// oceanGLSL.vert
// vertex program for Ocean water simulation
// 05 Aug 2005
// adapted for Ogre by nfz
// converted from HLSL to GLSL
// original shader source from Render Monkey 1.6 Reflections Refractions.rfx

// 06 Aug 2005: moved uvw calculation from fragment program into vertex program 

uniform vec3 scale;
uniform vec3 eyePosition;
uniform vec2 waveSpeed;
uniform float noiseSpeed;
uniform float time_0_X;

varying vec3 uvw;
varying vec3 normal;
varying vec3 vVec;

void main(void)
{
   gl_Position = ftransform();
   
   // uvw is the calculated uvw coordinates based on vertex position
   // GLSL uses xy instead of xz for uv and z is depth so do some swizzling
   vec3 lookupPos = gl_Vertex.xzy * scale.xzy;
   lookupPos .x += waveSpeed.x * time_0_X;
   lookupPos .y += waveSpeed.y * time_0_X;
   lookupPos .z += lookupPos.y + noiseSpeed * time_0_X;
   uvw = lookupPos;
   
   //  the view vector needs to be in vertex space
   vVec = gl_Vertex.xyz - eyePosition;
   normal = gl_Normal;
}