mirror of https://gitlab.freedesktop.org/mesa/mesa
100 lines
3.9 KiB
C
100 lines
3.9 KiB
C
/*
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* Copyright © 2019 Google, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include "compiler/nir/nir_builder.h"
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#include "ir3_nir.h"
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/**
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* This pass lowers load_barycentric_at_offset to dsx.3d/dsy.3d and alu
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* instructions.
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*/
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static nir_def *
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ir3_nir_lower_load_barycentric_at_offset_instr(nir_builder *b, nir_instr *instr,
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void *data)
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{
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nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
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enum glsl_interp_mode interp_mode = nir_intrinsic_interp_mode(intr);
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#define chan(var, c) nir_channel(b, var, c)
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nir_def *off = intr->src[0].ssa;
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/* note: at_offset is defined to be relative to the center of the pixel */
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nir_def *ij = nir_load_barycentric_pixel(b, 32, .interp_mode = interp_mode);
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/* Need helper invocations for our ddx/ddys to work. */
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if (b->shader->info.stage == MESA_SHADER_FRAGMENT)
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b->shader->info.fs.needs_quad_helper_invocations = true;
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if (interp_mode != INTERP_MODE_SMOOTH) {
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/* Offset our pixel center ij by the offset argument (units of pixels)
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* times the derivatives of ij in screen space.
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*/
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nir_def *new_ij = ij;
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new_ij = nir_ffma(b, chan(off, 0), nir_fddx(b, ij), new_ij);
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new_ij = nir_ffma(b, chan(off, 1), nir_fddy(b, ij), new_ij);
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return new_ij;
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} else {
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nir_def *center_w = nir_frcp(b, nir_load_persp_center_rhw_ir3(b, 32));
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/* scaled ij -- ij comes in multiplied by by 1/center_w so multiply that
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* back out, plus add center_w as the 3rd component for taking the
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* derivatives.
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*
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* We actually suspect that we should be using rhw here instead of center_w,
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* but no tests seem to distinguish between the two.
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*/
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nir_def *sij =
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nir_vec3(b, nir_fmul(b, chan(ij, 0), center_w), nir_fmul(b, chan(ij, 1), center_w), center_w);
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/* Get the offset value from pixel center for ij, and also for w. */
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nir_def *pos = sij;
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pos = nir_ffma(b, chan(off, 0), nir_fddx(b, sij), pos);
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pos = nir_ffma(b, chan(off, 1), nir_fddy(b, sij), pos);
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/* convert back into screen space, dividing by the offset 1/w */
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return nir_fmul(b, nir_trim_vector(b, pos, 2),
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nir_frcp(b, chan(pos, 2)));
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}
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}
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static bool
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ir3_nir_lower_load_barycentric_at_offset_filter(const nir_instr *instr,
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const void *data)
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{
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return (instr->type == nir_instr_type_intrinsic &&
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nir_instr_as_intrinsic(instr)->intrinsic ==
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nir_intrinsic_load_barycentric_at_offset);
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}
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bool
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ir3_nir_lower_load_barycentric_at_offset(nir_shader *shader)
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{
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assert(shader->info.stage == MESA_SHADER_FRAGMENT);
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return nir_shader_lower_instructions(
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shader, ir3_nir_lower_load_barycentric_at_offset_filter,
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ir3_nir_lower_load_barycentric_at_offset_instr, NULL);
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}
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