Add more GPU accel support detection and more libpicam error checks (#257)

photon-core/src/main/java/org/photonvision/raspi/PicamJNI.java

@@ -85,7 +85,7 @@ public class PicamJNI {
     }
 
     public static boolean isSupported() {
-        return libraryLoaded && getSensorModel() != SensorModel.Disconnected;
+        return libraryLoaded && isVCSMSupported() && getSensorModel() != SensorModel.Disconnected;
     }
 
     public static SensorModel getSensorModel() {
@@ -105,6 +105,9 @@ public class PicamJNI {
 
     private static native String getSensorModelRaw();
 
+    // This is the main thing we need that isn't supported on Pi 4s, which makes it a good check
+    private static native boolean isVCSMSupported();
+
     // Everything here is static because multiple picams are unsupported at the hardware level
 
     /**

photon-core/src/main/java/org/photonvision/vision/camera/ZeroCopyPicamSource.java

@@ -136,19 +136,22 @@ public class ZeroCopyPicamSource extends VisionSource {
         @Override
         public void setExposure(double exposure) {
             lastExposure = exposure;
-            PicamJNI.setExposure((int) Math.round(exposure));
+            var success = PicamJNI.setExposure((int) Math.round(exposure));
+            if (!success) logger.warn("Couldn't set Pi camera exposure");
         }
 
         @Override
         public void setBrightness(int brightness) {
             lastBrightness = brightness;
-            PicamJNI.setBrightness(brightness);
+            var success = PicamJNI.setBrightness(brightness);
+            if (!success) logger.warn("Couldn't set Pi camera brightness");
         }
 
         @Override
         public void setGain(int gain) {
             lastGain = gain;
-            PicamJNI.setGain(gain);
+            var success = PicamJNI.setGain(gain);
+            if (!success) logger.warn("Couldn't set Pi camera gain");
         }
 
         @Override
@@ -159,8 +162,14 @@ public class ZeroCopyPicamSource extends VisionSource {
         @Override
         protected void setVideoModeInternal(VideoMode videoMode) {
             var mode = (FPSRatedVideoMode) videoMode;
-            PicamJNI.destroyCamera();
-            PicamJNI.createCamera(mode.width, mode.height, mode.fpsActual);
+            var success = PicamJNI.destroyCamera();
+            if (!success)
+                throw new RuntimeException(
+                        "Couldn't destroy a zero copy Pi camera while switching video modes");
+            success = PicamJNI.createCamera(mode.width, mode.height, mode.fpsActual);
+            if (!success)
+                throw new RuntimeException(
+                        "Couldn't create a zero copy Pi camera while switching video modes");
 
             // We don't store last settings on the native side, and when you change video mode these get
             // reset on MMAL's end

photon-core/src/main/java/org/photonvision/vision/frame/provider/AcceleratedPicamFrameProvider.java

@@ -35,7 +35,13 @@ public class AcceleratedPicamFrameProvider implements FrameProvider {
         this.settables = visionSettables;
 
         var vidMode = settables.getCurrentVideoMode();
-        PicamJNI.createCamera(vidMode.width, vidMode.height, vidMode.fps);
+        var success = PicamJNI.createCamera(vidMode.width, vidMode.height, vidMode.fps);
+        if (!success) {
+            success = PicamJNI.destroyCamera();
+            if (!success) throw new RuntimeException("Couldn't destroy Pi camera after init failure!");
+            throw new RuntimeException(
+                    "Couldn't initialize zero copy Pi camera; check stdout for native code logs");
+        }
     }
 
     @Override

photon-core/src/main/java/org/photonvision/vision/processes/VisionSourceManager.java

@@ -302,8 +302,9 @@ public class VisionSourceManager {
         var cameraSources = new ArrayList<VisionSource>();
         for (var configuration : camConfigs) {
             if (configuration.baseName.startsWith("mmal service") && PicamJNI.isSupported()) {
-                configuration.cameraType = CameraType.ZeroCopyPicam;
                 var piCamSrc = new ZeroCopyPicamSource(configuration);
+
+                configuration.cameraType = CameraType.ZeroCopyPicam;
                 cameraSources.add(piCamSrc);
                 continue;
             }