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.

internal/runner/blender/detect.go

@@ -1,45 +1,116 @@
-// Package blender: GPU backend detection for HIP vs NVIDIA.
+// Package blender: host GPU backend detection for AMD/NVIDIA/Intel.
 package blender
 
 import (
 	"bufio"
-	"fmt"
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strconv"
 	"strings"
-
-	"jiggablend/pkg/scripts"
 )
 
-// DetectGPUBackends runs a minimal Blender script to detect whether HIP (AMD) and/or
-// NVIDIA (CUDA/OptiX) devices are available. Use this to decide whether to force CPU
-// for Blender < 4.x (only force when HIP is present, since HIP has no official support pre-4).
-func DetectGPUBackends(blenderBinary, scriptDir string) (hasHIP, hasNVIDIA bool, err error) {
-	scriptPath := filepath.Join(scriptDir, "detect_gpu_backends.py")
-	if err := os.WriteFile(scriptPath, []byte(scripts.DetectGPUBackends), 0644); err != nil {
-		return false, false, fmt.Errorf("write detection script: %w", err)
-	}
-	defer os.Remove(scriptPath)
+// DetectGPUBackends detects whether AMD, NVIDIA, and/or Intel GPUs are available
+// using host-level hardware probing only.
+func DetectGPUBackends() (hasAMD, hasNVIDIA, hasIntel bool, ok bool) {
+	return detectGPUBackendsFromHost()
+}
 
-	env := TarballEnv(blenderBinary, os.Environ())
-	cmd := exec.Command(blenderBinary, "-b", "--python", scriptPath)
-	cmd.Env = env
-	cmd.Dir = scriptDir
-	out, err := cmd.CombinedOutput()
+func detectGPUBackendsFromHost() (hasAMD, hasNVIDIA, hasIntel bool, ok bool) {
+	if amd, nvidia, intel, found := detectGPUBackendsFromDRM(); found {
+		return amd, nvidia, intel, true
+	}
+	if amd, nvidia, intel, found := detectGPUBackendsFromLSPCI(); found {
+		return amd, nvidia, intel, true
+	}
+	return false, false, false, false
+}
+
+func detectGPUBackendsFromDRM() (hasAMD, hasNVIDIA, hasIntel bool, ok bool) {
+	entries, err := os.ReadDir("/sys/class/drm")
 	if err != nil {
-		return false, false, fmt.Errorf("run blender detection: %w (output: %s)", err, string(out))
+		return false, false, false, false
+	}
+
+	for _, entry := range entries {
+		name := entry.Name()
+		if !isDRMCardNode(name) {
+			continue
+		}
+
+		vendorPath := filepath.Join("/sys/class/drm", name, "device", "vendor")
+		vendorRaw, err := os.ReadFile(vendorPath)
+		if err != nil {
+			continue
+		}
+		vendor := strings.TrimSpace(strings.ToLower(string(vendorRaw)))
+		switch vendor {
+		case "0x1002":
+			hasAMD = true
+			ok = true
+		case "0x10de":
+			hasNVIDIA = true
+			ok = true
+		case "0x8086":
+			hasIntel = true
+			ok = true
+		}
+	}
+
+	return hasAMD, hasNVIDIA, hasIntel, ok
+}
+
+func isDRMCardNode(name string) bool {
+	if !strings.HasPrefix(name, "card") {
+		return false
+	}
+	if strings.Contains(name, "-") {
+		// Connector entries like card0-DP-1 are not GPU device nodes.
+		return false
+	}
+	if len(name) <= len("card") {
+		return false
+	}
+	_, err := strconv.Atoi(strings.TrimPrefix(name, "card"))
+	return err == nil
+}
+
+func detectGPUBackendsFromLSPCI() (hasAMD, hasNVIDIA, hasIntel bool, ok bool) {
+	if _, err := exec.LookPath("lspci"); err != nil {
+		return false, false, false, false
+	}
+
+	out, err := exec.Command("lspci").CombinedOutput()
+	if err != nil {
+		return false, false, false, false
 	}
 
 	scanner := bufio.NewScanner(strings.NewReader(string(out)))
 	for scanner.Scan() {
-		line := strings.TrimSpace(scanner.Text())
-		switch line {
-		case "HAS_HIP":
-			hasHIP = true
-		case "HAS_NVIDIA":
+		line := strings.ToLower(strings.TrimSpace(scanner.Text()))
+		if !isGPUControllerLine(line) {
+			continue
+		}
+
+		if strings.Contains(line, "nvidia") {
 			hasNVIDIA = true
+			ok = true
+		}
+		if strings.Contains(line, "amd") || strings.Contains(line, "ati") || strings.Contains(line, "radeon") {
+			hasAMD = true
+			ok = true
+		}
+		if strings.Contains(line, "intel") {
+			hasIntel = true
+			ok = true
 		}
 	}
-	return hasHIP, hasNVIDIA, scanner.Err()
+
+	return hasAMD, hasNVIDIA, hasIntel, ok
+}
+
+func isGPUControllerLine(line string) bool {
+	return strings.Contains(line, "vga compatible controller") ||
+		strings.Contains(line, "3d controller") ||
+		strings.Contains(line, "display controller")
 }