//
// Simple passthrough vertex shader
//
attribute vec3 in_Position;                  // (x,y,z)
//attribute vec3 in_Normal;                  // (x,y,z)     unused in this shader.
attribute vec4 in_Colour;                    // (r,g,b,a)
attribute vec2 in_TextureCoord;              // (u,v)

varying vec2 v_vTexcoord;
varying vec4 v_vColour;

void main() {
    vec4 object_space_pos = vec4( in_Position.x, in_Position.y, in_Position.z, 1.0);
    gl_Position = gm_Matrices[MATRIX_WORLD_VIEW_PROJECTION] * object_space_pos;
    
    v_vColour = in_Colour;
    v_vTexcoord = in_TextureCoord;
}

//######################_==_YOYO_SHADER_MARKER_==_######################@~
//
// Simple passthrough fragment shader
//
varying vec2 v_vTexcoord;
varying vec4 v_vColour;

uniform vec2 dimension;
uniform int tile_type;

uniform int useMask;
uniform int preserveAlpha;
uniform sampler2D mask;
uniform sampler2D fore;
uniform float opacity;

float sampleMask() {
	if(useMask == 0) return 1.;
	vec4 m = texture2D( mask, v_vTexcoord );
	return (m.r + m.g + m.b) / 3. * m.a;
}

void main() {
	vec4 _col0 = texture2D( gm_BaseTexture, v_vTexcoord );
	vec2 _frtx = tile_type == 1? fract(v_vTexcoord * dimension) : v_vTexcoord;
	vec4 _col1 = texture2D( fore, _frtx );
	_col1.a   *= opacity * sampleMask();
	
	vec4 base  = _col0 * (1. - opacity);
	
	//////////////////////////////////////////////////////////////////////////////////////////////////////////////
	
		float lum   = dot(_col1.rgb, vec3(0.2126, 0.7152, 0.0722));
		vec4  blend = lum > .5? _col0 + (2. * (_col1 - .5)) : _col0 + (2. * _col1 - 1.);
	
	//////////////////////////////////////////////////////////////////////////////////////////////////////////////
	
	vec4  mx  = base + blend * opacity;
	float po  = preserveAlpha == 1? _col1.a : opacity;
	float al  = _col1.a + _col0.a * (1. - _col1.a);
	vec4  res = mix(_col0, mx, po);
	
	res.rgb /= al;
	res.a = preserveAlpha == 1? _col0.a : res.a;
	
    gl_FragColor = res;
}