Data commit

Task/Image-convolution/BBC-BASIC/image-convolution.basic

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+      Width% = 200
+      Height% = 200
+
+      DIM out&(Width%-1, Height%-1, 2)
+
+      VDU 23,22,Width%;Height%;8,16,16,128
+      *DISPLAY Lena
+      OFF
+
+      DIM filter%(2, 2)
+      filter%() = -1, -1, -1, -1, 12, -1, -1, -1, -1
+
+      REM Do the convolution:
+      FOR Y% = 1 TO Height%-2
+        FOR X% = 1 TO Width%-2
+          R% = 0 : G% = 0 : B% = 0
+          FOR I% = -1 TO 1
+            FOR J% = -1 TO 1
+              C% = TINT((X%+I%)*2, (Y%+J%)*2)
+              F% = filter%(I%+1,J%+1)
+              R% += F% * (C% AND &FF)
+              G% += F% * (C% >> 8 AND &FF)
+              B% += F% * (C% >> 16)
+            NEXT
+          NEXT
+          IF R% < 0 R% = 0 ELSE IF R% > 1020 R% = 1020
+          IF G% < 0 G% = 0 ELSE IF G% > 1020 G% = 1020
+          IF B% < 0 B% = 0 ELSE IF B% > 1020 B% = 1020
+          out&(X%, Y%, 0) = R% / 4 + 0.5
+          out&(X%, Y%, 1) = G% / 4 + 0.5
+          out&(X%, Y%, 2) = B% / 4 + 0.5
+        NEXT
+      NEXT Y%
+
+      REM Display:
+      GCOL 1
+      FOR Y% = 0 TO Height%-1
+        FOR X% = 0 TO Width%-1
+          COLOUR 1, out&(X%,Y%,0), out&(X%,Y%,1), out&(X%,Y%,2)
+          LINE X%*2,Y%*2,X%*2,Y%*2
+        NEXT
+      NEXT Y%
+
+      REPEAT
+        WAIT 1
+      UNTIL FALSE