以下是Shader但是无法实现文字渐变效果，求指点！
// Copyright © 2017-2018 Xiamen Yaji Software Co., Ltd.
CCEffect %{
techniques:
-
passes:
-
vert: label-vs:vert
frag: label-fs:frag
blendState:
targets:
- blend: true
rasterizerState:
cullMode: none
properties:
mainTexture: { value: white }
alphaThreshold: { value: 0.5 }
angle: {
value: 0.0, editor: { tooltip: "角度", range: [0.0, 360.0] }}
offset: {
value: 0.0, editor: { tooltip: "偏移" }}
uvRatio: {
value: 1.0, editor: { tooltip: "比例" }}
beginColor: {
value: [1, 1, 1, 1], editor: { type: color, tooltip: "初始颜色" }}
endColor: {
value: [1, 1, 1, 1], editor: { type: color, tooltip: "结束颜色" }}
-
}%
CCProgram label-vs %{
precision highp float;
#include <builtin/uniforms/cc-global>
#if USE_LOCAL
#include <builtin/uniforms/cc-local>
#endif
in vec3 a_position;
in vec4 a_color;
out vec4 v_color;
#if USE_TEXTURE
in vec2 a_uv0;
out vec2 v_uv0;
#endif
vec4 vert () {
vec4 pos = vec4(a_position, 1);
#if CC_USE_MODEL
pos = cc_matViewProj * cc_matWorld * pos;
#else
pos = cc_matViewProj * pos;
#endif
#if USE_TEXTURE
v_uv0 = a_uv0;
#endif
v_color = a_color;
return pos;
}
}%
CCProgram label-fs %{
precision highp float;
#include <builtin/internal/alpha-test>
#include <builtin/uniforms/cc-global>
in vec4 v_color;
#if USE_TEXTURE
in vec2 v_uv0;
uniform sampler2D mainTexture;
#endif
uniform Factor {
float angle;
float offset;
float uvRatio;
};
uniform Constant {
vec4 beginColor;
vec4 endColor;
};
vec4 frag () {
vec4 o = vec4(1, 1, 1, 1);
#if USE_TEXTURE
texture(mainTexture, v_uv0);
#endif
o *= v_color;
ALPHA_TEST(o);
float angleInRadians = radians(angle);
float ratio = clamp((v_uv0.y * cos(angleInRadians) + v_uv0.x * sin(angleInRadians) + offset) * uvRatio, 0.0, 1.0);
float beginRatio = 1.0 - ratio;
float endRatio = ratio;
o = vec4(
o.r * (beginColor.r * beginRatio + endColor.r * endRatio),
o.g * (beginColor.g * beginRatio + endColor.g * endRatio),
o.b * (beginColor.b * beginRatio + endColor.b * endRatio),
o.a * (beginColor.a * beginRatio + endColor.a * endRatio)
);
return o;
}
}%