123 lines
No EOL
3.9 KiB
GLSL
123 lines
No EOL
3.9 KiB
GLSL
// This shader is mostly an adaptation of the shader found at
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// http://www.bonzaisoftware.com/water_tut.html and its glsl conversion
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// available at http://forum.bonzaisoftware.com/viewthread.php?tid=10
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// © Michael Horsch - 2005
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// Major update and revisions - 2011-10-07
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// © Emilian Huminiuc and Vivian Meazza
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#version 120
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varying vec4 waterTex1;
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varying vec4 waterTex2;
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varying vec3 viewerdir;
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varying vec3 lightdir;
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varying vec3 normal;
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varying vec3 rawNormal;
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varying vec3 VTangent;
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varying vec3 VBinormal;
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varying vec3 WorldPos;
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varying vec2 TopoUV;
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uniform float WindE, WindN;
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uniform int rembrandt_enabled;
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uniform float osg_SimulationTime;
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uniform mat4 osg_ViewMatrixInverse;
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attribute vec3 tangent;
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attribute vec3 binormal;
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// constants for the cartezian to geodetic conversion.
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const float a = 6378137.0; //float a = equRad;
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const float squash = 0.9966471893352525192801545;
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const float latAdjust = 0.9999074159800018; //geotiff source for the depth map
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const float lonAdjust = 0.9999537058469516; //actual extents: +-180.008333333333326/+-90.008333333333340
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/////// functions /////////
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void rotationmatrix(in float angle, out mat4 rotmat)
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{
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rotmat = mat4( cos( angle ), -sin( angle ), 0.0, 0.0,
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sin( angle ), cos( angle ), 0.0, 0.0,
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0.0 , 0.0 , 1.0, 0.0,
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0.0 , 0.0 , 0.0, 1.0 );
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}
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void main(void)
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{
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mat4 RotationMatrix;
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rawNormal= gl_Normal;
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normal = gl_NormalMatrix * gl_Normal;
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VTangent = normalize(gl_NormalMatrix * tangent);
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VBinormal = normalize(gl_NormalMatrix * binormal);
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viewerdir = vec3(gl_ModelViewMatrixInverse[3]) - vec3(gl_Vertex);
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vec4 t1 = vec4(0.0, osg_SimulationTime * 0.005217, 0.0, 0.0);
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vec4 t2 = vec4(0.0, osg_SimulationTime * -0.0012, 0.0, 0.0);
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float Angle;
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float windFactor = sqrt(WindE * WindE + WindN * WindN) * 0.05;
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if (WindN == 0.0 && WindE == 0.0) {
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Angle = 0.0;
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}else{
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Angle = atan(-WindN, WindE) - atan(1.0);
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}
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rotationmatrix(Angle, RotationMatrix);
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waterTex1 = gl_MultiTexCoord0 * RotationMatrix - t1 * windFactor;
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rotationmatrix(Angle, RotationMatrix);
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waterTex2 = gl_MultiTexCoord0 * RotationMatrix - t2 * windFactor;
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WorldPos = (osg_ViewMatrixInverse *gl_ModelViewMatrix * gl_Vertex).xyz;
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///FIXME: convert cartezian coordinates to geodetic, this
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///FIXME: duplicates parts of code in SGGeodesy.cxx
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////////////////////////////////////////////////////////////////////////////
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float e2 = abs(1.0 - squash * squash);
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float ra2 = 1.0/(a * a);
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float e4 = e2 * e2;
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float XXpYY = WorldPos.x * WorldPos.x + WorldPos.y * WorldPos.y;
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float Z = WorldPos.z;
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float sqrtXXpYY = sqrt(XXpYY);
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float p = XXpYY * ra2;
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float q = Z*Z*(1.0-e2)*ra2;
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float r = 1.0/6.0*(p + q - e4);
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float s = e4 * p * q/(4.0*r*r*r);
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if ( s >= 2.0 && s <= 0.0)
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s = 0.0;
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float t = pow(1.0+s+sqrt(s*2.0+s*s), 1.0/3.0);
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float u = r + r*t + r/t;
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float v = sqrt(u*u + e4*q);
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float w = (e2*u+ e2*v-e2*q)/(2.0*v);
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float k = sqrt(u+v+w*w)-w;
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float D = k*sqrtXXpYY/(k+e2);
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vec2 NormPosXY = normalize(WorldPos.xy);
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vec2 NormPosXZ = normalize(vec2(D, WorldPos.z));
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float signS = sign(WorldPos.y);
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if (-0.00015 <= WorldPos.y && WorldPos.y<=.00015)
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signS = 1.0;
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float signT = sign(WorldPos.z);
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if (-0.0002 <= WorldPos.z && WorldPos.z<=.0002)
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signT = 1.0;
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float cosLon = dot(NormPosXY, vec2(1.0,0.0));
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float cosLat = dot(abs(NormPosXZ), vec2(1.0,0.0));
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TopoUV.s = signS * lonAdjust * degrees(acos(cosLon))/180.;
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TopoUV.t = signT * latAdjust * degrees(acos(cosLat))/90.;
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TopoUV.s = TopoUV.s * 0.5 + 0.5;
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TopoUV.t = TopoUV.t * 0.5 + 0.5;
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//FIXME end/////////////////////////////////////////////////////////////////
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gl_Position = ftransform();
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} |