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compiler/spirv: implement 16-bit atan2 

v2:
 - fix huge_val for 16-bit, it was mean't to be 2^14 not 10^14.

v3:
 - rebase on top of new bool sized opcodes
 - use nir_b2f helper
 - use nir_fmul_imm helper

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
This commit is contained in:
Iago Toral Quiroga 2018-04-18 10:07:54 +02:00
parent 1c8de08ec9
commit f18554e2ce
1 changed files with 11 additions and 7 deletions
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18
src/compiler/spirv/vtn_glsl450.c
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@ -290,8 +290,11 @@ build_atan(nir_builder *b, nir_ssa_def *y_over_x)
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);
nir_ssa_def *one = nir_imm_float(b, 1);
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
@ -321,9 +324,10 @@ build_atan2(nir_builder *b, nir_ssa_def *y, nir_ssa_def *x)
* floating point representations with at least the dynamic range of ATI's
* 24-bit representation.
*/
nir_ssa_def *huge = nir_imm_float(b, 1e18f);
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_float(b, 0.25), one);
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);
@ -350,9 +354,9 @@ build_atan2(nir_builder *b, nir_ssa_def *y, nir_ssa_def *x)
/* Calculate the arctangent and fix up the result if we had flipped the
* coordinate system.
*/
nir_ssa_def *arc = nir_fadd(b, nir_fmul(b, nir_b2f32(b, flip),
nir_imm_float(b, M_PI_2f)),
build_atan(b, tan));
nir_ssa_def *arc =
nir_fadd(b, nir_fmul_imm(b, nir_b2f(b, flip, bit_size), M_PI_2f),
build_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