misc/libfreetype/src/tools/cordic.py
branchwebgl
changeset 9521 8054d9d775fd
parent 9282 92af50454cf2
parent 9519 b8b5c82eb61b
child 9950 2759212a27de
--- a/misc/libfreetype/src/tools/cordic.py	Fri Oct 11 11:55:31 2013 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,79 +0,0 @@
-# compute arctangent table for CORDIC computations in fttrigon.c
-import sys, math
-
-#units  = 64*65536.0   # don't change !!
-units  = 256
-scale  = units/math.pi
-shrink = 1.0
-comma  = ""
-
-def calc_val( x ):
-    global units, shrink
-    angle  = math.atan(x)
-    shrink = shrink * math.cos(angle)
-    return angle/math.pi * units
-
-def  print_val( n, x ):
-    global comma
-
-    lo  = int(x)
-    hi  = lo + 1
-    alo = math.atan(lo)
-    ahi = math.atan(hi)
-    ax  = math.atan(2.0**n)
-
-    errlo = abs( alo - ax )
-    errhi = abs( ahi - ax )
-
-    if ( errlo < errhi ):
-      hi = lo
-
-    sys.stdout.write( comma + repr( int(hi) ) )
-    comma = ", "
-
-
-print ""
-print "table of arctan( 1/2^n ) for PI = " + repr(units/65536.0) + " units"
-
-# compute range of "i"
-r = [-1]
-r = r + range(32)
-
-for n in r:
-
-    if n >= 0:
-        x = 1.0/(2.0**n)    # tangent value
-    else:
-        x = 2.0**(-n)
-
-    angle  = math.atan(x)    # arctangent
-    angle2 = angle*scale     # arctangent in FT_Angle units
-
-    # determine which integer value for angle gives the best tangent
-    lo  = int(angle2)
-    hi  = lo + 1
-    tlo = math.tan(lo/scale)
-    thi = math.tan(hi/scale)
-
-    errlo = abs( tlo - x )
-    errhi = abs( thi - x )
-
-    angle2 = hi
-    if errlo < errhi:
-        angle2 = lo
-
-    if angle2 <= 0:
-        break
-
-    sys.stdout.write( comma + repr( int(angle2) ) )
-    comma = ", "
-
-    shrink = shrink * math.cos( angle2/scale)
-
-
-print
-print "shrink factor    = " + repr( shrink )
-print "shrink factor 2  = " + repr( shrink * (2.0**32) )
-print "expansion factor = " + repr(1/shrink)
-print ""
-