generating paint diff from old draw cmd buf

assets/bios/pipcode.bas

@@ -2,11 +2,12 @@
 20 s=cput(1,"POLL")
 30 if s><0 then goto 900
 40 l=cget(1,0)
-41 print("length: "+l+", pixels: "+l/3)
-50 for i=0 to l step 3
+41 REM print("length: "+l+", pixels: "+l/3)
+50 for i=0 to l-1 step 3
 60 m=peek(i)*160+peek(i+1)
 62 p=peek(i+2)
 63 poke(-1048576-m,p)
 70 next
-899 end
+80 REM poke(-1070977,0)
+90 goto 20
 900 print("Polling failed: "+s)

src/net/torvald/terrarum/modulecomputers/tsvmperipheral/WorldRadar.kt

@@ -77,6 +77,8 @@ class WorldRadar(pngfile: FileHandle) : BlockTransferInterface(false, true) {
         return sendSize
     }
 
+    private var oldCmdbuf = HashMap<Int,Byte>(1024)
+
     override fun writeoutImpl(inputData: ByteArray) {
         val inputString = inputData.trimNull().toString(VM.CHARSET)
 
@@ -116,8 +118,8 @@ class WorldRadar(pngfile: FileHandle) : BlockTransferInterface(false, true) {
                 }
             }}
 
-            cmdbuf.keys.sorted().forEach { key ->
-                val value = cmdbuf[key]!!.toInt()
+            (oldCmdbuf.keys union cmdbuf.keys).sorted().forEach { key ->
+                val value = (cmdbuf[key] ?: AIR_OUT).toInt()
                 val x = key % 256
                 val y = key / 256
                 messageComposeBuffer.write(y)
@@ -125,6 +127,7 @@ class WorldRadar(pngfile: FileHandle) : BlockTransferInterface(false, true) {
                 messageComposeBuffer.write(value)
             }
 
+            oldCmdbuf = cmdbuf
         }
     }
 }