X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Flight.cpp;h=8196fedffcc820fa58d317f10b364dd2e29da27e;hb=c162340973463580cc5013d8b53ea87975637bf2;hp=08380a180e495d6edf284d3eb11ec4fdbbbedc76;hpb=3d29be24e089b1c267409f05b897ce3f03e99a07;p=oweals%2Fminetest.git

diff --git a/src/light.cpp b/src/light.cpp
index 08380a180..8196fedff 100644
--- a/src/light.cpp
+++ b/src/light.cpp
@@ -18,371 +18,73 @@ 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
 
-// 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.
- */
-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, 1.1, 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,
+struct LightingParams {
+	float a, b, c; // Lighting curve polynomial coefficients
+	float boost, center, sigma; // Lighting curve parametric boost
+	float gamma; // Lighting curve gamma correction
 };
-#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
+static LightingParams params;
 
-#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] = 
+float decode_light_f(float x)
 {
-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,
-};*/
+	if (x >= 1.0f) // x is often 1.0f
+		return 1.0f;
+	x = std::fmax(x, 0.0f);
+	float brightness = ((params.a * x + params.b) * x + params.c) * x;
+	brightness += params.boost *
+		std::exp(-0.5f * sqr((x - params.center) / params.sigma));
+	if (brightness <= 0.0f) // May happen if parameters are extreme
+		return 0.0f;
+	if (brightness >= 1.0f)
+		return 1.0f;
+	return powf(brightness, 1.0f / params.gamma);
+}
 
-// 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] = 
+// Initialize or update the light value tables using the specified gamma
+void set_light_table(float gamma)
 {
-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)
+// Lighting curve bounding gradients
+	const float alpha = rangelim(g_settings->getFloat("lighting_alpha"), 0.0f, 3.0f);
+	const float beta  = rangelim(g_settings->getFloat("lighting_beta"), 0.0f, 3.0f);
+// Lighting curve polynomial coefficients
+	params.a = alpha + beta - 2.0f;
+	params.b = 3.0f - 2.0f * alpha - beta;
+	params.c = alpha;
+// Lighting curve parametric boost
+	params.boost = rangelim(g_settings->getFloat("lighting_boost"), 0.0f, 0.4f);
+	params.center = rangelim(g_settings->getFloat("lighting_boost_center"), 0.0f, 1.0f);
+	params.sigma = rangelim(g_settings->getFloat("lighting_boost_spread"), 0.0f, 0.4f);
+// Lighting curve gamma correction
+	params.gamma = rangelim(gamma, 0.33f, 3.0f);
+
+// Boundary values should be fixed
+	light_LUT[0] = 0;
+	light_LUT[LIGHT_SUN] = 255;
+
+	for (size_t i = 1; i < LIGHT_SUN; i++) {
+		float brightness = decode_light_f((float)i / LIGHT_SUN);
+		// Strictly speaking, rangelim is not necessary here—if the implementation
+		// is conforming. But we don’t want problems in any case.
+		light_LUT[i] = rangelim((s32)(255.0f * brightness), 0, 255);
+		// Ensure light brightens with each level
+		if (i > 1 && light_LUT[i] <= light_LUT[i - 1])
+			light_LUT[i] = light_LUT[i - 1] + 1;
+	}
+}
 
-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
-
-