[Mesa-dev] [PATCH 2/7] nir: Add a lowering pass for YUV textures
Jason Ekstrand
jason at jlekstrand.net
Fri May 6 00:37:15 UTC 2016
On Thu, May 5, 2016 at 5:04 PM, Kristian Høgsberg <krh at bitplanet.net> wrote:
> From: Kristian Høgsberg Kristensen <kristian.h.kristensen at intel.com>
>
> This lowers sampling from YUV textures to 1) one or more texture
> instructions to sample each plane and 2) color space conversion to RGB.
> ---
> src/compiler/nir/nir.h | 7 +++
> src/compiler/nir/nir_lower_tex.c | 118
> +++++++++++++++++++++++++++++++++++++++
> 2 files changed, 125 insertions(+)
>
> diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> index d85ea17..cf6d49d 100644
> --- a/src/compiler/nir/nir.h
> +++ b/src/compiler/nir/nir.h
> @@ -2273,6 +2273,13 @@ typedef struct nir_lower_tex_options {
> bool lower_rect;
>
> /**
> + * If true, convert yuv to rgb.
> + */
> + unsigned lower_y_uv_external;
> + unsigned lower_y_u_v_external;
> + unsigned lower_yx_xuxv_external;
> +
> + /**
> * To emulate certain texture wrap modes, this can be used
> * to saturate the specified tex coord to [0.0, 1.0]. The
> * bits are according to sampler #, ie. if, for example:
> diff --git a/src/compiler/nir/nir_lower_tex.c
> b/src/compiler/nir/nir_lower_tex.c
> index 16fee9a..c8aebb4 100644
> --- a/src/compiler/nir/nir_lower_tex.c
> +++ b/src/compiler/nir/nir_lower_tex.c
> @@ -167,6 +167,108 @@ lower_rect(nir_builder *b, nir_tex_instr *tex)
> tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
> }
>
> +static nir_ssa_def *
> +sample_plane(nir_builder *b, nir_tex_instr *tex, int plane)
> +{
> + assert(tex->dest.is_ssa);
> + assert(nir_tex_instr_dest_size(tex) == 4);
> + assert(nir_alu_type_get_base_type(tex->dest_type) == nir_type_float);
> + assert(tex->op == nir_texop_tex);
> + assert(tex->coord_components == 2);
> +
> + nir_tex_instr *plane_tex = nir_tex_instr_create(b->shader, 2);
> + plane_tex->src[0].src = tex->src[0].src;
>
You should use nir_src_copy here
> + plane_tex->src[0].src_type = nir_tex_src_coord;
> + plane_tex->src[1].src = nir_src_for_ssa(nir_imm_int(b, plane));
> + plane_tex->src[1].src_type = nir_tex_src_plane;
> + plane_tex->op = nir_texop_tex;
> + plane_tex->sampler_dim = 2;
> + plane_tex->dest_type = nir_type_float;
> + plane_tex->coord_components = 2;
> +
> + plane_tex->texture_index = tex->texture_index;
>
This should use nir_copy_deref. Right now, the deref is supposed to be
ralloc parented to the instruciton so you have to make a copy. One of
these days, I'm going to clean that up.
> + plane_tex->texture = tex->texture;
> + plane_tex->sampler_index = tex->sampler_index;
> + plane_tex->sampler = tex->sampler;
>
Same here
> +
> + nir_ssa_dest_init(&plane_tex->instr, &plane_tex->dest, 4, 32, NULL);
> +
> + nir_builder_instr_insert(b, &plane_tex->instr);
> +
> + return &plane_tex->dest.ssa;
> +}
> +
> +static void
> +convert_yuv_to_rgb(nir_builder *b, nir_tex_instr *tex,
> + nir_ssa_def *y, nir_ssa_def *u, nir_ssa_def *v)
> +{
> + nir_const_value m[3] = {
> + { .f32 = { 1.0f, 0.0f, 1.59602678f, 0.0f } },
> + { .f32 = { 1.0f, -0.39176229f, -0.81296764f, 0.0f } },
> + { .f32 = { 1.0f, 2.01723214f, 0.0f, 0.0f } }
> + };
> +
> + nir_ssa_def *yuv =
> + nir_vec4(b,
> + nir_fmul(b, nir_imm_float(b, 1.16438356f),
> + nir_fadd(b, y, nir_imm_float(b, -0.0625f))),
> + nir_channel(b, nir_fadd(b, u, nir_imm_float(b, -0.5f)), 0),
> + nir_channel(b, nir_fadd(b, v, nir_imm_float(b, -0.5f)), 0),
> + nir_imm_float(b, 0.0));
> +
> + nir_ssa_def *red = nir_fdot4(b, yuv, nir_build_imm(b, 4, m[0]));
> + nir_ssa_def *green = nir_fdot4(b, yuv, nir_build_imm(b, 4, m[1]));
> + nir_ssa_def *blue = nir_fdot4(b, yuv, nir_build_imm(b, 4, m[2]));
>
I didn't bother checking your math here, but I've seen the results so it's
probably ok.
> +
> + nir_ssa_def *result = nir_vec4(b, red, green, blue, nir_imm_float(b,
> 1.0f));
> +
> + nir_ssa_def_rewrite_uses_after(&tex->dest.ssa, nir_src_for_ssa(result),
> + result->parent_instr);
>
You can just use ssa_def_rewrite_uses here. No need to use the _after
version.
With those fixed, this and the other NIR patch are
Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
> +}
> +
> +static void
> +lower_y_uv_external(nir_builder *b, nir_tex_instr *tex)
> +{
> + b->cursor = nir_after_instr(&tex->instr);
> +
> + nir_ssa_def *y = sample_plane(b, tex, 0);
> + nir_ssa_def *uv = sample_plane(b, tex, 1);
> +
> + convert_yuv_to_rgb(b, tex,
> + nir_channel(b, y, 0),
> + nir_channel(b, uv, 0),
> + nir_channel(b, uv, 1));
> +}
> +
> +static void
> +lower_y_u_v_external(nir_builder *b, nir_tex_instr *tex)
> +{
> + b->cursor = nir_after_instr(&tex->instr);
> +
> + nir_ssa_def *y = sample_plane(b, tex, 0);
> + nir_ssa_def *u = sample_plane(b, tex, 1);
> + nir_ssa_def *v = sample_plane(b, tex, 2);
> +
> + convert_yuv_to_rgb(b, tex,
> + nir_channel(b, y, 0),
> + nir_channel(b, u, 0),
> + nir_channel(b, v, 0));
> +}
> +
> +static void
> +lower_yx_xuxv_external(nir_builder *b, nir_tex_instr *tex)
> +{
> + b->cursor = nir_after_instr(&tex->instr);
> +
> + nir_ssa_def *y = sample_plane(b, tex, 0);
> + nir_ssa_def *xuxv = sample_plane(b, tex, 1);
> +
> + convert_yuv_to_rgb(b, tex,
> + nir_channel(b, y, 0),
> + nir_channel(b, xuxv, 1),
> + nir_channel(b, xuxv, 3));
> +}
> +
> static void
> saturate_src(nir_builder *b, nir_tex_instr *tex, unsigned sat_mask)
> {
> @@ -351,6 +453,22 @@ nir_lower_tex_block(nir_block *block, void
> *void_state)
> state->progress = true;
> }
>
> + if ((1 << tex->texture_index) & options->lower_y_uv_external) {
> + lower_y_uv_external(b, tex);
> + state->progress = true;
> + }
> +
> + if ((1 << tex->texture_index) & options->lower_y_u_v_external) {
> + lower_y_u_v_external(b, tex);
> + state->progress = true;
> + }
> +
> + if ((1 << tex->texture_index) & options->lower_yx_xuxv_external) {
> + lower_yx_xuxv_external(b, tex);
> + state->progress = true;
> + }
> +
> +
> if (sat_mask) {
> saturate_src(b, tex, sat_mask);
> state->progress = true;
> --
> 2.5.0
>
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