From: Roland Scheidegger <[email protected]>
Not used since ages, and it wouldn't work at all with explicit derivatives now
(not that it did before as it ignored them but now the code would just use
the derivs pre-projected which would be quite random numbers).
---
src/gallium/auxiliary/gallivm/lp_bld_sample.c | 751 +++++++++++--------------
1 file changed, 313 insertions(+), 438 deletions(-)
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_sample.c
b/src/gallium/auxiliary/gallivm/lp_bld_sample.c
index ce05522..3fac981 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_sample.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_sample.c
@@ -1493,323 +1493,135 @@ lp_build_cube_lookup(struct lp_build_sample_context
*bld,
struct lp_derivatives *derivs_out, /* optional */
boolean need_derivs)
{
+ /*
+ * Do per-pixel face selection. We cannot however (as we used to do)
+ * simply calculate the derivs afterwards (which is very bogus for
+ * explicit derivs btw) because the values would be "random" when
+ * not all pixels lie on the same face. So what we do here is just
+ * calculate the derivatives after scaling the coords by the absolute
+ * value of the inverse major axis, and essentially do rho calculation
+ * steps as if it were a 3d texture. This is perfect if all pixels hit
+ * the same face, but not so great at edges, I believe the max error
+ * should be sqrt(2) with no_rho_approx or 2 otherwise (essentially
measuring
+ * the 3d distance between 2 points on the cube instead of measuring up/down
+ * the edge). Still this is possibly a win over just selecting the same face
+ * for all pixels. Unfortunately, something like that doesn't work for
+ * explicit derivatives.
+ */
struct lp_build_context *coord_bld = &bld->coord_bld;
LLVMBuilderRef builder = bld->gallivm->builder;
struct gallivm_state *gallivm = bld->gallivm;
LLVMValueRef si, ti, ri;
+ struct lp_build_context *cint_bld = &bld->int_coord_bld;
+ struct lp_type intctype = cint_bld->type;
+ LLVMValueRef signs, signt, signr, signma;
+ LLVMValueRef as, at, ar, face, face_s, face_t;
+ LLVMValueRef as_ge_at, maxasat, ar_ge_as_at;
+ LLVMValueRef snewx, tnewx, snewy, tnewy, snewz, tnewz;
+ LLVMValueRef tnegi, rnegi;
+ LLVMValueRef ma, mai, imahalfpos;
+ LLVMValueRef posHalf = lp_build_const_vec(gallivm, coord_bld->type, 0.5);
+ LLVMValueRef signmask = lp_build_const_int_vec(gallivm, intctype,
+ 1 << (intctype.width - 1));
+ LLVMValueRef signshift = lp_build_const_int_vec(gallivm, intctype,
+ intctype.width -1);
+ LLVMValueRef facex = lp_build_const_int_vec(gallivm, intctype,
PIPE_TEX_FACE_POS_X);
+ LLVMValueRef facey = lp_build_const_int_vec(gallivm, intctype,
PIPE_TEX_FACE_POS_Y);
+ LLVMValueRef facez = lp_build_const_int_vec(gallivm, intctype,
PIPE_TEX_FACE_POS_Z);
+ LLVMValueRef s = coords[0];
+ LLVMValueRef t = coords[1];
+ LLVMValueRef r = coords[2];
+
+ assert(PIPE_TEX_FACE_NEG_X == PIPE_TEX_FACE_POS_X + 1);
+ assert(PIPE_TEX_FACE_NEG_Y == PIPE_TEX_FACE_POS_Y + 1);
+ assert(PIPE_TEX_FACE_NEG_Z == PIPE_TEX_FACE_POS_Z + 1);
- if (1 || coord_bld->type.length > 4) {
- /*
- * Do per-pixel face selection. We cannot however (as we used to do)
- * simply calculate the derivs afterwards (which is very bogus for
- * explicit derivs btw) because the values would be "random" when
- * not all pixels lie on the same face. So what we do here is just
- * calculate the derivatives after scaling the coords by the absolute
- * value of the inverse major axis, and essentially do rho calculation
- * steps as if it were a 3d texture. This is perfect if all pixels hit
- * the same face, but not so great at edges, I believe the max error
- * should be sqrt(2) with no_rho_approx or 2 otherwise (essentially
measuring
- * the 3d distance between 2 points on the cube instead of measuring
up/down
- * the edge). Still this is possibly a win over just selecting the same
face
- * for all pixels. Unfortunately, something like that doesn't work for
- * explicit derivatives.
- */
- struct lp_build_context *cint_bld = &bld->int_coord_bld;
- struct lp_type intctype = cint_bld->type;
- LLVMValueRef signs, signt, signr, signma;
- LLVMValueRef as, at, ar, face, face_s, face_t;
- LLVMValueRef as_ge_at, maxasat, ar_ge_as_at;
- LLVMValueRef snewx, tnewx, snewy, tnewy, snewz, tnewz;
- LLVMValueRef tnegi, rnegi;
- LLVMValueRef ma, mai, imahalfpos;
- LLVMValueRef posHalf = lp_build_const_vec(gallivm, coord_bld->type, 0.5);
- LLVMValueRef signmask = lp_build_const_int_vec(gallivm, intctype,
- 1 << (intctype.width -
1));
- LLVMValueRef signshift = lp_build_const_int_vec(gallivm, intctype,
- intctype.width -1);
- LLVMValueRef facex = lp_build_const_int_vec(gallivm, intctype,
PIPE_TEX_FACE_POS_X);
- LLVMValueRef facey = lp_build_const_int_vec(gallivm, intctype,
PIPE_TEX_FACE_POS_Y);
- LLVMValueRef facez = lp_build_const_int_vec(gallivm, intctype,
PIPE_TEX_FACE_POS_Z);
- LLVMValueRef s = coords[0];
- LLVMValueRef t = coords[1];
- LLVMValueRef r = coords[2];
-
- assert(PIPE_TEX_FACE_NEG_X == PIPE_TEX_FACE_POS_X + 1);
- assert(PIPE_TEX_FACE_NEG_Y == PIPE_TEX_FACE_POS_Y + 1);
- assert(PIPE_TEX_FACE_NEG_Z == PIPE_TEX_FACE_POS_Z + 1);
+ /*
+ * get absolute value (for x/y/z face selection) and sign bit
+ * (for mirroring minor coords and pos/neg face selection)
+ * of the original coords.
+ */
+ as = lp_build_abs(&bld->coord_bld, s);
+ at = lp_build_abs(&bld->coord_bld, t);
+ ar = lp_build_abs(&bld->coord_bld, r);
+
+ /*
+ * major face determination: select x if x > y else select y
+ * select z if z >= max(x,y) else select previous result
+ * if some axis are the same we chose z over y, y over x - the
+ * dx10 spec seems to ask for it while OpenGL doesn't care (if we
+ * wouldn't care could save a select or two if using different
+ * compares and doing at_g_as_ar last since tnewx and tnewz are the
+ * same).
+ */
+ as_ge_at = lp_build_cmp(coord_bld, PIPE_FUNC_GREATER, as, at);
+ maxasat = lp_build_max(coord_bld, as, at);
+ ar_ge_as_at = lp_build_cmp(coord_bld, PIPE_FUNC_GEQUAL, ar, maxasat);
+ if (need_derivs && (derivs_in ||
+ ((gallivm_debug & GALLIVM_DEBUG_NO_QUAD_LOD) &&
+ (gallivm_debug & GALLIVM_DEBUG_NO_RHO_APPROX)))) {
/*
- * get absolute value (for x/y/z face selection) and sign bit
- * (for mirroring minor coords and pos/neg face selection)
- * of the original coords.
+ * XXX: This is really really complex.
+ * It is a bit overkill to use this for implicit derivatives as well,
+ * no way this is worth the cost in practice, but seems to be the
+ * only way for getting accurate and per-pixel lod values.
*/
- as = lp_build_abs(&bld->coord_bld, s);
- at = lp_build_abs(&bld->coord_bld, t);
- ar = lp_build_abs(&bld->coord_bld, r);
-
+ LLVMValueRef imapos, tmp, ddx[3], ddy[3];
+ LLVMValueRef madx, mady, madxdivma, madydivma;
+ LLVMValueRef sdxi, tdxi, rdxi, signsdx, signtdx, signrdx;
+ LLVMValueRef sdyi, tdyi, rdyi, signsdy, signtdy, signrdy;
+ LLVMValueRef tdxnegi, rdxnegi, tdynegi, rdynegi;
+ LLVMValueRef sdxnewx, sdxnewy, sdxnewz, tdxnewx, tdxnewy, tdxnewz;
+ LLVMValueRef sdynewx, sdynewy, sdynewz, tdynewx, tdynewy, tdynewz;
+ LLVMValueRef face_sdx, face_tdx, face_sdy, face_tdy;
+ LLVMValueRef posHalf = lp_build_const_vec(coord_bld->gallivm,
+ coord_bld->type, 0.5);
