blob: b61b0bb3966db2dd191aec85c47f54254327f2b1 (
plain)
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
139
|
/**
* @file atmosphericsV.glsl
*
* $LicenseInfo:firstyear=2005&license=viewerlgpl$
* $/LicenseInfo$
*/
// varying param funcs
void setSunlitColor(vec3 v);
void setAmblitColor(vec3 v);
void setAdditiveColor(vec3 v);
void setAtmosAttenuation(vec3 v);
void setPositionEye(vec3 v);
vec3 getAdditiveColor();
//varying vec4 vary_CloudUVs;
//varying float vary_CloudDensity;
// Inputs
uniform vec4 morphFactor;
uniform vec3 camPosLocal;
//uniform vec4 camPosWorld;
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 distance_multiplier;
uniform vec4 max_y;
uniform vec4 glow;
void calcAtmospherics(vec3 inPositionEye) {
vec3 P = inPositionEye;
setPositionEye(P);
//(TERRAIN) limit altitude
if (P.y > max_y.x) P *= (max_y.x / P.y);
if (P.y < -max_y.x) P *= (-max_y.x / P.y);
vec3 tmpLightnorm = lightnorm.xyz;
vec3 Pn = normalize(P);
float Plen = length(P);
vec4 temp1 = vec4(0);
vec3 temp2 = vec3(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 + vec4(haze_density.r) * 0.25) * (density_multiplier.x * max_y.x);
//I had thought blue_density and haze_density should have equal weighting,
//but attenuation due to haze_density tends to seem too strong
temp1 = blue_density + vec4(haze_density.r);
blue_weight = blue_density / temp1;
haze_weight = vec4(haze_density.r) / temp1;
//(TERRAIN) compute sunlight from lightnorm only (for short rays like terrain)
temp2.y = max(0.0, tmpLightnorm.y);
temp2.y = 1. / temp2.y;
sunlight *= exp( - light_atten * temp2.y);
// main atmospheric scattering line integral
temp2.z = Plen * density_multiplier.x;
// Transparency (-> temp1)
// ATI Bugfix -- can't store temp1*temp2.z*distance_multiplier.x in a variable because the ati
// compiler gets confused.
temp1 = exp(-temp1 * temp2.z * distance_multiplier.x);
//final atmosphere attenuation factor
setAtmosAttenuation(temp1.rgb);
//vary_AtmosAttenuation = distance_multiplier / 10000.;
//vary_AtmosAttenuation = density_multiplier * 100.;
//vary_AtmosAttenuation = vec4(Plen / 100000., 0., 0., 1.);
//compute haze glow
//(can use temp2.x as temp because we haven't used it yet)
temp2.x = dot(Pn, tmpLightnorm.xyz);
temp2.x = 1. - temp2.x;
//temp2.x is 0 at the sun and increases away from sun
temp2.x = max(temp2.x, .03); //was glow.y
//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;
//increase ambient when there are more clouds
vec4 tmpAmbient = ambient + (vec4(1.) - ambient) * cloud_shadow.x * 0.5;
//haze color
setAdditiveColor(
vec3(blue_horizon * blue_weight * (sunlight*(1.-cloud_shadow.x) + tmpAmbient)
+ (haze_horizon.r * haze_weight) * (sunlight*(1.-cloud_shadow.x) * temp2.x
+ tmpAmbient)));
//brightness of surface both sunlight and ambient
setSunlitColor(vec3(sunlight * .5));
setAmblitColor(vec3(tmpAmbient * .25));
setAdditiveColor(getAdditiveColor() * vec3(1.0 - temp1));
// vary_SunlitColor = vec3(0);
// vary_AmblitColor = vec3(0);
// vary_AdditiveColor = vec4(Pn, 1.0);
/*
const float cloudShadowScale = 100.;
// Get cloud uvs for shadowing
vec3 cloudPos = inPositionEye + camPosWorld - cloudShadowScale / 2.;
vary_CloudUVs.xy = cloudPos.xz / cloudShadowScale;
// We can take uv1 and multiply it by (TerrainSpan / CloudSpan)
// cloudUVs *= (((worldMaxZ - worldMinZ) * 20) /40000.);
vary_CloudUVs *= (10000./40000.);
// Offset by sun vector * (CloudAltitude / CloudSpan)
vary_CloudUVs.x += tmpLightnorm.x / tmpLightnorm.y * (3000./40000.);
vary_CloudUVs.y += tmpLightnorm.z / tmpLightnorm.y * (3000./40000.);
*/
}
|
