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libgimpmath: add various GimpMatrix4 functions 

Add gimp_matrix4_{identity,mult,transform_point}().
This commit is contained in:
Ell 2020-01-06 16:12:11 +02:00
parent edfc837e7d
commit e3bc877a42
3 changed files with 106 additions and 0 deletions
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3
devel-docs/libgimpmath/libgimpmath3-sections.txt
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@ -38,7 +38,10 @@ gimp_matrix3_is_identity
gimp_matrix3_is_diagonal
gimp_matrix3_is_affine
gimp_matrix3_is_simple
gimp_matrix4_identity
gimp_matrix4_mult
gimp_matrix4_to_deg
gimp_matrix4_transform_point
GIMP_TYPE_MATRIX2
GIMP_TYPE_PARAM_MATRIX2
GIMP_IS_PARAM_SPEC_MATRIX2

91
libgimpmath/gimpmatrix.c
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@ -885,6 +885,50 @@ gimp_matrix3_is_simple (const GimpMatrix3 *matrix)
return TRUE;
}
/**
* gimp_matrix4_identity:
* @matrix: A matrix.
*
* Sets the matrix to the identity matrix.
*/
void
gimp_matrix4_identity (GimpMatrix4 *matrix)
{
gint i, j;
for (i = 0; i < 4; i++)
{
for (j = 0; j < 4; j++)
matrix->coeff[i][j] = i == j;
}
}
/**
* gimp_matrix4_mult:
* @matrix1: The first input matrix.
* @matrix2: The second input matrix which will be overwritten by the result.
*
* Multiplies two matrices and puts the result into the second one.
*/
void
gimp_matrix4_mult (const GimpMatrix4 *matrix1,
GimpMatrix4 *matrix2)
{
GimpMatrix4 result = {};
gint i, j, k;
for (i = 0; i < 4; i++)
{
for (j = 0; j < 4; j++)
{
for (k = 0; k < 4; k++)
result.coeff[i][j] += matrix1->coeff[i][k] * matrix2->coeff[k][j];
}
}
*matrix2 = result;
}
/**
* gimp_matrix4_to_deg:
* @matrix:
@ -904,3 +948,50 @@ gimp_matrix4_to_deg (const GimpMatrix4 *matrix,
*b = 180 * (asin (matrix->coeff[2][0]) / G_PI_2);
*c = 180 * (asin (matrix->coeff[2][1]) / G_PI_2);
}
/**
* gimp_matrix4_transform_point:
* @matrix: The transformation matrix.
* @x: The source X coordinate.
* @y: The source Y coordinate.
* @z: The source Z coordinate.
* @newx: The transformed X coordinate.
* @newy: The transformed Y coordinate.
* @newz: The transformed Z coordinate.
*
* Transforms a point in 3D as specified by the transformation matrix.
*/
gdouble
gimp_matrix4_transform_point (const GimpMatrix4 *matrix,
gdouble x,
gdouble y,
gdouble z,
gdouble *newx,
gdouble *newy,
gdouble *newz)
{
gdouble neww;
*newx = matrix->coeff[0][0] * x +
matrix->coeff[0][1] * y +
matrix->coeff[0][2] * z +
matrix->coeff[0][3];
*newy = matrix->coeff[1][0] * x +
matrix->coeff[1][1] * y +
matrix->coeff[1][2] * z +
matrix->coeff[1][3];
*newz = matrix->coeff[2][0] * x +
matrix->coeff[2][1] * y +
matrix->coeff[2][2] * z +
matrix->coeff[2][3];
neww = matrix->coeff[3][0] * x +
matrix->coeff[3][1] * y +
matrix->coeff[3][2] * z +
matrix->coeff[3][3];
*newx /= neww;
*newy /= neww;
*newz /= neww;
return neww;
}

12
libgimpmath/gimpmatrix.h
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@ -131,11 +131,23 @@ void gimp_matrix3_transform_point (const GimpMatrix3 *matrix,
/* GimpMatrix4 */
/*****************/
void gimp_matrix4_identity (GimpMatrix4 *matrix);
void gimp_matrix4_mult (const GimpMatrix4 *matrix1,
GimpMatrix4 *matrix2);
void gimp_matrix4_to_deg (const GimpMatrix4 *matrix,
gdouble *a,
gdouble *b,
gdouble *c);
gdouble gimp_matrix4_transform_point (const GimpMatrix4 *matrix,
gdouble x,
gdouble y,
gdouble z,
gdouble *newx,
gdouble *newy,
gdouble *newz);
G_END_DECLS