Refactor runner and installation scripts for improved functionality

- Removed the `--disable-hiprt` flag from the runner command, simplifying the rendering options for users.
- Updated the `jiggablend-runner` script and README to reflect the removal of the HIPRT control flag, enhancing clarity in usage instructions.
- Enhanced the installation script to provide clearer examples for running the jiggablend manager and runner, improving user experience during setup.
- Implemented a more robust GPU backend detection mechanism, allowing for better compatibility with various hardware configurations.

pkg/scripts/scripts.go

@@ -11,6 +11,3 @@ var UnhideObjects string
 //go:embed scripts/render_blender.py.template
 var RenderBlenderTemplate string
 
-//go:embed scripts/detect_gpu_backends.py
-var DetectGPUBackends string
-

pkg/scripts/scripts/detect_gpu_backends.py

@@ -1,39 +0,0 @@
-# Minimal script to detect HIP (AMD) and NVIDIA (CUDA/OptiX) backends for Cycles.
-# Run with: blender -b --python detect_gpu_backends.py
-# Prints HAS_HIP and/or HAS_NVIDIA to stdout, one per line.
-import sys
-
-def main():
-    try:
-        prefs = bpy.context.preferences
-        if not hasattr(prefs, 'addons') or 'cycles' not in prefs.addons:
-            return
-        cprefs = prefs.addons['cycles'].preferences
-        has_hip = False
-        has_nvidia = False
-        for device_type in ('HIP', 'CUDA', 'OPTIX'):
-            try:
-                cprefs.compute_device_type = device_type
-                cprefs.refresh_devices()
-                devs = []
-                if hasattr(cprefs, 'get_devices'):
-                    devs = cprefs.get_devices()
-                elif hasattr(cprefs, 'devices') and cprefs.devices:
-                    devs = list(cprefs.devices) if hasattr(cprefs.devices, '__iter__') else [cprefs.devices]
-                if devs:
-                    if device_type == 'HIP':
-                        has_hip = True
-                    if device_type in ('CUDA', 'OPTIX'):
-                        has_nvidia = True
-            except Exception:
-                pass
-        if has_hip:
-            print('HAS_HIP', flush=True)
-        if has_nvidia:
-            print('HAS_NVIDIA', flush=True)
-    except Exception as e:
-        print('ERROR', str(e), file=sys.stderr, flush=True)
-        sys.exit(1)
-
-import bpy
-main()

pkg/scripts/scripts/render_blender.py.template

@@ -175,13 +175,9 @@ if render_settings_override:
 if current_engine == 'CYCLES':
     # Check if CPU rendering is forced
     force_cpu = False
-    disable_hiprt = False
     if render_settings_override and render_settings_override.get('force_cpu'):
         force_cpu = render_settings_override.get('force_cpu', False)
         print("Force CPU rendering is enabled - skipping GPU detection")
-    if render_settings_override and render_settings_override.get('disable_hiprt'):
-        disable_hiprt = render_settings_override.get('disable_hiprt', False)
-        print("Disable HIPRT flag is enabled")
     
     # Ensure Cycles addon is enabled
     try:
@@ -213,9 +209,10 @@ if current_engine == 'CYCLES':
                 traceback.print_exc()
                 sys.exit(1)
 
-        # Check all devices and choose the best GPU type
-        # Device type preference order (most performant first)
-        device_type_preference = ['OPTIX', 'CUDA', 'HIP', 'ONEAPI', 'METAL']
+        # Check all devices and choose the best GPU type.
+        # Explicit fallback policy: NVIDIA -> Intel -> AMD -> CPU.
+        # (OPTIX/CUDA are NVIDIA, ONEAPI is Intel, HIP/OPENCL are AMD)
+        device_type_preference = ['OPTIX', 'CUDA', 'ONEAPI', 'HIP', 'OPENCL']
         gpu_available = False
         best_device_type = None
         best_gpu_devices = []
@@ -325,16 +322,7 @@ if current_engine == 'CYCLES':
                 try:
                     if best_device_type == 'HIP':
                         # HIPRT (HIP Ray Tracing) for AMD GPUs
-                        if disable_hiprt:
-                            if hasattr(cycles_prefs, 'use_hiprt'):
-                                cycles_prefs.use_hiprt = False
-                                print(f"  Disabled HIPRT (HIP Ray Tracing) via runner compatibility flag")
-                            elif hasattr(scene.cycles, 'use_hiprt'):
-                                scene.cycles.use_hiprt = False
-                                print(f"  Disabled HIPRT (HIP Ray Tracing) via runner compatibility flag")
-                            else:
-                                print(f"  HIPRT toggle not available on this Blender version")
-                        elif hasattr(cycles_prefs, 'use_hiprt'):
+                        if hasattr(cycles_prefs, 'use_hiprt'):
                             cycles_prefs.use_hiprt = True
                             print(f"  Enabled HIPRT (HIP Ray Tracing) for faster rendering")
                         elif hasattr(scene.cycles, 'use_hiprt'):
@@ -356,16 +344,6 @@ if current_engine == 'CYCLES':
                             scene.cycles.use_optix_denoising = True
                             print(f"  Enabled OptiX denoising (if OptiX available)")
                         print(f"  CUDA ray tracing active")
-                    elif best_device_type == 'METAL':
-                        # MetalRT for Apple Silicon (if available)
-                        if hasattr(scene.cycles, 'use_metalrt'):
-                            scene.cycles.use_metalrt = True
-                            print(f"  Enabled MetalRT (Metal Ray Tracing) for faster rendering")
-                        elif hasattr(cycles_prefs, 'use_metalrt'):
-                            cycles_prefs.use_metalrt = True
-                            print(f"  Enabled MetalRT (Metal Ray Tracing) for faster rendering")
-                        else:
-                            print(f"  MetalRT not available")
                     elif best_device_type == 'ONEAPI':
                         # Intel oneAPI - Embree might be available
                         if hasattr(scene.cycles, 'use_embree'):