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Merge pull request #20 from HamAndChris/fix_linear_interpolation 

Fix type conversion bugs in linear interpolation functions
This commit is contained in:
Petteri Aimonen 2020-10-23 08:22:13 +03:00 committed by GitHub
parent 66365d5888 2859cbf31d
commit 54c1f9276a
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 33 additions and 3 deletions
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4
libfixmath/fix16.c
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@ -485,7 +485,7 @@ fix16_t fix16_mod(fix16_t x, fix16_t y)
fix16_t fix16_lerp8(fix16_t inArg0, fix16_t inArg1, uint8_t inFract)
{
int64_t tempOut = int64_mul_i32_i32(inArg0, ((1 << 8) - inFract));
int64_t tempOut = int64_mul_i32_i32(inArg0, (((int32_t)1 << 8) - inFract));
tempOut = int64_add(tempOut, int64_mul_i32_i32(inArg1, inFract));
tempOut = int64_shift(tempOut, -8);
return (fix16_t)int64_lo(tempOut);
@ -502,7 +502,7 @@ fix16_t fix16_lerp16(fix16_t inArg0, fix16_t inArg1, uint16_t inFract)
fix16_t fix16_lerp32(fix16_t inArg0, fix16_t inArg1, uint32_t inFract)
{
int64_t tempOut;
tempOut = ((int64_t)inArg0 * (0 - inFract));
tempOut = ((int64_t)inArg0 * (((int64_t)1<<32) - inFract));
tempOut += ((int64_t)inArg1 * inFract);
tempOut >>= 32;
return (fix16_t)tempOut;

2
libfixmath/int64.h
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@ -19,7 +19,7 @@ static inline int64_t int64_neg(int64_t x) { return (-x); }
static inline int64_t int64_sub(int64_t x, int64_t y) { return (x - y); }
static inline int64_t int64_shift(int64_t x, int8_t y) { return (y < 0 ? (x >> -y) : (x << y)); }
static inline int64_t int64_mul_i32_i32(int32_t x, int32_t y) { return (x * y); }
static inline int64_t int64_mul_i32_i32(int32_t x, int32_t y) { return ((int64_t)x * y); }
static inline int64_t int64_mul_i64_i32(int64_t x, int32_t y) { return (x * y); }
static inline int64_t int64_div_i64_i32(int64_t x, int32_t y) { return (x / y); }

30
unittests/fix16_unittests.c
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@ -330,6 +330,36 @@ int main()
TEST(failures == 0);
}
#ifndef FIXMATH_NO_64BIT
{
COMMENT("Running linear interpolation test cases");
TEST(fix16_lerp8(0, 2, 0) == 0);
TEST(fix16_lerp8(0, 2, 127) == 0);
TEST(fix16_lerp8(0, 2, 128) == 1);
TEST(fix16_lerp8(0, 2, 255) == 1);
TEST(fix16_lerp8(fix16_minimum, fix16_maximum, 0) == fix16_minimum);
TEST(fix16_lerp8(fix16_minimum, fix16_maximum, 255) == (fix16_maximum - (1<<24)));
TEST(fix16_lerp8(-fix16_maximum, fix16_maximum, 128) == 0);
TEST(fix16_lerp16(0, 2, 0) == 0);
TEST(fix16_lerp16(0, 2, 0x7fff) == 0);
TEST(fix16_lerp16(0, 2, 0x8000) == 1);
TEST(fix16_lerp16(0, 2, 0xffff) == 1);
TEST(fix16_lerp16(fix16_minimum, fix16_maximum, 0) == fix16_minimum);
TEST(fix16_lerp16(fix16_minimum, fix16_maximum, 0xffff) == (fix16_maximum - (1<<16)));
TEST(fix16_lerp16(-fix16_maximum, fix16_maximum, 0x8000) == 0);
TEST(fix16_lerp32(0, 2, 0) == 0);
TEST(fix16_lerp32(0, 2, 0x7fffffff) == 0);
TEST(fix16_lerp32(0, 2, 0x80000000) == 1);
TEST(fix16_lerp32(0, 2, 0xffffffff) == 1);
TEST(fix16_lerp32(fix16_minimum, fix16_maximum, 0) == fix16_minimum);
TEST(fix16_lerp32(fix16_minimum, fix16_maximum, 0xffffffff) == (fix16_maximum - 1));
TEST(fix16_lerp32(-fix16_maximum, fix16_maximum, 0x80000000) == 0);
}
#endif
if (status != 0)
fprintf(stdout, "\n\nSome tests FAILED!\n");