/**
|
* @license
|
* Copyright (c) 2000-2005, Sean O'Neil (s_p_oneil@hotmail.com)
|
* All rights reserved.
|
*
|
* Redistribution and use in source and binary forms, with or without
|
* modification, are permitted provided that the following conditions
|
* are met:
|
*
|
* * Redistributions of source code must retain the above copyright notice,
|
* this list of conditions and the following disclaimer.
|
* * Redistributions in binary form must reproduce the above copyright notice,
|
* this list of conditions and the following disclaimer in the documentation
|
* and/or other materials provided with the distribution.
|
* * Neither the name of the project nor the names of its contributors may be
|
* used to endorse or promote products derived from this software without
|
* specific prior written permission.
|
*
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
|
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
*
|
* Modifications made by Analytical Graphics, Inc.
|
*/
|
|
// Code: http://sponeil.net/
|
// GPU Gems 2 Article: https://developer.nvidia.com/gpugems/GPUGems2/gpugems2_chapter16.html
|
|
#ifdef COLOR_CORRECT
|
uniform vec3 u_hsbShift; // Hue, saturation, brightness
|
#endif
|
|
uniform vec4 u_cameraAndRadiiAndDynamicAtmosphereColor; // Camera height, outer radius, inner radius, dynamic atmosphere color flag
|
|
const float g = -0.95;
|
const float g2 = g * g;
|
|
varying vec3 v_rayleighColor;
|
varying vec3 v_mieColor;
|
varying vec3 v_toCamera;
|
varying vec3 v_positionEC;
|
|
void main (void)
|
{
|
float lightEnum = u_cameraAndRadiiAndDynamicAtmosphereColor.w;
|
vec3 lightDirection =
|
czm_viewerPositionWC * float(lightEnum == 0.0) +
|
czm_lightDirectionWC * float(lightEnum == 1.0) +
|
czm_sunDirectionWC * float(lightEnum == 2.0);
|
lightDirection = normalize(lightDirection);
|
|
// Extra normalize added for Android
|
float cosAngle = dot(lightDirection, normalize(v_toCamera)) / length(v_toCamera);
|
float rayleighPhase = 0.75 * (1.0 + cosAngle * cosAngle);
|
float miePhase = 1.5 * ((1.0 - g2) / (2.0 + g2)) * (1.0 + cosAngle * cosAngle) / pow(1.0 + g2 - 2.0 * g * cosAngle, 1.5);
|
|
vec3 rgb = rayleighPhase * v_rayleighColor + miePhase * v_mieColor;
|
|
#ifndef HDR
|
const float exposure = 2.0;
|
rgb = vec3(1.0) - exp(-exposure * rgb);
|
#endif
|
|
#ifdef COLOR_CORRECT
|
// Convert rgb color to hsb
|
vec3 hsb = czm_RGBToHSB(rgb);
|
// Perform hsb shift
|
hsb.x += u_hsbShift.x; // hue
|
hsb.y = clamp(hsb.y + u_hsbShift.y, 0.0, 1.0); // saturation
|
hsb.z = hsb.z > czm_epsilon7 ? hsb.z + u_hsbShift.z : 0.0; // brightness
|
// Convert shifted hsb back to rgb
|
rgb = czm_HSBToRGB(hsb);
|
#endif
|
|
// Alter alpha based on how close the viewer is to the ground (1.0 = on ground, 0.0 = at edge of atmosphere)
|
float atmosphereAlpha = clamp((u_cameraAndRadiiAndDynamicAtmosphereColor.y - u_cameraAndRadiiAndDynamicAtmosphereColor.x) / (u_cameraAndRadiiAndDynamicAtmosphereColor.y - u_cameraAndRadiiAndDynamicAtmosphereColor.z), 0.0, 1.0);
|
|
// Alter alpha based on time of day (0.0 = night , 1.0 = day)
|
float nightAlpha = (lightEnum != 0.0) ? clamp(dot(normalize(czm_viewerPositionWC), lightDirection), 0.0, 1.0) : 1.0;
|
atmosphereAlpha *= pow(nightAlpha, 0.5);
|
|
gl_FragColor = vec4(rgb, mix(rgb.b, 1.0, atmosphereAlpha) * smoothstep(0.0, 1.0, czm_morphTime));
|
}
|
