[Piglit] [PATCH 2/2] arb_shader_bit_encoding: Test inputs modified by abs/neg/neg-abs.

[Matt Turner]

floatBitsToInt(abs(x)) is not equivalent to abs(floatBitsToInt(x)).
---
floatBitsTo* with abs/neg/neg-abs fail on the i965 driver, presumably
because an optimization pass decides that the conversion and modifier
can be performed at once, but doesn't take into account that the hardware
does it in the reverse order.

Unexpectedly, intBitsToFloat with a modifier on the input function passes.
I initially thought that it was because I was generating the expected values
incorrectly (which lead to hunk #5 in this patch). But even fixing that,
the tests still unexpectedly pass, so I'm not sure if the driver is actually
doing the right thing, or if my generator is doing the wrong thing.


 generated_tests/gen_shader_bit_encoding_tests.py | 96 ++++++++++++++++--------
 1 file changed, 64 insertions(+), 32 deletions(-)

diff --git a/generated_tests/gen_shader_bit_encoding_tests.py b/generated_tests/gen_shader_bit_encoding_tests.py
index a6ff674..cce9164 100644
--- a/generated_tests/gen_shader_bit_encoding_tests.py
+++ b/generated_tests/gen_shader_bit_encoding_tests.py
@@ -43,6 +43,12 @@ def uintBitsToFloat(u):
 def passthrough(f):
     return f
 
+def neg(num):
+    return -num
+
+def neg_abs(num):
+    return -abs(num)
+
 def vec4(f):
     return [f, f, f, f]
 
@@ -96,6 +102,13 @@ funcs = {
     }
 }
 
+modifier_funcs = {
+    '':            passthrough,
+    'abs':         abs,
+    'neg':         neg,
+    'neg_abs':     neg_abs
+}
+
 requirements = {
     'ARB_shader_bit_encoding': {
         'version': '1.30',
@@ -137,13 +150,13 @@ template = Template(dedent("""\
         % if execution_stage == 'vs':
         color = vec4(0.0, 1.0, 0.0, 1.0);
 
-        if (expected.x != ${func}(given.x))
+        if (expected.x != ${func}(${in_modifier_func}(given.x)))
                 color.r = 1.0;
-        if (expected.xy != ${func}(given.xy))
+        if (expected.xy != ${func}(${in_modifier_func}(given.xy)))
                 color.r = 1.0;
-        if (expected.xyz != ${func}(given.xyz))
+        if (expected.xyz != ${func}(${in_modifier_func}(given.xyz)))
                 color.r = 1.0;
-        if (expected != ${func}(given))
+        if (expected != ${func}(${in_modifier_func}(given)))
                 color.r = 1.0;
         % endif
     }
@@ -166,13 +179,13 @@ template = Template(dedent("""\
         % if execution_stage == 'fs':
         frag_color = vec4(0.0, 1.0, 0.0, 1.0);
 
-        if (expected.x != ${func}(given.x))
+        if (expected.x != ${func}(${in_modifier_func}(given.x)))
                 frag_color.r = 1.0;
-        if (expected.xy != ${func}(given.xy))
+        if (expected.xy != ${func}(${in_modifier_func}(given.xy)))
                 frag_color.r = 1.0;
-        if (expected.xyz != ${func}(given.xyz))
+        if (expected.xyz != ${func}(${in_modifier_func}(given.xyz)))
                 frag_color.r = 1.0;
-        if (expected != ${func}(given))
+        if (expected != ${func}(${in_modifier_func}(given)))
                 frag_color.r = 1.0;
         % else:
         frag_color = color;
@@ -191,7 +204,11 @@ template = Template(dedent("""\
 
     # ${name}
     uniform ${input_type} given ${' '.join(str(in_func(d)) for d in data)}
-    uniform ${output_type} expected ${' '.join(str(out_func(d)) for d in data)}
+    % if func in ('floatBitsToInt', 'floatBitsToUint'):
+    uniform ${output_type} expected ${' '.join(str(out_func(modifier_func(d))) for d in data)}
+    % else:
+    uniform ${output_type} expected ${' '.join(str(modifier_func(out_func(d))) for d in data)}
+    % endif
     draw arrays GL_TRIANGLE_FAN 0 4
     probe all rgba 0.0 1.0 0.0 1.0
     % endfor
@@ -209,26 +226,41 @@ for api, requirement in requirements.iteritems():
 
         for execution_stage in ('vs', 'fs'):
             file_extension = 'frag' if execution_stage == 'fs' else 'vert'
-            filename = os.path.join('spec',
-                                    api,
-                                    'execution',
-                                    'built-in-functions',
-                                    "{0}-{1}.shader_test".format(execution_stage,
-                                                                 func))
-            print filename
-
-            dirname = os.path.dirname(filename)
-            if not os.path.exists(dirname):
-                os.makedirs(dirname)
-
-            f = open(filename, 'w')
-            f.write(template.render(version=version,
-                                    extensions=extensions,
-                                    execution_stage=execution_stage,
-                                    func=func,
-                                    in_func=in_func,
-                                    out_func=out_func,
-                                    input_type=input_type,
-                                    output_type=output_type,
-                                    test_data=test_data))
-            f.close()
+
+            for in_modifier_func, modifier_func in modifier_funcs.iteritems():
+                # Modifying the sign of an unsigned number doesn't make sense.
+                if func == 'uintBitsToFloat' and in_modifier_func != '':
+                    continue
+
+                modifier_name = '-' + in_modifier_func if in_modifier_func != '' else ''
+                filename = os.path.join('spec',
+                                        api,
+                                        'execution',
+                                        'built-in-functions',
+                                        "{0}-{1}{2}.shader_test".format(execution_stage,
+                                                                        func,
+                                                                        modifier_name))
+                print filename
+
+                dirname = os.path.dirname(filename)
+                if not os.path.exists(dirname):
+                    os.makedirs(dirname)
+
+                if in_modifier_func == 'neg':
+                    in_modifier_func = '-'
+                elif in_modifier_func == 'neg_abs':
+                    in_modifier_func = '-abs'
+
+                f = open(filename, 'w')
+                f.write(template.render(version=version,
+                                        extensions=extensions,
+                                        execution_stage=execution_stage,
+                                        func=func,
+                                        modifier_func=modifier_func,
+                                        in_modifier_func=in_modifier_func,
+                                        in_func=in_func,
+                                        out_func=out_func,
+                                        input_type=input_type,
+                                        output_type=output_type,
+                                        test_data=test_data))
+                f.close()
-- 
1.8.1.5