# -*- encoding: utf-8 -*-
##
## Copyright (C) 2012 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
##
## 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; version 3 only.
##
## 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.
##


from ..shader import Shader


class GameShader(Shader):
    def __init__(self):
        Shader.__init__(self, '''
            attribute vec3 in_position;
            attribute vec2 in_texcoord;
            attribute vec4 in_color;

            uniform mat4 mvp;

            varying vec2 texcoord;
            varying vec4 color;

            void main()
            {
                gl_Position = mvp * vec4(in_position, 1.0);
                texcoord = in_texcoord;
                color = in_color;
            }
        ''', '''
            varying vec2 texcoord;
            varying vec4 color;

            uniform sampler2D color_map;

            void main()
            {
                gl_FragColor = texture2D(color_map, texcoord) * color;
            }
        ''')


class BackgroundShader(Shader):
    def __init__(self):
        Shader.__init__(self, '''
            attribute vec3 in_position;
            attribute vec2 in_texcoord;
            attribute vec4 in_color;

            uniform mat4 mvp;

            varying vec2 texcoord;
            varying vec4 color;

            void main()
            {
                gl_Position = mvp * vec4(in_position, 1.0);
                texcoord = in_texcoord;
                color = in_color;
            }
        ''', '''
            varying vec2 texcoord;
            varying vec4 color;

            uniform sampler2D color_map;
            uniform float fog_scale;
            uniform float fog_end;
            uniform vec4 fog_color;

            void main()
            {
                vec4 temp_color = texture2D(color_map, texcoord) * color;
                float depth = gl_FragCoord.z / gl_FragCoord.w;
                float fog_density = clamp((fog_end - depth) * fog_scale, 0.0, 1.0);
                gl_FragColor = vec4(mix(fog_color, temp_color, fog_density).rgb, temp_color.a);
            }
        ''')


class PassthroughShader(Shader):
    def __init__(self):
        Shader.__init__(self, '''
            attribute vec2 in_position;
            attribute vec2 in_texcoord;

            uniform mat4 mvp;

            varying vec2 texcoord;

            void main()
            {
                gl_Position = mvp * vec4(in_position, 0.0, 1.0);
                texcoord = in_texcoord;
            }
        ''', '''
            varying vec2 texcoord;

            uniform sampler2D color_map;

            void main()
            {
                gl_FragColor = texture2D(color_map, texcoord);
            }
        ''')