Biome dust node: Only place on 'walkable' cubic non-liquid drawtypes

[minetest.git] / src / light.cpp

diff --git a/src/light.cpp b/src/light.cpp
index 4a3ca5a60767c8388429f59e0a025935f80e7375..575bc2c72a876c6690e5b8b7d68ba990690f0265 100644 (file)
--- a/src/light.cpp
+++ b/src/light.cpp
@@ -18,8 +18,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 #include "light.h"
-#include <math.h>
+#include <cmath>
 #include "util/numeric.h"
+#include "settings.h"
 
 #ifndef SERVER
 
@@ -32,52 +33,27 @@ u8 light_LUT[LIGHT_MAX+1];
 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);
-
-       // this table is pure arbitrary values, made so that
-       // at gamma 2.2 the game looks not too dark at light=1,
-       // and mostly linear for the rest of the scale.
-       // we could try to inverse the gamma power function, but this
-       // is simpler and quicker.
-       static const int adjustments[LIGHT_MAX + 1] = {
-               -67,
-               -91,
-               -125,
-               -115,
-               -104,
-               -85,
-               -70,
-               -63,
-               -56,
-               -49,
-               -42,
-               -35,
-               -28,
-               -22,
-               0
-       };
-
-       gamma = rangelim(gamma, 1.0, 3.0);
-
-       float brightness = brightness_step;
+// lighting curve derivatives
+       const float alpha = g_settings->getFloat("lighting_alpha");
+       const float beta  = g_settings->getFloat("lighting_beta");
+// lighting curve coefficients
+       const float a = alpha + beta - 2;
+       const float b = 3 - 2 * alpha - beta;
+       const float c = alpha;
+// gamma correction
+       gamma = rangelim(gamma, 0.5, 3.0);
 
        for (size_t i = 0; i < LIGHT_MAX; i++) {
-               light_LUT[i] = (u8)(255 * powf(brightness / 255.0f, 1.0 / gamma));
-               light_LUT[i] = rangelim(light_LUT[i] + adjustments[i], 0, 255);
-               if (i > 1 && light_LUT[i] < light_LUT[i - 1])
+               float x = i;
+               x /= LIGHT_MAX;
+               float brightness = a * x * x * x + b * x * x + c * x;
+               brightness = powf(brightness, 1.0 / gamma);
+               light_LUT[i] = rangelim((u32)(255 * brightness), 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;
 }