/**

 * $Id$

 *

 * Assorted shader definitions (optionally) used by the PVR2 rendering

 * engine.

 * 

 * This file is preprocessed by genglsl to produce shaders.c and shaders.h.

 *

 * Copyright (c) 2007-2010 Nathan Keynes.

 *

 * This program 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 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

/**

 * Quick reference for predefined variables

 * Vertex shader input variables:

 *   vec4 gl_Color;

 *   vec4 gl_SecondaryColor;

 *   vec3 gl_Normal;

 *   vec4 gl_Vertex;

 *   vec4 gl_MultiTexCoord0;

 *   vec4 gl_MultiTexCoord1; 

 *   vec4 gl_MultiTexCoord2;

 *   vec4 gl_MultiTexCoord3; 

 *   vec4 gl_MultiTexCoord4;

 *   vec4 gl_MultiTexCoord5;

 *   vec4 gl_MultiTexCoord6;

 *   vec4 gl_MultiTexCoord7;

 *   float gl_FogCoord;

 *

 * Vertex shader output variables:

 *   vec4 gl_Position;    // must be written to

 *   float gl_PointSize;  // may be written to

 *   vec4 gl_ClipVertex;  // may be written to

 *   varying vec4 gl_FrontColor; 

 *   varying vec4 gl_BackColor; 

 *   varying vec4 gl_FrontSecondaryColor; 

 *   varying vec4 gl_BackSecondaryColor; 

 *   varying vec4 gl_TexCoord[]; // at most will be gl_MaxTextureCoords

 *   varying float gl_FogFragCoord;

 *

 * Fragment shader input variables:

 *   varying vec4 gl_Color; 

 *   varying vec4 gl_SecondaryColor; 

 *   varying vec4 gl_TexCoord[]; // at most will be gl_MaxTextureCoords

 *   varying float gl_FogFragCoord;

 *   varying vec2 gl_PointCoord;

 *

 * Fragme shader output variables:

 *   vec4 gl_FragCoord; 

 *   bool gl_FrontFacing; 

 *   vec4 gl_FragColor; 

 *   vec4 gl_FragData[gl_MaxDrawBuffers]; 

 *   float gl_FragDepth;

 */

#include "../config.h"

#vertex DEFAULT_VERTEX_SHADER

uniform mat4 view_matrix;

attribute vec4 in_vertex;

attribute vec4 in_colour;

attribute vec4 in_colour2; /* rgb = colour, a = fog */

attribute vec4 in_texcoord; /* uv = coord, z = palette, w = mode */

varying vec4 frag_colour;

varying vec4 frag_colour2;

varying vec4 frag_texcoord;

void main()

{

    vec4 tmp = view_matrix * in_vertex;

    float w = in_vertex.z;

    gl_Position  = tmp * w;

    frag_colour = in_colour;

    frag_colour2 = in_colour2;

    frag_texcoord = in_texcoord;

}

#fragment DEFAULT_FRAGMENT_SHADER

#ifdef HAVE_GLES2

precision mediump float;

#endif

uniform float alpha_ref;

uniform sampler2D primary_texture;

uniform sampler2D palette_texture;

uniform vec3 fog_colour1;

uniform vec3 fog_colour2;

varying vec4 frag_colour;

varying vec4 frag_colour2;

varying vec4 frag_texcoord;

void main()

{

	vec4 tex = texture2D( primary_texture, frag_texcoord.xy );

	if( frag_texcoord.z >= 0.0 ) {

	    tex = texture2D( palette_texture, vec2(frag_texcoord.z + (tex.a*0.249023), 0.5) );

	}

	/* HACK: unfortunately we have to maintain compatibility with GLSL 1.20,

	 * which only supports varying float. So since we're propagating texcoord

	 * anyway, overload the last component to indicate texture mode. 

	 */

        vec3 main_colour;

	if( frag_texcoord.w == 0.0 ) {

            main_colour = frag_colour.rgb * tex.rgb + frag_colour2.rgb;

	    gl_FragColor.a = frag_colour.a * tex.a;

	} else if( frag_texcoord.w >= 1.5 ) {

            main_colour = frag_colour.rgb;

	    gl_FragColor.a = frag_colour.a;

	} else {

	    main_colour =  mix(frag_colour.rgb,tex.rgb,tex.a) + frag_colour2.rgb;

	    gl_FragColor.a = frag_colour.a;

	}

        if( gl_FragColor.a < alpha_ref ) {

            discard;

        } else { 

   	    if( frag_colour2.a >= 0.0 ) {

                gl_FragColor.rgb = mix( main_colour, fog_colour1, frag_colour2.a );

            } else {

                gl_FragColor.rgb = mix( main_colour, fog_colour2, -frag_colour2.a );

            }

        } 

}

#program pvr2_shader = DEFAULT_VERTEX_SHADER DEFAULT_FRAGMENT_SHADER

#ifndef HAVE_OPENGL_FIXEDFUNC

/* In this case we also need a basic shader to actually display the output */

#vertex BASIC_VERTEX_SHADER

uniform mat4 view_matrix;

attribute vec2 in_vertex;

attribute vec4 in_colour;

attribute vec2 in_texcoord; /* uv = coord, z = palette, w = mode */

varying vec4 frag_colour;

varying vec2 frag_texcoord;

void main()

{

    gl_Position = view_matrix * vec4(in_vertex.x,in_vertex.y,0.0,1.0);

    frag_colour = in_colour;

    frag_texcoord = in_texcoord;

}

#fragment BASIC_FRAGMENT_SHADER

#ifdef HAVE_GLES2

precision mediump float;

#endif

uniform sampler2D primary_texture;

varying vec4 frag_colour;

varying vec2 frag_texcoord;

void main()

{

	vec4 tex = texture2D( primary_texture, frag_texcoord.xy );

        gl_FragColor.rgb = mix( frag_colour.rgb, tex.rgb, frag_colour.a );

}

#program basic_shader = BASIC_VERTEX_SHADER BASIC_FRAGMENT_SHADER

#endif