1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
|
/**
* @file WLSkyV.glsl
*
* Copyright (c) 2005-$CurrentYear$, Linden Research, Inc.
* $License$
*/
// SKY ////////////////////////////////////////////////////////////////////////
// The vertex shader for creating the atmospheric sky
///////////////////////////////////////////////////////////////////////////////
// Output parameters
varying vec4 vary_HazeColor;
// Inputs
uniform vec3 camPosLocal;
uniform vec4 lightnorm;
uniform vec4 sunlight_color;
uniform vec4 ambient;
uniform vec4 blue_horizon;
uniform vec4 blue_density;
uniform vec4 haze_horizon;
uniform vec4 haze_density;
uniform vec4 cloud_shadow;
uniform vec4 density_multiplier;
uniform vec4 max_y;
uniform vec4 glow;
uniform vec4 cloud_color;
uniform vec4 cloud_scale;
void main()
{
// World / view / projection
gl_Position = ftransform();
gl_TexCoord[0] = gl_MultiTexCoord0;
// Get relative position
vec3 P = gl_Vertex.xyz - camPosLocal.xyz + vec3(0,50,0);
//vec3 P = gl_Vertex.xyz + vec3(0,50,0);
// Set altitude
if (P.y > 0.)
{
P *= (max_y.x / P.y);
}
else
{
P *= (-32000. / P.y);
}
// Can normalize then
vec3 Pn = normalize(P);
float Plen = length(P);
// Initialize temp variables
vec4 temp1 = vec4(0.);
vec4 temp2 = vec4(0.);
vec4 blue_weight;
vec4 haze_weight;
vec4 sunlight = sunlight_color;
vec4 light_atten;
// Sunlight attenuation effect (hue and brightness) due to atmosphere
// this is used later for sunlight modulation at various altitudes
light_atten = (blue_density * 1.0 + haze_density.x * 0.25) * (density_multiplier.x * max_y.x);
// Calculate relative weights
temp1 = blue_density + haze_density.x;
blue_weight = blue_density / temp1;
haze_weight = haze_density.x / temp1;
// Compute sunlight from P & lightnorm (for long rays like sky)
temp2.y = max(0., max(0., Pn.y) * 1.0 + lightnorm.y );
temp2.y = 1. / temp2.y;
sunlight *= exp( - light_atten * temp2.y);
// Distance
temp2.z = Plen * density_multiplier.x;
// Transparency (-> temp1)
// ATI Bugfix -- can't store temp1*temp2.z in a variable because the ati
// compiler gets confused.
temp1 = exp(-temp1 * temp2.z);
// Compute haze glow
temp2.x = dot(Pn, lightnorm.xyz);
temp2.x = 1. - temp2.x;
// temp2.x is 0 at the sun and increases away from sun
temp2.x = max(temp2.x, .001);
// Set a minimum "angle" (smaller glow.y allows tighter, brighter hotspot)
temp2.x *= glow.x;
// Higher glow.x gives dimmer glow (because next step is 1 / "angle")
temp2.x = pow(temp2.x, glow.z);
// glow.z should be negative, so we're doing a sort of (1 / "angle") function
// Add "minimum anti-solar illumination"
temp2.x += .25;
// Haze color above cloud
vary_HazeColor = ( blue_horizon * blue_weight * (sunlight + ambient)
+ (haze_horizon.r * haze_weight) * (sunlight * temp2.x + ambient)
);
// Increase ambient when there are more clouds
vec4 tmpAmbient = ambient;
tmpAmbient += (1. - tmpAmbient) * cloud_shadow.x * 0.5;
// Dim sunlight by cloud shadow percentage
sunlight *= (1. - cloud_shadow.x);
// Haze color below cloud
vec4 additiveColorBelowCloud = ( blue_horizon * blue_weight * (sunlight + tmpAmbient)
+ (haze_horizon.r * haze_weight) * (sunlight * temp2.x + tmpAmbient)
);
// Final atmosphere additive
vary_HazeColor *= (1. - temp1);
// Attenuate cloud color by atmosphere
temp1 = sqrt(temp1); //less atmos opacity (more transparency) below clouds
// At horizon, blend high altitude sky color towards the darker color below the clouds
vary_HazeColor += (additiveColorBelowCloud - vary_HazeColor) * (1. - sqrt(temp1));
// won't compile on mac without this being set
//vary_AtmosAttenuation = vec3(0.0,0.0,0.0);
}
|