--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hostsupport/hostopenvg/genheader/make_alpha_rcp.py	Wed Oct 06 17:59:01 2010 +0100
@@ -0,0 +1,78 @@
+#! /usr/bin/python
+# Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and /or associated documentation files
+# (the "Materials "), to deal in the Materials without restriction,
+# including without limitation the rights to use, copy, modify, merge,
+# publish, distribute, sublicense, and/or sell copies of the Materials,
+# and to permit persons to whom the Materials are furnished to do so,
+# subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Materials.
+#
+# THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+# DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE MATERIALS OR
+# THE USE OR OTHER DEALINGS IN THE MATERIALS.
+
+from c_utils import *
+
+# \todo Might require a more accurate table for lookups.
+
+RCP_BITS = 8
+RCP_DATATYPE_BITS = RCP_BITS + 8
+
+def tofx(f):
+    return int(f * (1<<RCP_BITS) + 0.5)
+
+def alpha_to_uintrcp(alpha):
+    if alpha == 0:
+        rf = 255 # Max out
+    else:
+        rf = 255.0/alpha
+    i = tofx(rf)
+    assert(i < (1<<RCP_DATATYPE_BITS))
+    return i
+
+def test_error():
+    max_err = 0
+    for alpha in range(1, 256):
+        for color in range(0, 256):
+            if color > alpha:
+                # Undefined result -> ignore test.
+                continue
+            fa = alpha / 255.0
+            fc = color / 255.0
+            ex = fc / fa
+            exi = int(ex * 255.0 + 0.5)
+            ia = alpha_to_uintrcp(alpha)
+            m = (ia * color) >> RCP_BITS
+            e = abs(exi - m)
+            if e > max_err:
+                print ia * color
+                print alpha, color, exi, m, fa, fc, ex, ia / float(1<<RCP_BITS), ia
+                max_err = e
+    print max_err
+    return max_err
+
+if __name__ == '__main__':
+    vals = []
+    for alpha in range(0, 256):
+       i = alpha_to_uintrcp(alpha)
+       vals += [i]
+    
+    begin_include_guard("_SFALPHARCP_H_") 
+    print ""
+    make_include("riDefs.h")
+    print ""
+    begin_namespace("OpenVGRI")
+    make_constant("ALPHA_RCP_BITS", RCP_BITS)
+    make_array("static const", "RIuint16", "sc_alphaRcp", vals, hex_formatter)
+    end_namespace()
+    end_include_guard()
+