[Cogl] [PATCH 4/4] gles2: Support the GL_EXT_unpack_subimage extension

Robert Bragg robert at sixbynine.org
Thu Mar 22 17:52:42 PDT 2012


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

On Thu, Mar 22, 2012 at 5:32 PM, Neil Roberts <neil at linux.intel.com> wrote:

> This extension lets you upload texture data from a subregion of a
> buffer by passing GL_UNPACK_ROW_LENGTH, GL_UNPACK_SKIP_PIXELS and
> GL_UNPACK_SKIP_ROWS to glPixelStore. When this extension is available
> the GLES texture driver will now avoid making a copy of the bitmap
> when a subregion is used.
>
> Note that Mesa doesn't currently advertise this extension but I've
> made a patch to propose it:
>
> http://lists.freedesktop.org/archives/mesa-dev/2012-March/020191.html
> ---
>  cogl/cogl-internal.h                        |    3 +-
>  cogl/driver/gles/cogl-gles.c                |    3 +
>  cogl/driver/gles/cogl-texture-driver-gles.c |   60
> +++++++++++++++++++++++----
>  3 files changed, 56 insertions(+), 10 deletions(-)
>
> diff --git a/cogl/cogl-internal.h b/cogl/cogl-internal.h
> index 4f53cc3..284fc97 100644
> --- a/cogl/cogl-internal.h
> +++ b/cogl/cogl-internal.h
> @@ -101,7 +101,8 @@ typedef enum
>   COGL_PRIVATE_FEATURE_VBOS = 1L<<6,
>   COGL_PRIVATE_FEATURE_EXT_PACKED_DEPTH_STENCIL = 1L<<7,
>   COGL_PRIVATE_FEATURE_OES_PACKED_DEPTH_STENCIL = 1L<<8,
> -  COGL_PRIVATE_FEATURE_TEXTURE_FORMAT_BGRA8888 = 1L<<9
> +  COGL_PRIVATE_FEATURE_TEXTURE_FORMAT_BGRA8888 = 1L<<9,
> +  COGL_PRIVATE_FEATURE_UNPACK_SUBIMAGE = 1L<<10
>  } CoglPrivateFeatureFlags;
>
>  /* Sometimes when evaluating pipelines, either during comparisons or
> diff --git a/cogl/driver/gles/cogl-gles.c b/cogl/driver/gles/cogl-gles.c
> index 102a19f..d7503b7 100644
> --- a/cogl/driver/gles/cogl-gles.c
> +++ b/cogl/driver/gles/cogl-gles.c
> @@ -293,6 +293,9 @@ _cogl_driver_update_features (CoglContext *context,
>    if (_cogl_check_extension ("GL_EXT_texture_format_BGRA8888",
> gl_extensions))
>     private_flags |= COGL_PRIVATE_FEATURE_TEXTURE_FORMAT_BGRA8888;
>
> +  if (_cogl_check_extension ("GL_EXT_unpack_subimage", gl_extensions))
> +    private_flags |= COGL_PRIVATE_FEATURE_UNPACK_SUBIMAGE;
> +
>   /* Cache features */
>   context->private_feature_flags |= private_flags;
>   context->feature_flags |= flags;
> diff --git a/cogl/driver/gles/cogl-texture-driver-gles.c
> b/cogl/driver/gles/cogl-texture-driver-gles.c
> index f2690da..e6a67d6 100644
> --- a/cogl/driver/gles/cogl-texture-driver-gles.c
> +++ b/cogl/driver/gles/cogl-texture-driver-gles.c
> @@ -52,6 +52,18 @@
>  #define GL_MAX_3D_TEXTURE_SIZE_OES 0x8073
>  #endif
>
> +/* This extension isn't available for GLES 1.1 so these won't be
> +   defined */
> +#ifndef GL_UNPACK_ROW_LENGTH
> +#define GL_UNPACK_ROW_LENGTH 0x0CF2
> +#endif
> +#ifndef GL_UNPACK_SKIP_ROWS
> +#define GL_UNPACK_SKIP_ROWS 0x0CF3
> +#endif
> +#ifndef GL_UNPACK_SKIP_PIXELS
> +#define GL_UNPACK_SKIP_PIXELS 0x0CF4
> +#endif
> +
>  static void
>  _cogl_texture_driver_gen (CoglContext *ctx,
>                           GLenum gl_target,
> @@ -83,11 +95,38 @@ _cogl_texture_driver_gen (CoglContext *ctx,
>  }
>
>  static void
> -_cogl_texture_driver_prep_gl_for_pixels_upload (CoglContext *context,
> +prep_gl_for_pixels_upload_full (CoglContext *ctx,
> +                                int pixels_rowstride,
> +                                int pixels_src_x,
> +                                int pixels_src_y,
> +                                int pixels_bpp)
> +{
> +  if ((ctx->private_feature_flags & COGL_PRIVATE_FEATURE_UNPACK_SUBIMAGE))
> +    {
> +      GE( ctx, glPixelStorei (GL_UNPACK_ROW_LENGTH,
> +                              pixels_rowstride / pixels_bpp) );
> +
> +      GE( ctx, glPixelStorei (GL_UNPACK_SKIP_PIXELS, pixels_src_x) );
> +      GE( ctx, glPixelStorei (GL_UNPACK_SKIP_ROWS, pixels_src_y) );
> +    }
> +  else
> +    {
> +      g_assert (pixels_src_x == 0);
> +      g_assert (pixels_src_y == 0);
> +    }
> +
> +  _cogl_texture_prep_gl_alignment_for_pixels_upload (pixels_rowstride);
> +}
> +
> +static void
> +_cogl_texture_driver_prep_gl_for_pixels_upload (CoglContext *ctx,
>                                                  int pixels_rowstride,
>                                                 int pixels_bpp)
>  {
> -  _cogl_texture_prep_gl_alignment_for_pixels_upload (pixels_rowstride);
> +  prep_gl_for_pixels_upload_full (ctx,
> +                                  pixels_rowstride,
> +                                  0, 0, /* src_x/y */
> +                                  pixels_bpp);
>  }
>
>  static void
> @@ -108,7 +147,8 @@ prepare_bitmap_alignment_for_upload (CoglContext *ctx,
>    int width = cogl_bitmap_get_width (src_bmp);
>   int alignment = 1;
>
> -  if (src_rowstride == 0)
> +  if ((ctx->private_feature_flags & COGL_PRIVATE_FEATURE_UNPACK_SUBIMAGE)
> ||
> +      src_rowstride == 0)
>     return cogl_object_ref (src_bmp);
>
>   /* Work out the alignment of the source rowstride */
> @@ -146,11 +186,13 @@ _cogl_texture_driver_upload_subregion_to_gl
> (CoglContext *ctx,
>   CoglBitmap *slice_bmp;
>   int rowstride;
>
> -  /* If we are copying a sub region of the source bitmap then we need
> -     to copy it because GLES does not support GL_UNPACK_ROW_LENGTH */
> -  if (src_x != 0 || src_y != 0 ||
> -      width != cogl_bitmap_get_width (source_bmp) ||
> -      height != cogl_bitmap_get_height (source_bmp))
> +  /* If we have the GL_EXT_unpack_subimage extension then we can
> +     upload from subregions directly. Otherwise we may need to copy
> +     the bitmap */
> +  if (!(ctx->private_feature_flags &
> COGL_PRIVATE_FEATURE_UNPACK_SUBIMAGE) &&
> +      (src_x != 0 || src_y != 0 ||
> +       width != cogl_bitmap_get_width (source_bmp) ||
> +       height != cogl_bitmap_get_height (source_bmp)))
>     {
>       slice_bmp =
>         _cogl_bitmap_new_with_malloc_buffer (ctx,
> @@ -168,7 +210,7 @@ _cogl_texture_driver_upload_subregion_to_gl
> (CoglContext *ctx,
>    rowstride = cogl_bitmap_get_rowstride (slice_bmp);
>
>   /* Setup gl alignment to match rowstride and top-left corner */
> -  _cogl_texture_driver_prep_gl_for_pixels_upload (ctx, rowstride, bpp);
> +  prep_gl_for_pixels_upload_full (ctx, rowstride, src_x, src_y, bpp);
>
>   data = _cogl_bitmap_bind (slice_bmp, COGL_BUFFER_ACCESS_READ, 0);
>
> --
> 1.7.3.16.g9464b
>
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> Cogl at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/cogl
>
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