/*****************************************************************************
The Dark Mod GPL Source Code

This file is part of the The Dark Mod Source Code, originally based
on the Doom 3 GPL Source Code as published in 2011.

The Dark Mod Source Code is free software: you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation, either version 3 of the License,
or (at your option) any later version. For details, see LICENSE.TXT.

Project: The Dark Mod (http://www.thedarkmod.com/)

******************************************************************************/
#version 140
// !!ARBvp1.0 OPTION ARB_position_invariant ;

#pragma tdm_include "tdm_transform.glsl"

in vec4 attr_Position;
in vec4 attr_TexCoord;
out vec4 var_color;
out vec4 var_tc1;
out vec4 var_tc2;
uniform vec4 u_localParam0;
uniform vec4 u_localParam1;
uniform vec4 u_localParam2;

void main() {
	
	// SteveL #3879: Do not distort where the sampled texel would come from a surface closer than
	// the water surface. Fix for water distorting player weapon etc. Amendments to frag prog.
	// SteveL #4306: Output the "depth" of water between the player and the background into the alpha
	// channel, so that subsequent material stages can use it to blend correctly between their own colour and 
	// the background color, giving the impression of murky water containing sediment. 
	//
	//
	// input:
	// 
	// attrib[8] (former texcoord[0]) TEX0 texcoords
	//
	// local[0]	scroll
	// local[1]	deform magnitude (1.0 is reasonable, 2.0 is twice as wavy, 0.5 is half as wavy, etc)
	// local[2]  depth of this material needed to completely hide the background. #4306
	//
	// output:
	// 
	// texCoord[1] is the model surface texture coords
	// texCoord[2] is the copied deform magnitude
	// vertex color is used to pass the depth from local[2] to the fragment shader #4306
	
	vec4 R0, R1, R2;                                                                                    //TEMP	R0, R1, R2;
	
	// texture 1 takes the texture coordinates and adds a scroll
	var_tc1 = (attr_TexCoord) + (u_localParam0);                                                        //ADD		result.texcoord[1], vertex.attrib[8], program.local[0];
	
	// texture 2 takes the deform magnitude and scales it by the projection distance
	vec4 vec = vec4(1, 0, 0, 1);                                                                        //PARAM	vec = { 1, 0, 0, 1 };
	
	R0 = vec;                                                                                           //MOV		R0, vec;
	R0.z = dot(attr_Position, transpose(u_modelViewMatrix)[2]);                                         //DP4		R0.z, vertex.position, state.matrix.modelview.row[2];
	
	R1 = vec4(dot(R0, transpose(u_projectionMatrix)[0]));                                               //DP4		R1, R0, state.matrix.projection.row[0];
	R2 = vec4(dot(R0, transpose(u_projectionMatrix)[3]));                                               //DP4		R2, R0, state.matrix.projection.row[3];
	
	// don't let the recip get near zero for polygons that cross the view plane
	R2 = max(R2, vec4(1));                                                                              //MAX		R2, R2, 1;
	
	R2 = vec4(1.0 / R2.w);                                                                              //RCP		R2, R2.w;
	R1 = (R1) * (R2);                                                                                   //MUL		R1, R1, R2;
	
	// clamp the distance so the the deformations don't get too wacky near the view
	R1 = min(R1, vec4(0.02));                                                                           //MIN		R1, R1, 0.02;
	
	var_tc2 = (R1) * (u_localParam1);                                                                   //MUL		result.texcoord[2], R1, program.local[1];
	var_color = u_localParam2;                                                                          //MOV     result.color, program.local[2];
	gl_Position = tdm_transform(attr_Position);
}