mesa, util: move RGB9E5 conversion functions to gallium/util

Also use MAX3 and incorporate Ian's suggestion in texformat.c.

I don't think wrapping u_format_rgb9e5.h in another header and thus making it
more complicated is worth it.

2 files changed, 165 insertions, 1 deletions

diff --git a/src/gallium/auxiliary/util/u_format_other.c b/src/gallium/auxiliary/util/u_format_other.c
index a44cc01673b..1beb61868eb 100644
--- a/src/gallium/auxiliary/util/u_format_other.c
+++ b/src/gallium/auxiliary/util/u_format_other.c
@@ -28,7 +28,7 @@
 
 #include "u_math.h"
 #include "u_format_other.h"
-#include "../../../mesa/main/rgb9e5.h"
+#include "u_format_rgb9e5.h"
 
 
 void
diff --git a/src/gallium/auxiliary/util/u_format_rgb9e5.h b/src/gallium/auxiliary/util/u_format_rgb9e5.h
new file mode 100644
index 00000000000..c2a3f6f3e9d
--- /dev/null
+++ b/src/gallium/auxiliary/util/u_format_rgb9e5.h
@@ -0,0 +1,164 @@
+/*
+ * Copyright (C) 2011 Marek Olšák <[email protected]>
+ *
+ * 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 AUTHORS OR COPYRIGHT HOLDERS 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.
+ */
+
+/* Copied from EXT_texture_shared_exponent and edited. */
+
+#ifndef RGB9E5_H
+#define RGB9E5_H
+
+#include <math.h>
+#include <assert.h>
+
+#define RGB9E5_EXPONENT_BITS          5
+#define RGB9E5_MANTISSA_BITS          9
+#define RGB9E5_EXP_BIAS               15
+#define RGB9E5_MAX_VALID_BIASED_EXP   31
+
+#define MAX_RGB9E5_EXP               (RGB9E5_MAX_VALID_BIASED_EXP - RGB9E5_EXP_BIAS)
+#define RGB9E5_MANTISSA_VALUES       (1<<RGB9E5_MANTISSA_BITS)
+#define MAX_RGB9E5_MANTISSA          (RGB9E5_MANTISSA_VALUES-1)
+#define MAX_RGB9E5                   (((float)MAX_RGB9E5_MANTISSA)/RGB9E5_MANTISSA_VALUES * (1<<MAX_RGB9E5_EXP))
+#define EPSILON_RGB9E5               ((1.0/RGB9E5_MANTISSA_VALUES) / (1<<RGB9E5_EXP_BIAS))
+
+typedef union {
+   unsigned int raw;
+   float value;
+   struct {
+#if defined(MESA_BIG_ENDIAN) || defined(PIPE_ARCH_BIG_ENDIAN)
+      unsigned int negative:1;
+      unsigned int biasedexponent:8;
+      unsigned int mantissa:23;
+#else
+      unsigned int mantissa:23;
+      unsigned int biasedexponent:8;
+      unsigned int negative:1;
+#endif
+   } field;
+} float754;
+
+typedef union {
+   unsigned int raw;
+   struct {
+#if defined(MESA_BIG_ENDIAN) || defined(PIPE_ARCH_BIG_ENDIAN)
+      unsigned int biasedexponent:RGB9E5_EXPONENT_BITS;
+      unsigned int b:RGB9E5_MANTISSA_BITS;
+      unsigned int g:RGB9E5_MANTISSA_BITS;
+      unsigned int r:RGB9E5_MANTISSA_BITS;
+#else
+      unsigned int r:RGB9E5_MANTISSA_BITS;
+      unsigned int g:RGB9E5_MANTISSA_BITS;
+      unsigned int b:RGB9E5_MANTISSA_BITS;
+      unsigned int biasedexponent:RGB9E5_EXPONENT_BITS;
+#endif
+   } field;
+} rgb9e5;
+
+static INLINE float rgb9e5_ClampRange(float x)
+{
+   if (x > 0.0) {
+      if (x >= MAX_RGB9E5) {
+         return MAX_RGB9E5;
+      } else {
+         return x;
+      }
+   } else {
+      /* NaN gets here too since comparisons with NaN always fail! */
+      return 0.0;
+   }
+}
+
+/* Ok, FloorLog2 is not correct for the denorm and zero values, but we
+   are going to do a max of this value with the minimum rgb9e5 exponent
+   that will hide these problem cases. */
+static INLINE int rgb9e5_FloorLog2(float x)
+{
+   float754 f;
+
+   f.value = x;
+   return (f.field.biasedexponent - 127);
+}
+
+static INLINE unsigned float3_to_rgb9e5(const float rgb[3])
+{
+   rgb9e5 retval;
+   float maxrgb;
+   int rm, gm, bm;
+   float rc, gc, bc;
+   int exp_shared, maxm;
+   double denom;
+
+   rc = rgb9e5_ClampRange(rgb[0]);
+   gc = rgb9e5_ClampRange(rgb[1]);
+   bc = rgb9e5_ClampRange(rgb[2]);
+
+   maxrgb = MAX3(rc, gc, bc);
+   exp_shared = MAX2(-RGB9E5_EXP_BIAS-1, rgb9e5_FloorLog2(maxrgb)) + 1 + RGB9E5_EXP_BIAS;
+   assert(exp_shared <= RGB9E5_MAX_VALID_BIASED_EXP);
+   assert(exp_shared >= 0);
+   /* This pow function could be replaced by a table. */
+   denom = pow(2, exp_shared - RGB9E5_EXP_BIAS - RGB9E5_MANTISSA_BITS);
+
+   maxm = (int) floor(maxrgb / denom + 0.5);
+   if (maxm == MAX_RGB9E5_MANTISSA+1) {
+      denom *= 2;
+      exp_shared += 1;
+      assert(exp_shared <= RGB9E5_MAX_VALID_BIASED_EXP);
+   } else {
+      assert(maxm <= MAX_RGB9E5_MANTISSA);
+   }
+
+   rm = (int) floor(rc / denom + 0.5);
+   gm = (int) floor(gc / denom + 0.5);
+   bm = (int) floor(bc / denom + 0.5);
+
+   assert(rm <= MAX_RGB9E5_MANTISSA);
+   assert(gm <= MAX_RGB9E5_MANTISSA);
+   assert(bm <= MAX_RGB9E5_MANTISSA);
+   assert(rm >= 0);
+   assert(gm >= 0);
+   assert(bm >= 0);
+
+   retval.field.r = rm;
+   retval.field.g = gm;
+   retval.field.b = bm;
+   retval.field.biasedexponent = exp_shared;
+
+   return retval.raw;
+}
+
+static INLINE void rgb9e5_to_float3(unsigned rgb, float retval[3])
+{
+   rgb9e5 v;
+   int exponent;
+   float scale;
+
+   v.raw = rgb;
+   exponent = v.field.biasedexponent - RGB9E5_EXP_BIAS - RGB9E5_MANTISSA_BITS;
+   scale = (float) pow(2, exponent);
+
+   retval[0] = v.field.r * scale;
+   retval[1] = v.field.g * scale;
+   retval[2] = v.field.b * scale;
+}
+
+#endif