[PATCH weston v2 01/20] weston_surface: Add surface-to-buffer and buffer-to-surface matrices

[Derek Foreman]

On 09/01/15 02:52 PM, Giulio Camuffo wrote:
> I have a comment below, the rest looks good to me.
> 
> 
> 2014-10-16 18:55 GMT+03:00 Derek Foreman <derekf at osg.samsung.com>:
>> From: Jason Ekstrand <jason at jlekstrand.net>
>>
>> ---
>>  src/compositor.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  src/compositor.h |  6 ++++
>>  2 files changed, 90 insertions(+)
>>
>> diff --git a/src/compositor.c b/src/compositor.c
>> index 4540911..c85cf2e 100644
>> --- a/src/compositor.c
>> +++ b/src/compositor.c
>> @@ -615,6 +615,9 @@ weston_surface_create(struct weston_compositor *compositor)
>>         wl_list_init(&surface->subsurface_list);
>>         wl_list_init(&surface->subsurface_list_pending);
>>
>> +       weston_matrix_init(&surface->buffer_to_surface_matrix);
>> +       weston_matrix_init(&surface->surface_to_buffer_matrix);
>> +
>>         return surface;
>>  }
>>
>> @@ -2304,6 +2307,82 @@ weston_surface_commit_subsurface_order(struct weston_surface *surface)
>>  }
>>
>>  static void
>> +weston_surface_build_buffer_matrix(struct weston_surface *surface,
>> +                                  struct weston_matrix *matrix)
>> +{
>> +       struct weston_buffer_viewport *vp = &surface->buffer_viewport;
>> +       double src_width, src_height, dest_width, dest_height;
>> +
>> +       weston_matrix_init(matrix);
>> +
>> +       if (vp->buffer.src_width == wl_fixed_from_int(-1)) {
>> +               src_width = surface->width_from_buffer;
>> +               src_height = surface->height_from_buffer;
>> +       } else {
>> +               src_width = wl_fixed_to_double(vp->buffer.src_width);
>> +               src_height = wl_fixed_to_double(vp->buffer.src_height);
>> +       }
>> +
>> +       if (vp->surface.width == -1) {
>> +               dest_width = src_width;
>> +               dest_height = src_height;
>> +       } else {
>> +               dest_width = vp->surface.width;
>> +               dest_height = vp->surface.height;
>> +       }
>> +
>> +       if (src_width != dest_width || src_height != dest_height)
>> +               weston_matrix_scale(matrix,
>> +                                   src_width / dest_width,
>> +                                   src_height / dest_height, 1);
>> +
>> +       if (vp->buffer.src_width != wl_fixed_from_int(-1))
>> +               weston_matrix_translate(matrix,
>> +                                       wl_fixed_to_double(vp->buffer.src_x),
>> +                                       wl_fixed_to_double(vp->buffer.src_y),
>> +                                       0);
>> +
>> +       switch (vp->buffer.transform) {
>> +       case WL_OUTPUT_TRANSFORM_FLIPPED:
>> +       case WL_OUTPUT_TRANSFORM_FLIPPED_90:
>> +       case WL_OUTPUT_TRANSFORM_FLIPPED_180:
>> +       case WL_OUTPUT_TRANSFORM_FLIPPED_270:
>> +               weston_matrix_scale(matrix, -1, 1, 1);
>> +               weston_matrix_translate(matrix,
>> +                                       surface->width_from_buffer, 0, 0);
>> +               break;
>> +       }
>> +
>> +       switch (vp->buffer.transform) {
>> +       default:
>> +       case WL_OUTPUT_TRANSFORM_NORMAL:
>> +       case WL_OUTPUT_TRANSFORM_FLIPPED:
>> +               break;
>> +       case WL_OUTPUT_TRANSFORM_90:
>> +       case WL_OUTPUT_TRANSFORM_FLIPPED_90:
>> +               weston_matrix_rotate_xy(matrix, 0, 1);
>> +               weston_matrix_translate(matrix,
>> +                                       surface->height_from_buffer, 0, 0);
> 
> This may be me and matrices not being good friends, but shouldn't this
> be 'width_from_buffer'?

I think this math is ok.  It's a 90 degree rotation so the shift we want
is height pixels.  We rotate then translate so the translation isn't
altered by the rotation...

(also, I just checked, and this rotation works properly :)

>> +               break;
>> +       case WL_OUTPUT_TRANSFORM_180:
>> +       case WL_OUTPUT_TRANSFORM_FLIPPED_180:
>> +               weston_matrix_rotate_xy(matrix, -1, 0);
>> +               weston_matrix_translate(matrix,
>> +                                       surface->width_from_buffer,
>> +                                       surface->height_from_buffer, 0);
>> +               break;
>> +       case WL_OUTPUT_TRANSFORM_270:
>> +       case WL_OUTPUT_TRANSFORM_FLIPPED_270:
>> +               weston_matrix_rotate_xy(matrix, 0, -1);
>> +               weston_matrix_translate(matrix,
>> +                                       0, surface->width_from_buffer, 0);
>> +               break;
>> +       }
>> +
>> +       weston_matrix_scale(matrix, vp->buffer.scale, vp->buffer.scale, 1);
>> +}
>> +
>> +static void
>>  weston_surface_commit_state(struct weston_surface *surface,
>>                             struct weston_surface_state *state)
>>  {
>> @@ -2320,6 +2399,11 @@ weston_surface_commit_state(struct weston_surface *surface,
>>                 weston_surface_attach(surface, state->buffer);
>>         weston_surface_state_set_buffer(state, NULL);
>>
>> +       weston_surface_build_buffer_matrix(surface,
>> +                                          &surface->surface_to_buffer_matrix);
>> +       weston_matrix_invert(&surface->buffer_to_surface_matrix,
>> +                            &surface->surface_to_buffer_matrix);
>> +
>>         if (state->newly_attached || state->buffer_viewport.changed) {
>>                 weston_surface_update_size(surface);
>>                 if (surface->configure)
>> diff --git a/src/compositor.h b/src/compositor.h
>> index 0fbca33..95900ed 100644
>> --- a/src/compositor.h
>> +++ b/src/compositor.h
>> @@ -893,6 +893,12 @@ struct weston_surface {
>>         /* All the pending state, that wl_surface.commit will apply. */
>>         struct weston_surface_state pending;
>>
>> +       /* Matrices representating of the full transformation between
>> +        * buffer and surface coordinates.  These matrices are updated
>> +        * using the weston_surface_build_buffer_matrix function. */
>> +       struct weston_matrix buffer_to_surface_matrix;
>> +       struct weston_matrix surface_to_buffer_matrix;
>> +
>>         /*
>>          * If non-NULL, this function will be called on
>>          * wl_surface::commit after a new buffer has been set up for
>> --
>> 2.1.1
>>
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>> wayland-devel at lists.freedesktop.org
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