79 lines
2.7 KiB
C
79 lines
2.7 KiB
C
/*
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* Copyright (C) 2019 Andreas Baierl
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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 "nir.h"
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#include "nir_builder.h"
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/* Lower gl_FragCoord and transform the w component
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* according to the following pseudocode:
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*
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* gl_FragCoord.xyz = gl_FragCoord_orig.xyz
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* gl_FragCoord.w = 1.0 / gl_FragCoord_orig.w
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*
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*/
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static bool
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lower_fragcoord_wtrans_filter(const nir_instr *instr, UNUSED const void *_options)
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{
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if (instr->type != nir_instr_type_intrinsic)
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return false;
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nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
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if (intr->intrinsic == nir_intrinsic_load_frag_coord)
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return true;
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if (intr->intrinsic != nir_intrinsic_load_deref)
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return false;
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nir_variable *var = nir_intrinsic_get_var(intr, 0);
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if (var->data.mode != nir_var_shader_in)
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return false;
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return var->data.location == VARYING_SLOT_POS;
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}
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static nir_ssa_def *
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lower_fragcoord_wtrans_impl(nir_builder *b, nir_instr *instr,
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UNUSED void *_options)
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{
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nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
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return nir_vec4(b,
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nir_channel(b, &intr->dest.ssa, 0),
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nir_channel(b, &intr->dest.ssa, 1),
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nir_channel(b, &intr->dest.ssa, 2),
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nir_frcp(b, nir_channel(b, &intr->dest.ssa, 3)));
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}
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bool
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nir_lower_fragcoord_wtrans(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(shader,
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lower_fragcoord_wtrans_filter,
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lower_fragcoord_wtrans_impl,
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NULL);
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}
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