1.x使用shader與2.x使用shader有所不同，2.x的使用例子很多，1.x少些，這裏列出使用流光shader例子。
1.創建頂點shader
代碼：
module.exports =
`
attribute vec4 a_position;
attribute vec2 a_texCoord;
attribute vec4 a_color;
varying vec2 v_texCoord;
varying vec4 v_fragmentColor;
void main()
{
gl_Position = CC_PMatrix * a_position;
v_fragmentColor = a_color;
v_texCoord = a_texCoord;
}
`
2.創建片段shader
代碼：
module.exports =
`
#ifdef GL_ES
precision mediump float;
#endif
varying vec2 v_texCoord;
uniform float sys_time;
void main()
{
vec4 src_color = texture2D(CC_Texture0, v_texCoord).rgba;
float width = 0.2;
float start = sys_time * 1.2;
float strength = 0.02;
float offset = 0.2;
if( v_texCoord.x < (start - offset * v_texCoord.y) && v_texCoord.x > (start - offset * v_texCoord.y - width))
{
vec3 improve = strength * vec3(255, 255, 255);
vec3 result = improve * vec3( src_color.r, src_color.g, src_color.b);
gl_FragColor = vec4(result, src_color.a);
} else {
gl_FragColor = src_color;
}
}
`
3.爲了方便使用，寫一個ShaderUtils，使用時只需要傳入修改shader的Sprite和shader的名字。
代碼：
// ShaderUtils.js
var ShaderUtils = {
shaderPrograms: {},
setShader: function(sprite, shaderName) {
var glProgram = this.shaderPrograms[shaderName];
if (!glProgram) {
glProgram = new cc.GLProgram();
var vert = require(cc.js.formatStr("%s.vert", shaderName));
var frag = require(cc.js.formatStr("%s.frag", shaderName));
glProgram.initWithString(vert, frag);
if (!cc.sys.isNative) {
glProgram.initWithVertexShaderByteArray(vert, frag);
glProgram.addAttribute(cc.macro.ATTRIBUTE_NAME_POSITION, cc.macro.VERTEX_ATTRIB_POSITION);
glProgram.addAttribute(cc.macro.ATTRIBUTE_NAME_COLOR, cc.macro.VERTEX_ATTRIB_COLOR);
glProgram.addAttribute(cc.macro.ATTRIBUTE_NAME_TEX_COORD, cc.macro.VERTEX_ATTRIB_TEX_COORDS);
}
glProgram.link();
glProgram.updateUniforms();
this.shaderPrograms[shaderName] = glProgram;
}
sprite._sgNode.setShaderProgram(glProgram);
return glProgram;
},
};
module.exports = ShaderUtils;
4.創建對象組件設置shader，控制效果
代碼：
var ShaderUtils = require("ShaderUtils");
cc.Class({
extends: cc.Component,
properties: {
sp: cc.Sprite,
},
onLoad : function(){
this._time = 0;
this._sin = 0;
this._program = ShaderUtils.setShader(this.sp, "Fluxay");
},
update (dt) {
this._time += 2 * dt;
this._program.use();
this._sin = Math.sin(this._time);
if(this._sin > 0.99){
this._sin = 0;
this._time = 0;
}
if(cc.sys.isNative){
var glProgram_state = cc.GLProgramState.getOrCreateWithGLProgram(this._program);
glProgram_state.setUniformFloat("sys_time", this._sin);
} else {
this._program.setUniformLocationWith1f(this._program.getUniformLocationForName("sys_time"), this._sin);
}
},
});
