bgfx/examples/common/font/fs_font_distance_field.sc

$input v_color0, v_texcoord0

#include "../../common/common.sh"

SAMPLERCUBE(u_texColor, 0);

void main()
{	
	vec4 color = textureCube(u_texColor, v_texcoord0.xyz);
	int index = int(v_texcoord0.w*4.0 + 0.5);
	float rgba[4];
	rgba[0] = color.z;
	rgba[1] = color.y;
	rgba[2] = color.x;
	rgba[3] = color.w;
	float dist = rgba[index];

	float dx = length(dFdx(v_texcoord0.xyz) );
	float dy = length(dFdy(v_texcoord0.xyz) );
	float w = 16.0*0.5*(dx+dy);

	float alpha = smoothstep(0.5-w, 0.5+w, dist);
	gl_FragColor = vec4(v_color0.xyz, v_color0.w*alpha);
}