diff options
Diffstat (limited to 'src/compiler/nir/nir_lower_clip.c')
| -rw-r--r-- | src/compiler/nir/nir_lower_clip.c | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/src/compiler/nir/nir_lower_clip.c b/src/compiler/nir/nir_lower_clip.c new file mode 100644 index 00000000000..0ca6a289396 --- /dev/null +++ b/src/compiler/nir/nir_lower_clip.c @@ -0,0 +1,339 @@ +/* + * 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. + * + * Authors: + * Rob Clark <[email protected]> + */ + +#include "nir.h" +#include "nir_builder.h" + +#define MAX_CLIP_PLANES 8 + +/* Generates the lowering code for user-clip-planes, generating CLIPDIST + * from UCP[n] + CLIPVERTEX or POSITION. Additionally, an optional pass + * for fragment shaders to insert conditional kill's based on the inter- + * polated CLIPDIST + * + * NOTE: should be run after nir_lower_outputs_to_temporaries() (or at + * least in scenarios where you can count on each output written once + * and only once). + */ + + +static nir_variable * +create_clipdist_var(nir_shader *shader, unsigned drvloc, + bool output, gl_varying_slot slot) +{ + nir_variable *var = rzalloc(shader, nir_variable); + + var->data.driver_location = drvloc; + var->type = glsl_vec4_type(); + var->data.mode = output ? nir_var_shader_out : nir_var_shader_in; + var->name = ralloc_asprintf(var, "clipdist_%d", drvloc); + var->data.index = 0; + var->data.location = slot; + + if (output) { + exec_list_push_tail(&shader->outputs, &var->node); + shader->num_outputs++; /* TODO use type_size() */ + } + else { + exec_list_push_tail(&shader->inputs, &var->node); + shader->num_inputs++; /* TODO use type_size() */ + } + return var; +} + +static void +store_clipdist_output(nir_builder *b, nir_variable *out, nir_ssa_def **val) +{ + nir_intrinsic_instr *store; + + store = nir_intrinsic_instr_create(b->shader, nir_intrinsic_store_output); + store->num_components = 4; + store->const_index[0] = out->data.driver_location; + store->const_index[1] = 0xf; /* wrmask */ + store->src[0].ssa = nir_vec4(b, val[0], val[1], val[2], val[3]); + store->src[0].is_ssa = true; + store->src[1] = nir_src_for_ssa(nir_imm_int(b, 0)); + nir_builder_instr_insert(b, &store->instr); +} + +static void +load_clipdist_input(nir_builder *b, nir_variable *in, nir_ssa_def **val) +{ + nir_intrinsic_instr *load; + + load = nir_intrinsic_instr_create(b->shader, nir_intrinsic_load_input); + load->num_components = 4; + load->const_index[0] = in->data.driver_location; + load->src[0] = nir_src_for_ssa(nir_imm_int(b, 0)); + nir_ssa_dest_init(&load->instr, &load->dest, 4, NULL); + nir_builder_instr_insert(b, &load->instr); + + val[0] = nir_channel(b, &load->dest.ssa, 0); + val[1] = nir_channel(b, &load->dest.ssa, 1); + val[2] = nir_channel(b, &load->dest.ssa, 2); + val[3] = nir_channel(b, &load->dest.ssa, 3); +} + +struct find_output_state +{ + unsigned drvloc; + nir_ssa_def *def; +}; + +static bool +find_output_in_block(nir_block *block, void *void_state) +{ + struct find_output_state *state = void_state; + nir_foreach_instr(block, instr) { + + if (instr->type == nir_instr_type_intrinsic) { + nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr); + if ((intr->intrinsic == nir_intrinsic_store_output) && + intr->const_index[0] == state->drvloc) { + assert(state->def == NULL); + assert(intr->src[0].is_ssa); + assert(nir_src_as_const_value(intr->src[1])); + state->def = intr->src[0].ssa; + +#if !defined(DEBUG) + /* for debug builds, scan entire shader to assert + * if output is written multiple times. For release + * builds just assume all is well and bail when we + * find first: + */ + return false; +#endif + } + } + } + + return true; +} + +/* TODO: maybe this would be a useful helper? + * NOTE: assumes each output is written exactly once (and unconditionally) + * so if needed nir_lower_outputs_to_temporaries() + */ +static nir_ssa_def * +find_output(nir_shader *shader, unsigned drvloc) +{ + struct find_output_state state = { + .drvloc = drvloc, + }; + + nir_foreach_function(shader, function) { + if (function->impl) { + nir_foreach_block_reverse(function->impl, + find_output_in_block, &state); + } + } + + return state.def; +} + +/* + * VS lowering + */ + +static void +lower_clip_vs(nir_function_impl *impl, unsigned ucp_enables, + nir_ssa_def *cv, nir_variable **out) +{ + nir_ssa_def *clipdist[MAX_CLIP_PLANES]; + nir_builder b; + + nir_builder_init(&b, impl); + + /* NIR should ensure that, even in case of loops/if-else, there + * should be only a single predecessor block to end_block, which + * makes the perfect place to insert the clipdist calculations. + * + * NOTE: in case of early return's, these would have to be lowered + * to jumps to end_block predecessor in a previous pass. Not sure + * if there is a good way to sanity check this, but for now the + * users of this pass don't support sub-routines. + */ + assert(impl->end_block->predecessors->entries == 1); + b.cursor = nir_after_cf_list(&impl->body); + + for (int plane = 0; plane < MAX_CLIP_PLANES; plane++) { + if (ucp_enables & (1 << plane)) { + nir_ssa_def *ucp = + nir_load_system_value(&b, nir_intrinsic_load_user_clip_plane, plane); + + /* calculate clipdist[plane] - dot(ucp, cv): */ + clipdist[plane] = nir_fdot4(&b, ucp, cv); + } + else { + /* 0.0 == don't-clip == disabled: */ + clipdist[plane] = nir_imm_float(&b, 0.0); + } + } + + if (ucp_enables & 0x0f) + store_clipdist_output(&b, out[0], &clipdist[0]); + if (ucp_enables & 0xf0) + store_clipdist_output(&b, out[1], &clipdist[4]); + + nir_metadata_preserve(impl, nir_metadata_dominance); +} + +/* ucp_enables is bitmask of enabled ucp's. Actual ucp values are + * passed in to shader via user_clip_plane system-values + */ +void +nir_lower_clip_vs(nir_shader *shader, unsigned ucp_enables) +{ + int clipvertex = -1; + int position = -1; + int maxloc = -1; + nir_ssa_def *cv; + nir_variable *out[2] = { NULL }; + + if (!ucp_enables) + return; + + /* find clipvertex/position outputs: */ + nir_foreach_variable(var, &shader->outputs) { + int loc = var->data.driver_location; + + /* keep track of last used driver-location.. we'll be + * appending CLIP_DIST0/CLIP_DIST1 after last existing + * output: + */ + maxloc = MAX2(maxloc, loc); + + switch (var->data.location) { + case VARYING_SLOT_POS: + position = loc; + break; + case VARYING_SLOT_CLIP_VERTEX: + clipvertex = loc; + break; + case VARYING_SLOT_CLIP_DIST0: + case VARYING_SLOT_CLIP_DIST1: + /* if shader is already writing CLIPDIST, then + * there should be no user-clip-planes to deal + * with. + */ + return; + } + } + + if (clipvertex != -1) + cv = find_output(shader, clipvertex); + else if (position != -1) + cv = find_output(shader, position); + else + return; + + /* insert CLIPDIST outputs: */ + if (ucp_enables & 0x0f) + out[0] = + create_clipdist_var(shader, ++maxloc, true, VARYING_SLOT_CLIP_DIST0); + if (ucp_enables & 0xf0) + out[1] = + create_clipdist_var(shader, ++maxloc, true, VARYING_SLOT_CLIP_DIST1); + + nir_foreach_function(shader, function) { + if (!strcmp(function->name, "main")) + lower_clip_vs(function->impl, ucp_enables, cv, out); + } +} + +/* + * FS lowering + */ + +static void +lower_clip_fs(nir_function_impl *impl, unsigned ucp_enables, + nir_variable **in) +{ + nir_ssa_def *clipdist[MAX_CLIP_PLANES]; + nir_builder b; + + nir_builder_init(&b, impl); + b.cursor = nir_before_cf_list(&impl->body); + + if (ucp_enables & 0x0f) + load_clipdist_input(&b, in[0], &clipdist[0]); + if (ucp_enables & 0xf0) + load_clipdist_input(&b, in[1], &clipdist[4]); + + for (int plane = 0; plane < MAX_CLIP_PLANES; plane++) { + if (ucp_enables & (1 << plane)) { + nir_intrinsic_instr *discard; + nir_ssa_def *cond; + + cond = nir_flt(&b, clipdist[plane], nir_imm_float(&b, 0.0)); + + discard = nir_intrinsic_instr_create(b.shader, + nir_intrinsic_discard_if); + discard->src[0] = nir_src_for_ssa(cond); + nir_builder_instr_insert(&b, &discard->instr); + } + } +} + +/* insert conditional kill based on interpolated CLIPDIST + */ +void +nir_lower_clip_fs(nir_shader *shader, unsigned ucp_enables) +{ + nir_variable *in[2]; + int maxloc = -1; + + if (!ucp_enables) + return; + + nir_foreach_variable(var, &shader->inputs) { + int loc = var->data.driver_location; + + /* keep track of last used driver-location.. we'll be + * appending CLIP_DIST0/CLIP_DIST1 after last existing + * input: + */ + maxloc = MAX2(maxloc, loc); + } + + /* The shader won't normally have CLIPDIST inputs, so we + * must add our own: + */ + /* insert CLIPDIST outputs: */ + if (ucp_enables & 0x0f) + in[0] = + create_clipdist_var(shader, ++maxloc, false, + VARYING_SLOT_CLIP_DIST0); + if (ucp_enables & 0xf0) + in[1] = + create_clipdist_var(shader, ++maxloc, false, + VARYING_SLOT_CLIP_DIST1); + + nir_foreach_function(shader, function) { + if (!strcmp(function->name, "main")) + lower_clip_fs(function->impl, ucp_enables, in); + } +} |