动态材质

使用约束

使用动态材质

1. 在shader里配置自定义uniform buffer。

   layout(set=0, binding=10) uniform ColorInfo
   {
       vec2 diffvec2;
       vec3 diffvec3;
       vec2 diffvec4;
       vec2 diffvec5;
       vec4 color;
   }
   colorInfo;

   说明

   CG Kit仅支持shader中uniform结构的变量类型：int、float、vec2、vec3、vec4、mat4。

2. 在cgmat文件的resource节点下增加constants节点，与自定义uniform buffer做映射。
   渲染框架支持顶点shader或像素shader里配置uniform buffer，用户需要在cgmat文件中配置自定义uniform buffer信息和初始值。

   "resource": {
           "texture": [
               {
                   "uri": "cubemaps/02/cubemap_02_nomip.ktx",
                   "name": "envTexture",
                   "samplerIndex": 0
               }
           ],
           "sampler": [{ }],
           "constants": [
               {
                   "name": "ColorInfo",
                   "type": "UNIFORM",
                   "value": [
                       {
                           "name": "diffvec2",
                           "type": "vec2",
                           "value": [
                               1,
                               0
                           ]
                       },
                       {
                           "name": "diffvec3",
                           "type": "vec3",
                           "value": [
                               1,
                               0,
                               1
                           ]
                       },
                       {
                           "name": "diffvec4",
                           "type": "vec2",
                           "value": [
                               1,
                               0
                           ]
                       },
                       {
                           "name": "diffvec5",
                           "type": "vec2",
                           "value": [
                               1,
                               0
                           ]
                       },
                       {
                           "name": "color",
                           "type": "color",
                           "value": [
                               255,
                               0,
                               0,
                               255
                           ]
                       }
                   ]
               }
           ],
           "shader": [
               {
                   "uri": "shaders/color.frag",
                   "type": "SHADER_STAGE_TYPE_FRAGMENT"
               },
               {
                   "uri": "shaders/static.vert",
                   "type": "SHADER_STAGE_TYPE_VERTEX"
               }
           ]
       }

   说明

   CG Kit仅支持cgmat配置文件中uniform结构的变量类型：uint、float、vec2、vec3、vec4、mat4、color（即Color类，对应shader里的vec4）。

3. 通过SetConstantValue修改自定义uniform buffer中变量的值，实现材质的动态变化效果。

   MeshRenderer* meshRenderer = m_cubeObject->GetComponent<MeshRenderer>();
   for (auto materialInstance : meshRenderer->GetMaterialInstances()) {
       const String unionName = "ColorInfo";
       const String varName = "color";
       uint32_t index = materialInstance->GetConstantValueIndex(unionName, varName);
       switch (m_colorFlag) {
           case 0: {
               // Red
               materialInstance->SetConstantValue(index, Color::RED);
               break;
           }
           case 1: {
               // Green
               materialInstance->SetConstantValue(index, Color::GREEN);
               break;
           }
           case 2: {
               // Blue
               materialInstance->SetConstantValue(index, Color::BLUE);
               break;
           }
           default:
               break;
       }