mesa: Fix _mesa_swizzle_and_convert integer conversions to clamp properly

Fix various conversion paths that involved integer data types of different
sizes (uint16_t to uint8_t, int16_t to uint8_t, etc) that were not
being clamped properly.

Also, one of the paths was incorrectly assigning the value 12, instead of 1,
to the constant "one".

v2:
- Create auxiliary clamping functions and use them in all paths that
  required clamp because of different source and destination sizes
  and signed-unsigned conversions.

v3:
- Create MIN_INT macro and use it.

v4:
- Add _mesa_float_to_[un]signed() and mesa_half_to_[un]signed() auxiliary
  functions.
- Add clamp for float-to-integer conversions in _mesa_swizzle_and_convert()

Signed-off-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/src/mesa/main/format_utils.h b/src/mesa/main/format_utils.h
index df53edf..4e63200 100644
--- a/src/mesa/main/format_utils.h
+++ b/src/mesa/main/format_utils.h
@@ -32,10 +32,12 @@
 #define FORMAT_UTILS_H
 
 #include "imports.h"
+#include "macros.h"
 
 /* Only guaranteed to work for BITS <= 32 */
 #define MAX_UINT(BITS) ((BITS) == 32 ? UINT32_MAX : ((1u << (BITS)) - 1))
 #define MAX_INT(BITS) ((int)MAX_UINT((BITS) - 1))
+#define MIN_INT(BITS) ((BITS) == 32 ? INT32_MIN : (-(1 << (BITS - 1))))
 
 /* Extends an integer of size SRC_BITS to one of size DST_BITS linearly */
 #define EXTEND_NORMALIZED_INT(X, SRC_BITS, DST_BITS) \
@@ -138,6 +140,64 @@ _mesa_snorm_to_snorm(int x, unsigned src_bits, unsigned dst_bits)
       return x >> (src_bits - dst_bits);
 }
 
+static inline unsigned
+_mesa_unsigned_to_unsigned(unsigned src, unsigned dst_size)
+{
+   return MIN2(src, MAX_UINT(dst_size));
+}
+
+static inline int
+_mesa_unsigned_to_signed(unsigned src, unsigned dst_size)
+{
+   return MIN2(src, MAX_INT(dst_size));
+}
+
+static inline int
+_mesa_signed_to_signed(int src, unsigned dst_size)
+{
+   return CLAMP(src, MIN_INT(dst_size), MAX_INT(dst_size));
+}
+
+static inline unsigned
+_mesa_signed_to_unsigned(int src, unsigned dst_size)
+{
+   return CLAMP(src, 0, MAX_UINT(dst_size));
+}
+
+static inline unsigned
+_mesa_float_to_unsigned(float src, unsigned dst_bits)
+{
+   if (src < 0.0f)
+      return 0;
+   if (src > (float)MAX_UINT(dst_bits))
+       return MAX_UINT(dst_bits);
+   return _mesa_signed_to_unsigned(src, dst_bits);
+}
+
+static inline unsigned
+_mesa_float_to_signed(float src, unsigned dst_bits)
+{
+   if (src < (float)(-MAX_INT(dst_bits)))
+      return -MAX_INT(dst_bits);
+   if (src > (float)MAX_INT(dst_bits))
+       return MAX_INT(dst_bits);
+   return _mesa_signed_to_signed(src, dst_bits);
+}
+
+static inline unsigned
+_mesa_half_to_unsigned(uint16_t src, unsigned dst_bits)
+{
+   if (_mesa_half_is_negative(src))
+      return 0;
+   return _mesa_unsigned_to_unsigned(_mesa_float_to_half(src), dst_bits);
+}
+
+static inline unsigned
+_mesa_half_to_signed(uint16_t src, unsigned dst_bits)
+{
+   return _mesa_float_to_signed(_mesa_half_to_float(src), dst_bits);
+}
+
 bool
 _mesa_format_to_array(mesa_format, GLenum *type, int *num_components,
                       uint8_t swizzle[4], bool *normalized);