[Mesa-dev] [PATCH 1/3] u_format: implement fetch_rgba_uint and fetch_rgba_sint for integer formats

[Marek Olšák]

Fetching int as float and vice versa is not allowed.
Fetching unsigned int as signed int and vice versa is not allowed either.
Doing conversions like that isn't allowed in OpenGL.

The three hooks could be consolidated into one fetch hook, which would fetch
uint as uint32, sint as sint32, and everything else as float. The receiving
parameter would be void*. This would be useful for implementing vertex fetches
for shader model 4.0, which has untyped registers.
---
 src/gallium/auxiliary/util/u_format.h        |   22 +++++++++++++++++++++-
 src/gallium/auxiliary/util/u_format_pack.py  |    2 ++
 src/gallium/auxiliary/util/u_format_table.py |   12 +++++++++---
 3 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/src/gallium/auxiliary/util/u_format.h b/src/gallium/auxiliary/util/u_format.h
index 9694c90..874ea7e 100644
--- a/src/gallium/auxiliary/util/u_format.h
+++ b/src/gallium/auxiliary/util/u_format.h
@@ -254,7 +254,7 @@ struct util_format_description
    /**
     * Fetch a single pixel (i, j) from a block.
     *
-    * Only defined for non-depth-stencil formats.
+    * Only defined for non-depth-stencil and non-integer formats.
     */
    void
    (*fetch_rgba_float)(float *dst,
@@ -358,6 +358,26 @@ struct util_format_description
    (*pack_rgba_sint)(uint8_t *dst, unsigned dst_stride,
                      const int *src, unsigned src_stride,
                      unsigned width, unsigned height);
+
+   /**
+    * Fetch a single pixel (i, j) from a block.
+    *
+    * Only defined for unsigned (pure) integer formats.
+    */
+   void
+   (*fetch_rgba_uint)(uint32_t *dst,
+                      const uint8_t *src,
+                      unsigned i, unsigned j);
+
+   /**
+    * Fetch a single pixel (i, j) from a block.
+    *
+    * Only defined for signed (pure) integer formats.
+    */
+   void
+   (*fetch_rgba_sint)(int32_t *dst,
+                      const uint8_t *src,
+                      unsigned i, unsigned j);
 };
 
 
diff --git a/src/gallium/auxiliary/util/u_format_pack.py b/src/gallium/auxiliary/util/u_format_pack.py
index fff409f..0b3a890 100644
--- a/src/gallium/auxiliary/util/u_format_pack.py
+++ b/src/gallium/auxiliary/util/u_format_pack.py
@@ -686,6 +686,7 @@ def generate(formats):
 
                 generate_format_unpack(format, channel, native_type, suffix)
                 generate_format_pack(format, channel, native_type, suffix)
+                generate_format_fetch(format, channel, native_type, suffix)
 
                 channel = Channel(SIGNED, False, True, 32)
                 native_type = 'int'
@@ -699,6 +700,7 @@ def generate(formats):
 
                 generate_format_unpack(format, channel, native_type, suffix)
                 generate_format_pack(format, channel, native_type, suffix)   
+                generate_format_fetch(format, channel, native_type, suffix)
 
                 native_type = 'unsigned'
                 suffix = 'unsigned'
diff --git a/src/gallium/auxiliary/util/u_format_table.py b/src/gallium/auxiliary/util/u_format_table.py
index 07beb38..8edb505 100755
--- a/src/gallium/auxiliary/util/u_format_table.py
+++ b/src/gallium/auxiliary/util/u_format_table.py
@@ -169,17 +169,23 @@ def write_format_table(formats):
             print "   &util_format_%s_unpack_unsigned, /* unpack_rgba_uint */" % format.short_name() 
             print "   &util_format_%s_pack_unsigned, /* pack_rgba_uint */" % format.short_name()
             print "   &util_format_%s_unpack_signed, /* unpack_rgba_sint */" % format.short_name()
-            print "   &util_format_%s_pack_signed  /* pack_rgba_sint */" % format.short_name()
+            print "   &util_format_%s_pack_signed,  /* pack_rgba_sint */" % format.short_name()
+            print "   &util_format_%s_fetch_unsigned,  /* fetch_rgba_uint */" % format.short_name()
+            print "   NULL  /* fetch_rgba_sint */"
         elif format.colorspace != ZS and format.channels[0].pure == True and format.channels[0].type == SIGNED:
             print "   &util_format_%s_unpack_unsigned, /* unpack_rgba_uint */" % format.short_name()
             print "   &util_format_%s_pack_unsigned, /* pack_rgba_uint */" % format.short_name()
             print "   &util_format_%s_unpack_signed, /* unpack_rgba_sint */" % format.short_name()
-            print "   &util_format_%s_pack_signed  /* pack_rgba_sint */" % format.short_name()
+            print "   &util_format_%s_pack_signed,  /* pack_rgba_sint */" % format.short_name()
+            print "   NULL,  /* fetch_rgba_uint */"
+            print "   &util_format_%s_fetch_signed  /* fetch_rgba_sint */" % format.short_name()
         else:
             print "   NULL, /* unpack_rgba_uint */" 
             print "   NULL, /* pack_rgba_uint */" 
             print "   NULL, /* unpack_rgba_sint */" 
-            print "   NULL  /* pack_rgba_sint */" 
+            print "   NULL, /* pack_rgba_sint */"
+            print "   NULL, /* fetch_rgba_uint */"
+            print "   NULL  /* fetch_rgba_sint */"
         print "};"
         print
         
-- 
1.7.4.1