| /* |
| * Copyright (C) 2021 Collabora, Ltd. |
| * |
| * 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 "pan_ir.h" |
| #include "compiler/nir/nir_builder.h" |
| |
| /* Sample positions are supplied in a packed 8:8 fixed-point vec2 format in GPU |
| * memory indexed by the sample. We lower in NIR to take advantage of possible |
| * ALU optimizations at the end. This is convenient for Bifrost, since the |
| * sample positions are passed in this format and it saves the driver from any |
| * system value handling. For Midgard, it's a bit suboptimal (fp16 positions |
| * could be supplied directly), but this lets us unify the implementation, and |
| * it's a pretty trivial difference */ |
| |
| static bool |
| pan_lower_sample_pos_impl(struct nir_builder *b, |
| nir_instr *instr, UNUSED void *data) |
| { |
| if (instr->type != nir_instr_type_intrinsic) |
| return false; |
| |
| nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr); |
| if (intr->intrinsic != nir_intrinsic_load_sample_pos) |
| return false; |
| |
| b->cursor = nir_before_instr(instr); |
| |
| /* Elements are 4 bytes */ |
| nir_ssa_def *addr = nir_iadd(b, |
| nir_load_sample_positions_pan(b), |
| nir_u2u64(b, nir_imul_imm(b, nir_load_sample_id(b), 4))); |
| |
| /* Decode 8:8 fixed-point */ |
| nir_ssa_def *raw = nir_load_global(b, addr, 2, 2, 16); |
| nir_ssa_def *decoded = nir_fmul_imm(b, nir_i2f16(b, raw), 1.0 / 256.0); |
| |
| /* Make NIR validator happy */ |
| if (decoded->bit_size != nir_dest_bit_size(intr->dest)) |
| decoded = nir_f2fN(b, decoded, nir_dest_bit_size(intr->dest)); |
| |
| nir_ssa_def_rewrite_uses(&intr->dest.ssa, decoded); |
| return true; |
| } |
| |
| bool |
| pan_lower_sample_pos(nir_shader *shader) |
| { |
| if (shader->info.stage != MESA_SHADER_FRAGMENT) |
| return false; |
| |
| return nir_shader_instructions_pass(shader, |
| pan_lower_sample_pos_impl, |
| nir_metadata_block_index | nir_metadata_dominance, |
| NULL); |
| } |
