/*
* Copyright © 2018 Red Hat Inc.
+ * Copyright © 2015 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
return nir_vec(b, res, lo->num_components);
}
+
+/**
+ * Compute xs[0] + xs[1] + xs[2] + ... using fadd.
+ */
+static nir_ssa_def *
+build_fsum(nir_builder *b, nir_ssa_def **xs, int terms)
+{
+ nir_ssa_def *accum = xs[0];
+
+ for (int i = 1; i < terms; i++)
+ accum = nir_fadd(b, accum, xs[i]);
+
+ return accum;
+}
+
+nir_ssa_def *
+nir_atan(nir_builder *b, nir_ssa_def *y_over_x)
+{
+ const uint32_t bit_size = y_over_x->bit_size;
+
+ nir_ssa_def *abs_y_over_x = nir_fabs(b, y_over_x);
+ nir_ssa_def *one = nir_imm_floatN_t(b, 1.0f, bit_size);
+
+ /*
+ * range-reduction, first step:
+ *
+ * / y_over_x if |y_over_x| <= 1.0;
+ * x = <
+ * \ 1.0 / y_over_x otherwise
+ */
+ nir_ssa_def *x = nir_fdiv(b, nir_fmin(b, abs_y_over_x, one),
+ nir_fmax(b, abs_y_over_x, one));
+
+ /*
+ * approximate atan by evaluating polynomial:
+ *
+ * x * 0.9999793128310355 - x^3 * 0.3326756418091246 +
+ * x^5 * 0.1938924977115610 - x^7 * 0.1173503194786851 +
+ * x^9 * 0.0536813784310406 - x^11 * 0.0121323213173444
+ */
+ nir_ssa_def *x_2 = nir_fmul(b, x, x);
+ nir_ssa_def *x_3 = nir_fmul(b, x_2, x);
+ nir_ssa_def *x_5 = nir_fmul(b, x_3, x_2);
+ nir_ssa_def *x_7 = nir_fmul(b, x_5, x_2);
+ nir_ssa_def *x_9 = nir_fmul(b, x_7, x_2);
+ nir_ssa_def *x_11 = nir_fmul(b, x_9, x_2);
+
+ nir_ssa_def *polynomial_terms[] = {
+ nir_fmul_imm(b, x, 0.9999793128310355f),
+ nir_fmul_imm(b, x_3, -0.3326756418091246f),
+ nir_fmul_imm(b, x_5, 0.1938924977115610f),
+ nir_fmul_imm(b, x_7, -0.1173503194786851f),
+ nir_fmul_imm(b, x_9, 0.0536813784310406f),
+ nir_fmul_imm(b, x_11, -0.0121323213173444f),
+ };
+
+ nir_ssa_def *tmp =
+ build_fsum(b, polynomial_terms, ARRAY_SIZE(polynomial_terms));
+
+ /* range-reduction fixup */
+ tmp = nir_fadd(b, tmp,
+ nir_fmul(b, nir_b2f(b, nir_flt(b, one, abs_y_over_x), bit_size),
+ nir_fadd_imm(b, nir_fmul_imm(b, tmp, -2.0f), M_PI_2)));
+
+ /* sign fixup */
+ return nir_fmul(b, tmp, nir_fsign(b, y_over_x));
+}
+
+nir_ssa_def *
+nir_atan2(nir_builder *b, nir_ssa_def *y, nir_ssa_def *x)
+{
+ assert(y->bit_size == x->bit_size);
+ const uint32_t bit_size = x->bit_size;
+
+ nir_ssa_def *zero = nir_imm_floatN_t(b, 0, bit_size);
+ nir_ssa_def *one = nir_imm_floatN_t(b, 1, bit_size);
+
+ /* If we're on the left half-plane rotate the coordinates π/2 clock-wise
+ * for the y=0 discontinuity to end up aligned with the vertical
+ * discontinuity of atan(s/t) along t=0. This also makes sure that we
+ * don't attempt to divide by zero along the vertical line, which may give
+ * unspecified results on non-GLSL 4.1-capable hardware.
+ */
+ nir_ssa_def *flip = nir_fge(b, zero, x);
+ nir_ssa_def *s = nir_bcsel(b, flip, nir_fabs(b, x), y);
+ nir_ssa_def *t = nir_bcsel(b, flip, y, nir_fabs(b, x));
+
+ /* If the magnitude of the denominator exceeds some huge value, scale down
+ * the arguments in order to prevent the reciprocal operation from flushing
+ * its result to zero, which would cause precision problems, and for s
+ * infinite would cause us to return a NaN instead of the correct finite
+ * value.
+ *
+ * If fmin and fmax are respectively the smallest and largest positive
+ * normalized floating point values representable by the implementation,
+ * the constants below should be in agreement with:
+ *
+ * huge <= 1 / fmin
+ * scale <= 1 / fmin / fmax (for |t| >= huge)
+ *
+ * In addition scale should be a negative power of two in order to avoid
+ * loss of precision. The values chosen below should work for most usual
+ * floating point representations with at least the dynamic range of ATI's
+ * 24-bit representation.
+ */
+ const double huge_val = bit_size >= 32 ? 1e18 : 16384;
+ nir_ssa_def *huge = nir_imm_floatN_t(b, huge_val, bit_size);
+ nir_ssa_def *scale = nir_bcsel(b, nir_fge(b, nir_fabs(b, t), huge),
+ nir_imm_floatN_t(b, 0.25, bit_size), one);
+ nir_ssa_def *rcp_scaled_t = nir_frcp(b, nir_fmul(b, t, scale));
+ nir_ssa_def *s_over_t = nir_fmul(b, nir_fmul(b, s, scale), rcp_scaled_t);
+
+ /* For |x| = |y| assume tan = 1 even if infinite (i.e. pretend momentarily
+ * that ∞/∞ = 1) in order to comply with the rather artificial rules
+ * inherited from IEEE 754-2008, namely:
+ *
+ * "atan2(±∞, −∞) is ±3π/4
+ * atan2(±∞, +∞) is ±π/4"
+ *
+ * Note that this is inconsistent with the rules for the neighborhood of
+ * zero that are based on iterated limits:
+ *
+ * "atan2(±0, −0) is ±π
+ * atan2(±0, +0) is ±0"
+ *
+ * but GLSL specifically allows implementations to deviate from IEEE rules
+ * at (0,0), so we take that license (i.e. pretend that 0/0 = 1 here as
+ * well).
+ */
+ nir_ssa_def *tan = nir_bcsel(b, nir_feq(b, nir_fabs(b, x), nir_fabs(b, y)),
+ one, nir_fabs(b, s_over_t));
+
+ /* Calculate the arctangent and fix up the result if we had flipped the
+ * coordinate system.
+ */
+ nir_ssa_def *arc =
+ nir_fadd(b, nir_fmul_imm(b, nir_b2f(b, flip, bit_size), M_PI_2),
+ nir_atan(b, tan));
+
+ /* Rather convoluted calculation of the sign of the result. When x < 0 we
+ * cannot use fsign because we need to be able to distinguish between
+ * negative and positive zero. We don't use bitwise arithmetic tricks for
+ * consistency with the GLSL front-end. When x >= 0 rcp_scaled_t will
+ * always be non-negative so this won't be able to distinguish between
+ * negative and positive zero, but we don't care because atan2 is
+ * continuous along the whole positive y = 0 half-line, so it won't affect
+ * the result significantly.
+ */
+ return nir_bcsel(b, nir_flt(b, nir_fmin(b, y, rcp_scaled_t), zero),
+ nir_fneg(b, arc), arc);
+}
+
+nir_ssa_def *
+nir_get_texture_size(nir_builder *b, nir_tex_instr *tex)
+{
+ b->cursor = nir_before_instr(&tex->instr);
+
+ nir_tex_instr *txs;
+
+ unsigned num_srcs = 1; /* One for the LOD */
+ for (unsigned i = 0; i < tex->num_srcs; i++) {
+ if (tex->src[i].src_type == nir_tex_src_texture_deref ||
+ tex->src[i].src_type == nir_tex_src_sampler_deref ||
+ tex->src[i].src_type == nir_tex_src_texture_offset ||
+ tex->src[i].src_type == nir_tex_src_sampler_offset ||
+ tex->src[i].src_type == nir_tex_src_texture_handle ||
+ tex->src[i].src_type == nir_tex_src_sampler_handle)
+ num_srcs++;
+ }
+
+ txs = nir_tex_instr_create(b->shader, num_srcs);
+ txs->op = nir_texop_txs;
+ txs->sampler_dim = tex->sampler_dim;
+ txs->is_array = tex->is_array;
+ txs->is_shadow = tex->is_shadow;
+ txs->is_new_style_shadow = tex->is_new_style_shadow;
+ txs->texture_index = tex->texture_index;
+ txs->sampler_index = tex->sampler_index;
+ txs->dest_type = nir_type_int;
+
+ unsigned idx = 0;
+ for (unsigned i = 0; i < tex->num_srcs; i++) {
+ if (tex->src[i].src_type == nir_tex_src_texture_deref ||
+ tex->src[i].src_type == nir_tex_src_sampler_deref ||
+ tex->src[i].src_type == nir_tex_src_texture_offset ||
+ tex->src[i].src_type == nir_tex_src_sampler_offset ||
+ tex->src[i].src_type == nir_tex_src_texture_handle ||
+ tex->src[i].src_type == nir_tex_src_sampler_handle) {
+ nir_src_copy(&txs->src[idx].src, &tex->src[i].src, txs);
+ txs->src[idx].src_type = tex->src[i].src_type;
+ idx++;
+ }
+ }
+ /* Add in an LOD because some back-ends require it */
+ txs->src[idx].src = nir_src_for_ssa(nir_imm_int(b, 0));
+ txs->src[idx].src_type = nir_tex_src_lod;
+
+ nir_ssa_dest_init(&txs->instr, &txs->dest,
+ nir_tex_instr_dest_size(txs), 32, NULL);
+ nir_builder_instr_insert(b, &txs->instr);
+
+ return &txs->dest.ssa;
+}
+
+nir_ssa_def *
+nir_get_texture_lod(nir_builder *b, nir_tex_instr *tex)
+{
+ b->cursor = nir_before_instr(&tex->instr);
+
+ nir_tex_instr *tql;
+
+ unsigned num_srcs = 0;
+ for (unsigned i = 0; i < tex->num_srcs; i++) {
+ if (tex->src[i].src_type == nir_tex_src_coord ||
+ tex->src[i].src_type == nir_tex_src_texture_deref ||
+ tex->src[i].src_type == nir_tex_src_sampler_deref ||
+ tex->src[i].src_type == nir_tex_src_texture_offset ||
+ tex->src[i].src_type == nir_tex_src_sampler_offset ||
+ tex->src[i].src_type == nir_tex_src_texture_handle ||
+ tex->src[i].src_type == nir_tex_src_sampler_handle)
+ num_srcs++;
+ }
+
+ tql = nir_tex_instr_create(b->shader, num_srcs);
+ tql->op = nir_texop_lod;
+ tql->coord_components = tex->coord_components;
+ tql->sampler_dim = tex->sampler_dim;
+ tql->is_array = tex->is_array;
+ tql->is_shadow = tex->is_shadow;
+ tql->is_new_style_shadow = tex->is_new_style_shadow;
+ tql->texture_index = tex->texture_index;
+ tql->sampler_index = tex->sampler_index;
+ tql->dest_type = nir_type_float;
+
+ unsigned idx = 0;
+ for (unsigned i = 0; i < tex->num_srcs; i++) {
+ if (tex->src[i].src_type == nir_tex_src_coord ||
+ tex->src[i].src_type == nir_tex_src_texture_deref ||
+ tex->src[i].src_type == nir_tex_src_sampler_deref ||
+ tex->src[i].src_type == nir_tex_src_texture_offset ||
+ tex->src[i].src_type == nir_tex_src_sampler_offset ||
+ tex->src[i].src_type == nir_tex_src_texture_handle ||
+ tex->src[i].src_type == nir_tex_src_sampler_handle) {
+ nir_src_copy(&tql->src[idx].src, &tex->src[i].src, tql);
+ tql->src[idx].src_type = tex->src[i].src_type;
+ idx++;
+ }
+ }
+
+ nir_ssa_dest_init(&tql->instr, &tql->dest, 2, 32, NULL);
+ nir_builder_instr_insert(b, &tql->instr);
+
+ /* The LOD is the y component of the result */
+ return nir_channel(b, &tql->dest.ssa, 1);
+}
projects / mesa.git / blobdiff