mirror of
https://github.com/MaSzyna-EU07/maszyna.git
synced 2026-03-22 15:05:03 +01:00
358 lines
14 KiB
C++
358 lines
14 KiB
C++
#include "stdafx.h"
|
|
#include "skydome.h"
|
|
#include "color.h"
|
|
#include "utilities.h"
|
|
|
|
// sky gradient based on "A practical analytic model for daylight"
|
|
// by A. J. Preetham Peter Shirley Brian Smits (University of Utah)
|
|
|
|
float CSkyDome::m_distributionluminance[ 5 ][ 2 ] = { // Perez distributions
|
|
{ 0.17872f , -1.46303f }, // a = darkening or brightening of the horizon
|
|
{ -0.35540f , 0.42749f }, // b = luminance gradient near the horizon,
|
|
{ -0.02266f , 5.32505f }, // c = relative intensity of the circumsolar region
|
|
{ 0.12064f , -2.57705f }, // d = width of the circumsolar region
|
|
{ -0.06696f , 0.37027f } // e = relative backscattered light
|
|
};
|
|
float CSkyDome::m_distributionxcomp[ 5 ][ 2 ] = {
|
|
{ -0.01925f , -0.25922f },
|
|
{ -0.06651f , 0.00081f },
|
|
{ -0.00041f , 0.21247f },
|
|
{ -0.06409f , -0.89887f },
|
|
{ -0.00325f , 0.04517f }
|
|
};
|
|
float CSkyDome::m_distributionycomp[ 5 ][ 2 ] = {
|
|
{ -0.01669f , -0.26078f },
|
|
{ -0.09495f , 0.00921f },
|
|
{ -0.00792f , 0.21023f },
|
|
{ -0.04405f , -1.65369f },
|
|
{ -0.01092f , 0.05291f }
|
|
};
|
|
|
|
float CSkyDome::m_zenithxmatrix[ 3 ][ 4 ] = {
|
|
{ 0.00165f, -0.00375f, 0.00209f, 0.00000f },
|
|
{ -0.02903f, 0.06377f, -0.03202f, 0.00394f },
|
|
{ 0.11693f, -0.21196f, 0.06052f, 0.25886f }
|
|
};
|
|
float CSkyDome::m_zenithymatrix[ 3 ][ 4 ] = {
|
|
{ 0.00275f, -0.00610f, 0.00317f, 0.00000f },
|
|
{ -0.04214f, 0.08970f, -0.04153f, 0.00516f },
|
|
{ 0.15346f, -0.26756f, 0.06670f, 0.26688f }
|
|
};
|
|
|
|
//******************************************************************************//
|
|
|
|
CSkyDome::CSkyDome (int const Tesselation) :
|
|
m_tesselation( Tesselation ) {
|
|
|
|
// SetSunPosition( Math3D::vector3(75.0f, 0.0f, 0.0f) );
|
|
SetTurbidity( 3.0f );
|
|
SetExposure( true, 20.0f );
|
|
SetOvercastFactor( 0.05f );
|
|
SetGammaCorrection( 2.2f );
|
|
Generate();
|
|
}
|
|
|
|
CSkyDome::~CSkyDome() {
|
|
}
|
|
|
|
//******************************************************************************//
|
|
|
|
void CSkyDome::Generate() {
|
|
// radius of dome
|
|
float const radius = 1.0f;
|
|
float const offset = 0.1f * radius; // horizontal offset, a cheap way to prevent a gap between ground and horizon
|
|
|
|
// create geometry chunk
|
|
int const latitudes = m_tesselation / 2 / 2; // half-sphere only
|
|
int const longitudes = m_tesselation;
|
|
|
|
std::uint16_t index = 0;
|
|
|
|
for( int i = 0; i <= latitudes; ++i ) {
|
|
|
|
float const latitude = M_PI * ( -0.5f + (float)( i ) / latitudes / 2 ); // half-sphere only
|
|
float const z = std::sin( latitude );
|
|
float const zr = std::cos( latitude );
|
|
|
|
for( int j = 0; j <= longitudes; ++j ) {
|
|
|
|
float const longitude = 2.0 * M_PI * (float)( j ) / longitudes;
|
|
float const x = std::cos( longitude );
|
|
float const y = std::sin( longitude );
|
|
/*
|
|
m_vertices.emplace_back( float3( x * zr, y * zr - offset, z ) * radius );
|
|
// we aren't using normals, but the code is left here in case it's ever needed
|
|
// m_normals.emplace_back( float3( x * zr, -y * zr, -z ) );
|
|
*/
|
|
// cartesian to opengl swap: -x, -z, -y
|
|
m_vertices.emplace_back( glm::vec3( -x * zr, -z - offset, -y * zr ) * radius );
|
|
m_colours.emplace_back( glm::vec3( 0.75f, 0.75f, 0.75f ) ); // placeholder
|
|
|
|
if( (i == 0) || (j == 0) ) {
|
|
// initial edge of the dome, don't start indices yet
|
|
++index;
|
|
}
|
|
else {
|
|
// indices for two triangles, formed between current and previous latitude
|
|
m_indices.emplace_back( index - 1 - (longitudes + 1) );
|
|
m_indices.emplace_back( index - 1 );
|
|
m_indices.emplace_back( index );
|
|
m_indices.emplace_back( index );
|
|
m_indices.emplace_back( index - ( longitudes + 1 ) );
|
|
m_indices.emplace_back( index - 1 - ( longitudes + 1 ) );
|
|
++index;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CSkyDome::Update( glm::vec3 const &Sun ) {
|
|
|
|
if( true == SetSunPosition( Sun ) ) {
|
|
// build colors if there's a change in sun position
|
|
RebuildColors();
|
|
}
|
|
}
|
|
|
|
// render skydome to screen
|
|
void CSkyDome::Render() {
|
|
|
|
if (!m_shader)
|
|
{
|
|
gl::shader vert("vbocolor.vert");
|
|
gl::shader frag("color.frag");
|
|
m_shader = std::make_unique<gl::program>(std::vector<std::reference_wrapper<const gl::shader>>({vert, frag}));
|
|
}
|
|
|
|
if( m_vertexbuffer == -1 ) {
|
|
m_vao = std::make_unique<gl::vao>();
|
|
|
|
// build the buffers
|
|
::glGenBuffers( 1, &m_vertexbuffer );
|
|
::glBindBuffer( GL_ARRAY_BUFFER, m_vertexbuffer );
|
|
::glBufferData( GL_ARRAY_BUFFER, m_vertices.size() * sizeof( glm::vec3 ), m_vertices.data(), GL_STATIC_DRAW );
|
|
m_vao->setup_attrib(0, 3, GL_FLOAT, sizeof(glm::vec3), 0);
|
|
|
|
::glGenBuffers( 1, &m_coloursbuffer );
|
|
::glBindBuffer( GL_ARRAY_BUFFER, m_coloursbuffer );
|
|
::glBufferData( GL_ARRAY_BUFFER, m_colours.size() * sizeof( glm::vec3 ), m_colours.data(), GL_DYNAMIC_DRAW );
|
|
m_vao->setup_attrib(1, 3, GL_FLOAT, sizeof(glm::vec3), 0);
|
|
|
|
::glGenBuffers( 1, &m_indexbuffer );
|
|
::glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, m_indexbuffer );
|
|
::glBufferData( GL_ELEMENT_ARRAY_BUFFER, m_indices.size() * sizeof( unsigned short ), m_indices.data(), GL_STATIC_DRAW );
|
|
// NOTE: vertex and index source data is superfluous past this point, but, eh
|
|
|
|
m_vao->unbind();
|
|
}
|
|
|
|
m_shader->bind();
|
|
m_vao->bind();
|
|
|
|
glDrawElements( GL_TRIANGLES, static_cast<GLsizei>( m_indices.size() ), GL_UNSIGNED_SHORT, reinterpret_cast<void const*>( 0 ) );
|
|
}
|
|
|
|
bool CSkyDome::SetSunPosition( glm::vec3 const &Direction ) {
|
|
|
|
if( Direction == m_sundirection ) {
|
|
|
|
return false;
|
|
}
|
|
|
|
m_sundirection = Direction;
|
|
m_thetasun = std::acos( m_sundirection.y );
|
|
m_phisun = std::atan2( m_sundirection.z, m_sundirection.x );
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
void CSkyDome::SetTurbidity( float const Turbidity ) {
|
|
|
|
m_turbidity = clamp( Turbidity, 1.0f, 512.0f );
|
|
}
|
|
|
|
void CSkyDome::SetExposure( bool const Linearexposure, float const Expfactor ) {
|
|
|
|
m_linearexpcontrol = Linearexposure;
|
|
m_expfactor = 1.0f / clamp( Expfactor, 1.0f, std::numeric_limits<float>::infinity() );
|
|
}
|
|
|
|
void CSkyDome::SetGammaCorrection( float const Gamma ) {
|
|
|
|
m_gammacorrection = 1.0f / clamp( Gamma, std::numeric_limits<float>::epsilon(), std::numeric_limits<float>::infinity() );
|
|
}
|
|
|
|
void CSkyDome::SetOvercastFactor( float const Overcast ) {
|
|
|
|
m_overcast = clamp( Overcast, 0.0f, 1.0f ) * 0.75f; // going above 0.65 makes the model go pretty bad, appearance-wise
|
|
}
|
|
|
|
void CSkyDome::GetPerez( float *Perez, float Distribution[ 5 ][ 2 ], const float Turbidity ) {
|
|
|
|
Perez[ 0 ] = Distribution[ 0 ][ 0 ] * Turbidity + Distribution[ 0 ][ 1 ];
|
|
Perez[ 1 ] = Distribution[ 1 ][ 0 ] * Turbidity + Distribution[ 1 ][ 1 ];
|
|
Perez[ 2 ] = Distribution[ 2 ][ 0 ] * Turbidity + Distribution[ 2 ][ 1 ];
|
|
Perez[ 3 ] = Distribution[ 3 ][ 0 ] * Turbidity + Distribution[ 3 ][ 1 ];
|
|
Perez[ 4 ] = Distribution[ 4 ][ 0 ] * Turbidity + Distribution[ 4 ][ 1 ];
|
|
}
|
|
|
|
float CSkyDome::GetZenith( float Zenithmatrix[ 3 ][ 4 ], const float Theta, const float Turbidity ) {
|
|
|
|
const float theta2 = Theta*Theta;
|
|
const float theta3 = Theta*theta2;
|
|
|
|
return ( Zenithmatrix[0][0] * theta3 + Zenithmatrix[0][1] * theta2 + Zenithmatrix[0][2] * Theta + Zenithmatrix[0][3]) * Turbidity * Turbidity +
|
|
( Zenithmatrix[1][0] * theta3 + Zenithmatrix[1][1] * theta2 + Zenithmatrix[1][2] * Theta + Zenithmatrix[1][3]) * Turbidity +
|
|
( Zenithmatrix[2][0] * theta3 + Zenithmatrix[2][1] * theta2 + Zenithmatrix[2][2] * Theta + Zenithmatrix[2][3]);
|
|
|
|
}
|
|
|
|
float CSkyDome::PerezFunctionO1( float Perezcoeffs[ 5 ], const float Thetasun, const float Zenithval ) {
|
|
|
|
const float val = ( 1.0f + Perezcoeffs[ 0 ] * std::exp( Perezcoeffs[ 1 ] ) ) *
|
|
( 1.0f + Perezcoeffs[ 2 ] * std::exp( Perezcoeffs[ 3 ] * Thetasun ) + Perezcoeffs[ 4 ] * std::pow( std::cos( Thetasun ), 2 ) );
|
|
|
|
return Zenithval / val;
|
|
}
|
|
|
|
float CSkyDome::PerezFunctionO2( float Perezcoeffs[ 5 ], const float Icostheta, const float Gamma, const float Cosgamma2, const float Zenithval ) {
|
|
// iCosTheta = 1.0f / cosf(theta)
|
|
// cosGamma2 = SQR( cosf( gamma ) )
|
|
return Zenithval * ( 1.0f + Perezcoeffs[ 0 ] * std::exp( Perezcoeffs[ 1 ] * Icostheta ) ) *
|
|
( 1.0f + Perezcoeffs[ 2 ] * std::exp( Perezcoeffs[ 3 ] * Gamma ) + Perezcoeffs[ 4 ] * Cosgamma2 );
|
|
}
|
|
|
|
void CSkyDome::RebuildColors() {
|
|
|
|
// get zenith luminance
|
|
float const chi = ( (4.0f / 9.0f) - (m_turbidity / 120.0f) ) * ( M_PI - (2.0f * m_thetasun) );
|
|
float zenithluminance = ( (4.0453f * m_turbidity) - 4.9710f ) * std::tan( chi ) - (0.2155f * m_turbidity) + 2.4192f;
|
|
|
|
// get x / y zenith
|
|
float zenithx = GetZenith( m_zenithxmatrix, m_thetasun, m_turbidity );
|
|
float zenithy = GetZenith( m_zenithymatrix, m_thetasun, m_turbidity );
|
|
|
|
// get perez function parametrs
|
|
float perezluminance[5], perezx[5], perezy[5];
|
|
GetPerez( perezluminance, m_distributionluminance, m_turbidity );
|
|
GetPerez( perezx, m_distributionxcomp, m_turbidity );
|
|
GetPerez( perezy, m_distributionycomp, m_turbidity );
|
|
|
|
// make some precalculation
|
|
zenithx = PerezFunctionO1( perezx, m_thetasun, zenithx );
|
|
zenithy = PerezFunctionO1( perezy, m_thetasun, zenithy );
|
|
zenithluminance = PerezFunctionO1( perezluminance, m_thetasun, zenithluminance );
|
|
|
|
// start with fresh average for the new pass
|
|
glm::vec3 averagecolor, averagehorizoncolor;
|
|
|
|
// trough all vertices
|
|
glm::vec3 vertex;
|
|
glm::vec3 color, colorconverter, shiftedcolor;
|
|
|
|
for ( unsigned int i = 0; i < m_vertices.size(); ++i ) {
|
|
// grab it
|
|
vertex = glm::normalize( m_vertices[ i ] );
|
|
|
|
// angle between sun and vertex
|
|
const float gamma = std::acos( glm::dot( vertex, m_sundirection ) );
|
|
|
|
// warning : major hack!!! .. i had to do something with values under horizon
|
|
//vertex.y = Clamp<float>( vertex.y, 0.05f, 1.0f );
|
|
if ( vertex.y < 0.05f ) vertex.y = 0.05f;
|
|
|
|
// from paper:
|
|
// const float theta = arccos( vertex.y );
|
|
// const float iCosTheta = 1.0f / cosf( theta );
|
|
// optimized:
|
|
// iCosTheta =
|
|
// = 1.0f / cosf( arccos( vertex.y ) );
|
|
// = 1.0f / vertex.y;
|
|
float const icostheta = 1.0f / vertex.y;
|
|
float const cosgamma2 = std::pow( std::cos( gamma ), 2 );
|
|
|
|
// Compute x,y values
|
|
float const x = PerezFunctionO2( perezx, icostheta, gamma, cosgamma2, zenithx );
|
|
float const y = PerezFunctionO2( perezy, icostheta, gamma, cosgamma2, zenithy );
|
|
|
|
// luminance(Y) for clear & overcast sky
|
|
float const yclear = std::max( 0.01f, PerezFunctionO2( perezluminance, icostheta, gamma, cosgamma2, zenithluminance ) );
|
|
float const yover = std::max( 0.01f, zenithluminance * ( 1.0f + 2.0f * vertex.y ) / 3.0f );
|
|
|
|
float const Y = interpolate( yclear, yover, m_overcast );
|
|
float const X = (x / y) * Y;
|
|
float const Z = ((1.0f - x - y) / y) * Y;
|
|
|
|
colorconverter = glm::vec3( X, Y, Z );
|
|
color = colors::XYZtoRGB( colorconverter );
|
|
|
|
colorconverter = colors::RGBtoHSV(color);
|
|
if ( m_linearexpcontrol ) {
|
|
// linear scale
|
|
colorconverter.z *= m_expfactor;
|
|
} else {
|
|
// exp scale
|
|
colorconverter.z = 1.0f - std::exp( -m_expfactor * colorconverter.z );
|
|
}
|
|
|
|
// desaturate sky colour, based on overcast level
|
|
if( colorconverter.y > 0.0f ) {
|
|
colorconverter.y *= ( 1.0f - m_overcast );
|
|
}
|
|
|
|
// override the hue, based on sun height above the horizon. crude way to deal with model shortcomings
|
|
// correction begins when the sun is higher than 10 degrees above the horizon, and fully in effect at 10+15 degrees
|
|
float const degreesabovehorizon = 90.0f - m_thetasun * ( 180.0f / M_PI );
|
|
auto const sunbasedphase = clamp( (1.0f / 15.0f) * ( degreesabovehorizon - 10.0f ), 0.0f, 1.0f );
|
|
// correction is applied in linear manner from the bottom, becomes fully in effect for vertices with y = 0.50
|
|
auto const heightbasedphase = clamp( vertex.y * 2.0f, 0.0f, 1.0f );
|
|
// this height-based factor is reduced the farther the sun is up in the sky
|
|
float const shiftfactor = clamp( interpolate(heightbasedphase, sunbasedphase, sunbasedphase), 0.0f, 1.0f );
|
|
// h = 210 makes for 'typical' sky tone
|
|
shiftedcolor = glm::vec3( 210.0f, colorconverter.y, colorconverter.z );
|
|
shiftedcolor = colors::HSVtoRGB( shiftedcolor );
|
|
|
|
color = colors::HSVtoRGB(colorconverter);
|
|
|
|
color = interpolate( color, shiftedcolor, shiftfactor );
|
|
/*
|
|
// gamma control
|
|
color.x = std::pow( color.x, m_gammacorrection );
|
|
color.x = std::pow( color.y, m_gammacorrection );
|
|
color.x = std::pow( color.z, m_gammacorrection );
|
|
*/
|
|
// crude correction for the times where the model breaks (late night)
|
|
// TODO: use proper night sky calculation for these times instead
|
|
if( ( color.x <= 0.05f )
|
|
&& ( color.y <= 0.05f ) ) {
|
|
// darken the sky as the sun goes deeper below the horizon
|
|
// 15:50:75 is picture-based night sky colour. it may not be accurate but looks 'right enough'
|
|
color.z = 0.75f * std::max( color.z + m_sundirection.y, 0.075f );
|
|
color.x = 0.20f * color.z;
|
|
color.y = 0.65f * color.z;
|
|
color = color * ( 1.15f - vertex.y ); // simple gradient, darkening towards the top
|
|
}
|
|
// save
|
|
m_colours[ i ] = color;
|
|
averagecolor += color;
|
|
if( ( m_vertices.size() - i ) <= ( m_tesselation * 2 ) ) {
|
|
// calculate horizon colour from the bottom band of tris
|
|
averagehorizoncolor += color;
|
|
}
|
|
}
|
|
// NOTE: average reduced to 25% makes nice tint value for clouds lit from behind
|
|
// down the road we could interpolate between it and full strength average, to improve accuracy of cloud appearance
|
|
m_averagecolour = glm::max( glm::vec3(), averagecolor / static_cast<float>( m_vertices.size() ) );
|
|
m_averagehorizoncolour = glm::max( glm::vec3(), averagehorizoncolor / static_cast<float>( m_tesselation * 2 ) );
|
|
|
|
if( m_coloursbuffer != -1 ) {
|
|
// the colour buffer was already initialized, so on this run we update its content
|
|
::glBindBuffer( GL_ARRAY_BUFFER, m_coloursbuffer );
|
|
::glBufferSubData( GL_ARRAY_BUFFER, 0, m_colours.size() * sizeof( glm::vec3 ), m_colours.data() );
|
|
}
|
|
|
|
}
|
|
|
|
//******************************************************************************//
|