axmol/core/renderer/shaders/label_outline.frag

47 lines
1.4 KiB
GLSL

#version 310 es
precision highp float;
precision highp int;
layout(location = 0) in vec4 v_fragmentColor;
layout(location = 1) in vec2 v_texCoord;
layout(binding = 0) uniform sampler2D u_tex0;
layout(std140, binding = 0) uniform fs_ub {
vec4 u_effectColor;
vec4 u_textColor;
int u_effectType;
};
layout(location = 0) out vec4 FragColor;
void main()
{
vec4 texColor = texture(u_tex0, v_texCoord);
// fontAlpha == 1 means the area of solid text (without edge)
// fontAlpha == 0 means the area outside text, including outline area
// fontAlpha == (0, 1) means the edge of text
float fontAlpha = texColor.a;
// outlineAlpha == 1 means the area of 'solid text' and 'solid outline'
// outlineAlpha == 0 means the transparent area outside text and outline
// outlineAlpha == (0, 1) means the edge of outline
float outlineAlpha = texColor.r;
if (u_effectType == 0) // draw text
{
FragColor = v_fragmentColor * vec4(u_textColor.rgb, u_textColor.a * fontAlpha);
}
else if (u_effectType == 1) // draw outline
{
// multipy (1.0 - fontAlpha) to make the inner edge of outline smoother and make the text itself transparent.
FragColor = v_fragmentColor * vec4(u_effectColor.rgb, u_effectColor.a * outlineAlpha * (1.0 - fontAlpha));
}
else // draw shadow
{
FragColor = v_fragmentColor * vec4(u_effectColor.rgb, u_effectColor.a * outlineAlpha);
}
}