[Mesa-dev] [PATCH 7/8] i965/gen7: Enable the features required for GL_ARB_sample_shading
Ian Romanick
idr at freedesktop.org
Thu Oct 17 00:20:07 CEST 2013
On 10/16/2013 02:57 PM, Anuj Phogat wrote:
> On Tue, Oct 15, 2013 at 3:48 PM, Kenneth Graunke <kenneth at whitecape.org> wrote:
>> On 10/14/2013 10:12 AM, Anuj Phogat wrote:
>>> - Enable GEN7_WM_MSDISPMODE_PERSAMPLE, GEN7_WM_POSOFFSET_SAMPLE,
>>> GEN7_WM_OMASK_TO_RENDER_TARGET as per extension's specification.
>>> - Don't enable GEN7_WM_16_DISPATCH_ENABLE when GEN7_WM_MSDISPMODE_PERSAMPLE
>>> is enabled. Refer IVB PRM Vol. 2, Part 1, Page 288 for details.
>>>
>>> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
>>> ---
>>> src/mesa/drivers/dri/i965/gen7_wm_state.c | 70 +++++++++++++++++++++++++++++--
>>> 1 file changed, 67 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/src/mesa/drivers/dri/i965/gen7_wm_state.c b/src/mesa/drivers/dri/i965/gen7_wm_state.c
>>> index a2046c3..0267e0e 100644
>>> --- a/src/mesa/drivers/dri/i965/gen7_wm_state.c
>>> +++ b/src/mesa/drivers/dri/i965/gen7_wm_state.c
>>> @@ -82,9 +82,15 @@ upload_wm_state(struct brw_context *brw)
>>> GEN7_WM_BARYCENTRIC_INTERPOLATION_MODE_SHIFT;
>>>
>>> /* _NEW_COLOR, _NEW_MULTISAMPLE */
>>> + /* Enable if the pixel shader kernel generates and outputs oMask.
>>> + */
>>> if (fp->program.UsesKill || ctx->Color.AlphaEnabled ||
>>> - ctx->Multisample.SampleAlphaToCoverage)
>>> + ctx->Multisample.SampleAlphaToCoverage ||
>>> + (ctx->Multisample.SampleShading &&
>>> + (fp->program.Base.OutputsWritten &
>>> + BITFIELD64_BIT(FRAG_RESULT_SAMPLE_MASK)))) {
>>> dw1 |= GEN7_WM_KILL_ENABLE;
>>> + }
>>>
>>> /* _NEW_BUFFERS */
>>> if (brw_color_buffer_write_enabled(brw) || writes_depth ||
>>> @@ -97,7 +103,25 @@ upload_wm_state(struct brw_context *brw)
>>> dw1 |= GEN7_WM_MSRAST_ON_PATTERN;
>>> else
>>> dw1 |= GEN7_WM_MSRAST_OFF_PIXEL;
>>> - dw2 |= GEN7_WM_MSDISPMODE_PERPIXEL;
>>> + /* From arb_sample_shading specification:
>>> + * "If MULTISAMPLE or SAMPLE_SHADING_ARB is disabled, sample shading
>>> + * has no effect."
>>> + *
>>> + * "Using gl_SampleID in a fragment shader causes the entire shader
>>> + * to be evaluated per-sample."
>>> + * "Using gl_SamplePosition in a fragment shader causes the entire
>>> + * shader to be evaluated per-sample."
>>> + *
>>> + * I interprate the above four lines as enable the sample shading
>>> + * if fragment shader uses gl_SampleID or gl_SamplePosition.
>>> + */
>>> + if (ctx->Multisample.Enabled &&
>>> + (ctx->Multisample.SampleShading ||
>>> + brw->fragment_program->Base.InputsRead & VARYING_BIT_SAMPLE_ID ||
>>> + brw->fragment_program->Base.InputsRead & VARYING_BIT_SAMPLE_POS))
>>> + dw2 |= GEN7_WM_MSDISPMODE_PERSAMPLE;
>>> + else
>>> + dw2 |= GEN7_WM_MSDISPMODE_PERPIXEL;
>>> } else {
>>> dw1 |= GEN7_WM_MSRAST_OFF_PIXEL;
>>> dw2 |= GEN7_WM_MSDISPMODE_PERSAMPLE;
>>> @@ -129,6 +153,8 @@ upload_ps_state(struct brw_context *brw)
>>> uint32_t dw2, dw4, dw5;
>>> const int max_threads_shift = brw->is_haswell ?
>>> HSW_PS_MAX_THREADS_SHIFT : IVB_PS_MAX_THREADS_SHIFT;
>>> + bool msdispmode_persample = false;
>>> + bool multisampled_fbo = ctx->DrawBuffer->Visual.samples > 1;
>>>
>>> /* BRW_NEW_PS_BINDING_TABLE */
>>> BEGIN_BATCH(2);
>>> @@ -169,6 +195,34 @@ upload_ps_state(struct brw_context *brw)
>>> if (brw->wm.prog_data->nr_params > 0)
>>> dw4 |= GEN7_PS_PUSH_CONSTANT_ENABLE;
>>>
>>> + /* From the IVB PRM, volume 2 part 1, page 287:
>>> + * "This bit is inserted in the PS payload header and made available to
>>> + * the DataPort (either via the message header or via header bypass) to
>>> + * indicate that oMask data (one or two phases) is included in Render
>>> + * Target Write messages. If present, the oMask data is used to mask off
>>> + * samples."
>>> + */
>>> + if (ctx->Extensions.ARB_sample_shading &&
>>> + (brw->fragment_program->Base.OutputsWritten &
>>> + BITFIELD64_BIT(FRAG_RESULT_SAMPLE_MASK)))
>>> + dw4 |= GEN7_PS_OMASK_TO_RENDER_TARGET;
>>> +
>>> + /* From the IVB PRM, volume 2 part 1, page 287:
>>> + * "If the PS kernel does not need the Position XY Offsets to
>>> + * compute a Position Value, then this field should be programmed
>>> + * to POSOFFSET_NONE."
>>> + * "SW Recommendation: If the PS kernel needs the Position Offsets
>>> + * to compute a Position XY value, this field should match Position
>>> + * ZW Interpolation Mode to ensure a consistent position.xyzw
>>> + * computation."
>>> + * We only require XY sample offsets. So, this recommendation doesn't
>>> + * look useful at the moment. We might need this in future.
>>> + */
>>> + if (brw->fragment_program->Base.InputsRead & VARYING_BIT_SAMPLE_POS)
>>> + dw4 |= GEN7_PS_POSOFFSET_SAMPLE;
>>> + else
>>> + dw4 |= GEN7_PS_POSOFFSET_NONE;
>>> +
>>> /* CACHE_NEW_WM_PROG | _NEW_COLOR
>>> *
>>> * The hardware wedges if you have this bit set but don't turn on any dual
>>> @@ -185,7 +239,17 @@ upload_ps_state(struct brw_context *brw)
>>> dw4 |= GEN7_PS_ATTRIBUTE_ENABLE;
>>>
>>> dw4 |= GEN7_PS_8_DISPATCH_ENABLE;
>>> - if (brw->wm.prog_data->prog_offset_16)
>>> + msdispmode_persample =
>>> + ctx->Multisample.Enabled &&
>>> + (ctx->Multisample.SampleShading ||
>>> + brw->fragment_program->Base.InputsRead & VARYING_BIT_SAMPLE_ID ||
>>> + brw->fragment_program->Base.InputsRead & VARYING_BIT_SAMPLE_POS);
>>
>> There are two copies of this expression in the Gen7 patch. You should
>> probably pull this up earlier, and remove the second copy (like you did
>> for the SNB code).
>>
> These expressions appear in different functions upload_ps_state() and
> upload_wm_state(). That's the reason I couldn't do what I did for SNB.
So... this code appears in three places? Sounds like it could be a
helper function. _mesa_is_sample_shading_enabled(ctx, prog).
>> Otherwise, the same comments for patch 6 apply. This looks good.
>>
>> Patch 8 is Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
>>
>>> + /* In case of non 1x (i.e 4x, 8x) multisampling with MDISPMODE_PERSAMPLE,
>>> + * only one of SIMD8 and SIMD16 should be enabled.
>>> + */
>>> + if (brw->wm.prog_data->prog_offset_16 &&
>>> + !(multisampled_fbo && msdispmode_persample))
>>> dw4 |= GEN7_PS_16_DISPATCH_ENABLE;
>>>
>>> dw5 |= (brw->wm.prog_data->first_curbe_grf <<
>>>
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