Video plugin: don't open webcam unless a feed is using it.

Author: xian

src/jsMain/kotlin/baaahs/plugin/webcam/DefaultVideoProvider.kt

@@ -16,6 +16,7 @@ actual val DefaultVideoProvider: VideoProvider
     get() = BrowserWebCamVideoProvider
 
 object BrowserWebCamVideoProvider : VideoProvider {
+    private var isOpen = false
     private var isPlaying = false
 
     private val videoElement = (document.createElement("video") as HTMLVideoElement).apply {
@@ -29,10 +30,6 @@ object BrowserWebCamVideoProvider : VideoProvider {
 
     private val logger = Logger<BrowserWebCamVideoProvider>()
 
-    init {
-        startCamera()
-    }
-
     private fun startCamera() {
         logger.info { "Initializing." }
         if (!window.isSecureContext) {
@@ -60,11 +57,20 @@ object BrowserWebCamVideoProvider : VideoProvider {
     }
 
     override fun isReady(): Boolean = isPlaying
+        .also { ensureOpen() }
 
     override fun getTextureResource(): TextureResource {
+        ensureOpen()
         return TextureResource(videoElement.unsafeCast<TexImageSource>())
     }
 
+    private fun ensureOpen() {
+        if (!isOpen) {
+            isOpen = true
+            startCamera()
+        }
+    }
+
     private val Window.isSecureContext: Boolean
         get() = asDynamic().isSecureContext as Boolean
 }

src/jvmMain/kotlin/baaahs/plugin/webcam/DefaultVideoProvider.kt

@@ -6,27 +6,28 @@ import com.danielgergely.kgl.TextureResource
 import com.github.eduramiba.webcamcapture.drivers.NativeDriver
 import com.github.sarxos.webcam.Webcam
 import org.lwjgl.opengl.GL11
+import java.awt.image.BufferedImage
 
 actual val DefaultVideoProvider: VideoProvider
     get() = WebcamCaptureVideoProvider
 
 
 object WebcamCaptureVideoProvider : VideoProvider {
     private var textureResource: TextureResource? = null
+    private var isOpen = false
 
     private val webcam: Webcam = run {
         Webcam.setDriver(NativeDriver())
         Webcam.getDefault()
     }
+    private val noImage = BufferedImage(1, 1, BufferedImage.TYPE_INT_RGB)
 
-    init {
-        webcam.open()
-    }
-
-    override fun isReady(): Boolean = true
+    override fun isReady(): Boolean = isOpen.also { ensureOpen() }
 
     override fun getTextureResource(): TextureResource {
-        val image = webcam.image
+        ensureOpen()
+
+        val image: BufferedImage = webcam.image ?: noImage
         if (textureResource == null || textureResource!!.width != image.width || textureResource!!.height != image.height) {
             val vals = ByteBuffer(image.width * image.height * 3)
             textureResource = TextureResource(
@@ -55,4 +56,9 @@ object WebcamCaptureVideoProvider : VideoProvider {
         return textureResource!!
     }
 
+    private fun ensureOpen() {
+        if (!isOpen) {
+            isOpen = webcam.open(true)
+        }
+    }
 }