// This shader is mostly an adaptation of the shader found at // http://www.bonzaisoftware.com/water_tut.html and its glsl conversion // available at http://forum.bonzaisoftware.com/viewthread.php?tid=10 // © Michael Horsch - 2005 // Major update and revisions - 2011-10-07 // © Emilian Huminiuc and Vivian Meazza #version 120 varying vec4 waterTex1; varying vec4 waterTex2; varying vec4 waterTex4; //varying vec4 ecPosition; varying vec3 relPos; varying vec3 specular_light; varying vec3 viewerdir; varying vec3 lightdir; //varying vec3 normal; varying float earthShade; varying float yprime_alt; varying float mie_angle; uniform float osg_SimulationTime; uniform float WindE, WindN; uniform float hazeLayerAltitude; uniform float terminator; uniform float terrain_alt; uniform float avisibility; uniform float visibility; uniform float overcast; uniform float ground_scattering; // This is the value used in the skydome scattering shader - use the same here for consistency? const float EarthRadius = 5800000.0; const float terminator_width = 200000.0; float light_func (in float x, in float a, in float b, in float c, in float d, in float e) { //x = x - 0.5; // use the asymptotics to shorten computations if (x < -15.0) {return 0.0;} return e / pow((1.0 + a * exp(-b * (x-c)) ),(1.0/d)); } ////fog "include"//////// // uniform int fogType; // // void fog_Func(int type); ///////////////////////// /////// functions ///////// void rotationmatrix(in float angle, out mat4 rotmat) { rotmat = mat4( cos( angle ), -sin( angle ), 0.0, 0.0, sin( angle ), cos( angle ), 0.0, 0.0, 0.0 , 0.0 , 1.0, 0.0, 0.0 , 0.0 , 0.0, 1.0 ); } void main(void) { mat4 RotationMatrix; // vec3 N = normalize(gl_Normal); // normal = N; vec4 ecPosition = gl_ModelViewMatrix * gl_Vertex; viewerdir = vec3(gl_ModelViewMatrixInverse[3]) - vec3(gl_Vertex); lightdir = normalize(vec3(gl_ModelViewMatrixInverse * gl_LightSource[0].position)); waterTex4 = vec4( ecPosition.xzy, 0.0 ); vec4 t1 = vec4(0.0, osg_SimulationTime * 0.005217, 0.0, 0.0); vec4 t2 = vec4(0.0, osg_SimulationTime * -0.0012, 0.0, 0.0); float Angle; float windFactor = sqrt(WindE * WindE + WindN * WindN) * 0.05; if (WindN == 0.0 && WindE == 0.0) { Angle = 0.0; }else{ Angle = atan(-WindN, WindE) - atan(1.0); } rotationmatrix(Angle, RotationMatrix); waterTex1 = gl_MultiTexCoord0 * RotationMatrix - t1 * windFactor; rotationmatrix(Angle, RotationMatrix); waterTex2 = gl_MultiTexCoord0 * RotationMatrix - t2 * windFactor; // fog_Func(fogType); gl_Position = ftransform(); // here start computations for the haze layer float yprime; float lightArg; float intensity; float vertex_alt; float scattering; // we need several geometrical quantities // first current altitude of eye position in model space vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0); // and relative position to vector relPos = gl_Vertex.xyz - ep.xyz; // unfortunately, we need the distance in the vertex shader, although the more accurate version // is later computed in the fragment shader again float dist = length(relPos); // altitude of the vertex in question, somehow zero leads to artefacts, so ensure it is at least 100m vertex_alt = max(gl_Vertex.z,100.0); scattering = 0.5 + 0.5 * ground_scattering + 0.5* (1.0 - ground_scattering) * smoothstep(hazeLayerAltitude -100.0, hazeLayerAltitude + 100.0, vertex_alt); // branch dependent on daytime if (terminator < 1000000.0) // the full, sunrise and sunset computation { // establish coordinates relative to sun position //vec3 lightFull = (gl_ModelViewMatrixInverse * gl_LightSource[0].position).xyz; //vec3 lightHorizon = normalize(vec3(lightFull.x,lightFull.y, 0.0)); vec3 lightHorizon = normalize(vec3(lightdir.x,lightdir.y, 0.0)); // yprime is the distance of the vertex into sun direction yprime = -dot(relPos, lightHorizon); // this gets an altitude correction, higher terrain gets to see the sun earlier yprime_alt = yprime - sqrt(2.0 * EarthRadius * vertex_alt); // two times terminator width governs how quickly light fades into shadow // now the light-dimming factor earthShade = 0.6 * (1.0 - smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt)) + 0.4; // parametrized version of the Flightgear ground lighting function lightArg = (terminator-yprime_alt)/100000.0; specular_light.b = light_func(lightArg, 1.330e-05, 0.264, 3.827, 1.08e-05, 1.0); specular_light.g = light_func(lightArg, 3.931e-06, 0.264, 3.827, 7.93e-06, 1.0); specular_light.r = light_func(lightArg, 8.305e-06, 0.161, 3.827, 3.04e-05, 1.0); specular_light = specular_light * scattering; // correct ambient light intensity and hue before sunrise if (earthShade < 0.5) { intensity = length(specular_light.rgb); specular_light.xyz = intensity * normalize(mix(specular_light.xyz, vec3 (0.45, 0.6, 0.8), 1.0 -smoothstep(0.1, 0.7,earthShade) )); } // directional scattering for low sun if (lightArg < 10.0) //{mie_angle = (0.5 * dot(normalize(relPos), normalize(lightFull)) ) + 0.5;} {mie_angle = (0.5 * dot(normalize(relPos), lightdir) ) + 0.5;} else {mie_angle = 1.0;} // the haze gets the light at the altitude of the haze top if the vertex in view is below // but the light at the vertex if the vertex is above vertex_alt = max(vertex_alt,hazeLayerAltitude); if (vertex_alt > hazeLayerAltitude) { if (dist > 0.8 * avisibility) { vertex_alt = mix(vertex_alt, hazeLayerAltitude, smoothstep(0.8*avisibility, avisibility, dist)); yprime_alt = yprime -sqrt(2.0 * EarthRadius * vertex_alt); } } else { vertex_alt = hazeLayerAltitude; yprime_alt = yprime -sqrt(2.0 * EarthRadius * vertex_alt); } } else // the faster, full-day version without lightfields { //vertex_alt = max(gl_Vertex.z,100.0); earthShade = 1.0; mie_angle = 1.0; if (terminator > 3000000.0) {specular_light = vec3 (1.0, 1.0, 1.0);} else { lightArg = (terminator/100000.0 - 10.0)/20.0; specular_light.b = 0.78 + lightArg * 0.21; specular_light.g = 0.907 + lightArg * 0.091; specular_light.r = 0.904 + lightArg * 0.092; } specular_light = specular_light * scattering; yprime_alt = -sqrt(2.0 * EarthRadius * hazeLayerAltitude); } }