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-rw-r--r--src/gallium/auxiliary/gallivm/lp_bld_sample.c113
1 files changed, 74 insertions, 39 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_sample.c b/src/gallium/auxiliary/gallivm/lp_bld_sample.c
index e1cfd78e885..9b0a92c9cb9 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_sample.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_sample.c
@@ -232,6 +232,7 @@ lp_build_rho(struct lp_build_sample_context *bld,
unsigned length = coord_bld->type.length;
unsigned num_quads = length / 4;
boolean rho_per_quad = rho_bld->type.length != length;
+ boolean no_rho_opt = (gallivm_debug & GALLIVM_DEBUG_NO_RHO_APPROX) && (dims > 1);
unsigned i;
LLVMValueRef i32undef = LLVMGetUndef(LLVMInt32TypeInContext(gallivm->context));
LLVMValueRef rho_xvec, rho_yvec;
@@ -264,12 +265,13 @@ lp_build_rho(struct lp_build_sample_context *bld,
else {
rho = lp_build_swizzle_scalar_aos(coord_bld, cube_rho, 0, 4);
}
- if (gallivm_debug & GALLIVM_DEBUG_NO_RHO_APPROX) {
- rho = lp_build_sqrt(rho_bld, rho);
- }
/* Could optimize this for single quad just skip the broadcast */
cubesize = lp_build_extract_broadcast(gallivm, bld->float_size_in_type,
rho_bld->type, float_size, index0);
+ if (no_rho_opt) {
+ /* skipping sqrt hence returning rho squared */
+ cubesize = lp_build_mul(rho_bld, cubesize, cubesize);
+ }
rho = lp_build_mul(rho_bld, cubesize, rho);
}
else if (derivs && !(bld->static_texture_state->target == PIPE_TEXTURE_CUBE)) {
@@ -281,7 +283,11 @@ lp_build_rho(struct lp_build_sample_context *bld,
floatdim = lp_build_extract_broadcast(gallivm, bld->float_size_in_type,
coord_bld->type, float_size, indexi);
- if ((gallivm_debug & GALLIVM_DEBUG_NO_RHO_APPROX) && (dims > 1)) {
+ /*
+ * note that for rho_per_quad case could reduce math (at some shuffle
+ * cost), but for now use same code to per-pixel lod case.
+ */
+ if (no_rho_opt) {
ddx[i] = lp_build_mul(coord_bld, floatdim, derivs->ddx[i]);
ddy[i] = lp_build_mul(coord_bld, floatdim, derivs->ddy[i]);
ddx[i] = lp_build_mul(coord_bld, ddx[i], ddx[i]);
@@ -295,7 +301,7 @@ lp_build_rho(struct lp_build_sample_context *bld,
ddmax[i] = lp_build_mul(coord_bld, floatdim, ddmax[i]);
}
}
- if ((gallivm_debug & GALLIVM_DEBUG_NO_RHO_APPROX) && (dims > 1)) {
+ if (no_rho_opt) {
rho_xvec = lp_build_add(coord_bld, ddx[0], ddx[1]);
rho_yvec = lp_build_add(coord_bld, ddy[0], ddy[1]);
if (dims > 2) {
@@ -303,19 +309,8 @@ lp_build_rho(struct lp_build_sample_context *bld,
rho_yvec = lp_build_add(coord_bld, rho_yvec, ddy[2]);
}
rho = lp_build_max(coord_bld, rho_xvec, rho_yvec);
-
- if (rho_per_quad) {
- /*
- * note for this case without per-pixel lod could reduce math more
- * (at some shuffle cost), but for now only do sqrt after packing,
- * otherwise would also need different code to per-pixel lod case.
- */
- rho = lp_build_pack_aos_scalars(bld->gallivm, coord_bld->type,
- rho_bld->type, rho, 0);
- }
- rho = lp_build_sqrt(rho_bld, rho);
-
- }
+ /* skipping sqrt hence returning rho squared */
+ }
else {
rho = ddmax[0];
if (dims > 1) {
@@ -324,13 +319,13 @@ lp_build_rho(struct lp_build_sample_context *bld,
rho = lp_build_max(coord_bld, rho, ddmax[2]);
}
}
- if (rho_per_quad) {
- /*
- * rho_vec contains per-pixel rho, convert to scalar per quad.
- */
- rho = lp_build_pack_aos_scalars(bld->gallivm, coord_bld->type,
- rho_bld->type, rho, 0);
- }
+ }
+ if (rho_per_quad) {
+ /*
+ * rho_vec contains per-pixel rho, convert to scalar per quad.
+ */
+ rho = lp_build_pack_aos_scalars(bld->gallivm, coord_bld->type,
+ rho_bld->type, rho, 0);
}
}
else {
@@ -362,7 +357,7 @@ lp_build_rho(struct lp_build_sample_context *bld,
}
}
- if ((gallivm_debug & GALLIVM_DEBUG_NO_RHO_APPROX) && (dims > 1)) {
+ if (no_rho_opt) {
static const unsigned char swizzle01[] = { /* no-op swizzle */
0, 1,
LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
@@ -407,16 +402,9 @@ lp_build_rho(struct lp_build_sample_context *bld,
rho_bld->type, rho, 0);
}
else {
- /*
- * on some cpus with half-speed 8-wide sqrt (e.g. SNB but not IVB)
- * doing pack/sqrt/unpack/swizzle might be better for 8-wide case,
- * same is true for cpus having faster scalars than 4-wide vecs
- * for 4-wide case (where pack/unpack would be no-ops anyway).
- * (Same is true really for cube_rho case above.)
- */
rho = lp_build_swizzle_scalar_aos(coord_bld, rho, 0, 4);
}
- rho = lp_build_sqrt(rho_bld, rho);
+ /* skipping sqrt hence returning rho squared */
}
else {
ddx_ddy[0] = lp_build_abs(coord_bld, ddx_ddy[0]);
@@ -636,7 +624,7 @@ lp_build_brilinear_rho(struct lp_build_context *bld,
/*
* The pre factor will make the intersections with the exact powers of two
- * happen precisely where we want then to be, which means that the integer
+ * happen precisely where we want them to be, which means that the integer
* part will not need any post adjustments.
*/
rho = lp_build_mul(bld, rho,
@@ -666,6 +654,34 @@ lp_build_brilinear_rho(struct lp_build_context *bld,
/**
+ * Fast implementation of iround(log2(sqrt(x))), based on
+ * log2(x^n) == n*log2(x).
+ *
+ * Gives accurate results all the time.
+ * (Could be trivially extended to handle other power-of-two roots.)
+ */
+static LLVMValueRef
+lp_build_ilog2_sqrt(struct lp_build_context *bld,
+ LLVMValueRef x)
+{
+ LLVMBuilderRef builder = bld->gallivm->builder;
+ LLVMValueRef ipart;
+ struct lp_type i_type = lp_int_type(bld->type);
+ LLVMValueRef one = lp_build_const_int_vec(bld->gallivm, i_type, 1);
+
+ assert(bld->type.floating);
+
+ assert(lp_check_value(bld->type, x));
+
+ /* ipart = log2(x) + 0.5 = 0.5*(log2(x^2) + 1.0) */
+ ipart = lp_build_extract_exponent(bld, x, 1);
+ ipart = LLVMBuildAShr(builder, ipart, one, "");
+
+ return ipart;
+}
+
+
+/**
* Generate code to compute texture level of detail (lambda).
* \param derivs partial derivatives of (s, t, r, q) with respect to X and Y
* \param lod_bias optional float vector with the shader lod bias
@@ -740,6 +756,8 @@ lp_build_lod_selector(struct lp_build_sample_context *bld,
}
else {
LLVMValueRef rho;
+ boolean rho_squared = (gallivm_debug & GALLIVM_DEBUG_NO_RHO_APPROX) &&
+ (bld->dims > 1);
rho = lp_build_rho(bld, texture_unit, s, t, r, cube_rho, derivs);
@@ -760,16 +778,28 @@ lp_build_lod_selector(struct lp_build_sample_context *bld,
if (mip_filter == PIPE_TEX_MIPFILTER_NONE ||
mip_filter == PIPE_TEX_MIPFILTER_NEAREST) {
/*
- * Don't actually need both all the time, ipart is needed
- * for nearest mipfilter, pos_or_zero if min != mag.
+ * Don't actually need both values all the time, lod_ipart is
+ * needed for nearest mipfilter, lod_positive if min != mag.
*/
- *out_lod_ipart = lp_build_ilog2(lodf_bld, rho);
+ if (rho_squared) {
+ *out_lod_ipart = lp_build_ilog2_sqrt(lodf_bld, rho);
+ }
+ else {
+ *out_lod_ipart = lp_build_ilog2(lodf_bld, rho);
+ }
*out_lod_positive = lp_build_cmp(lodf_bld, PIPE_FUNC_GREATER,
rho, lodf_bld->one);
return;
}
if (mip_filter == PIPE_TEX_MIPFILTER_LINEAR &&
- !(gallivm_debug & GALLIVM_DEBUG_NO_BRILINEAR)) {
+ !(gallivm_debug & GALLIVM_DEBUG_NO_BRILINEAR) &&
+ !rho_squared) {
+ /*
+ * This can't work if rho is squared. Not sure if it could be
+ * fixed while keeping it worthwile, could also do sqrt here
+ * but brilinear and no_rho_opt seems like a combination not
+ * making much sense anyway so just use ordinary path below.
+ */
lp_build_brilinear_rho(lodf_bld, rho, BRILINEAR_FACTOR,
out_lod_ipart, out_lod_fpart);
*out_lod_positive = lp_build_cmp(lodf_bld, PIPE_FUNC_GREATER,
@@ -784,6 +814,11 @@ lp_build_lod_selector(struct lp_build_sample_context *bld,
else {
lod = lp_build_fast_log2(lodf_bld, rho);
}
+ if (rho_squared) {
+ /* log2(x^2) == 0.5*log2(x) */
+ lod = lp_build_mul(lodf_bld, lod,
+ lp_build_const_vec(bld->gallivm, lodf_bld->type, 0.5F));
+ }
/* add shader lod bias */
if (lod_bias) {
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-18 18:17:34 +0000