mesa/src/compiler/nir/nir_lower_pntc_ytransform.c

137 lines
4.9 KiB
C

/*
* Copyright © 2020 Igalia S.L.
*
* 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"
#include "program/prog_instruction.h"
/* Lower gl_PointCoord to account for user requested point-coord origin
* and for whether draw buffer is flipped.
*/
typedef struct {
const gl_state_index16 *pntc_state_tokens;
nir_shader *shader;
nir_builder b;
nir_variable *pntc_transform;
} lower_pntc_ytransform_state;
static nir_ssa_def *
get_pntc_transform(lower_pntc_ytransform_state *state)
{
if (state->pntc_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_PntcYTransform");
var->num_state_slots = 1;
var->state_slots = ralloc_array(var, nir_state_slot, 1);
var->state_slots[0].swizzle = SWIZZLE_XYZW;
memcpy(var->state_slots[0].tokens, state->pntc_state_tokens,
sizeof(var->state_slots[0].tokens));
var->data.how_declared = nir_var_hidden;
state->pntc_transform = var;
}
return nir_load_var(&state->b, state->pntc_transform);
}
static void
lower_load_pointcoord(lower_pntc_ytransform_state *state,
nir_intrinsic_instr *intr)
{
nir_builder *b = &state->b;
b->cursor = nir_after_instr(&intr->instr);
nir_ssa_def *pntc = &intr->dest.ssa;
nir_ssa_def *transform = get_pntc_transform(state);
nir_ssa_def *y = nir_channel(b, pntc, 1);
/* The offset is 1 if we're flipping, 0 otherwise. */
nir_ssa_def *offset = nir_channel(b, transform, 1);
/* Flip the sign of y if we're flipping. */
nir_ssa_def *scaled = nir_fmul(b, y, nir_channel(b, transform, 0));
/* Reassemble the vector. */
nir_ssa_def *flipped_pntc = nir_vec2(b,
nir_channel(b, pntc, 0),
nir_fadd(b, offset, scaled));
nir_ssa_def_rewrite_uses_after(&intr->dest.ssa, flipped_pntc,
flipped_pntc->parent_instr);
}
static void
lower_pntc_ytransform_block(lower_pntc_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_deref) {
nir_deref_instr *deref = nir_src_as_deref(intr->src[0]);
nir_variable *var = nir_deref_instr_get_variable(deref);
if ((var->data.mode == nir_var_shader_in &&
var->data.location == VARYING_SLOT_PNTC) ||
(var->data.mode == nir_var_system_value &&
var->data.location == SYSTEM_VALUE_POINT_COORD)) {
lower_load_pointcoord(state, intr);
}
}
}
}
}
bool
nir_lower_pntc_ytransform(nir_shader *shader,
const gl_state_index16 pntc_state_tokens[][STATE_LENGTH])
{
if (!shader->options->lower_wpos_pntc)
return false;
lower_pntc_ytransform_state state = {
.pntc_state_tokens = *pntc_state_tokens,
.shader = shader,
.pntc_transform = NULL,
};
assert(shader->info.stage == MESA_SHADER_FRAGMENT);
nir_foreach_function(function, shader) {
if (function->impl) {
nir_builder_init(&state.b, function->impl);
nir_foreach_block(block, function->impl) {
lower_pntc_ytransform_block(&state, block);
}
nir_metadata_preserve(function->impl, nir_metadata_block_index |
nir_metadata_dominance);
}
}
return state.pntc_transform != NULL;
}