ItemCAO removal (#6279)

[minetest.git] / src / light.cpp

diff --git a/src/light.cpp b/src/light.cpp
index fec800874b717f20e8017ec63e7012cf089ec7a0..575bc2c72a876c6690e5b8b7d68ba990690f0265 100644 (file)
--- a/src/light.cpp
+++ b/src/light.cpp
@@ -1,144 +1,61 @@
 /*
-Minetest-c55
-Copyright (C) 2010 celeron55, Perttu Ahola <celeron55@gmail.com>
+Minetest
+Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
 
 This program is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2 of the License, or
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
+GNU Lesser General Public License for more details.
 
-You should have received a copy of the GNU General Public License along
+You should have received a copy of the GNU Lesser General Public License along
 with this program; if not, write to the Free Software Foundation, Inc.,
 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
 #include "light.h"
+#include <cmath>
+#include "util/numeric.h"
+#include "settings.h"
 
-/*u32 daynight_cache_ratios[DAYNIGHT_CACHE_COUNT] =
-{
-       1000,
-       600,
-       300
-};*/
-
-u8 light_decode_table[LIGHT_MAX+1] = 
-{
-0,
-6,
-8,
-11,
-14,
-19,
-26,
-34,
-45,
-61,
-81,
-108,
-143,
-191,
-255,
-};
-/*u8 light_decode_table[LIGHT_MAX+1] = 
-{
-0,
-3,
-6,
-10,
-18,
-25,
-35,
-50,
-75,
-95,
-120,
-150,
-185,
-215,
-255,
-};*/
-/*u8 light_decode_table[LIGHT_MAX+1] = 
-{
-0,
-5,
-12,
-22,
-35,
-50,
-65,
-85,
-100,
-120,
-140,
-160,
-185,
-215,
-255,
-};*/
-// LIGHT_MAX is 14, 0-14 is 15 values
-/*u8 light_decode_table[LIGHT_MAX+1] = 
-{
-0,
-9,
-12,
-14,
-16,
-20,
-26,
-34,
-45,
-61,
-81,
-108,
-143,
-191,
-255,
-};*/
-
-#if 0
-/*
-#!/usr/bin/python
+#ifndef SERVER
 
-from math import *
-from sys import stdout
+// Length of LIGHT_MAX+1 means LIGHT_MAX is the last value.
+// LIGHT_SUN is read as LIGHT_MAX from here.
 
-# We want 0 at light=0 and 255 at light=LIGHT_MAX
-LIGHT_MAX = 14
-#FACTOR = 0.69
-FACTOR = 0.75
+u8 light_LUT[LIGHT_MAX+1];
 
-L = []
-for i in range(1,LIGHT_MAX+1):
-    L.append(int(round(255.0 * FACTOR ** (i-1))))
-L.append(0)
+// the const ref to light_LUT is what is actually used in the code.
+const u8 *light_decode_table = light_LUT;
 
-L.reverse()
-for i in L:
-    stdout.write(str(i)+",\n")
-*/
-u8 light_decode_table[LIGHT_MAX+1] = 
+/** Initialize or update the light value tables using the specified \p gamma.
+ */
+void set_light_table(float gamma)
 {
-0,
-6,
-8,
-11,
-14,
-19,
-26,
-34,
-45,
-61,
-81,
-108,
-143,
-191,
-255,
-};
+// 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++) {
+               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;
+       }
+       light_LUT[LIGHT_MAX] = 255;
+}
 #endif
 
-