gallium: add initial pure integer support (v2)

This add support for unsigned/signed integer types via adding a 'pure' bit
in the format description table. It adds 4 new u_format get/put hooks,
for get/put uint and get/put sint so that accessors can get native access
to the integer bits. This is used to avoid precision loss via float converting
paths.

It doesn't add any float fetchers for these types at the moment, GL doesn't
require float fetching from these types and I expect we'll introduce a lot
of hidden bugs if we start allowing such conversions without an API mandating
it.

It adds all formats from EXT_texture_integer and EXT_texture_rg.

0 regressions on llvmpipe here with this.

(there is some more follow on code in my gallium-int-work branch, bringing
 softpipe and mesa to a pretty integer clean state)

v2: fixup python generator to get signed->unsigned and unsigned->signed
fetches working.

Signed-off-by: Dave Airlie <[email protected]>

1 files changed, 15 insertions, 3 deletions

diff --git a/src/gallium/auxiliary/util/u_format_parse.py b/src/gallium/auxiliary/util/u_format_parse.py
index ddb9f2443d9..73a4bcb2100 100755
--- a/src/gallium/auxiliary/util/u_format_parse.py
+++ b/src/gallium/auxiliary/util/u_format_parse.py
@@ -52,9 +52,10 @@ VERY_LARGE = 99999999999999999999999
 class Channel:
     '''Describe the channel of a color channel.'''
     
-    def __init__(self, type, norm, size, name = ''):
+    def __init__(self, type, norm, pure, size, name = ''):
         self.type = type
         self.norm = norm
+        self.pure = pure
         self.size = size
         self.sign = type in (SIGNED, FIXED, FLOAT)
         self.name = name
@@ -63,11 +64,13 @@ class Channel:
         s = str(self.type)
         if self.norm:
             s += 'n'
+        if self.pure:
+            s += 'p'
         s += str(self.size)
         return s
 
     def __eq__(self, other):
-        return self.type == other.type and self.norm == other.norm and self.size == other.size
+        return self.type == other.type and self.norm == other.norm and self.pure == other.pure and self.size == other.size
 
     def max(self):
         '''Maximum representable number.'''
@@ -158,6 +161,8 @@ class Format:
                     return True
                 if channel.norm != ref_channel.norm:
                     return True
+                if channel.pure != ref_channel.pure:
+                    return True
         return False
 
     def is_pot(self):
@@ -274,15 +279,22 @@ def parse(filename):
                 type = _type_parse_map[field[0]]
                 if field[1] == 'n':
                     norm = True
+                    pure = False
+                    size = int(field[2:])
+                elif field[1] == 'p':
+                    pure = True
+                    norm = False
                     size = int(field[2:])
                 else:
                     norm = False
+                    pure = False
                     size = int(field[1:])
             else:
                 type = VOID
                 norm = False
+                pure = False
                 size = 0
-            channel = Channel(type, norm, size, names[i])
+            channel = Channel(type, norm, pure, size, names[i])
             channels.append(channel)
 
         format = Format(name, layout, block_width, block_height, channels, swizzles, colorspace)