cocos2dx中使用自定义uniform变量

来源：互联网发布：林清轩芦荟胶知乎编辑：程序博客网时间：2024/04/28 00:24

cocos2dx引擎本身提供了一定数量的uniform

static const char * COCOS2D_SHADER_UNIFORMS =        "uniform mat4 CC_PMatrix;\n"        "uniform mat4 CC_MVMatrix;\n"        "uniform mat4 CC_MVPMatrix;\n"        "uniform mat3 CC_NormalMatrix;\n"        "uniform vec4 CC_Time;\n"        "uniform vec4 CC_SinTime;\n"        "uniform vec4 CC_CosTime;\n"        "uniform vec4 CC_Random01;\n"        "uniform sampler2D CC_Texture0;\n"        "uniform sampler2D CC_Texture1;\n"        "uniform sampler2D CC_Texture2;\n"        "uniform sampler2D CC_Texture3;\n"        "//CC INCLUDES END\n\n";

但并不能满足我们所有的需要，这时就需要使用自定义uniform
首先写好我们的shader，带上自定义uniform变量

const char* vert = R"(    attribute vec4 a_position;    attribute vec2 a_texCoord;    varying vec2 v_texCoord;    void main()    {        gl_Position = CC_PMatrix * a_position;        v_texCoord = a_texCoord;    })";const char* frag = R"(    varying vec2 v_texCoord;    // 自定义uniform变量    uniform float custom;    void main()    {        vec4 col = texture2D(CC_Texture0, v_texCoord);        gl_FragColor = col*custom;        gl_FragColor.a = col.a;    })";

下一步就需要在程序中设置这个uniform变量的值，我们可以每一帧对他进行一些改变，从而产生一些动画效果。

GLProgram* p = GLProgram::createWithByteArrays(vert, frag);GLProgramCache::getInstance()->addGLProgram(p, "custom");auto sprite = Sprite::create("HelloWorld.png");addChild(sprite);sprite->setPosition(visibleSize.width / 2, visibleSize.height / 2);auto shaderState = GLProgramState::getOrCreateWithGLProgramName("custom");//设置自定义uniform变量的值shaderState->setUniformFloat("custom", 0.2f);sprite->setGLProgramState(shaderState);

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