ref: 1018d7a7091fd5e0433f501a3474cdc3fec322cc
dir: /libfreetype/test_trig.c/
#include <ft2build.h> #include FT_FREETYPE_H #include FT_TRIGONOMETRY_H #include <math.h> #include <stdio.h> #define PI 3.14159265358979323846 #define SPI (PI/FT_ANGLE_PI) /* the precision in 16.16 fixed float points of the checks. Expect */ /* between 2 and 5 noise LSB bits during operations, due to */ /* rounding errors.. */ #define THRESHOLD 64 static error = 0; static void test_cos( void ) { FT_Fixed f1, f2; double d1, d2; int i; for ( i = 0; i < FT_ANGLE_2PI; i += 0x10000 ) { f1 = FT_Cos(i); d1 = f1/65536.0; d2 = cos( i*SPI ); f2 = (FT_Fixed)(d2*65536.0); if ( abs( f2-f1 ) > THRESHOLD ) { error = 1; printf( "FT_Cos[%3d] = %.7f cos[%3d] = %.7f\n", (i >> 16), f1/65536.0, (i >> 16), d2 ); } } } static void test_sin( void ) { FT_Fixed f1, f2; double d1, d2; int i; for ( i = 0; i < FT_ANGLE_2PI; i += 0x10000 ) { f1 = FT_Sin(i); d1 = f1/65536.0; d2 = sin( i*SPI ); f2 = (FT_Fixed)(d2*65536.0); if ( abs( f2-f1 ) > THRESHOLD ) { error = 1; printf( "FT_Sin[%3d] = %.7f sin[%3d] = %.7f\n", (i >> 16), f1/65536.0, (i >> 16), d2 ); } } } static void test_tan( void ) { FT_Fixed f1, f2; double d1, d2; int i; for ( i = 0; i < FT_ANGLE_PI2-0x2000000; i += 0x10000 ) { f1 = FT_Tan(i); d1 = f1/65536.0; d2 = tan( i*SPI ); f2 = (FT_Fixed)(d2*65536.0); if ( abs( f2-f1 ) > THRESHOLD ) { error = 1; printf( "FT_Tan[%3d] = %.7f tan[%3d] = %.7f\n", (i >> 16), f1/65536.0, (i >> 16), d2 ); } } } static void test_atan2( void ) { FT_Fixed c2, s2; double l, a, c1, s1; int i, j; for ( i = 0; i < FT_ANGLE_2PI; i += 0x10000 ) { l = 5.0; a = i*SPI; c1 = l * cos(a); s1 = l * sin(a); c2 = (FT_Fixed)(c1*65536.0); s2 = (FT_Fixed)(s1*65536.0); j = FT_Atan2( c2, s2 ); if ( j < 0 ) j += FT_ANGLE_2PI; if ( abs( i - j ) > 1 ) { printf( "FT_Atan2( %.7f, %.7f ) = %.5f, atan = %.5f\n", c2/65536.0, s2/65536.0, j/65536.0, i/65536.0 ); } } } static void test_unit( void ) { FT_Vector v; double a, c1, s1; FT_Fixed c2, s2; int i; for ( i = 0; i < FT_ANGLE_2PI; i += 0x10000 ) { FT_Vector_Unit( &v, i ); a = ( i*SPI ); c1 = cos(a); s1 = sin(a); c2 = (FT_Fixed)(c1*65536.0); s2 = (FT_Fixed)(s1*65536.0); if ( abs( v.x-c2 ) > THRESHOLD || abs( v.y-s2 ) > THRESHOLD ) { error = 1; printf( "FT_Vector_Unit[%3d] = ( %.7f, %.7f ) vec = ( %.7f, %.7f )\n", (i >> 16), v.x/65536.0, v.y/65536.0, c1, s1 ); } } } static void test_length( void ) { FT_Vector v; FT_Fixed l, l2; int i; for ( i = 0; i < FT_ANGLE_2PI; i += 0x10000 ) { l = (FT_Fixed)(500.0*65536.0); v.x = (FT_Fixed)( l * cos( i*SPI ) ); v.y = (FT_Fixed)( l * sin( i*SPI ) ); l2 = FT_Vector_Length( &v ); if ( abs( l2-l ) > THRESHOLD ) { error = 1; printf( "FT_Length( %.7f, %.7f ) = %.5f, length = %.5f\n", v.x/65536.0, v.y/65536.0, l2/65536.0, l/65536.0 ); } } } static void test_rotate( void ) { FT_Fixed c2, s2, c4, s4; FT_Vector v; double l, ra, a, c1, s1, cra, sra, c3, s3; int i, j, rotate; for ( rotate = 0; rotate < FT_ANGLE_2PI; rotate += 0x10000 ) { ra = rotate*SPI; cra = cos( ra ); sra = sin( ra ); for ( i = 0; i < FT_ANGLE_2PI; i += 0x10000 ) { l = 500.0; a = i*SPI; c1 = l * cos(a); s1 = l * sin(a); v.x = c2 = (FT_Fixed)(c1*65536.0); v.y = s2 = (FT_Fixed)(s1*65536.0); FT_Vector_Rotate( &v, rotate ); c3 = c1 * cra - s1 * sra; s3 = c1 * sra + s1 * cra; c4 = (FT_Fixed)(c3*65536.0); s4 = (FT_Fixed)(s3*65536.0); if ( abs( c4 - v.x ) > THRESHOLD || abs( s4 - v.y ) > THRESHOLD ) { error = 1; printf( "FT_Rotate( (%.7f,%.7f), %.5f ) = ( %.7f, %.7f ), rot = ( %.7f, %.7f )\n", c1, s1, ra, c2/65536.0, s2/65536.0, c4/65536.0, s4/65536.0 ); } } } } int main( void ) { test_cos(); test_sin(); test_tan(); test_atan2(); test_unit(); test_length(); test_rotate(); if (!error) printf( "trigonometry test ok !\n" ); return !error; }