added checkerpick test script with example for mouse motion selection on a grid

git-svn-id: svn://anubis/anaglym/trunk@308 99a6e188-d820-4881-8870-2d33a10e2619

.todo

@@ -1,2 +1,3 @@
+add ag.pickOne
 add gradient functionality
 fix blending of overlay drawing routines

tests/checkerpick.lua

@@ -0,0 +1,26 @@
+function init_event()
+    local checker_texture = ag.loadTexture("checker.jpg")
+    ground = ag.createBox(8, 8, 0.1, {static = true})
+    ground:setTexture(checker_texture)
+    ag.setCamera(10, -10, 10, 0, 0, 0)
+    hilite = ag.createBox(2, 2, 0.1, {static = true})
+    hilite:setColor(0.3, 0.5, 1)
+    hilite:setPosition(1, 1, 0.1)
+
+    ag.setCursorVisible(true)
+end
+
+function mouse_motion_event(x, y, xrel, yrel)
+    objects = ag.pickObjects(x, y)
+    for i, obj in ipairs(objects) do
+        if obj == ground then
+            x = obj.pick_pos[1]
+            y = obj.pick_pos[2]
+            xp = 2 * math.floor(x / 2) + 1
+            yp = 2 * math.floor(y / 2) + 1
+            if xp >= -3 and xp <= 3 and yp >= -3 and yp <= 3 then
+                hilite:setPosition(xp, yp, 0.1)
+            end
+        end
+    end
+end