d3dretrace: Add support for half float formats

Use MESA half-float to float conversion function.
Mesa uses MIT compatibel license which should fit apitrace license.
Copyright header remains untouched.

Signed-off-by: Patrick Rudolph <siro@das-labor.org>

1 files changed, 133 insertions, 0 deletions

diff --git a/helpers/halffloat.hpp b/helpers/halffloat.hpp
new file mode 100644
index 00000000..eacb9f91
--- /dev/null
+++ b/helpers/halffloat.hpp
@@ -0,0 +1,133 @@
+/**************************************************************************
+ *
+ * Copyright 2010 Luca Barbieri
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+
+#ifndef U_HALF_H
+#define U_HALF_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+union fi {
+   float f;
+   int32_t i;
+   uint32_t ui;
+};
+
+/*
+ * References for float <-> half conversions
+ *
+ *  http://fgiesen.wordpress.com/2012/03/28/half-to-float-done-quic/
+ *  https://gist.github.com/2156668
+ *  https://gist.github.com/2144712
+ */
+
+static inline uint16_t
+util_float_to_half(float f)
+{
+   uint32_t sign_mask  = 0x80000000;
+   uint32_t round_mask = ~0xfff;
+   uint32_t f32inf = 0xff << 23;
+   uint32_t f16inf = 0x1f << 23;
+   uint32_t sign;
+   union fi magic;
+   union fi f32;
+   uint16_t f16;
+
+   magic.ui = 0xf << 23;
+
+   f32.f = f;
+
+   /* Sign */
+   sign = f32.ui & sign_mask;
+   f32.ui ^= sign;
+
+   if (f32.ui == f32inf) {
+      /* Inf */
+      f16 = 0x7c00;
+   } else if (f32.ui > f32inf) {
+      /* NaN */
+      f16 = 0x7e00;
+   } else {
+      /* Number */
+      f32.ui &= round_mask;
+      f32.f  *= magic.f;
+      f32.ui -= round_mask;
+
+      /*
+       * Clamp to max finite value if overflowed.
+       * OpenGL has completely undefined rounding behavior for float to
+       * half-float conversions, and this matches what is mandated for float
+       * to fp11/fp10, which recommend round-to-nearest-finite too.
+       * (d3d10 is deeply unhappy about flushing such values to infinity, and
+       * while it also mandates round-to-zero it doesn't care nearly as much
+       * about that.)
+       */
+      if (f32.ui > f16inf)
+         f32.ui = f16inf - 1;
+
+      f16 = f32.ui >> 13;
+   }
+
+   /* Sign */
+   f16 |= sign >> 16;
+
+   return f16;
+}
+
+static inline float
+util_half_to_float(uint16_t f16)
+{
+   union fi infnan;
+   union fi magic;
+   union fi f32;
+
+   infnan.ui = 0x8f << 23;
+   infnan.f = 65536.0f;
+   magic.ui  = 0xef << 23;
+
+   /* Exponent / Mantissa */
+   f32.ui = (f16 & 0x7fff) << 13;
+
+   /* Adjust */
+   f32.f *= magic.f;
+
+   /* Inf / NaN */
+   if (f32.f >= infnan.f)
+      f32.ui |= 0xff << 23;
+
+   /* Sign */
+   f32.ui |= (f16 & 0x8000) << 16;
+
+   return f32.f;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* U_HALF_H */