Workbench: Hardware raytraced shadows

Implement optional hardware raytraced shadows for the Workbench engine.

They can be enabled in the `Preferences > Viewport > Quality` settings.
The option will be shown as inactive if the current backend/GPU doesn't
support hardware ray queries (only Vulkan is supported ATM).
A new `gpu.capabilities.ray_query_support_get()` has been added to the
Python API to support this UI functionality.

The visual results are the same as the stencil shadows implementation,
but it provides a significant performance boost on modern hardware.

The raytracing functionality has been implemented in a fragment shader
that mimics the output of stencil-based implementation, so the render
pipeline stays mostly the same.

Co-authored by: Jeroen Bakker

Pull Request: https://projects.blender.org/blender/blender/pulls/161047

tests/python/modules/gpu_info.py

@@ -9,6 +9,7 @@ Use this script as `blender --background --python gpu_info.py`.
 """
 import bpy
 import sys
+import json
 
 # Render with workbench to initialize the GPU backend otherwise it would fail when running in
 # background mode as the GPU backend won't be initialized.
@@ -21,9 +22,14 @@ bpy.ops.render.render(animation=False, write_still=False)
 # Import GPU module only after GPU backend has been initialized.
 import gpu
 
-print('GPU_VENDOR:' + gpu.platform.vendor_get())
-print('GPU_RENDERER:' + gpu.platform.renderer_get())
-print('GPU_VERSION:' + gpu.platform.version_get())
-print('GPU_DEVICE_TYPE:' + gpu.platform.device_type_get())
+print('<GPU_INFO>')
+print(json.dumps({
+    "VENDOR": gpu.platform.vendor_get(),
+    "RENDERER": gpu.platform.renderer_get(),
+    "VERSION": gpu.platform.version_get(),
+    "DEVICE_TYPE": gpu.platform.device_type_get(),
+    "RAY_QUERY_SUPPORT": gpu.capabilities.ray_query_support_get(),
+}))
+print('</GPU_INFO>')
 
 sys.exit(0)

tests/python/modules/render_report.py

@@ -18,6 +18,7 @@ import time
 import multiprocessing
 import traceback
 import re
+import json
 
 from pathlib import Path
 
@@ -229,7 +230,7 @@ def diff_output(test, oiiotool, fail_threshold, fail_percent, verbose, update):
     return test
 
 
-def get_gpu_device_vendor(blender, gpu_backend):
+def get_gpu_device_info(blender, gpu_backend):
     command = [
         blender,
         "--background",
@@ -239,15 +240,28 @@ def get_gpu_device_vendor(blender, gpu_backend):
         "--python",
         str(pathlib.Path(__file__).parent / "gpu_info.py")
     ]
-    try:
-        completed_process = subprocess.run(command, stdout=subprocess.PIPE, universal_newlines=True)
-        for line in completed_process.stdout.splitlines():
-            if line.startswith("GPU_DEVICE_TYPE:"):
-                vendor = line.split(':')[1].upper()
-                return vendor
-    except Exception:
-        return None
-    return None
+
+    completed_process = subprocess.run(command, stdout=subprocess.PIPE, universal_newlines=True)
+    info = completed_process.stdout.split("<GPU_INFO>")[1].split("</GPU_INFO>")[0]
+    return json.loads(info)
+
+
+def get_gpu_device_vendor(blender, gpu_backend):
+    return get_gpu_device_info(blender, gpu_backend)["DEVICE_TYPE"]
+
+
+def get_gpu_device_ray_queries_support(blender, gpu_backend):
+    command = [
+        blender,
+        "--background",
+        "--factory-startup",
+        "--gpu-backend",
+        gpu_backend,
+        "--python-expr",
+        'import gpu; gpu.init(); print("GPU_RAY_QUERIES_SUPPORT:", gpu.capabilities.ray_query_support_get())'
+    ]
+    completed_process = subprocess.run(command, stdout=subprocess.PIPE, universal_newlines=True)
+    return "GPU_RAY_QUERIES_SUPPORT: True" in completed_process.stdout
 
 
 class Report:

tests/python/workbench_render_tests.py

@@ -37,10 +37,17 @@ BLOCKLIST_AMD_VK = [
     ".*"
 ]
 
+BLOCKLIST_NON_RT = [
+    "shadows_rt.blend",
+]
+
 
 def setup():
     import bpy
 
+    # The setting will be ignored if the system/backend doesn't support ray queries.
+    bpy.context.preferences.system.use_rt_shadows = not bpy.context.scene.get("Workbench_disable_rt", False)
+
     for scene in bpy.data.scenes:
         if scene.get("Workbench_skip_setup", False):
             continue
@@ -113,11 +120,16 @@ def main():
     if args.gpu_backend == "vulkan":
         blocklist += BLOCKLIST_VULKAN
 
-    gpu_vendor = render_report.get_gpu_device_vendor(args.blender, args.gpu_backend)
+    gpu_info = render_report.get_gpu_device_info(args.blender, args.gpu_backend)
+    gpu_vendor = gpu_info["DEVICE_TYPE"]
+
     if os.getenv("BLENDER_TEST_IGNORE_VENDOR_BLOCKLIST") is None:
         if gpu_vendor == "AMD" and args.gpu_backend == "vulkan":
             blocklist += BLOCKLIST_AMD_VK
 
+    if not gpu_info["RAY_QUERY_SUPPORT"]:
+        blocklist += BLOCKLIST_NON_RT
+
     report = WorkbenchReport("Workbench", args.outdir, args.oiiotool, variation=args.gpu_backend, blocklist=blocklist)
     if args.gpu_backend == "vulkan":
         report.set_compare_engine('workbench', 'opengl')