glsl/builtins: Fix textureGrad() for Array samplers.

We were incorrectly assuming that the coordinate's dimensionality is
equal to the gradient's dimensionality.  For array types, the coordinate
has one more component.

Fixes 12 subcases of oglconform's glsl-bif-tex-grad test.

NOTE: This is a candidate for stable release branches.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>

src/glsl/builtins/tools/texture_builtins.py

@@ -56,7 +56,7 @@ def get_txs_dim(sampler_type):
 def generate_sigs(g, tex_inst, sampler_type, variant = 0, unused_fields = 0):
     coord_dim = get_coord_dim(sampler_type)
     extra_dim = get_extra_dim(sampler_type, variant & Proj, unused_fields)
-    offset_dim = get_sampler_dim(sampler_type)
+    sampler_dim = get_sampler_dim(sampler_type)
 
     if variant & Single:
         return_type = "float"
@@ -76,12 +76,12 @@ def generate_sigs(g, tex_inst, sampler_type, variant = 0, unused_fields = 0):
     elif ((tex_inst == "txf" or tex_inst == "txs") and "Buffer" not in sampler_type and "Rect" not in sampler_type):
         print "\n       (declare (in) int lod)",
     elif tex_inst == "txd":
-        grad_type = vec_type("", coord_dim)
+        grad_type = vec_type("", sampler_dim)
         print "\n       (declare (in) " + grad_type + " dPdx)",
         print "\n       (declare (in) " + grad_type + " dPdy)",
 
     if variant & Offset:
-        print "\n       (declare (const_in) " + vec_type("i", offset_dim) + " offset)",
+        print "\n       (declare (const_in) " + vec_type("i", sampler_dim) + " offset)",
     if tex_inst == "txb":
         print "\n       (declare (in) float bias)",