On Thu, Aug 14, 2014 at 4:11 AM, Iago Toral Quiroga <ito...@igalia.com> wrote: > For this we will need to move PrimitiveID information, delivered in the thread > payload in r0.1, to a separate register (we use GS_OPCODE_SET_PRIMITIVE_ID > for this), then map the corresponding varying slot to that register in the > setup_payload() method. > > Notice that we cannot use a virtual register as the destination for the > PrimitiveID because we need to map all input attributes to hardware registers > in setup_payload(), which happens before virtual registers are mapped to > hardware registers. We could work around that issue if we were able to compute > the first non-payload register in emit_prolog() and move the PrimitiveID > information to that register, but we can't because at that point we still > don't know the final number uniforms that will be included in the payload. > > So, what we do is to place PrimitiveID information in r1, which is always > delivered as part of the payload but its only populated with data > relevant for transform feedback when we set GEN6_GS_SVBI_PAYLOAD_ENABLE > in the 3DSTATE_GS state packet. > > When we implement transform feedback, we wil make sure to move the value of r1 > to another register before we overwrite it with the PrimitiveID. > --- > src/mesa/drivers/dri/i965/gen6_gs_visitor.cpp | 69 > ++++++++++++++++++++++++++- > src/mesa/drivers/dri/i965/gen6_gs_visitor.h | 2 + > 2 files changed, 70 insertions(+), 1 deletion(-) > > diff --git a/src/mesa/drivers/dri/i965/gen6_gs_visitor.cpp > b/src/mesa/drivers/dri/i965/gen6_gs_visitor.cpp > index 4a440eb..b45c381 100644 > --- a/src/mesa/drivers/dri/i965/gen6_gs_visitor.cpp > +++ b/src/mesa/drivers/dri/i965/gen6_gs_visitor.cpp > @@ -31,6 +31,8 @@ > > #include "gen6_gs_visitor.h" > > +const unsigned MAX_GS_INPUT_VERTICES = 6; > + > namespace brw { > > void > @@ -38,6 +40,7 @@ gen6_gs_visitor::emit_prolog() > { > vec4_gs_visitor::emit_prolog(); > > + this->current_annotation = "gen6 prolog"; > /* Gen6 geometry shaders require to allocate an initial VUE handle via > * FF_SYNC message, however the documentation remarks that only one thread > * can write to the URB simultaneously and the FF_SYNC message provides > the > @@ -59,7 +62,6 @@ gen6_gs_visitor::emit_prolog() > * flags for the next vertex come right after the data items and flags for > * the previous vertex. > */ > - this->current_annotation = "gen6 prolog";
Seems like this belongs in "i965/gen6/gs: Add initial implementation for a gen6 geometry shader visitor." (Or, perhaps just drop the change...) Patches 21-26 (gs-support-snb-for-submission-02092014) i965/gen6/gs: Implement support for gl_PrimitiveIdIn. i965/gen6/gs: Assign geometry shader VUE map properly. i965/gen6/gs: Enable texture units and upload sampler state. i965/gen6/gs: implement GS_OPCODE_SVB_WRITE opcode i965/gen6/gs: implement GS_OPCODE_SVB_SET_DST_INDEX opcode i965/gen6/gs: implement GS_OPCODE_FF_SYNC_SET_PRIMITIVES opcode Reviewed-by: Jordan Justen <jordan.l.jus...@intel.com> > this->vertex_output = src_reg(this, > glsl_type::uint_type, > (prog_data->vue_map.num_slots + 1) * > @@ -94,6 +96,30 @@ gen6_gs_visitor::emit_prolog() > */ > this->prim_count = src_reg(this, glsl_type::uint_type); > emit(MOV(dst_reg(this->prim_count), 0u)); > + > + /* PrimitveID is delivered in r0.1 of the thread payload. If the program > + * needs it we have to move it to a separate register where we can map > + * the atttribute. > + * > + * Notice that we cannot use a virtual register for this, because we need > to > + * map all input attributes to hardware registers in setup_payload(), > + * which happens before virtual registers are mapped to hardware > registers. > + * We could work around that issue if we were able to compute the first > + * non-payload register here and move the PrimitiveID information to that > + * register, but we can't because at this point we don't know the final > + * number uniforms that will be included in the payload. > + * > + * So, what we do is to place PrimitiveID information in r1, which is > always > + * delivered as part of the payload, but its only populated with data > + * relevant for transform feedback when we set GEN6_GS_SVBI_PAYLOAD_ENABLE > + * in the 3DSTATE_GS state packet. That information can be obtained by > other > + * means though, so we can safely use r1 for this purpose. > + */ > + if (c->prog_data.include_primitive_id) { > + this->primitive_id = > + src_reg(retype(brw_vec8_grf(1, 0), BRW_REGISTER_TYPE_UD)); > + emit(GS_OPCODE_SET_PRIMITIVE_ID, dst_reg(this->primitive_id)); > + } > } > > void > @@ -410,4 +436,45 @@ gen6_gs_visitor::emit_thread_end() > inst->mlen = 1; > } > > +void > +gen6_gs_visitor::setup_payload() > +{ > + int attribute_map[BRW_VARYING_SLOT_COUNT * MAX_GS_INPUT_VERTICES]; > + > + /* Attributes are going to be interleaved, so one register contains two > + * attribute slots. > + */ > + int attributes_per_reg = 2; > + > + /* If a geometry shader tries to read from an input that wasn't written by > + * the vertex shader, that produces undefined results, but it shouldn't > + * crash anything. So initialize attribute_map to zeros--that ensures > that > + * these undefined results are read from r0. > + */ > + memset(attribute_map, 0, sizeof(attribute_map)); > + > + int reg = 0; > + > + /* The payload always contains important data in r0. */ > + reg++; > + > + /* r1 is always part of the payload and it holds information relevant > + * for transform feedback when we set the GEN6_GS_SVBI_PAYLOAD_ENABLE bit > in > + * the 3DSTATE_GS packet. We will overwrite it with the PrimitiveID > + * information (and move the original value to a virtual register if > + * necessary). > + */ > + if (c->prog_data.include_primitive_id) > + attribute_map[VARYING_SLOT_PRIMITIVE_ID] = attributes_per_reg * reg; > + reg++; > + > + reg = setup_uniforms(reg); > + > + reg = setup_varying_inputs(reg, attribute_map, attributes_per_reg); > + > + lower_attributes_to_hw_regs(attribute_map, true); > + > + this->first_non_payload_grf = reg; > +} > + > } /* namespace brw */ > diff --git a/src/mesa/drivers/dri/i965/gen6_gs_visitor.h > b/src/mesa/drivers/dri/i965/gen6_gs_visitor.h > index 7af6405..8d2386c 100644 > --- a/src/mesa/drivers/dri/i965/gen6_gs_visitor.h > +++ b/src/mesa/drivers/dri/i965/gen6_gs_visitor.h > @@ -52,6 +52,7 @@ protected: > int base_mrf, > int last_mrf, > int urb_offset); > + virtual void setup_payload(); > > private: > src_reg vertex_output; > @@ -59,6 +60,7 @@ private: > src_reg temp; > src_reg first_vertex; > src_reg prim_count; > + src_reg primitive_id; > }; > > } /* namespace brw */ > -- > 1.9.1 > > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev