gallivm: honor explicit derivatives values for cube maps.

This is trivial now, though need to make sure we pass all the necessary
derivative values (which is 3 each for ddx/ddy not 2).
Passes piglit arb_shader_texture_lod-texgradcube test.

v2: add the forgotten abs() for all incoming derivatives (discovered
by new piglit arb_shader_texture_lod-texgradcube test, though more by
luck as it was failing only for exactly one pixel...).

Reviewed-by: Jose Fonseca <jfonseca@vmware.com>

4 files changed, 60 insertions, 28 deletions

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_sample.c b/src/gallium/auxiliary/gallivm/lp_bld_sample.c
index 5d5092155cf..fe29d258c9d 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_sample.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_sample.c
@@ -1287,6 +1287,7 @@ lp_build_cube_lookup(struct lp_build_sample_context *bld,
                      LLVMValueRef s,
                      LLVMValueRef t,
                      LLVMValueRef r,
+                     const struct lp_derivatives *derivs, /* optional */
                      LLVMValueRef *face,
                      LLVMValueRef *face_s,
                      LLVMValueRef *face_t,
@@ -1296,7 +1297,6 @@ lp_build_cube_lookup(struct lp_build_sample_context *bld,
    LLVMBuilderRef builder = bld->gallivm->builder;
    struct gallivm_state *gallivm = bld->gallivm;
    LLVMValueRef si, ti, ri;
-   boolean implicit_derivs = TRUE;
    boolean need_derivs = TRUE;
 
    if (1 || coord_bld->type.length > 4) {
@@ -1334,9 +1334,9 @@ lp_build_cube_lookup(struct lp_build_sample_context *bld,
       assert(PIPE_TEX_FACE_NEG_Z == PIPE_TEX_FACE_POS_Z + 1);
 
       /*
-       * TODO do this only when needed, and implement explicit derivs (trivial).
+       * TODO do this only when needed.
        */
-      if (need_derivs && implicit_derivs) {
+      if (need_derivs && !derivs) {
          LLVMValueRef ddx_ddy[2], tmp[2];
          /*
           * This isn't quite the same as the "ordinary" path since
@@ -1374,9 +1374,16 @@ lp_build_cube_lookup(struct lp_build_sample_context *bld,
          dmax[2] = lp_build_max(coord_bld, tmp[0], tmp[1]);
       }
       else if (need_derivs) {
-         /* dmax[0] = lp_build_max(coord_bld, derivs->ddx[0], derivs->ddy[0]);
-         dmax[1] = lp_build_max(coord_bld, derivs->ddx[1], derivs->ddy[1]);
-         dmax[2] = lp_build_max(coord_bld, derivs->ddx[2], derivs->ddy[2]); */
+         LLVMValueRef abs_ddx[3], abs_ddy[3];
+         abs_ddx[0] = lp_build_abs(coord_bld, derivs->ddx[0]);
+         abs_ddx[1] = lp_build_abs(coord_bld, derivs->ddx[1]);
+         abs_ddx[2] = lp_build_abs(coord_bld, derivs->ddx[2]);
+         abs_ddy[0] = lp_build_abs(coord_bld, derivs->ddy[0]);
+         abs_ddy[1] = lp_build_abs(coord_bld, derivs->ddy[1]);
+         abs_ddy[2] = lp_build_abs(coord_bld, derivs->ddy[2]);
+         dmax[0] = lp_build_max(coord_bld, abs_ddx[0], abs_ddy[0]);
+         dmax[1] = lp_build_max(coord_bld, abs_ddx[1], abs_ddy[1]);
+         dmax[2] = lp_build_max(coord_bld, abs_ddx[2], abs_ddy[2]);
       }
 
       si = LLVMBuildBitCast(builder, s, lp_build_vec_type(gallivm, intctype), "");
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_sample.h b/src/gallium/auxiliary/gallivm/lp_bld_sample.h
index 5026b0a1250..72af813d42f 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_sample.h
+++ b/src/gallium/auxiliary/gallivm/lp_bld_sample.h
@@ -433,6 +433,7 @@ lp_build_cube_lookup(struct lp_build_sample_context *bld,
                      LLVMValueRef s,
                      LLVMValueRef t,
                      LLVMValueRef r,
+                     const struct lp_derivatives *derivs, /* optional */
                      LLVMValueRef *face,
                      LLVMValueRef *face_s,
                      LLVMValueRef *face_t,
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c b/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c
index 3b950eac959..d2cc0f362a3 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c
@@ -1102,7 +1102,7 @@ lp_build_sample_common(struct lp_build_sample_context *bld,
     */
    if (target == PIPE_TEXTURE_CUBE) {
       LLVMValueRef face, face_s, face_t;
-      lp_build_cube_lookup(bld, *s, *t, *r, &face, &face_s, &face_t, &cube_rho);
+      lp_build_cube_lookup(bld, *s, *t, *r, derivs, &face, &face_s, &face_t, &cube_rho);
       *s = face_s; /* vec */
       *t = face_t; /* vec */
       /* use 'r' to indicate cube face */
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_tgsi_soa.c b/src/gallium/auxiliary/gallivm/lp_bld_tgsi_soa.c
index e802d5b1b62..d8c419b7ac6 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_tgsi_soa.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_tgsi_soa.c
@@ -1277,8 +1277,7 @@ emit_tex( struct lp_build_tgsi_soa_context *bld,
    LLVMValueRef offsets[3] = { NULL };
    struct lp_derivatives derivs;
    struct lp_derivatives *deriv_ptr = NULL;
-   unsigned num_coords;
-   unsigned dims;
+   unsigned num_coords, num_derivs, num_offsets;
    unsigned i;
 
    if (!bld->sampler) {
@@ -1292,37 +1291,52 @@ emit_tex( struct lp_build_tgsi_soa_context *bld,
    switch (inst->Texture.Texture) {
    case TGSI_TEXTURE_1D:
       num_coords = 1;
-      dims = 1;
+      num_offsets = 1;
+      num_derivs = 1;
       break;
    case TGSI_TEXTURE_1D_ARRAY:
       num_coords = 2;
-      dims = 1;
+      num_offsets = 1;
+      num_derivs = 1;
       break;
    case TGSI_TEXTURE_2D:
    case TGSI_TEXTURE_RECT:
       num_coords = 2;
-      dims = 2;
+      num_offsets = 2;
+      num_derivs = 2;
       break;
    case TGSI_TEXTURE_SHADOW1D:
    case TGSI_TEXTURE_SHADOW1D_ARRAY:
       num_coords = 3;
-      dims = 1;
+      num_offsets = 1;
+      num_derivs = 1;
       break;
    case TGSI_TEXTURE_SHADOW2D:
    case TGSI_TEXTURE_SHADOWRECT:
    case TGSI_TEXTURE_2D_ARRAY:
+      num_coords = 3;
+      num_offsets = 2;
+      num_derivs = 2;
+      break;
    case TGSI_TEXTURE_CUBE:
       num_coords = 3;
-      dims = 2;
+      num_offsets = 2;
+      num_derivs = 3;
       break;
    case TGSI_TEXTURE_3D:
       num_coords = 3;
-      dims = 3;
+      num_offsets = 3;
+      num_derivs = 3;
       break;
    case TGSI_TEXTURE_SHADOW2D_ARRAY:
+      num_coords = 4;
+      num_offsets = 2;
+      num_derivs = 2;
+      break;
    case TGSI_TEXTURE_SHADOWCUBE:
       num_coords = 4;
-      dims = 2;
+      num_offsets = 2;
+      num_derivs = 3;
       break;
    default:
       assert(0);
@@ -1362,20 +1376,20 @@ emit_tex( struct lp_build_tgsi_soa_context *bld,
 
    if (modifier == LP_BLD_TEX_MODIFIER_EXPLICIT_DERIV) {
       unsigned dim;
-      for (dim = 0; dim < dims; ++dim) {
+      for (dim = 0; dim < num_derivs; ++dim) {
          derivs.ddx[dim] = lp_build_emit_fetch( &bld->bld_base, inst, 1, dim );
          derivs.ddy[dim] = lp_build_emit_fetch( &bld->bld_base, inst, 2, dim );
       }
       deriv_ptr = &derivs;
       unit = inst->Src[3].Register.Index;
-   }  else {
+   } else {
       unit = inst->Src[1].Register.Index;
    }
 
    /* some advanced gather instructions (txgo) would require 4 offsets */
    if (inst->Texture.NumOffsets == 1) {
       unsigned dim;
-      for (dim = 0; dim < dims; dim++) {
+      for (dim = 0; dim < num_offsets; dim++) {
          offsets[dim] = lp_build_emit_fetch_texoffset(&bld->bld_base, inst, 0, dim );
       }
    }
@@ -1406,7 +1420,7 @@ emit_sample(struct lp_build_tgsi_soa_context *bld,
    LLVMValueRef offsets[3] = { NULL };
    struct lp_derivatives derivs;
    struct lp_derivatives *deriv_ptr = NULL;
-   unsigned num_coords, dims;
+   unsigned num_coords, num_offsets, num_derivs;
    unsigned i;
 
    if (!bld->sampler) {
@@ -1432,29 +1446,39 @@ emit_sample(struct lp_build_tgsi_soa_context *bld,
    switch (bld->sv[texture_unit].Resource) {
    case TGSI_TEXTURE_1D:
       num_coords = 1;
-      dims = 1;
+      num_offsets = 1;
+      num_derivs = 1;
       break;
    case TGSI_TEXTURE_1D_ARRAY:
       num_coords = 2;
-      dims = 1;
+      num_offsets = 1;
+      num_derivs = 1;
       break;
    case TGSI_TEXTURE_2D:
    case TGSI_TEXTURE_RECT:
       num_coords = 2;
-      dims = 2;
+      num_offsets = 2;
+      num_derivs = 2;
       break;
    case TGSI_TEXTURE_2D_ARRAY:
+      num_coords = 3;
+      num_offsets = 2;
+      num_derivs = 2;
+      break;
    case TGSI_TEXTURE_CUBE:
       num_coords = 3;
-      dims = 2;
+      num_offsets = 2;
+      num_derivs = 3;
       break;
    case TGSI_TEXTURE_3D:
       num_coords = 3;
-      dims = 3;
+      num_offsets = 3;
+      num_derivs = 3;
       break;
    case TGSI_TEXTURE_CUBE_ARRAY:
       num_coords = 4;
-      dims = 3;
+      num_offsets = 2;
+      num_derivs = 3;
       break;
    default:
       assert(0);
@@ -1505,7 +1529,7 @@ emit_sample(struct lp_build_tgsi_soa_context *bld,
 
    if (modifier == LP_BLD_TEX_MODIFIER_EXPLICIT_DERIV) {
       unsigned dim;
-      for (dim = 0; dim < dims; ++dim) {
+      for (dim = 0; dim < num_derivs; ++dim) {
          derivs.ddx[dim] = lp_build_emit_fetch( &bld->bld_base, inst, 3, dim );
          derivs.ddy[dim] = lp_build_emit_fetch( &bld->bld_base, inst, 4, dim );
       }
@@ -1515,7 +1539,7 @@ emit_sample(struct lp_build_tgsi_soa_context *bld,
    /* some advanced gather instructions (txgo) would require 4 offsets */
    if (inst->Texture.NumOffsets == 1) {
       unsigned dim;
-      for (dim = 0; dim < dims; dim++) {
+      for (dim = 0; dim < num_offsets; dim++) {
          offsets[dim] = lp_build_emit_fetch_texoffset(&bld->bld_base, inst, 0, dim );
       }
    }