On Thu, Jun 14, 2012 at 7:11 PM, Marek Olšák <mar...@gmail.com> wrote:
> instead of failing to allocate a renderbuffer. This also improves allocation
> of MSAA renderbuffers (untested).
>
> This also fixes piglit/get-renderbuffer-internalformat with non-renderable
> formats.
> ---
> src/mesa/state_tracker/st_cb_fbo.c | 63
> +++++++++++++++++++++++++++++++-----
> 1 file changed, 55 insertions(+), 8 deletions(-)
>
> diff --git a/src/mesa/state_tracker/st_cb_fbo.c
> b/src/mesa/state_tracker/st_cb_fbo.c
> index 953295c..5a21c8e 100644
> --- a/src/mesa/state_tracker/st_cb_fbo.c
> +++ b/src/mesa/state_tracker/st_cb_fbo.c
> @@ -72,8 +72,9 @@ st_renderbuffer_alloc_storage(struct gl_context * ctx,
> struct pipe_context *pipe = st->pipe;
> struct pipe_screen *screen = st->pipe->screen;
> struct st_renderbuffer *strb = st_renderbuffer(rb);
> - enum pipe_format format;
> + enum pipe_format format = PIPE_FORMAT_NONE;
> struct pipe_surface surf_tmpl;
> + unsigned nr_samples = 0;
>
> if (internalFormat == GL_RGBA16_SNORM && strb->software) {
> /* Special case for software accum buffers. Otherwise, if the
> @@ -84,12 +85,55 @@ st_renderbuffer_alloc_storage(struct gl_context * ctx,
> format = PIPE_FORMAT_R16G16B16A16_SNORM;
> }
> else {
> - format = st_choose_renderbuffer_format(screen, internalFormat,
> - rb->NumSamples);
> - }
> + /* Handle multisample renderbuffers first.
> + *
> + * From ARB_framebuffer_object:
> + * If <samples> is zero, then RENDERBUFFER_SAMPLES is set to zero.
> + * Otherwise <samples> represents a request for a desired minimum
> + * number of samples. Since different implementations may support
> + * different sample counts for multisampled rendering, the actual
> + * number of samples allocated for the renderbuffer image is
> + * implementation dependent. However, the resulting value for
> + * RENDERBUFFER_SAMPLES is guaranteed to be greater than or equal
> + * to <samples> and no more than the next larger sample count
> supported
> + * by the implementation.
> + *
> + * So let's find the supported number of samples closest to NumSamples.
> + * (NumSamples == 1) is treated the same as (NumSamples == 0).
> + */
> + if (rb->NumSamples > 1) {
> + unsigned i;
>
> - if (format == PIPE_FORMAT_NONE) {
> - return FALSE;
> + for (i = rb->NumSamples; i < ctx->Const.MaxSamples; i++) {
> + format = st_choose_renderbuffer_format(screen, internalFormat,
> i);
> +
> + if (format != PIPE_FORMAT_NONE) {
> + rb->NumSamples = i;
> + nr_samples = i;
> + break;
> + }
> + }
> + } else {
> + format = st_choose_renderbuffer_format(screen, internalFormat, 0);
> + }
> +
> + /* There is no supported renderable pipe format for internalformat.
> + * AllocStorage shouldn't fail because of an unsupported format,
> + * instead, unsupported formats should cause FBO incompleteness
> + * later, so let's set the closest sampler format we can get.
> + * This will also cause FBO incompleteness for unsupported sample
> + * counts, because the validation uses rb->NumSamples.
> + */
> + if (format == PIPE_FORMAT_NONE) {
> + format = st_choose_format(screen, internalFormat, GL_NONE, GL_NONE,
> + PIPE_TEXTURE_2D, 0,
> + PIPE_BIND_SAMPLER_VIEW);
> + }
> +
> + assert(format != PIPE_FORMAT_NONE);
> + if (format == PIPE_FORMAT_NONE) {
> + return FALSE; /* shouldn't happen unless there's a bug somewhere */
> + }
> }
>
> /* init renderbuffer fields */
> @@ -134,7 +178,7 @@ st_renderbuffer_alloc_storage(struct gl_context * ctx,
> template.depth0 = 1;
> template.array_size = 1;
> template.last_level = 0;
> - template.nr_samples = rb->NumSamples;
> + template.nr_samples = nr_samples;
> if (util_format_is_depth_or_stencil(format)) {
> template.bind = PIPE_BIND_DEPTH_STENCIL;
> }
> @@ -455,9 +499,12 @@ st_validate_attachment(struct gl_context *ctx,
> format = st_mesa_format_to_pipe_format(linearFormat);
> }
>
> + /* Check Renderbuffer->NumSamples (which is what the user expects) and
> + * not pipe_resource::nr_samples (which might be zero if NumSamples is
> + * unsupported). */
> return screen->is_format_supported(screen, format,
> PIPE_TEXTURE_2D,
> - stObj->pt->nr_samples, bindings);
> + att->Renderbuffer->NumSamples,
> bindings);
> }
I don't think this last bit of code will be reached for non-texture
attachments (which are allocated with RenderbufferStorage()). At the
beginning of st_validate_attachment() we check if the attachment type
is not a texture and return. I guess we could remove that check, but
then we need to get rid of stObj and get the attachment's format from
st_renderbuffer::texture->format, etc.
Just curious: have you tried NVIDIA's or AMD's driver to see what
happens when you try to allocate an unsupported renderbuffer format?
-Brian
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