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;

varying float v_distanceToCamera;
varying vec3 v_worldPosition;

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_worldPosition = (gm_Matrices[MATRIX_WORLD] * vec4(in_Position, 1.)).xyz;
	
    v_vColour = in_Colour;
    v_vTexcoord = in_TextureCoord;
	
	vec4 worldView = gm_Matrices[MATRIX_WORLD_VIEW] * object_space_pos;
	v_distanceToCamera = length(worldView.xyz);
}

//######################_==_YOYO_SHADER_MARKER_==_######################@~
#ifdef _YY_HLSL11_
	#extension GL_OES_standard_derivatives : enable
#endif

varying vec2 v_vTexcoord;
varying vec4 v_vColour;

varying float v_distanceToCamera;
varying vec3 v_worldPosition;

uniform float scale;
uniform vec2  shift;

uniform float axisBlend;

vec4 grid(vec2 pos, float scale) {
	#ifdef MACOS
		vec4 color = vec4(0.);
	#else
	    vec2 coord = pos * scale; // use the scale variable to set the distance between the lines
	    vec2 derivative = fwidth(coord);
	    vec2 grid  = abs(fract(coord - 0.5) - 0.5) / derivative;
	    float line = min(grid.x, grid.y);
	    float minimumy = min(derivative.y, 1.);
	    float minimumx = min(derivative.x, 1.);
	    vec4 color = vec4(.3, .3, .3, 1. - min(line, 1.));
	    // y axis
	    if(pos.x > -1. * minimumx / scale && pos.x < 1. * minimumx / scale)
	        color.y = 0.3 + axisBlend * 0.7;
	    // x axis
	    if(pos.y > -1. * minimumy / scale && pos.y < 1. * minimumy / scale)
	        color.x = 0.3 + axisBlend * 0.7;
	#endif
	
	
	
    return color;
}

void main() {
    gl_FragColor = grid( v_vTexcoord - 0.5 + shift, scale );
	gl_FragColor.a *= 1. - length(v_vTexcoord - 0.5) * 2.;
}