2011-12-27 21:18:07 +00:00
commit 9f98ea7e22
192 changed files with 77747 additions and 0 deletions
@@ -0,0 +1,76 @@
+// File: crn_math.cpp
+// See Copyright Notice and license at the end of inc/crnlib.h
+#include "crn_core.h"
+
+namespace crnlib
+{
+   namespace math
+   {
+      uint g_bitmasks[32] =
+      {
+         1U <<  0U,         1U <<  1U,          1U <<  2U,        1U <<  3U,
+         1U <<  4U,         1U <<  5U,          1U <<  6U,        1U <<  7U,
+         1U <<  8U,         1U <<  9U,          1U << 10U,        1U << 11U,
+         1U << 12U,         1U << 13U,          1U << 14U,        1U << 15U,
+         1U << 16U,         1U << 17U,          1U << 18U,        1U << 19U,
+         1U << 20U,         1U << 21U,          1U << 22U,        1U << 23U,
+         1U << 24U,         1U << 25U,          1U << 26U,        1U << 27U,
+         1U << 28U,         1U << 29U,          1U << 30U,        1U << 31U
+      };
+      
+      double compute_entropy(const uint8* p, uint n)
+      {
+         uint hist[256];
+         utils::zero_object(hist);
+         
+         for (uint i = 0; i < n; i++)
+            hist[*p++]++;
+         
+         double entropy = 0.0f;
+         
+         const double invln2 = 1.0f/log(2.0f);
+         for (uint i = 0; i < 256; i++)
+         {
+            if (!hist[i])
+               continue;
+               
+            double prob = static_cast<double>(hist[i]) / n;
+            entropy += (-log(prob) * invln2) * hist[i];
+         }
+         
+         return entropy;
+      }
+
+      void compute_lower_pow2_dim(int& width, int& height)
+      {
+         const int tex_width = width;
+         const int tex_height = height;
+
+         width = 1;
+         for ( ; ; )
+         {
+            if ((width * 2) > tex_width)
+               break;
+            width *= 2;
+         }
+
+         height = 1;
+         for ( ; ; )
+         {
+            if ((height * 2) > tex_height)
+               break;
+            height *= 2;
+         }
+      }         
+
+      void compute_upper_pow2_dim(int& width, int& height)
+      {
+         if (!math::is_power_of_2((uint32)width))
+            width = math::next_pow2((uint32)width);
+
+         if (!math::is_power_of_2((uint32)height))
+            height = math::next_pow2((uint32)height);
+      }         
+      
+   } // namespace math
+} // namespace crnlib