bgfx/examples/common/font/fs_font_distance_field_subpixel.sc
2013-04-22 22:42:11 +02:00

41 lines
1.3 KiB
Python

$input v_color0, v_texcoord0
#include "../../common/common.sh"
SAMPLERCUBE(u_texColor, 0);
uniform float u_inverse_gamma;
void main()
{
int index = int(v_texcoord0.w*4.0 + 0.5);
vec3 dx3 = dFdx(v_texcoord0.xyz);
vec3 dy3 = dFdy(v_texcoord0.xyz);
vec3 decal = 0.166667 * dx3;
vec3 sampleLeft = v_texcoord0.xyz - decal;
vec3 sampleRight = v_texcoord0.xyz + decal;
float left_dist = textureCube(u_texColor, sampleLeft).bgra[index];
float right_dist = textureCube(u_texColor, sampleRight).bgra[index];
//vec3 centerUV = 0.5 * (sampleLeft + sampleRight);
//float dist = textureCube(u_texColor, centerUV).bgra[index];
float dist = 0.5 * (left_dist + right_dist);
float dx = length(dx3);
float dy = length(dy3);
float w = 16.0*0.5*(dx+dy);
vec3 sub_color = smoothstep(0.5 -w, 0.5 + w, vec3(left_dist, dist, right_dist));
gl_FragColor.rgb = sub_color*v_color0.a;
//gl_FragColor.rgb = pow(gl_FragColor.rgb, vec3(u_inverse_gamma,u_inverse_gamma,u_inverse_gamma));
gl_FragColor.a = dist*v_color0.a;
//AR,AG,AB are the intensities gotten from the subpixel rendering engine.
//BR,BG,BB are the old background pixels.
//DR,DG,DB are the new background pixels.
//DR = A*AR*R + (1-(A*AR))*BR
//DG = A*AG*G + (1-(A*AG))*BG
//DB = A*AB*B + (1-(A*AB))*BB
}