[Mesa-dev] [PATCH 07/12] i965/blorp: Instruct vertex fetcher to provide prim instance id

[Kristian Høgsberg]

On Thu, Sep 1, 2016 at 8:43 AM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> On Aug 31, 2016 9:06 AM, "Topi Pohjolainen" <topi.pohjolainen at intel.com>
> wrote:
>>
>> This will indicate target layer (Render Target Array Index) needed
>> for layered clears.
>>
>> v2: Use 3DSTATE_VF_SGVS for gen8+
>>
>> Signed-off-by: Topi Pohjolainen <topi.pohjolainen at intel.com>
>> ---
>>  src/intel/blorp/blorp_genX_exec.h | 26 ++++++++++++++++++++++----
>>  1 file changed, 22 insertions(+), 4 deletions(-)
>>
>> diff --git a/src/intel/blorp/blorp_genX_exec.h
>> b/src/intel/blorp/blorp_genX_exec.h
>> index f44076e..7312847 100644
>> --- a/src/intel/blorp/blorp_genX_exec.h
>> +++ b/src/intel/blorp/blorp_genX_exec.h
>> @@ -298,8 +298,10 @@ blorp_emit_vertex_elements(struct blorp_batch *batch,
>>      * the URB. This is controlled by the 3DSTATE_VERTEX_BUFFERS and
>>      * 3DSTATE_VERTEX_ELEMENTS packets below. The VUE contents are as
>> follows:
>>      *   dw0: Reserved, MBZ.
>> -    *   dw1: Render Target Array Index. The HiZ op does not use indexed
>> -    *        vertices, so set the dword to 0.
>> +    *   dw1: Render Target Array Index. Below vertex fetcher gets
>> programmed
>> +    *        to assign this with primitive instance identifier which will
>> be
>> +    *        used for layered clears. All other renders have only one
>> instance
>> +    *        and therefore the value will be effectively zero.
>>      *   dw2: Viewport Index. The HiZ op disables viewport mapping and
>>      *        scissoring, so set the dword to 0.
>>      *   dw3: Point Width: The HiZ op does not emit the POINTLIST
>> primitive,
>> @@ -318,7 +320,7 @@ blorp_emit_vertex_elements(struct blorp_batch *batch,
>>      * "Vertex URB Entry (VUE) Formats".
>>      *
>>      * Only vertex position X and Y are going to be variable, Z is fixed
>> to
>> -    * zero and W to one. Header words dw0-3 are all zero. There is no
>> need to
>> +    * zero and W to one. Header words dw0,2,3 are zero. There is no need
>> to
>>      * include the fixed values in the vertex buffer. Vertex fetcher can
>> be
>>      * instructed to fill vertex elements with constant values of one and
>> zero
>>      * instead of reading them from the buffer.
>> @@ -332,7 +334,16 @@ blorp_emit_vertex_elements(struct blorp_batch *batch,
>>     ve[0].SourceElementFormat = ISL_FORMAT_R32G32B32A32_FLOAT;
>>     ve[0].SourceElementOffset = 0;
>>     ve[0].Component0Control = VFCOMP_STORE_0;
>> +
>> +   /* From Gen8 onwards hardware is no more instructed to overwrite
>> components
>> +    * using an element specifier. Instead one has separate
>> 3DSTATE_VF_SGVS
>> +    * (System Generated Value Setup) state packet for it.
>> +    */
>> +#if GEN_GEN >= 8
>>     ve[0].Component1Control = VFCOMP_STORE_0;
>> +#else
>> +   ve[0].Component1Control = VFCOMP_STORE_IID;
>> +#endif
>>     ve[0].Component2Control = VFCOMP_STORE_0;
>>     ve[0].Component3Control = VFCOMP_STORE_0;
>>
>> @@ -366,7 +377,14 @@ blorp_emit_vertex_elements(struct blorp_batch *batch,
>>     }
>>
>>  #if GEN_GEN >= 8
>> -   blorp_emit(batch, GENX(3DSTATE_VF_SGVS), sgvs);
>> +   /* Overwrite Render Target Array Index (2nd dword) in the VUE header
>> with
>> +    * primitive instance identifier. This is used for layered clears.
>> +    */
>> +   blorp_emit(batch, GENX(3DSTATE_VF_SGVS), sgvs) {
>> +      sgvs.InstanceIDEnable = true;
>> +      sgvs.InstanceIDComponentNumber = COMP_1;
>> +      sgvs.InstanceIDElementOffset = 0;
>> +   }
>
> I love the fact that we can use SVGS this way.  I cc'd Kristian so he can
> enjoy it too!
>
> Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>

Yeah, nice - we already did that in meta though.

>>     for (unsigned i = 0; i < num_elements; i++) {
>>        blorp_emit(batch, GENX(3DSTATE_VF_INSTANCING), vf) {
>> --
>> 2.5.5
>>
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