首页 > 代码库 > cocos2d-js Shader系列2：在cc.Sprite上使用Shader（黑白、灰度、造旧效果）
cocos2d-js Shader系列2：在cc.Sprite上使用Shader（黑白、灰度、造旧效果）
在Sprite中使用Shader做特殊的颜色处理比较简单，只需要把Shader程序绑定到Sprite上即可：
sprite.shaderProgram = alphaTestShader;
Cocos2d内置了一些Shader，详细可以看代码:
其中，CCShaderCache缓存了一些Shader实例，而GLProgram则对gl的api做了简单的封装让接口更友好。
需要注意的是，使用GLProgram编译shader程序时，cocos2d会自动加入了一些参数。
_compileShader: function (shader, type, source) { if (!source || !shader) return false; //var preStr = (type == this._glContext.VERTEX_SHADER) ? "precision highp float;\n" : "precision mediump float;\n"; source = "precision highp float; \n" + "uniform mat4 CC_PMatrix; \n" + "uniform mat4 CC_MVMatrix; \n" + "uniform mat4 CC_MVPMatrix; \n" + "uniform vec4 CC_Time; \n" + "uniform vec4 CC_SinTime; \n" + "uniform vec4 CC_CosTime; \n" + "uniform vec4 CC_Random01; \n" + "//CC INCLUDES END \n" + source; this._glContext.shaderSource(shader, source); this._glContext.compileShader(shader); var status = this._glContext.getShaderParameter(shader, this._glContext.COMPILE_STATUS); if (!status) { cc.log("cocos2d: ERROR: Failed to compile shader:\n" + this._glContext.getShaderSource(shader)); if (type == this._glContext.VERTEX_SHADER) cc.log("cocos2d: \n" + this.vertexShaderLog()); else cc.log("cocos2d: \n" + this.fragmentShaderLog()); } return ( status == 1 ); }
另外，绑定到sprite之后，cocos2d会自动设置一些值，我们只需要事先做个绑定即可，而这个绑定操作，也是有友好封装的。具体可以顺藤摸瓜看代码。
program.addAttribute(cc.ATTRIBUTE_NAME_POSITION, cc.VERTEX_ATTRIB_POSITION); program.addAttribute(cc.ATTRIBUTE_NAME_COLOR, cc.VERTEX_ATTRIB_COLOR); program.addAttribute(cc.ATTRIBUTE_NAME_TEX_COORD, cc.VERTEX_ATTRIB_TEX_COORDS);
在sprite上做效果，无非就是一些颜色变换或者说是滤镜而已。由于cocos没有原生的滤镜，不像flash那么方便，那么我们就要自己动手丰衣足食了。
下边实现两个灰度和造旧sepia的效果，类似Flash的ShaderFilter一样。
（绿色球就是原图，上下2个小球分别用不同的sepia参数得到的造旧效果）
var sugar4 = Sugar.create(0,0,2); sugar4.x = size.width/4; sugar4.y = size.height/1.5; this.addChild(sugar4); sugar4.scale = 3; var sugar = Sugar.create(0,0,2); sugar.x = size.width/2; sugar.y = size.height/2; this.addChild(sugar); sugar.scale = 3; var sugar2 = Sugar.create(0,0,2); sugar2.x = size.width/3; sugar2.y = size.height/3; this.addChild(sugar2); sugar2.scale = 2; var sugar3 = Sugar.create(0,0,2); sugar3.x = size.width/3*2; sugar3.y = size.height/3*2; this.addChild(sugar3); sugar3.scale = 2; Filter.grayScale(sugar); Filter.sepia(sugar2, 0.5); Filter.sepia(sugar3, 0.9);
Filter类的代码：
/** * Created by kenkozheng on 2014/11/4. */ /** * 只能用于控制Sprite的色调等，目标是实现类似Flash的内置基本滤镜 * 静态类 */ var Filter = { DEFAULT_VERTEX_SHADER: "attribute vec4 a_position; \n" + "attribute vec2 a_texCoord; \n" + "varying mediump vec2 v_texCoord; \n" + "void main() \n" + "{ \n" + " gl_Position = (CC_PMatrix * CC_MVMatrix) * a_position; \n" + " v_texCoord = a_texCoord; \n" + "}", GRAY_SCALE_FRAGMENT_SHADER: "varying vec2 v_texCoord; \n" + "uniform sampler2D CC_Texture0; \n" + "void main() \n" + "{ \n" + " vec4 texColor = texture2D(CC_Texture0, v_texCoord); \n" + " float gray = texColor.r * 0.299 + texColor.g * 0.587 + texColor.b * 0.114; \n" + " gl_FragColor = vec4(gray, gray, gray, texColor.a); \n" + "}", SEPIA_FRAGMENT_SHADER: "varying vec2 v_texCoord; \n" + "uniform sampler2D CC_Texture0; \n" + "uniform float u_degree; \n" + "void main() \n" + "{ \n" + " vec4 texColor = texture2D(CC_Texture0, v_texCoord); \n" + " float r = texColor.r * 0.393 + texColor.g * 0.769 + texColor.b * 0.189; \n" + " float g = texColor.r * 0.349 + texColor.g * 0.686 + texColor.b * 0.168; \n" + " float b = texColor.r * 0.272 + texColor.g * 0.534 + texColor.b * 0.131; \n" + " gl_FragColor = mix(texColor, vec4(r, g, b, texColor.a), u_degree); \n" + "}", programs:{}, /** * 灰度 * @param sprite */ grayScale: function (sprite) { var program = Filter.programs["grayScale"]; if(!program){ program = new cc.GLProgram(); program.initWithVertexShaderByteArray(Filter.DEFAULT_VERTEX_SHADER, Filter.GRAY_SCALE_FRAGMENT_SHADER); program.addAttribute(cc.ATTRIBUTE_NAME_POSITION, cc.VERTEX_ATTRIB_POSITION); //cocos会做初始化的工作 program.addAttribute(cc.ATTRIBUTE_NAME_TEX_COORD, cc.VERTEX_ATTRIB_TEX_COORDS); program.link(); program.updateUniforms(); Filter.programs["grayScale"] = program; } gl.useProgram(program.getProgram()); sprite.shaderProgram = program; }, /** * 造旧 * @param sprite * @param degree 旧的程度 0~1 */ sepia: function (sprite, degree) { var program = Filter.programs["sepia"+degree]; if(!program){ program = new cc.GLProgram(); program.initWithVertexShaderByteArray(Filter.DEFAULT_VERTEX_SHADER, Filter.SEPIA_FRAGMENT_SHADER); program.addAttribute(cc.ATTRIBUTE_NAME_POSITION, cc.VERTEX_ATTRIB_POSITION); //cocos会做初始化的工作 program.addAttribute(cc.ATTRIBUTE_NAME_TEX_COORD, cc.VERTEX_ATTRIB_TEX_COORDS); program.link(); program.updateUniforms(); var degreeLocation = program.getUniformLocationForName("u_degree"); program.setUniformLocationF32(degreeLocation, degree); Filter.programs["sepia"+degree] = program; } gl.useProgram(program.getProgram()); sprite.shaderProgram = program; } };
cocos2d-js Shader系列2：在cc.Sprite上使用Shader（黑白、灰度、造旧效果）
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