[Mesa-dev] [PATCH 5/8] radeonsi: implement SAMPLEPOS fragment shader input
Ilia Mirkin
imirkin at alum.mit.edu
Wed May 7 09:02:43 PDT 2014
On Wed, May 7, 2014 at 11:56 AM, Marek Olšák <maraeo at gmail.com> wrote:
> I could enable interpolation of gl_FragCoord at the sample instead of
> centroid and do:
>
> gl_SamplePos = fract(gl_FragCoord.xy);
Is that legal? I didn't think that sample position could be an output,
at least not with ARB_sample_shading (and not even with
ARB_gpu_shader5). Perhaps some other extension adds it.
> gl_FragCoord.xy = floor(gl_FragCoord.xy) + vec2(0.5); // center
>
> However, I wouldn't be able to get gl_FragCoord at the centroid.
>
> I'm also not sure how gl_FragCoord should be interpolated if sample
> shading is enabled.
>
> Marek
>
> On Wed, May 7, 2014 at 5:00 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>> On Wed, May 7, 2014 at 10:00 AM, Marek Olšák <maraeo at gmail.com> wrote:
>>> From: Marek Olšák <marek.olsak at amd.com>
>>>
>>> The sample positions are read from a constant buffer.
>>
>> FWIW I had to do the same thing in both nv50 and nvc0. I had proposed
>> that this should actually be done directly by the state tracker, but I
>> think claims were made to the effect that there might be hw which can
>> look up the positions directly. I figured radeon was such hw, but I
>> guess not.
>>
>> Anyways, seems like a nice refactor would be to have mesa/st (or
>> mesa/main) supply the constbufs and rip out the extra logic from
>> nv50/nvc0/radeonsi. [Certainly don't have to do it now, esp now that
>> you've done it this way.] The sample count is already handled this way
>> by mesa core.
>>
>> -ilia
>>
>>> ---
>>> src/gallium/drivers/radeon/cayman_msaa.c | 17 +++++++++++++++++
>>> src/gallium/drivers/radeon/r600_pipe_common.c | 1 +
>>> src/gallium/drivers/radeon/r600_pipe_common.h | 10 ++++++++++
>>> src/gallium/drivers/radeonsi/si_shader.c | 23 +++++++++++++++++++++++
>>> src/gallium/drivers/radeonsi/si_state.c | 25 +++++++++++++++++++++++++
>>> 5 files changed, 76 insertions(+)
>>>
>>> diff --git a/src/gallium/drivers/radeon/cayman_msaa.c b/src/gallium/drivers/radeon/cayman_msaa.c
>>> index 8727f3e..47fc5c4 100644
>>> --- a/src/gallium/drivers/radeon/cayman_msaa.c
>>> +++ b/src/gallium/drivers/radeon/cayman_msaa.c
>>> @@ -123,6 +123,23 @@ void cayman_get_sample_position(struct pipe_context *ctx, unsigned sample_count,
>>> }
>>> }
>>>
>>> +void cayman_init_msaa(struct pipe_context *ctx)
>>> +{
>>> + struct r600_common_context *rctx = (struct r600_common_context*)ctx;
>>> + int i;
>>> +
>>> + cayman_get_sample_position(ctx, 1, 0, rctx->sample_locations_1x[0]);
>>> +
>>> + for (i = 0; i < 2; i++)
>>> + cayman_get_sample_position(ctx, 2, i, rctx->sample_locations_2x[i]);
>>> + for (i = 0; i < 4; i++)
>>> + cayman_get_sample_position(ctx, 4, i, rctx->sample_locations_4x[i]);
>>> + for (i = 0; i < 8; i++)
>>> + cayman_get_sample_position(ctx, 8, i, rctx->sample_locations_8x[i]);
>>> + for (i = 0; i < 16; i++)
>>> + cayman_get_sample_position(ctx, 16, i, rctx->sample_locations_16x[i]);
>>> +}
>>> +
>>> void cayman_emit_msaa_sample_locs(struct radeon_winsys_cs *cs, int nr_samples)
>>> {
>>> switch (nr_samples) {
>>> diff --git a/src/gallium/drivers/radeon/r600_pipe_common.c b/src/gallium/drivers/radeon/r600_pipe_common.c
>>> index 70c4d1a..4c6cf0e 100644
>>> --- a/src/gallium/drivers/radeon/r600_pipe_common.c
>>> +++ b/src/gallium/drivers/radeon/r600_pipe_common.c
>>> @@ -154,6 +154,7 @@ bool r600_common_context_init(struct r600_common_context *rctx,
>>> r600_init_context_texture_functions(rctx);
>>> r600_streamout_init(rctx);
>>> r600_query_init(rctx);
>>> + cayman_init_msaa(&rctx->b);
>>>
>>> rctx->allocator_so_filled_size = u_suballocator_create(&rctx->b, 4096, 4,
>>> 0, PIPE_USAGE_DEFAULT, TRUE);
>>> diff --git a/src/gallium/drivers/radeon/r600_pipe_common.h b/src/gallium/drivers/radeon/r600_pipe_common.h
>>> index 4c3e9ce..8862d31 100644
>>> --- a/src/gallium/drivers/radeon/r600_pipe_common.h
>>> +++ b/src/gallium/drivers/radeon/r600_pipe_common.h
>>> @@ -357,6 +357,15 @@ struct r600_common_context {
>>> boolean saved_render_cond_cond;
>>> unsigned saved_render_cond_mode;
>>>
>>> + /* MSAA sample locations.
>>> + * The first index is the sample index.
>>> + * The second index is the coordinate: X, Y. */
>>> + float sample_locations_1x[1][2];
>>> + float sample_locations_2x[2][2];
>>> + float sample_locations_4x[4][2];
>>> + float sample_locations_8x[8][2];
>>> + float sample_locations_16x[16][2];
>>> +
>>> /* Copy one resource to another using async DMA. */
>>> void (*dma_copy)(struct pipe_context *ctx,
>>> struct pipe_resource *dst,
>>> @@ -472,6 +481,7 @@ extern const uint32_t eg_sample_locs_4x[4];
>>> extern const unsigned eg_max_dist_4x;
>>> void cayman_get_sample_position(struct pipe_context *ctx, unsigned sample_count,
>>> unsigned sample_index, float *out_value);
>>> +void cayman_init_msaa(struct pipe_context *ctx);
>>> void cayman_emit_msaa_sample_locs(struct radeon_winsys_cs *cs, int nr_samples);
>>> void cayman_emit_msaa_config(struct radeon_winsys_cs *cs, int nr_samples,
>>> int ps_iter_samples);
>>> diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
>>> index 0195e54..d8b7b9c 100644
>>> --- a/src/gallium/drivers/radeonsi/si_shader.c
>>> +++ b/src/gallium/drivers/radeonsi/si_shader.c
>>> @@ -559,6 +559,8 @@ static void declare_system_value(
>>> {
>>> struct si_shader_context *si_shader_ctx =
>>> si_shader_context(&radeon_bld->soa.bld_base);
>>> + struct lp_build_context *uint_bld = &radeon_bld->soa.bld_base.uint_bld;
>>> + struct gallivm_state *gallivm = &radeon_bld->gallivm;
>>> LLVMValueRef value = 0;
>>>
>>> switch (decl->Semantic.Name) {
>>> @@ -576,6 +578,27 @@ static void declare_system_value(
>>> value = get_sample_id(radeon_bld);
>>> break;
>>>
>>> + case TGSI_SEMANTIC_SAMPLEPOS:
>>> + {
>>> + LLVMBuilderRef builder = gallivm->builder;
>>> + LLVMValueRef desc = LLVMGetParam(si_shader_ctx->radeon_bld.main_fn, SI_PARAM_CONST);
>>> + LLVMValueRef buf_index = lp_build_const_int32(gallivm, NUM_PIPE_CONST_BUFFERS);
>>> + LLVMValueRef resource = build_indexed_load(si_shader_ctx, desc, buf_index);
>>> +
>>> + /* offset = sample_id * 8 (8 = 2 floats containing samplepos.xy) */
>>> + LLVMValueRef offset0 = lp_build_mul_imm(uint_bld, get_sample_id(radeon_bld), 8);
>>> + LLVMValueRef offset1 = LLVMBuildAdd(builder, offset0, lp_build_const_int32(gallivm, 4), "");
>>> +
>>> + LLVMValueRef pos[4] = {
>>> + load_const(builder, resource, offset0, radeon_bld->soa.bld_base.base.elem_type),
>>> + load_const(builder, resource, offset1, radeon_bld->soa.bld_base.base.elem_type),
>>> + lp_build_const_float(gallivm, 0),
>>> + lp_build_const_float(gallivm, 0)
>>> + };
>>> + value = lp_build_gather_values(gallivm, pos, 4);
>>> + break;
>>> + }
>>> +
>>> default:
>>> assert(!"unknown system value");
>>> return;
>>> diff --git a/src/gallium/drivers/radeonsi/si_state.c b/src/gallium/drivers/radeonsi/si_state.c
>>> index fd9de05..3c1af06 100644
>>> --- a/src/gallium/drivers/radeonsi/si_state.c
>>> +++ b/src/gallium/drivers/radeonsi/si_state.c
>>> @@ -1859,6 +1859,7 @@ static void si_set_framebuffer_state(struct pipe_context *ctx,
>>> const struct pipe_framebuffer_state *state)
>>> {
>>> struct si_context *sctx = (struct si_context *)ctx;
>>> + struct pipe_constant_buffer constbuf = {0};
>>> struct r600_surface *surf = NULL;
>>> struct r600_texture *rtex;
>>> int i;
>>> @@ -1924,6 +1925,30 @@ static void si_set_framebuffer_state(struct pipe_context *ctx,
>>> sctx->framebuffer.atom.num_dw += 18; /* MSAA sample locations */
>>> sctx->framebuffer.atom.dirty = true;
>>> sctx->msaa_config.dirty = true;
>>> +
>>> + /* Set sample locations as fragment shader constants. */
>>> + switch (sctx->framebuffer.nr_samples) {
>>> + case 1:
>>> + constbuf.user_buffer = sctx->b.sample_locations_1x;
>>> + break;
>>> + case 2:
>>> + constbuf.user_buffer = sctx->b.sample_locations_2x;
>>> + break;
>>> + case 4:
>>> + constbuf.user_buffer = sctx->b.sample_locations_4x;
>>> + break;
>>> + case 8:
>>> + constbuf.user_buffer = sctx->b.sample_locations_8x;
>>> + break;
>>> + case 16:
>>> + constbuf.user_buffer = sctx->b.sample_locations_16x;
>>> + break;
>>> + default:
>>> + assert(0);
>>> + }
>>> + constbuf.buffer_size = sctx->framebuffer.nr_samples * 2 * 4;
>>> + ctx->set_constant_buffer(ctx, PIPE_SHADER_FRAGMENT,
>>> + NUM_PIPE_CONST_BUFFERS, &constbuf);
>>> }
>>>
>>> static void si_emit_framebuffer_state(struct si_context *sctx, struct r600_atom *atom)
>>> --
>>> 1.9.1
>>>
>>> _______________________________________________
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>>> mesa-dev at lists.freedesktop.org
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