*/
#include "light.h"
-#include <math.h>
+#include <cmath>
#include "util/numeric.h"
+#include "settings.h"
#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,
-};
+static u8 light_LUT[LIGHT_SUN + 1];
+// The const ref to light_LUT is what is actually used in the code
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.
- */
+// Initialize or update the light value tables using the specified gamma
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;
+// 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 - 2.0f;
+ const float b = 3.0f - 2.0f * alpha - beta;
+ const float c = alpha;
+// Mid boost
+ const float d = g_settings->getFloat("lighting_boost");
+ const float e = g_settings->getFloat("lighting_boost_center");
+ const float f = g_settings->getFloat("lighting_boost_spread");
+// Gamma correction
+ gamma = rangelim(gamma, 0.5f, 3.0f);
+
+ for (size_t i = 0; i < LIGHT_SUN; i++) {
+ float x = i;
+ x /= LIGHT_SUN;
+ float brightness = a * x * x * x + b * x * x + c * x;
+ float boost = d * std::exp(-((x - e) * (x - e)) / (2.0f * f * f));
+ brightness = powf(brightness + boost, 1.0f / gamma);
+ light_LUT[i] = rangelim((u32)(255.0f * 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;
+ light_LUT[LIGHT_SUN] = 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] =
-{
-2,
-3,
-4,
-6,
-9,
-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,
-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,
-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
-
-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
-
-L = []
-for i in range(1,LIGHT_MAX+1):
- L.append(int(round(255.0 * FACTOR ** (i-1))))
-L.append(0)
-
-L.reverse()
-for i in L:
- stdout.write(str(i)+",\n")
-*/
-u8 light_decode_table[LIGHT_MAX+1] =
-{
-0,
-6,
-8,
-11,
-14,
-19,
-26,
-34,
-45,
-61,
-81,
-108,
-143,
-191,
-255,
-};
-#endif
-
-
projects / oweals / minetest.git / blobdiff