<div dir="auto">Ah, right. Thanks for the explanation! </div><div class="gmail_extra"> <div class="gmail_quote">On Jan 4, 2017 14:02, "Ilia Mirkin" <<a href="mailto:imirkin@alum.mit.edu">imirkin@alum.mit.edu</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Wed, Jan 4, 2017 at 4:24 AM, Erik Faye-Lund <<a href="mailto:kusmabite@gmail.com">kusmabite@gmail.com</a>> wrote: > On Jan 2, 2017 06:03, "Ilia Mirkin" <<a href="mailto:imirkin@alum.mit.edu">imirkin@alum.mit.edu</a>> wrote: > > Signed-off-by: Ilia Mirkin <<a href="mailto:imirkin@alum.mit.edu">imirkin@alum.mit.edu</a>> > --- > src/gallium/auxiliary/tgsi/tgsi_info.c | 2 +- > src/gallium/docs/source/tgsi.rst | 11 +++++++++++ > src/gallium/include/pipe/p_shader_tokens.h | 2 +- > 3 files changed, 13 insertions(+), 2 deletions(-) > > diff --git a/src/gallium/auxiliary/tgsi/tgsi_info.c > b/src/gallium/auxiliary/tgsi/tgsi_info.c > index 37549aa..e34b8c7 100644 > --- a/src/gallium/auxiliary/tgsi/tgsi_info.c > +++ b/src/gallium/auxiliary/tgsi/tgsi_info.c > @@ -106,7 +106,7 @@ static const struct tgsi_opcode_info > opcode_info[TGSI_OPCODE_LAST] = > { 1, 3, 0, 0, 0, 0, 0, COMP, "CMP", TGSI_OPCODE_CMP }, > { 1, 1, 0, 0, 0, 0, 0, CHAN, "SCS", TGSI_OPCODE_SCS }, > { 1, 2, 1, 0, 0, 0, 0, OTHR, "TXB", TGSI_OPCODE_TXB }, > - { 0, 1, 0, 0, 0, 0, 1, NONE, "", 69 }, /* removed */ > + { 1, 1, 0, 0, 0, 0, 0, OTHR, "FBFETCH", TGSI_OPCODE_FBFETCH }, > { 1, 2, 0, 0, 0, 0, 0, COMP, "DIV", TGSI_OPCODE_DIV }, > { 1, 2, 0, 0, 0, 0, 0, REPL, "DP2", TGSI_OPCODE_DP2 }, > { 1, 2, 1, 0, 0, 0, 0, OTHR, "TXL", TGSI_OPCODE_TXL }, > diff --git a/src/gallium/docs/source/tgsi.rst > b/src/gallium/docs/source/tgsi.rst > index d2d30b4..accbe1d 100644 > --- a/src/gallium/docs/source/tgsi.rst > +++ b/src/gallium/docs/source/tgsi.rst > @@ -2561,6 +2561,17 @@ Resource Access Opcodes > image, while .w will contain the number of samples for multi-sampled > images. > > +.. opcode:: FBFETCH - Load data from framebuffer > + > + Syntax: ``FBFETCH dst, output`` > + > + Example: ``FBFETCH TEMP[0], OUT[0]`` > + > + Returns the color of the current position in the framebuffer from > + before this fragment shader invocation. Always returns the same > + value from multiple calls for a particular output within a single > + invocation. > + > > > What does this instruction do under MRT? Tegra (AR20) has the ability to > select the MRT index... Fetches the relevant output's value. Just as with the new sysval-based implementation, DECL SV[0], COLOR[1] would fetch the value in RT1. This could be used to implement EXT_shader_framebuffer_fetch, although more cap's would be necessary to differentiate the use-cases. Cheers, -ilia </blockquote></div></div>