axmol/cocos/renderer/ccShader_Label_df_glow.frag

27 lines
800 B
GLSL

const char* ccLabelDistanceFieldGlow_frag = STRINGIFY(
\n#ifdef GL_ES\n
precision lowp float;
\n#endif\n
varying vec4 v_fragmentColor;
varying vec2 v_texCoord;
uniform sampler2D CC_Texture0;
uniform vec4 v_effectColor;
uniform vec4 v_textColor;
void main()
{
float dist = texture2D(CC_Texture0, v_texCoord).a;
//todo:Implementation 'fwidth' for glsl 1.0 \n
//float width = fwidth(dist); \n
//assign width for constant will lead to a little bit fuzzy,it's temporary measure.\n
float width = 0.04;
float alpha = smoothstep(0.5-width, 0.5+width, dist);
//glow \n
float mu = smoothstep(0.5, 1.0, sqrt(dist));
vec4 color = v_effectColor*(1.0-alpha) + v_textColor*alpha;
gl_FragColor = v_fragmentColor * vec4(color.rgb, max(alpha,mu)*color.a);
}
);