Add gradient example

2 files changed, 12 insertions, 25 deletions

diff --git a/examples/circle.sql b/examples/circle.sql
deleted file mode 100644
index 73e7118..0000000
--- a/examples/circle.sql
+++ /dev/null
@@ -1,25 +0,0 @@
-CREATE TEMP TABLE variables(name TEXT PRIMARY KEY, value Text);
-
-INSERT INTO images (width, height) VALUES (6, 6) RETURNING id;
-INSERT INTO variables VALUES ('image_id', last_insert_rowid());
-
-WITH RECURSIVE
-  image_id AS (SELECT value FROM variables WHERE name = 'image_id'),
-  horizontal(x) AS (
-    SELECT width FROM images WHERE id = (SELECT * FROM image_id)
-    UNION ALL
-    SELECT x - 1 FROM horizontal
-    WHERE x > 1
-  ),
-  vertical(y) AS (
-    SELECT height FROM images WHERE id = (SELECT * FROM image_id)
-    UNION ALL
-    SELECT y - 1 FROM vertical
-    WHERE y > 1
-  ),
-  pixels_temp(x, y, r, g, b) AS (
-    SELECT x, y, 255, 0, 0 FROM vertical, horizontal
-  )
-INSERT INTO pixels (image_id, x, y, r, g, b) SELECT (SELECT * FROM image_id), x, y, r, g, b FROM pixels_temp;
-
-DROP TABLE variables;
diff --git a/examples/gradient.sql b/examples/gradient.sql
new file mode 100644
index 0000000..9aa9010
--- /dev/null
+++ b/examples/gradient.sql
@@ -0,0 +1,12 @@
+INSERT INTO images (id, width, height) VALUES ('gradient', 200, 200) RETURNING id;
+
+WITH RECURSIVE
+  width AS (SELECT width FROM images WHERE id = 'gradient'),
+  height AS (SELECT height FROM images WHERE id = 'gradient'),
+  horizontal(x) AS
+    (SELECT * FROM width UNION ALL SELECT x - 1 FROM horizontal WHERE x > 1),
+  vertical(y) AS
+    (SELECT * FROM height UNION ALL SELECT y - 1 FROM vertical WHERE y > 1),
+  _pixels(x, y, r, g, b) AS
+    (SELECT x, y, mod(x, 255), mod(y, 255), 100 FROM vertical, horizontal)
+INSERT INTO pixels (image_id, x, y, r, g, b) SELECT 'gradient', x, y, r, g, b FROM _pixels;