Document zoom_fov in settingtypes.txt and minetest.conf.example

[dragonfireclient.git] / src / light.cpp

diff --git a/src/light.cpp b/src/light.cpp
index 765c6303a97218ff27f31f2bf470bdb1c5f91710..5dc01fcf0fd9d4f8a899febacb4565d52b77b574 100644 (file)
--- a/src/light.cpp
+++ b/src/light.cpp
@@ -18,31 +18,93 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 #include "light.h"
+#include <math.h>
+#include "util/numeric.h"
+
+#ifndef SERVER
 
-#if 1
-// Middle-raised variation of a_n+1 = a_n * 0.786
 // Length of LIGHT_MAX+1 means LIGHT_MAX is the last value.
 // LIGHT_SUN is read as LIGHT_MAX from here.
-u8 light_decode_table[LIGHT_MAX+1] = 
+
+u8 light_LUT[LIGHT_MAX+1] =
 {
-8,
-11+2,
-14+7,
-18+10,
-22+15,
-29+20,
-37+20,
-47+15,
-60+10,
-76+7,
-97+5,
-123+2,
-157,
-200,
-255,
+       /* Middle-raised variation of a_n+1 = a_n * 0.786
+        * Length of LIGHT_MAX+1 means LIGHT_MAX is the last value.
+        * LIGHT_SUN is read as LIGHT_MAX from here.
+        */
+       8,
+       11+2,
+       14+7,
+       18+10,
+       22+15,
+       29+20,
+       37+20,
+       47+15,
+       60+10,
+       76+7,
+       97+5,
+       123+2,
+       157,
+       200,
+       255,
 };
+
+const u8 *light_decode_table = light_LUT;
+
+/** Initialize or update the light value tables using the specified \p gamma.
+ *  If \p gamma == 1.0 then the light table is linear.  Typically values for
+ *  gamma range between 1.8 and 2.2.
+ *
+ *  @note The value for gamma will be restricted to the range 1.1 <= gamma <= 3.0.
+ *
+ *  @note This function is not, currently, a simple linear to gamma encoding
+ *        because adjustments are made so that a gamma of 1.8 gives the same
+ *        results as those hardcoded for use by the server.
+ */
+void set_light_table(float gamma)
+{
+       static const float brightness_step = 255.0f / (LIGHT_MAX + 1);
+
+       /* These are adjustment values that are added to the calculated light value
+        * after gamma is applied.  Currently they are used so that given a gamma
+        * of 1.8 the light values set by this function are the same as those
+        * hardcoded in the initalizer list for the declaration of light_LUT.
+        */
+       static const int adjustments[LIGHT_MAX + 1] = {
+                7,
+                7,
+                7,
+                5,
+                2,
+                0,
+               -7,
+               -20,
+               -31,
+               -39,
+               -43,
+               -45,
+               -40,
+               -25,
+               0
+       };
+
+       gamma = rangelim(gamma, 1.0, 3.0);
+
+       float brightness = brightness_step;
+
+       for (size_t i = 0; i < LIGHT_MAX; i++) {
+               light_LUT[i] = (u8)(255 * powf(brightness / 255.0f,  gamma));
+               light_LUT[i] = rangelim(light_LUT[i] + adjustments[i], 0, 255);
+               if (i > 1 && light_LUT[i] < light_LUT[i-1])
+                       light_LUT[i] = light_LUT[i-1] + 1;
+               brightness += brightness_step;
+       }
+       light_LUT[LIGHT_MAX] = 255;
+}
 #endif
 
+
+
 #if 0
 /*
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