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Light curve: Add and tune mid boost gaussian

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Create a closer match to the light curve of 0.4.16 stable.
Results in darker shadows while maintaining the 'brightness' and light
spread.
This commit is contained in:
paramat 2017-11-18 00:22:15 +00:00 committed by paramat
parent 76eb3f2b7a
commit 03c11a73d8
3 changed files with 34 additions and 17 deletions
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14
builtin/settingtypes.txt
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@ -574,9 +574,21 @@ zoom_fov (Field of view for zoom) int 15 7 160
# This setting is for the client only and is ignored by the server.
display_gamma (Gamma) float 1.0 0.5 3.0
# Gradient of light curve at minimum light level.
lighting_alpha (Darkness sharpness) float 0.0 0.0 4.0
lighting_beta (Lightness sharpness) float 0.0 0.0 4.0
# Gradient of light curve at maximum light level.
lighting_beta (Lightness sharpness) float 1.5 0.0 4.0
# Strength of light curve mid-boost.
lighting_boost (Light curve mid boost) float 0.2 0.0 1.0
# Center of light curve mid-boost.
lighting_boost_center (Light curve mid boost center) float 0.5 0.0 1.0
# Spread of light curve mid-boost.
# Standard deviation of the mid-boost gaussian.
lighting_boost_spread (Light curve mid boost spread) float 0.2 0.0 1.0
# Path to texture directory. All textures are first searched from here.
texture_path (Texture path) path

5
src/defaultsettings.cpp
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@ -163,8 +163,11 @@ void set_default_settings(Settings *settings)
settings->setDefault("connected_glass", "false");
settings->setDefault("smooth_lighting", "true");
settings->setDefault("lighting_alpha", "0.0");
settings->setDefault("lighting_beta", "0.0");
settings->setDefault("lighting_beta", "1.5");
settings->setDefault("display_gamma", "1.0");
settings->setDefault("lighting_boost", "0.2");
settings->setDefault("lighting_boost_center", "0.5");
settings->setDefault("lighting_boost_spread", "0.2");
settings->setDefault("texture_path", "");
settings->setDefault("shader_path", "");
settings->setDefault("video_driver", "opengl");

32
src/light.cpp
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@ -24,38 +24,40 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#ifndef SERVER
// Length of LIGHT_MAX+1 means LIGHT_MAX is the last value.
// 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];
u8 light_LUT[LIGHT_MAX+1];
// the const ref to light_LUT is what is actually used in the code.
// 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.
*/
// Initialize or update the light value tables using the specified gamma
void set_light_table(float gamma)
{
// lighting curve derivatives
// 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;
// Lighting curve coefficients
const float a = alpha + beta - 2.0f;
const float b = 3.0f - 2.0f * alpha - beta;
const float c = alpha;
// gamma correction
gamma = rangelim(gamma, 0.5, 3.0);
// 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_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);
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;
}
#endif