/**
* graphene_vec3_subtract:
* @a: a #graphene_vec3_t
* @b: a #graphene_vec3_t
* @res: (out caller-allocates): return location for the resulting vector
*
* Subtracts each component of the two given vectors.
*
* Since: 1.0
*/
void
graphene_vec3_subtract (const graphene_vec3_t *a,
const graphene_vec3_t *b,
graphene_vec3_t *res)
{
res->value = graphene_simd4f_sub (a->value, b->value);
}
/**
* graphene_point_near:
* @a: a #graphene_point_t
* @b: a #graphene_point_t
* @epsilon: threshold between the two points
*
* Checks whether the two points @a and @b are within
* the threshold of @epsilon.
*
* Returns: `true` if the distance is within @epsilon
*
* Since: 1.0
*/
bool
graphene_point_near (const graphene_point_t *a,
const graphene_point_t *b,
float epsilon)
{
graphene_simd4f_t s_a, s_b, res;
if (a == b)
return true;
s_a = graphene_simd4f_init (a->x, a->y, 0.f, 0.f);
s_b = graphene_simd4f_init (b->x, b->y, 0.f, 0.f);
res = graphene_simd4f_sub (s_a, s_b);
return fabsf (graphene_simd4f_get_x (res)) < epsilon &&
fabsf (graphene_simd4f_get_y (res)) < epsilon;
}
/**
* graphene_vec2_near:
* @v1: a #graphene_vec2_t
* @v2: a #graphene_vec2_t
* @epsilon: the threshold between the two vectors
*
* Compares the two given #graphene_vec2_t vectors and checks
* whether their values are within the given @epsilon.
*
* Returns: `true` if the two vectors are near each other
*
* Since: 1.2
*/
bool
graphene_vec2_near (const graphene_vec2_t *v1,
const graphene_vec2_t *v2,
float epsilon)
{
float epsilon_sq = epsilon * epsilon;
graphene_simd4f_t d;
if (v1 == v2)
return true;
if (v1 == NULL || v2 == NULL)
return false;
d = graphene_simd4f_sub (v1->value, v2->value);
return graphene_simd4f_get_x (graphene_simd4f_dot2 (d, d)) < epsilon_sq;
}
static void
matrix_project (gpointer data_)
{
MatrixBench *data = data_;
int i;
for (i = 0; i < N_ROUNDS; i++)
{
graphene_simd4f_t pback, qback, uback;
float t, x, y;
graphene_simd4x4f_vec3_mul (&(data->a[i]), &(data->pa[i]), &pback);
graphene_simd4x4f_vec3_mul (&(data->a[i]), &(data->qa[i]), &qback);
uback = graphene_simd4f_sub (data->pa[i], pback);
t = -1.0f * graphene_simd4f_get_z (pback) / graphene_simd4f_get_z (uback);
x = graphene_simd4f_get_x (pback) + t * graphene_simd4f_get_x (uback);
y = graphene_simd4f_get_y (pback) + t * graphene_simd4f_get_y (uback);
data->ra[i] = graphene_simd4f_init (x, y, 0.f, 0.f);
}
}
/**
* graphene_point_distance:
* @a: a #graphene_point_t
* @b: a #graphene_point_t
* @d_x: (out) (optional): distance component on the X axis
* @d_y: (out) (optional): distance component on the Y axis
*
* Computes the distance between @a and @b.
*
* Returns: the distance between the two points
*
* Since: 1.0
*/
float
graphene_point_distance (const graphene_point_t *a,
const graphene_point_t *b,
float *d_x,
float *d_y)
{
graphene_simd4f_t s_a, s_b, res;
if (a == b)
return 0.f;
s_a = graphene_simd4f_init (a->x, a->y, 0.f, 0.f);
s_b = graphene_simd4f_init (b->x, b->y, 0.f, 0.f);
res = graphene_simd4f_sub (s_a, s_b);
if (d_x != NULL)
*d_x = fabsf (graphene_simd4f_get_x (res));
if (d_y != NULL)
*d_y = fabsf (graphene_simd4f_get_y (res));
return graphene_simd4f_get_x (graphene_simd4f_length2 (res));
}
/**
* graphene_simd4f_sub:
* @a: a #graphene_simd4f_t
* @b: a #graphene_simd4f_t
*
* Creates a new #graphene_simd4f_t vector where each
* component is the subtraction of the respective components
* in @a and @b.
*
* |[<!-- lanugage="plain" -->
* {
* .x = a.x - b.x,
* .y = a.y - b.y,
* .z = a.z - b.z,
* .w = a.w - b.w
* }
* ]|
*
* Returns: the subtraction vector
*
* Since: 1.0
*/
graphene_simd4f_t
(graphene_simd4f_sub) (const graphene_simd4f_t a,
const graphene_simd4f_t b)
{
return graphene_simd4f_sub (a, b);
}
static gboolean
matrix_decompose_3d (const graphene_matrix_t *m,
graphene_point3d_t *scale_r,
float shear_r[3],
graphene_quaternion_t *rotate_r,
graphene_point3d_t *translate_r,
graphene_vec4_t *perspective_r)
{
graphene_matrix_t local, perspective;
float shear_xy, shear_xz, shear_yz;
float scale_x, scale_y, scale_z;
graphene_simd4f_t dot, cross;
if (graphene_matrix_get_value (m, 3, 3) == 0.f)
return FALSE;
local = *m;
/* normalize the matrix */
graphene_matrix_normalize (&local, &local);
/* perspective is used to solve for the perspective component,
* but it also provides an easy way to test for singularity of
* the upper 3x3 component
*/
perspective = local;
perspective.value.w = graphene_simd4f_init (0.f, 0.f, 0.f, 1.f);
if (graphene_matrix_determinant (&perspective) == 0.f)
return FALSE;
/* isolate the perspective */
if (graphene_simd4f_is_zero3 (local.value.w))
{
graphene_matrix_t tmp;
/* perspective_r is the right hand side of the equation */
perspective_r->value = local.value.w;
/* solve the equation by inverting perspective and multiplying
* the inverse with the perspective vector
*/
graphene_matrix_inverse (&perspective, &tmp);
graphene_matrix_transpose_transform_vec4 (&tmp, perspective_r, perspective_r);
/* clear the perspective partition */
local.value.w = graphene_simd4f_init (0.f, 0.f, 0.f, 1.f);
}
else
graphene_vec4_init (perspective_r, 0.f, 0.f, 0.f, 1.f);
/* next, take care of the translation partition */
translate_r->x = graphene_simd4f_get_x (local.value.w);
translate_r->y = graphene_simd4f_get_y (local.value.w);
translate_r->z = graphene_simd4f_get_z (local.value.w);
local.value.w = graphene_simd4f_init (0.f, 0.f, 0.f, graphene_simd4f_get_w (local.value.w));
/* now get scale and shear */
/* compute the X scale factor and normalize the first row */
scale_x = graphene_simd4f_get_x (graphene_simd4f_length4 (local.value.x));
local.value.x = graphene_simd4f_div (local.value.x, graphene_simd4f_splat (scale_x));
/* compute XY shear factor and the second row orthogonal to the first */
shear_xy = graphene_simd4f_get_x (graphene_simd4f_dot4 (local.value.x, local.value.y));
local.value.y = graphene_simd4f_sub (local.value.y, graphene_simd4f_mul (local.value.x, graphene_simd4f_splat (shear_xy)));
/* now, compute the Y scale factor and normalize the second row */
scale_y = graphene_simd4f_get_x (graphene_simd4f_length4 (local.value.y));
local.value.y = graphene_simd4f_div (local.value.y, graphene_simd4f_splat (scale_y));
shear_xy /= scale_y;
/* compute XZ and YZ shears, make the third row orthogonal */
shear_xz = graphene_simd4f_get_x (graphene_simd4f_dot4 (local.value.x, local.value.z));
local.value.z = graphene_simd4f_sub (local.value.z, graphene_simd4f_mul (local.value.x, graphene_simd4f_splat (shear_xz)));
shear_yz = graphene_simd4f_get_x (graphene_simd4f_dot4 (local.value.y, local.value.z));
local.value.z = graphene_simd4f_sub (local.value.z, graphene_simd4f_mul (local.value.y, graphene_simd4f_splat (shear_yz)));
/* next, get the Z scale and normalize the third row */
scale_z = graphene_simd4f_get_x (graphene_simd4f_length4 (local.value.z));
local.value.z = graphene_simd4f_div (local.value.z, graphene_simd4f_splat (scale_z));
shear_xz /= scale_z;
shear_yz /= scale_z;
shear_r[XY_SHEAR] = shear_xy;
shear_r[XZ_SHEAR] = shear_xz;
shear_r[YZ_SHEAR] = shear_yz;
/* at this point, the matrix is orthonormal. we check for a
* coordinate system flip. if the determinant is -1, then
* negate the matrix and the scaling factors
*/
dot = graphene_simd4f_cross3 (local.value.y, local.value.z);
cross = graphene_simd4f_dot4 (local.value.x, dot);
if (graphene_simd4f_get_x (cross) < 0.f)
{
scale_x *= -1.f;
scale_y *= -1.f;
scale_z *= -1.f;
graphene_simd4f_mul (local.value.x, graphene_simd4f_splat (-1.f));
graphene_simd4f_mul (local.value.y, graphene_simd4f_splat (-1.f));
graphene_simd4f_mul (local.value.z, graphene_simd4f_splat (-1.f));
}
graphene_point3d_init (scale_r, scale_x, scale_y, scale_z);
/* get the rotations out */
graphene_quaternion_init_from_matrix (rotate_r, &local);
return TRUE;
}
