[Cogl] [PATCH] matrix: Add a init_translation() contructor

[Robert Bragg]

Yeah this looks good to land in master to me:

Reviewed-by: Robert Bragg <robert at linux.intel.com>

thanks,
- Robert

On Thu, May 3, 2012 at 2:15 PM, Damien Lespiau <damien.lespiau at gmail.com> wrote:
> From: Damien Lespiau <damien.lespiau at intel.com>
>
> This allows people to initialize a matrix with a translation
> transformation. The options to do it at the moment were:
>
> * init_from_array() but it give cogl no information about the type of
>  matrix.
> * init_indentity() and then translate() but it means doing a lot of
>  computations for no reason.
> ---
>  cogl/cogl-matrix.c                                 |   34 ++++++++++++++++++++
>  cogl/cogl-matrix.h                                 |   24 ++++++++++++++
>  .../cogl-2.0-experimental-sections.txt             |    1 +
>  3 files changed, 59 insertions(+), 0 deletions(-)
>
> diff --git a/cogl/cogl-matrix.c b/cogl/cogl-matrix.c
> index a346a5c..1a569c6 100644
> --- a/cogl/cogl-matrix.c
> +++ b/cogl/cogl-matrix.c
> @@ -1596,6 +1596,40 @@ cogl_matrix_init_identity (CoglMatrix *matrix)
>   _COGL_MATRIX_DEBUG_PRINT (matrix);
>  }
>
> +/*
> + * Set a matrix to the (tx, ty, tz) translation matrix.
> + *
> + * @matix matrix.
> + * @tx x coordinate of the translation vector
> + * @ty y coordinate of the translation vector
> + * @tz z coordinate of the translation vector
> + */
> +static void
> +_cogl_matrix_init_translation (CoglMatrix *matrix,
> +                               float       tx,
> +                               float       ty,
> +                               float       tz)
> +{
> +  memcpy (matrix, identity, 16 * sizeof (float));
> +
> +  matrix->xw = tx;
> +  matrix->yw = ty;
> +  matrix->yw = tz;
> +
> +  matrix->type = COGL_MATRIX_TYPE_3D;
> +  matrix->flags = MAT_FLAG_TRANSLATION | MAT_DIRTY_INVERSE;
> +}
> +
> +void
> +cogl_matrix_init_translation (CoglMatrix *matrix,
> +                              float       tx,
> +                              float       ty,
> +                              float       tz)
> +{
> +  _cogl_matrix_init_translation (matrix, tx, ty, tz);
> +  _COGL_MATRIX_DEBUG_PRINT (matrix);
> +}
> +
>  #if 0
>  /*
>  * Test if the given matrix preserves vector lengths.
> diff --git a/cogl/cogl-matrix.h b/cogl/cogl-matrix.h
> index cca1823..b207e01 100644
> --- a/cogl/cogl-matrix.h
> +++ b/cogl/cogl-matrix.h
> @@ -127,6 +127,30 @@ void
>  cogl_matrix_init_identity (CoglMatrix *matrix);
>
>  /**
> + * cogl_matrix_init_translation:
> + * @matrix: A 4x4 transformation matrix
> + * @tx x coordinate of the translation vector
> + * @ty y coordinate of the translation vector
> + * @tz z coordinate of the translation vector
> + *
> + * Resets matrix to the (tx, ty, tz) translation matrix:
> + *
> + * |[
> + *   .xx=1; .xy=0; .xz=0; .xw=tx;
> + *   .yx=0; .yy=1; .yz=0; .yw=ty;
> + *   .zx=0; .zy=0; .zz=1; .zw=tz;
> + *   .wx=0; .wy=0; .wz=0; .ww=1;
> + * ]|
> + *
> + * Since: 2.0
> + */
> +void
> +cogl_matrix_init_translation (CoglMatrix *matrix,
> +                              float       tx,
> +                              float       ty,
> +                              float       tz);
> +
> +/**
>  * cogl_matrix_multiply:
>  * @result: The address of a 4x4 matrix to store the result in
>  * @a: A 4x4 transformation matrix
> diff --git a/doc/reference/cogl-2.0-experimental/cogl-2.0-experimental-sections.txt b/doc/reference/cogl-2.0-experimental/cogl-2.0-experimental-sections.txt
> index ca3340d..c9af2fb 100644
> --- a/doc/reference/cogl-2.0-experimental/cogl-2.0-experimental-sections.txt
> +++ b/doc/reference/cogl-2.0-experimental/cogl-2.0-experimental-sections.txt
> @@ -534,6 +534,7 @@ cogl_color_equal
>  CoglMatrix
>  cogl_matrix_init_identity
>  cogl_matrix_init_from_array
> +cogl_matrix_init_translation
>  cogl_matrix_copy
>  cogl_matrix_equal
>  cogl_matrix_free
> --
> 1.7.7.5
>
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