!!cvarf r_waterwarp
!!samps 3

#include "sys/defs.h"

//this is a post processing shader that is drawn fullscreen whenever the view is underwater.
//its generally expected to warp the view a little.

layout(location=0) varying vec2 v_stc;
layout(location=1) varying vec2 v_warp;
layout(location=2) varying vec2 v_edge;

#ifdef VERTEX_SHADER
void main ()
{
	gl_Position = ftetransform();
	v_stc = vec2(v_texcoord.x, /*1.0-*/v_texcoord.y);
	v_warp.s = e_time * 0.25 + v_texcoord.s;
	v_warp.t = e_time * 0.25 + v_texcoord.t;
	v_edge = v_texcoord.xy;
}
#endif
#ifdef FRAGMENT_SHADER
//uniform sampler2D s_t0;/*$currentrender*/
//uniform sampler2D s_t1;/*warp image*/
//uniform sampler2D s_t2;/*edge image*/
//uniform vec4 e_rendertexturescale;
//uniform float cvar_r_waterwarp;
#define e_rendertexturescale vec4(1.0,1.0,0.0,0.0)
void main ()
{
	vec2 amp		= (0.010 / 0.625) * cvar_r_waterwarp * texture2D(s_t2, v_edge).rg;
	vec3 offset	= (texture2D(s_t1, v_warp).rgb - 0.5) * 2.0;
	vec2 temp		= v_stc + offset.xy * amp;
	gl_FragColor	= texture2D(s_t0, temp*e_rendertexturescale.st);
}
#endif
