipass_convtest_threshold
             definitions["tile.multipass.convergencetest.threshold"] = thresh
             thresh_reduct = tile.multipass_convtest_threshold_reduction

export/halt.py

@@ -1,5 +1,8 @@
 from .. import utils
 
+# noise threshold has to be a little greater than 0
+SMALLEST_NOISE_THRESH = 0.0001
+
 
 def convert(scene):
     prefix = ""
@@ -13,24 +16,14 @@ def convert(scene):
     use_noise_thresh = halt.enable and halt.use_noise_thresh
     definitions["batch.haltthreshold.stoprendering.enable"] = use_noise_thresh
 
-    # noise threshold has to be a little greater than 0
-    SMALLEST_NOISE_THRESH = 0.0001
-
     if not use_noise_thresh:
         # Set a very low noise threshold so final renders use
         # the adaptive sampling to full advantage
         definitions["batch.haltthreshold"] = SMALLEST_NOISE_THRESH
 
     if halt.enable:
-        if halt.use_time:
-            definitions["batch.halttime"] = halt.time
-        else:
-            definitions["batch.halttime"] = 0
-
-        if halt.use_samples:
-            definitions["batch.haltspp"] = halt.samples
-        else:
-            definitions["batch.haltspp"] = 0
+        halt_time = halt.time if halt.use_time else 0
+        halt_spp = halt.samples if halt.use_samples else 0
 
         if halt.use_noise_thresh:
             if halt.noise_thresh == 0:
@@ -46,7 +39,14 @@ def convert(scene):
         # All halt conditions disabled.
         # Note that we have to explicitly set halttime and haltspp to 0 because
         # these properties are not deleted during a session parsing.
-        definitions["batch.halttime"] = 0
-        definitions["batch.haltspp"] = 0
+        halt_time = 0
+        halt_spp = 0
+
+    if utils.use_two_tiled_passes(scene):
+        aa = scene.luxcore.config.tile.path_sampling_aa_size
+        halt_spp = max(halt_spp, 2 * aa**2)
+
+    definitions["batch.haltspp"] = halt_spp
+    definitions["batch.halttime"] = halt_time
 
     return utils.create_props(prefix, definitions)

properties/config.py

@@ -16,7 +16,8 @@
 )
 
 AA_SAMPLE_DESC = (
-    "How many samples to compute per pass. Higher values increase memory usage, but lead to better performance"
+    "How many samples to compute per pass. Higher values increase memory usage, but lead to better performance. "
+    "Note that this number is squared, so e.g. a value of 5 will lead to 25 samples per pixel after one pass"
 )
 
 THRESH_REDUCT_DESC = (

ui/config.py

@@ -65,6 +65,9 @@ def draw(self, context):
                 row.prop(config.tile, "size")
                 row.prop(config.tile, "path_sampling_aa_size")
 
+                if utils.use_two_tiled_passes(context.scene):
+                    layout.label("(Doubling amount of samples because of denoiser)")
+
                 layout.prop(config.tile, "multipass_enable")
                 if config.tile.multipass_enable:
                     col = layout.column(align=True)

ui/denoiser.py

@@ -12,7 +12,7 @@ def draw(context, layout):
     col = layout.column()
 
     if denoiser.enabled:
-        if config.sampler == "METROPOLIS":
+        if config.sampler == "METROPOLIS" and not config.use_tiles:
             col.label("Metropolis sampler can lead to artifacts!", icon=icons.WARNING)
         if config.engine == "BIDIR" and config.filter != "NONE":
             col.label('Set filter to "None" to reduce blurriness', icon=icons.WARNING)

utils/__init__.py

@@ -551,6 +551,15 @@ def get_halt_conditions(scene):
         return scene.luxcore.halt
 
 
+def use_two_tiled_passes(scene):
+    # When combining the denoiser with tilepath in singlepass mode, we have to render
+    # two passes (twice as many samples) because the first pass is needed as denoiser
+    # warmup, and only during the second pass can the denoiser collect sample information.
+    config = scene.luxcore.config
+    using_tilepath = config.engine == "PATH" and config.use_tiles
+    return scene.luxcore.denoiser.enabled and using_tilepath and not config.tile.multipass_enable
+
+
 def pluralize(format_str, amount):
     formatted = format_str % amount
     if amount != 1: