bgfx/examples/common/font/fs_font_distance_field.sc

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2013-04-23 00:42:11 +04:00
$input v_color0, v_texcoord0
#include "../../common/common.sh"
SAMPLERCUBE(u_texColor, 0);
uniform float u_inverse_gamma;
void main()
{
vec4 color = textureCube(u_texColor, v_texcoord0.xyz);
int index = int(v_texcoord0.w*4.0 + 0.5);
float distance = color.bgra[index];
float dx = length(dFdx(v_texcoord0.xyz));
float dy = length(dFdy(v_texcoord0.xyz));
float w = 16.0*0.5*(dx+dy);
// alternatives that seems to give identical results
//float w = 16.0*max(dx,dy);
//float w = 16.0*length(vec2(dx,dy))/sqrt(2.0);
//float w = 16.0*length(fwidth(v_texcoord0.xyz))/sqrt(2.0);
float a = smoothstep(0.5-w, 0.5+w, distance);
//a = pow(a, u_inverse_gamma); //I'll deal with gamma later
gl_FragColor = vec4(v_color0.rgb, v_color0.a*a);
}