static nir_ssa_def * build_atan2(nir_builder *b, nir_ssa_def *y, nir_ssa_def *x) { nir_ssa_def *zero = nir_imm_float(b, 0.0f); /* If |x| >= 1.0e-8 * |y|: */ nir_ssa_def *condition = nir_fge(b, nir_fabs(b, x), nir_fmul(b, nir_imm_float(b, 1.0e-8f), nir_fabs(b, y))); /* Then...call atan(y/x) and fix it up: */ nir_ssa_def *atan1 = build_atan(b, nir_fdiv(b, y, x)); nir_ssa_def *r_then = nir_bcsel(b, nir_flt(b, x, zero), nir_fadd(b, atan1, nir_bcsel(b, nir_fge(b, y, zero), nir_imm_float(b, M_PIf), nir_imm_float(b, -M_PIf))), atan1); /* Else... */ nir_ssa_def *r_else = nir_fmul(b, nir_fsign(b, y), nir_imm_float(b, M_PI_2f)); return nir_bcsel(b, condition, r_then, r_else); }
static nir_ssa_def * build_atan(nir_builder *b, nir_ssa_def *y_over_x) { nir_ssa_def *abs_y_over_x = nir_fabs(b, y_over_x); nir_ssa_def *one = nir_imm_float(b, 1.0f); /* * 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(b, x, nir_imm_float(b, 0.9999793128310355f)), nir_fmul(b, x_3, nir_imm_float(b, -0.3326756418091246f)), nir_fmul(b, x_5, nir_imm_float(b, 0.1938924977115610f)), nir_fmul(b, x_7, nir_imm_float(b, -0.1173503194786851f)), nir_fmul(b, x_9, nir_imm_float(b, 0.0536813784310406f)), nir_fmul(b, x_11, nir_imm_float(b, -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)), nir_fadd(b, nir_fmul(b, tmp, nir_imm_float(b, -2.0f)), nir_imm_float(b, M_PI_2f)))); /* sign fixup */ return nir_fmul(b, tmp, nir_fsign(b, y_over_x)); }
/* NIR equiv of TGSI CMP instruction: */ static nir_ssa_def * nir_cmp(nir_builder *b, nir_ssa_def *src0, nir_ssa_def *src1, nir_ssa_def *src2) { return nir_bcsel(b, nir_flt(b, src0, nir_imm_float(b, 0.0)), src1, src2); }
static void handle_glsl450_alu(struct vtn_builder *b, enum GLSLstd450 entrypoint, const uint32_t *w, unsigned count) { struct nir_builder *nb = &b->nb; const struct glsl_type *dest_type = vtn_value(b, w[1], vtn_value_type_type)->type->type; struct vtn_value *val = vtn_push_value(b, w[2], vtn_value_type_ssa); val->ssa = vtn_create_ssa_value(b, dest_type); /* Collect the various SSA sources */ unsigned num_inputs = count - 5; nir_ssa_def *src[3] = { NULL, }; for (unsigned i = 0; i < num_inputs; i++) src[i] = vtn_ssa_value(b, w[i + 5])->def; switch (entrypoint) { case GLSLstd450Radians: val->ssa->def = nir_fmul(nb, src[0], nir_imm_float(nb, 0.01745329251)); return; case GLSLstd450Degrees: val->ssa->def = nir_fmul(nb, src[0], nir_imm_float(nb, 57.2957795131)); return; case GLSLstd450Tan: val->ssa->def = nir_fdiv(nb, nir_fsin(nb, src[0]), nir_fcos(nb, src[0])); return; case GLSLstd450Modf: { nir_ssa_def *sign = nir_fsign(nb, src[0]); nir_ssa_def *abs = nir_fabs(nb, src[0]); val->ssa->def = nir_fmul(nb, sign, nir_ffract(nb, abs)); nir_store_deref_var(nb, vtn_nir_deref(b, w[6]), nir_fmul(nb, sign, nir_ffloor(nb, abs)), 0xf); return; } case GLSLstd450ModfStruct: { nir_ssa_def *sign = nir_fsign(nb, src[0]); nir_ssa_def *abs = nir_fabs(nb, src[0]); assert(glsl_type_is_struct(val->ssa->type)); val->ssa->elems[0]->def = nir_fmul(nb, sign, nir_ffract(nb, abs)); val->ssa->elems[1]->def = nir_fmul(nb, sign, nir_ffloor(nb, abs)); return; } case GLSLstd450Step: val->ssa->def = nir_sge(nb, src[1], src[0]); return; case GLSLstd450Length: val->ssa->def = build_length(nb, src[0]); return; case GLSLstd450Distance: val->ssa->def = build_length(nb, nir_fsub(nb, src[0], src[1])); return; case GLSLstd450Normalize: val->ssa->def = nir_fdiv(nb, src[0], build_length(nb, src[0])); return; case GLSLstd450Exp: val->ssa->def = build_exp(nb, src[0]); return; case GLSLstd450Log: val->ssa->def = build_log(nb, src[0]); return; case GLSLstd450FClamp: val->ssa->def = build_fclamp(nb, src[0], src[1], src[2]); return; case GLSLstd450UClamp: val->ssa->def = nir_umin(nb, nir_umax(nb, src[0], src[1]), src[2]); return; case GLSLstd450SClamp: val->ssa->def = nir_imin(nb, nir_imax(nb, src[0], src[1]), src[2]); return; case GLSLstd450Cross: { unsigned yzx[4] = { 1, 2, 0, 0 }; unsigned zxy[4] = { 2, 0, 1, 0 }; val->ssa->def = nir_fsub(nb, nir_fmul(nb, nir_swizzle(nb, src[0], yzx, 3, true), nir_swizzle(nb, src[1], zxy, 3, true)), nir_fmul(nb, nir_swizzle(nb, src[0], zxy, 3, true), nir_swizzle(nb, src[1], yzx, 3, true))); return; } case GLSLstd450SmoothStep: { /* t = clamp((x - edge0) / (edge1 - edge0), 0, 1) */ nir_ssa_def *t = build_fclamp(nb, nir_fdiv(nb, nir_fsub(nb, src[2], src[0]), nir_fsub(nb, src[1], src[0])), nir_imm_float(nb, 0.0), nir_imm_float(nb, 1.0)); /* result = t * t * (3 - 2 * t) */ val->ssa->def = nir_fmul(nb, t, nir_fmul(nb, t, nir_fsub(nb, nir_imm_float(nb, 3.0), nir_fmul(nb, nir_imm_float(nb, 2.0), t)))); return; } case GLSLstd450FaceForward: val->ssa->def = nir_bcsel(nb, nir_flt(nb, nir_fdot(nb, src[2], src[1]), nir_imm_float(nb, 0.0)), src[0], nir_fneg(nb, src[0])); return; case GLSLstd450Reflect: /* I - 2 * dot(N, I) * N */ val->ssa->def = nir_fsub(nb, src[0], nir_fmul(nb, nir_imm_float(nb, 2.0), nir_fmul(nb, nir_fdot(nb, src[0], src[1]), src[1]))); return; case GLSLstd450Refract: { nir_ssa_def *I = src[0]; nir_ssa_def *N = src[1]; nir_ssa_def *eta = src[2]; nir_ssa_def *n_dot_i = nir_fdot(nb, N, I); nir_ssa_def *one = nir_imm_float(nb, 1.0); nir_ssa_def *zero = nir_imm_float(nb, 0.0); /* k = 1.0 - eta * eta * (1.0 - dot(N, I) * dot(N, I)) */ nir_ssa_def *k = nir_fsub(nb, one, nir_fmul(nb, eta, nir_fmul(nb, eta, nir_fsub(nb, one, nir_fmul(nb, n_dot_i, n_dot_i))))); nir_ssa_def *result = nir_fsub(nb, nir_fmul(nb, eta, I), nir_fmul(nb, nir_fadd(nb, nir_fmul(nb, eta, n_dot_i), nir_fsqrt(nb, k)), N)); /* XXX: bcsel, or if statement? */ val->ssa->def = nir_bcsel(nb, nir_flt(nb, k, zero), zero, result); return; } case GLSLstd450Sinh: /* 0.5 * (e^x - e^(-x)) */ val->ssa->def = nir_fmul(nb, nir_imm_float(nb, 0.5f), nir_fsub(nb, build_exp(nb, src[0]), build_exp(nb, nir_fneg(nb, src[0])))); return; case GLSLstd450Cosh: /* 0.5 * (e^x + e^(-x)) */ val->ssa->def = nir_fmul(nb, nir_imm_float(nb, 0.5f), nir_fadd(nb, build_exp(nb, src[0]), build_exp(nb, nir_fneg(nb, src[0])))); return; case GLSLstd450Tanh: /* (0.5 * (e^x - e^(-x))) / (0.5 * (e^x + e^(-x))) */ val->ssa->def = nir_fdiv(nb, nir_fmul(nb, nir_imm_float(nb, 0.5f), nir_fsub(nb, build_exp(nb, src[0]), build_exp(nb, nir_fneg(nb, src[0])))), nir_fmul(nb, nir_imm_float(nb, 0.5f), nir_fadd(nb, build_exp(nb, src[0]), build_exp(nb, nir_fneg(nb, src[0]))))); return; case GLSLstd450Asinh: val->ssa->def = nir_fmul(nb, nir_fsign(nb, src[0]), build_log(nb, nir_fadd(nb, nir_fabs(nb, src[0]), nir_fsqrt(nb, nir_fadd(nb, nir_fmul(nb, src[0], src[0]), nir_imm_float(nb, 1.0f)))))); return; case GLSLstd450Acosh: val->ssa->def = build_log(nb, nir_fadd(nb, src[0], nir_fsqrt(nb, nir_fsub(nb, nir_fmul(nb, src[0], src[0]), nir_imm_float(nb, 1.0f))))); return; case GLSLstd450Atanh: { nir_ssa_def *one = nir_imm_float(nb, 1.0); val->ssa->def = nir_fmul(nb, nir_imm_float(nb, 0.5f), build_log(nb, nir_fdiv(nb, nir_fadd(nb, one, src[0]), nir_fsub(nb, one, src[0])))); return; } case GLSLstd450Asin: val->ssa->def = build_asin(nb, src[0], 0.086566724, -0.03102955); return; case GLSLstd450Acos: val->ssa->def = nir_fsub(nb, nir_imm_float(nb, M_PI_2f), build_asin(nb, src[0], 0.08132463, -0.02363318)); return; case GLSLstd450Atan: val->ssa->def = build_atan(nb, src[0]); return; case GLSLstd450Atan2: val->ssa->def = build_atan2(nb, src[0], src[1]); return; case GLSLstd450Frexp: { nir_ssa_def *exponent; val->ssa->def = build_frexp(nb, src[0], &exponent); nir_store_deref_var(nb, vtn_nir_deref(b, w[6]), exponent, 0xf); return; } case GLSLstd450FrexpStruct: { assert(glsl_type_is_struct(val->ssa->type)); val->ssa->elems[0]->def = build_frexp(nb, src[0], &val->ssa->elems[1]->def); return; } default: val->ssa->def = nir_build_alu(&b->nb, vtn_nir_alu_op_for_spirv_glsl_opcode(entrypoint), src[0], src[1], src[2], NULL); return; } }