[Mesa-dev] [PATCH 04/17] nir: add lowering pass for y-transform
Jason Ekstrand
jason at jlekstrand.net
Sat May 14 20:43:01 UTC 2016
On Sat, May 14, 2016 at 12:23 PM, Rob Clark <robdclark at gmail.com> wrote:
> On Thu, May 12, 2016 at 10:17 PM, Jason Ekstrand <jason at jlekstrand.net>
> wrote:
> >
> >
> > On Mon, May 9, 2016 at 12:33 PM, Rob Clark <robdclark at gmail.com> wrote:
> >>
> >> From: Rob Clark <robclark at freedesktop.org>
> >>
> >> Signed-off-by: Rob Clark <robclark at freedesktop.org>
> >> Reviewed-by: Connor Abbott <cwabbott0 at gmail.com>
> >> ---
> >> src/compiler/Makefile.sources | 1 +
> >> src/compiler/nir/nir.h | 11 +
> >> src/compiler/nir/nir_lower_wpos_ytransform.c | 310
> >> +++++++++++++++++++++++++++
> >> 3 files changed, 322 insertions(+)
> >> create mode 100644 src/compiler/nir/nir_lower_wpos_ytransform.c
> >>
> >> diff --git a/src/compiler/Makefile.sources
> b/src/compiler/Makefile.sources
> >> index 2a52319..b542a1a 100644
> >> --- a/src/compiler/Makefile.sources
> >> +++ b/src/compiler/Makefile.sources
> >> @@ -208,6 +208,7 @@ NIR_FILES = \
> >> nir/nir_lower_vars_to_ssa.c \
> >> nir/nir_lower_var_copies.c \
> >> nir/nir_lower_vec_to_movs.c \
> >> + nir/nir_lower_wpos_ytransform.c \
> >> nir/nir_metadata.c \
> >> nir/nir_move_vec_src_uses_to_dest.c \
> >> nir/nir_normalize_cubemap_coords.c \
> >> diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> >> index 8a616d4..474ba63 100644
> >> --- a/src/compiler/nir/nir.h
> >> +++ b/src/compiler/nir/nir.h
> >> @@ -2374,6 +2374,17 @@ void nir_lower_two_sided_color(nir_shader
> *shader);
> >>
> >> void nir_lower_clamp_color_outputs(nir_shader *shader);
> >>
> >> +typedef struct nir_lower_wpos_ytransform_options {
> >> + int state_tokens[5];
> >> + bool fs_coord_origin_upper_left :1;
> >> + bool fs_coord_origin_lower_left :1;
> >> + bool fs_coord_pixel_center_integer :1;
> >> + bool fs_coord_pixel_center_half_integer :1;
> >
> >
> > Drive-by commentary: Why are we using two booleans for one boolean here?
> > All hardware should be either lower-left or upper-left and I'm going to
> > hazard that the other two are mutually exclusive as well. The pass
> > certainly seems to assume so.
>
> mostly just because gallium splits it out into two caps, and this
> matches the logic in the equiv tgsi lowering pass more closely..
>
> The way it is currently would, I think, work if there was some hw that
> supported both cases (which is, I assume, why the gallium part of it
> works the way it does)
>
Yeah, I guess I could see that. In that case, I suppose you could just not
run the pass? I guess you could have a case where HW supports both
gl_FragCoords modes but only one pixel-center mode. Whatever. I guess I'm
ok with 4 bools if it's useful.
>
> BR,
> -R
>
> > Let's just make it two booleans. If we come across hardware that puts
> the
> > pixel center at 0.75, 0.25 then we can make fs_coord_pixel_center an
> enum.
> > --Jason
> >
> >>
> >> +} nir_lower_wpos_ytransform_options;
> >> +
> >> +bool nir_lower_wpos_ytransform(nir_shader *shader,
> >> + const nir_lower_wpos_ytransform_options
> >> *options);
> >> +
> >> void nir_lower_atomics(nir_shader *shader,
> >> const struct gl_shader_program *shader_program);
> >> void nir_lower_to_source_mods(nir_shader *shader);
> >> diff --git a/src/compiler/nir/nir_lower_wpos_ytransform.c
> >> b/src/compiler/nir/nir_lower_wpos_ytransform.c
> >> new file mode 100644
> >> index 0000000..1d53530
> >> --- /dev/null
> >> +++ b/src/compiler/nir/nir_lower_wpos_ytransform.c
> >> @@ -0,0 +1,310 @@
> >> +/*
> >> + * Copyright © 2015 Red Hat
> >> + *
> >> + * Permission is hereby granted, free of charge, to any person
> obtaining
> >> a
> >> + * copy of this software and associated documentation files (the
> >> "Software"),
> >> + * to deal in the Software without restriction, including without
> >> limitation
> >> + * the rights to use, copy, modify, merge, publish, distribute,
> >> sublicense,
> >> + * and/or sell copies of the Software, and to permit persons to whom
> the
> >> + * Software is furnished to do so, subject to the following conditions:
> >> + *
> >> + * The above copyright notice and this permission notice (including the
> >> next
> >> + * paragraph) shall be included in all copies or substantial portions
> of
> >> the
> >> + * Software.
> >> + *
> >> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> >> EXPRESS OR
> >> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> >> MERCHANTABILITY,
> >> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
> >> SHALL
> >> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> >> OTHER
> >> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> >> ARISING FROM,
> >> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> DEALINGS
> >> IN THE
> >> + * SOFTWARE.
> >> + */
> >> +
> >> +#include "nir.h"
> >> +#include "nir_builder.h"
> >> +
> >> +/* Lower gl_FragCoord (and fddy) to account for driver's requested
> >> coordinate-
> >> + * origin and pixel-center vs. shader. If transformation is required,
> a
> >> + * gl_FbWposYTransform uniform is inserted (with the specified
> >> state-slots)
> >> + * and additional instructions are inserted to transform gl_FragCoord
> >> (and
> >> + * fddy src arg).
> >> + *
> >> + * This is based on the logic in emit_wpos()/emit_wpos_adjustment() in
> >> TGSI
> >> + * compiler.
> >> + *
> >> + * Run before nir_lower_io.
> >> + */
> >> +
> >> +typedef struct {
> >> + const nir_lower_wpos_ytransform_options *options;
> >> + nir_shader *shader;
> >> + nir_builder b;
> >> + nir_variable *transform;
> >> +} lower_wpos_ytransform_state;
> >> +
> >> +static nir_ssa_def *
> >> +get_transform(lower_wpos_ytransform_state *state)
> >> +{
> >> + if (state->transform == NULL) {
> >> + /* NOTE: name must be prefixed w/ "gl_" to trigger slot based
> >> + * special handling in uniform setup:
> >> + */
> >> + nir_variable *var = nir_variable_create(state->shader,
> >> + nir_var_uniform,
> >> + glsl_vec4_type(),
> >> + "gl_FbWposYTransform");
> >> +
> >> + var->num_state_slots = 1;
> >> + var->state_slots = ralloc_array(var, nir_state_slot, 1);
> >> + memcpy(var->state_slots[0].tokens, state->options->state_tokens,
> >> + sizeof(var->state_slots[0].tokens));
> >> +
> >> + state->transform = var;
> >> + }
> >> + return nir_load_var(&state->b, state->transform);
> >> +}
> >> +
> >> +/* NIR equiv of TGSI CMP instruction: */
> >> +static nir_ssa_def *
> >> +nir_cmp(nir_builder *b, nir_ssa_def *src0, nir_ssa_def *src1,
> nir_ssa_def
> >> *src2)
> >> +{
> >> + return nir_bcsel(b, nir_flt(b, src0, nir_imm_float(b, 0.0)), src1,
> >> src2);
> >> +}
> >> +
> >> +/* see emit_wpos_adjustment() in st_mesa_to_tgsi.c */
> >> +static void
> >> +emit_wpos_adjustment(lower_wpos_ytransform_state *state,
> >> + nir_intrinsic_instr *intr,
> >> + bool invert, float adjX, float adjY[2])
> >> +{
> >> + nir_builder *b = &state->b;
> >> + nir_variable *fragcoord = intr->variables[0]->var;
> >> + nir_ssa_def *wpostrans, *wpos_temp, *wpos_temp_y, *wpos_input;
> >> +
> >> + assert(intr->dest.is_ssa);
> >> +
> >> + b->cursor = nir_before_instr(&intr->instr);
> >> +
> >> + wpostrans = get_transform(state);
> >> + wpos_input = nir_load_var(b, fragcoord);
> >> +
> >> + /* First, apply the coordinate shift: */
> >> + if (adjX || adjY[0] || adjY[1]) {
> >> + if (adjY[0] != adjY[1]) {
> >> + /* Adjust the y coordinate by adjY[1] or adjY[0] respectively
> >> + * depending on whether inversion is actually going to be
> >> applied
> >> + * or not, which is determined by testing against the
> inversion
> >> + * state variable used below, which will be either +1 or -1.
> >> + */
> >> + nir_ssa_def *adj_temp;
> >> +
> >> + adj_temp = nir_cmp(b,
> >> + nir_channel(b, wpostrans, invert ? 2 : 0),
> >> + nir_imm_vec4(b, adjX, adjY[0], 0.0f, 0.0f),
> >> + nir_imm_vec4(b, adjX, adjY[1], 0.0f,
> 0.0f));
> >> +
> >> + wpos_temp = nir_fadd(b, wpos_input, adj_temp);
> >> + } else {
> >> + wpos_temp = nir_fadd(b,
> >> + wpos_input,
> >> + nir_imm_vec4(b, adjX, adjY[0], 0.0f,
> >> 0.0f));
> >> + }
> >> + wpos_input = wpos_temp;
> >> + } else {
> >> + /* MOV wpos_temp, input[wpos]
> >> + */
> >> + wpos_temp = wpos_input;
> >> + }
> >> +
> >> + /* Now the conditional y flip: STATE_FB_WPOS_Y_TRANSFORM.xy/zw will
> be
> >> + * inversion/identity, or the other way around if we're drawing to
> an
> >> FBO.
> >> + */
> >> + if (invert) {
> >> + /* MAD wpos_temp.y, wpos_input, wpostrans.xxxx, wpostrans.yyyy
> >> + */
> >> + wpos_temp_y = nir_ffma(b,
> >> + nir_channel(b, wpos_temp, 1),
> >> + nir_channel(b, wpostrans, 0),
> >> + nir_channel(b, wpostrans, 1));
> >> + } else {
> >> + /* MAD wpos_temp.y, wpos_input, wpostrans.zzzz, wpostrans.wwww
> >> + */
> >> + wpos_temp_y = nir_ffma(b,
> >> + nir_channel(b, wpos_temp, 1),
> >> + nir_channel(b, wpostrans, 2),
> >> + nir_channel(b, wpostrans, 3));
> >> + }
> >> +
> >> + wpos_temp = nir_vec4(b,
> >> + nir_channel(b, wpos_temp, 0),
> >> + wpos_temp_y,
> >> + nir_channel(b, wpos_temp, 2),
> >> + nir_channel(b, wpos_temp, 3));
> >> +
> >> + nir_ssa_def_rewrite_uses(&intr->dest.ssa,
> nir_src_for_ssa(wpos_temp));
> >> +}
> >> +
> >> +static void
> >> +lower_fragcoord(lower_wpos_ytransform_state *state, nir_intrinsic_instr
> >> *intr)
> >> +{
> >> + const nir_lower_wpos_ytransform_options *options = state->options;
> >> + nir_variable *fragcoord = intr->variables[0]->var;
> >> + float adjX = 0.0f;
> >> + float adjY[2] = { 0.0f, 0.0f };
> >> + bool invert = false;
> >> +
> >> + /* Based on logic in emit_wpos():
> >> + *
> >> + * Query the pixel center conventions supported by the pipe driver
> and
> >> set
> >> + * adjX, adjY to help out if it cannot handle the requested one
> >> internally.
> >> + *
> >> + * The bias of the y-coordinate depends on whether y-inversion takes
> >> place
> >> + * (adjY[1]) or not (adjY[0]), which is in turn dependent on whether
> >> we are
> >> + * drawing to an FBO (causes additional inversion), and whether the
> >> the pipe
> >> + * driver origin and the requested origin differ (the latter
> condition
> >> is
> >> + * stored in the 'invert' variable).
> >> + *
> >> + * For height = 100 (i = integer, h = half-integer, l = lower, u =
> >> upper):
> >> + *
> >> + * center shift only:
> >> + * i -> h: +0.5
> >> + * h -> i: -0.5
> >> + *
> >> + * inversion only:
> >> + * l,i -> u,i: ( 0.0 + 1.0) * -1 + 100 = 99
> >> + * l,h -> u,h: ( 0.5 + 0.0) * -1 + 100 = 99.5
> >> + * u,i -> l,i: (99.0 + 1.0) * -1 + 100 = 0
> >> + * u,h -> l,h: (99.5 + 0.0) * -1 + 100 = 0.5
> >> + *
> >> + * inversion and center shift:
> >> + * l,i -> u,h: ( 0.0 + 0.5) * -1 + 100 = 99.5
> >> + * l,h -> u,i: ( 0.5 + 0.5) * -1 + 100 = 99
> >> + * u,i -> l,h: (99.0 + 0.5) * -1 + 100 = 0.5
> >> + * u,h -> l,i: (99.5 + 0.5) * -1 + 100 = 0
> >> + */
> >> +
> >> + if (fragcoord->data.origin_upper_left) {
> >> + /* Fragment shader wants origin in upper-left */
> >> + if (options->fs_coord_origin_upper_left) {
> >> + /* the driver supports upper-left origin */
> >> + } else if (options->fs_coord_origin_lower_left) {
> >> + /* the driver supports lower-left origin, need to invert Y */
> >> + invert = true;
> >> + } else {
> >> + unreachable("invalid options");
> >> + }
> >> + } else {
> >> + /* Fragment shader wants origin in lower-left */
> >> + if (options->fs_coord_origin_lower_left) {
> >> + /* the driver supports lower-left origin */
> >> + } else if (options->fs_coord_origin_upper_left) {
> >> + /* the driver supports upper-left origin, need to invert Y */
> >> + invert = true;
> >> + } else {
> >> + unreachable("invalid options");
> >> + }
> >> + }
> >> +
> >> + if (fragcoord->data.pixel_center_integer) {
> >> + /* Fragment shader wants pixel center integer */
> >> + if (options->fs_coord_pixel_center_integer) {
> >> + /* the driver supports pixel center integer */
> >> + adjY[1] = 1.0f;
> >> + } else if (options->fs_coord_pixel_center_half_integer) {
> >> + /* the driver supports pixel center half integer, need to bias
> >> X,Y */
> >> + adjX = -0.5f;
> >> + adjY[0] = -0.5f;
> >> + adjY[1] = 0.5f;
> >> + } else {
> >> + unreachable("invalid options");
> >> + }
> >> + } else {
> >> + /* Fragment shader wants pixel center half integer */
> >> + if (options->fs_coord_pixel_center_half_integer) {
> >> + /* the driver supports pixel center half integer */
> >> + } else if (options->fs_coord_pixel_center_integer) {
> >> + /* the driver supports pixel center integer, need to bias X,Y
> */
> >> + adjX = adjY[0] = adjY[1] = 0.5f;
> >> + } else {
> >> + unreachable("invalid options");
> >> + }
> >> + }
> >> +
> >> + emit_wpos_adjustment(state, intr, invert, adjX, adjY);
> >> +}
> >> +
> >> +/* turns 'fddy(p)' into 'fddy(fmul(p, transform.x))' */
> >> +static void
> >> +lower_fddy(lower_wpos_ytransform_state *state, nir_alu_instr *fddy)
> >> +{
> >> + nir_builder *b = &state->b;
> >> + nir_ssa_def *p, *pt, *trans;
> >> +
> >> + b->cursor = nir_before_instr(&fddy->instr);
> >> +
> >> + p = nir_ssa_for_alu_src(b, fddy, 0);
> >> + trans = get_transform(state);
> >> + pt = nir_fmul(b, p, nir_channel(b, trans, 0));
> >> +
> >> + nir_instr_rewrite_src(&fddy->instr,
> >> + &fddy->src[0].src,
> >> + nir_src_for_ssa(pt));
> >> +}
> >> +
> >> +static bool
> >> +lower_wpos_ytransform_block(lower_wpos_ytransform_state *state,
> nir_block
> >> *block)
> >> +{
> >> + nir_foreach_instr_safe(instr, block) {
> >> + if (instr->type == nir_instr_type_intrinsic) {
> >> + nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
> >> + if (intr->intrinsic == nir_intrinsic_load_var) {
> >> + nir_deref_var *dvar = intr->variables[0];
> >> + nir_variable *var = dvar->var;
> >> +
> >> + if (strcmp(var->name, "gl_FragCoord") == 0) {
> >> + /* gl_FragCoord should not have array/struct deref's: */
> >> + assert(dvar->deref.child == NULL);
> >> + lower_fragcoord(state, intr);
> >> + }
> >> + }
> >> + } else if (instr->type == nir_instr_type_alu) {
> >> + nir_alu_instr *alu = nir_instr_as_alu(instr);
> >> + if (alu->op == nir_op_fddy)
> >> + lower_fddy(state, alu);
> >> + }
> >> + }
> >> +
> >> + return true;
> >> +}
> >> +
> >> +static void
> >> +lower_wpos_ytransform_impl(lower_wpos_ytransform_state *state,
> >> nir_function_impl *impl)
> >> +{
> >> + nir_builder_init(&state->b, impl);
> >> +
> >> + nir_foreach_block(block, impl) {
> >> + lower_wpos_ytransform_block(state, block);
> >> + }
> >> + nir_metadata_preserve(impl, nir_metadata_block_index |
> >> + nir_metadata_dominance);
> >> +}
> >> +
> >> +bool
> >> +nir_lower_wpos_ytransform(nir_shader *shader,
> >> + const nir_lower_wpos_ytransform_options
> >> *options)
> >> +{
> >> + lower_wpos_ytransform_state state = {
> >> + .options = options,
> >> + .shader = shader,
> >> + };
> >> +
> >> + assert(shader->stage == MESA_SHADER_FRAGMENT);
> >> +
> >> + nir_foreach_function(function, shader) {
> >> + if (function->impl)
> >> + lower_wpos_ytransform_impl(&state, function->impl);
> >> + }
> >> +
> >> + return state.transform != NULL;
> >> +}
> >> --
> >> 2.5.5
> >>
> >
>
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