/*
-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 <math.h>
+#include "util/numeric.h"
-// LIGHT_MAX is 14, 0-14 is 15 values
+#ifndef SERVER
+
+// Length of LIGHT_MAX+1 means LIGHT_MAX is the last value.
+// LIGHT_SUN is read as LIGHT_MAX from here.
+
+u8 light_LUT[LIGHT_MAX+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.
+ */
+ 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
+/*
+Made using this and:
+- adding 220 as the second last one
+- replacing the third last one (212) with 195
+
+#!/usr/bin/python
+
+from math import *
+from sys import stdout
+
+# We want 0 at light=0 and 255 at light=LIGHT_MAX
+LIGHT_MAX = 14
+#FACTOR = 0.69
+#FACTOR = 0.75
+FACTOR = 0.83
+START_FROM_ZERO = False
+
+L = []
+if START_FROM_ZERO:
+ for i in range(1,LIGHT_MAX+1):
+ L.append(int(round(255.0 * FACTOR ** (i-1))))
+ L.append(0)
+else:
+ for i in range(1,LIGHT_MAX+1):
+ L.append(int(round(255.0 * FACTOR ** (i-1))))
+ L.append(255)
+
+L.reverse()
+for i in L:
+ stdout.write(str(i)+",\n")
+*/
+u8 light_decode_table[LIGHT_MAX+1] =
+{
+23,
+27,
+33,
+40,
+48,
+57,
+69,
+83,
+100,
+121,
+146,
+176,
+195,
+220,
+255,
+};
+#endif
+
+#if 0
+// This is good
+// 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] =
+{
+8,
+11,
+14,
+18,
+22,
+29,
+37,
+47,
+60,
+76,
+97,
+123,
+157,
+200,
+255,
+};
+#endif
+
+#if 0
+// Use for debugging in dark
+u8 light_decode_table[LIGHT_MAX+1] =
+{
+58,
+64,
+72,
+80,
+88,
+98,
+109,
+121,
+135,
+150,
+167,
+185,
+206,
+229,
+255,
+};
+#endif
+
+// This is reasonable with classic lighting with a light source
/*u8 light_decode_table[LIGHT_MAX+1] =
{
-0,
+2,
+3,
+4,
+6,
9,
-12,
+13,
+18,
+25,
+32,
+35,
+45,
+57,
+69,
+79,
+255
+};*/
+
+
+// As in minecraft, a_n+1 = a_n * 0.8
+// NOTE: This doesn't really work that well because this defines
+// LIGHT_MAX as dimmer than LIGHT_SUN
+// NOTE: Uh, this has had 34 left out; forget this.
+/*u8 light_decode_table[LIGHT_MAX+1] =
+{
+8,
+11,
14,
-16,
-20,
+17,
+21,
+27,
+42,
+53,
+66,
+83,
+104,
+130,
+163,
+204,
+255,
+};*/
+
+// This was a quick try of more light, manually quickly made
+/*u8 light_decode_table[LIGHT_MAX+1] =
+{
+0,
+7,
+11,
+15,
+21,
+29,
+42,
+53,
+69,
+85,
+109,
+135,
+167,
+205,
+255,
+};*/
+
+// This was used for a long time, manually made
+/*u8 light_decode_table[LIGHT_MAX+1] =
+{
+0,
+6,
+8,
+11,
+14,
+19,
26,
34,
45,
191,
255,
};*/
-u8 light_decode_table[LIGHT_MAX+1] =
+
+/*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,
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
/*
projects / dragonfireclient.git / blobdiff