From b554b20c8d59d6046bdcec7c79fb61cd0e65811c Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Wed, 3 Sep 2014 15:55:19 -0400 Subject: math: Make vectors have an array instead of different fields. --- libdimension/dimension/math/vector.h | 104 +++++++++++++++++++---------------- 1 file changed, 57 insertions(+), 47 deletions(-) (limited to 'libdimension/dimension/math/vector.h') diff --git a/libdimension/dimension/math/vector.h b/libdimension/dimension/math/vector.h index 8eacee9..90b9a3d 100644 --- a/libdimension/dimension/math/vector.h +++ b/libdimension/dimension/math/vector.h @@ -32,26 +32,24 @@ /** A vector in 3 dimensions. */ typedef struct dmnsn_vector { - double x; /**< The x component. */ - double y; /**< The y component. */ - double z; /**< The z component. */ + double n[3]; /**< The components. */ } dmnsn_vector; /** A standard format string for vectors. */ #define DMNSN_VECTOR_FORMAT "<%g, %g, %g>" /** The appropriate arguements to printf() a vector. */ -#define DMNSN_VECTOR_PRINTF(v) (v).x, (v).y, (v).z +#define DMNSN_VECTOR_PRINTF(v) (v).n[0], (v).n[1], (v).n[2] /* Constants */ /** The zero vector. */ -static const dmnsn_vector dmnsn_zero = { 0.0, 0.0, 0.0 }; +static const dmnsn_vector dmnsn_zero = { { 0.0, 0.0, 0.0 } }; /** The x vector. */ -static const dmnsn_vector dmnsn_x = { 1.0, 0.0, 0.0 }; +static const dmnsn_vector dmnsn_x = { { 1.0, 0.0, 0.0 } }; /** The y vector. */ -static const dmnsn_vector dmnsn_y = { 0.0, 1.0, 0.0 }; +static const dmnsn_vector dmnsn_y = { { 0.0, 1.0, 0.0 } }; /** The z vector. */ -static const dmnsn_vector dmnsn_z = { 0.0, 0.0, 1.0 }; +static const dmnsn_vector dmnsn_z = { { 0.0, 0.0, 1.0 } }; /* Shorthand for vector construction */ @@ -59,7 +57,7 @@ static const dmnsn_vector dmnsn_z = { 0.0, 0.0, 1.0 }; DMNSN_INLINE dmnsn_vector dmnsn_new_vector(double x, double y, double z) { - dmnsn_vector v = { x, y, z }; + dmnsn_vector v = { { x, y, z } }; return v; } @@ -69,8 +67,11 @@ dmnsn_new_vector(double x, double y, double z) DMNSN_INLINE dmnsn_vector dmnsn_vector_negate(dmnsn_vector rhs) { - /* 3 negations */ - dmnsn_vector v = { -rhs.x, -rhs.y, -rhs.z }; + dmnsn_vector v; + unsigned int i; + for (i = 0; i < 3; ++i) { + v.n[i] = -rhs.n[i]; + } return v; } @@ -78,8 +79,11 @@ dmnsn_vector_negate(dmnsn_vector rhs) DMNSN_INLINE dmnsn_vector dmnsn_vector_add(dmnsn_vector lhs, dmnsn_vector rhs) { - /* 3 additions */ - dmnsn_vector v = { lhs.x + rhs.x, lhs.y + rhs.y, lhs.z + rhs.z }; + dmnsn_vector v; + unsigned int i; + for (i = 0; i < 3; ++i) { + v.n[i] = lhs.n[i] + rhs.n[i]; + } return v; } @@ -87,8 +91,11 @@ dmnsn_vector_add(dmnsn_vector lhs, dmnsn_vector rhs) DMNSN_INLINE dmnsn_vector dmnsn_vector_sub(dmnsn_vector lhs, dmnsn_vector rhs) { - /* 3 additions */ - dmnsn_vector v = { lhs.x - rhs.x, lhs.y - rhs.y, lhs.z - rhs.z }; + dmnsn_vector v; + unsigned int i; + for (i = 0; i < 3; ++i) { + v.n[i] = lhs.n[i] - rhs.n[i]; + } return v; } @@ -96,17 +103,11 @@ dmnsn_vector_sub(dmnsn_vector lhs, dmnsn_vector rhs) DMNSN_INLINE dmnsn_vector dmnsn_vector_mul(double lhs, dmnsn_vector rhs) { - /* 3 multiplications */ - dmnsn_vector v = { lhs*rhs.x, lhs*rhs.y, lhs*rhs.z }; - return v; -} - -/** Divide a vector by a scalar. */ -DMNSN_INLINE dmnsn_vector -dmnsn_vector_div(dmnsn_vector lhs, double rhs) -{ - /* 3 divisions */ - dmnsn_vector v = { lhs.x/rhs, lhs.y/rhs, lhs.z/rhs }; + dmnsn_vector v; + unsigned int i; + for (i = 0; i < 3; ++i) { + v.n[i] = lhs*rhs.n[i]; + } return v; } @@ -114,18 +115,22 @@ dmnsn_vector_div(dmnsn_vector lhs, double rhs) DMNSN_INLINE double dmnsn_vector_dot(dmnsn_vector lhs, dmnsn_vector rhs) { - /* 3 multiplications, 2 additions */ - return lhs.x*rhs.x + lhs.y*rhs.y + lhs.z*rhs.z; + double result = 0.0; + unsigned int i; + for (i = 0; i < 3; ++i) { + result += lhs.n[i]*rhs.n[i]; + } + return result; } /** Return the cross product of two vectors. */ DMNSN_INLINE dmnsn_vector dmnsn_vector_cross(dmnsn_vector lhs, dmnsn_vector rhs) { - /* 6 multiplications, 3 additions */ - dmnsn_vector v = { lhs.y*rhs.z - lhs.z*rhs.y, - lhs.z*rhs.x - lhs.x*rhs.z, - lhs.x*rhs.y - lhs.y*rhs.x }; + dmnsn_vector v; + v.n[0] = lhs.n[1]*rhs.n[2] - lhs.n[2]*rhs.n[1]; + v.n[1] = lhs.n[2]*rhs.n[0] - lhs.n[0]*rhs.n[2]; + v.n[2] = lhs.n[0]*rhs.n[1] - lhs.n[1]*rhs.n[0]; return v; } @@ -133,7 +138,6 @@ dmnsn_vector_cross(dmnsn_vector lhs, dmnsn_vector rhs) DMNSN_INLINE dmnsn_vector dmnsn_vector_proj(dmnsn_vector u, dmnsn_vector d) { - /* 1 division, 9 multiplications, 4 additions */ return dmnsn_vector_mul(dmnsn_vector_dot(u, d)/dmnsn_vector_dot(d, d), d); } @@ -141,7 +145,6 @@ dmnsn_vector_proj(dmnsn_vector u, dmnsn_vector d) DMNSN_INLINE double dmnsn_vector_norm(dmnsn_vector n) { - /* 1 sqrt, 3 multiplications, 2 additions */ return sqrt(dmnsn_vector_dot(n, n)); } @@ -149,35 +152,42 @@ dmnsn_vector_norm(dmnsn_vector n) DMNSN_INLINE dmnsn_vector dmnsn_vector_normalized(dmnsn_vector n) { - /* 1 sqrt, 3 divisions, 3 multiplications, 2 additions */ - return dmnsn_vector_div(n, dmnsn_vector_norm(n)); + return dmnsn_vector_mul(1.0/dmnsn_vector_norm(n), n); } /** Return the component-wise minimum of two vectors. */ DMNSN_INLINE dmnsn_vector dmnsn_vector_min(dmnsn_vector a, dmnsn_vector b) { - return dmnsn_new_vector( - dmnsn_min(a.x, b.x), - dmnsn_min(a.y, b.y), - dmnsn_min(a.z, b.z) - ); + dmnsn_vector v; + unsigned int i; + for (i = 0; i < 3; ++i) { + v.n[i] = dmnsn_min(a.n[i], b.n[i]); + } + return v; } /** Return the component-wise maximum of two vectors. */ DMNSN_INLINE dmnsn_vector dmnsn_vector_max(dmnsn_vector a, dmnsn_vector b) { - return dmnsn_new_vector( - dmnsn_max(a.x, b.x), - dmnsn_max(a.y, b.y), - dmnsn_max(a.z, b.z) - ); + dmnsn_vector v; + unsigned int i; + for (i = 0; i < 3; ++i) { + v.n[i] = dmnsn_max(a.n[i], b.n[i]); + } + return v; } /** Return whether a vector contains any NaN components. */ DMNSN_INLINE bool dmnsn_vector_isnan(dmnsn_vector v) { - return dmnsn_isnan(v.x) || dmnsn_isnan(v.y) || dmnsn_isnan(v.z); + unsigned int i; + for (i = 0; i < 3; ++i) { + if (dmnsn_isnan(v.n[i])) { + return true; + } + } + return false; } -- cgit v1.2.3