Shader里常见的业务逻辑

变量

• diffuse 是用户输入的颜色值
• map 是diffuseMap 是模型的贴图

Shader里的颜色处理

• diffuse 用户输入的颜色值(含alpha值的)
  • 包含用户输入的渐变色贴图

vec4 diffuseColor = vec4( diffuse, opacity );
#ifndef USE_MAP
    diffuseColor.rgb = pow(diffuseColor.rgb, vec3(2.2));
    #ifdef USE_GRADIENT
        #ifdef VERSION_1_3_0
            #ifndef STANDARD_SG
            #else
                diffuseColor.rgb = colorGradient();
            #endif
        #else
            diffuseColor.rgb = colorGradient();
        #endif
    #endif
#endif

• 贴图里的颜色
  • standard 情况下 diffuseColor和贴图color计算方式
    • 需要判断输入色阶与输出色阶 NEED_ADJUST_COLOR
    • 需要判断渐变色 USE_GRADIENT
  • 非standard (ThreeJS) 默认情况下的计算方式

#ifdef USE_MAP
    vec4 texelColor = texture2D( map, vUv );
    texelColor = mapTexelToLinear( texelColor );
    #ifdef DECOLOR  //灰度
        float gray = texelColor.r * 0.3 + texelColor.g * 0.59 + texelColor.b * 0.11;
        texelColor.r = gray;
        texelColor.g = gray;
        texelColor.b = gray;
    #endif
    // Tips: 
    // 1.所有改色函数只影响RGB
    // 2.改色函数里会对diffuseColor做gamma
    #ifdef STANDARD
        #ifdef VERSION_1_3_0
            #ifdef NEED_ADJUST_COLOR
                diffuseColor.rgb = changeColorV130(texelColor, gradationInputBlack, gradationInputWhite, gradationGamma, gradationOutputBlack, gradationOutputWhite, diffuseColor).rgb;
            #else
                #ifndef STANDARD_SG //不支持改色
                    diffuseColor.rgb = pow(diffuseColor.rgb, vec3(2.2));
                    diffuseColor.rgb *= texelColor.rgb;
                #else
                    #ifdef USE_GRADIENT
                        diffuseColor.rgb = colorGradient();
                        diffuseColor.rgb = changeColorV130(texelColor, gradationInputBlack, gradationInputWhite, gradationGamma, gradationOutputBlack, gradationOutputWhite, diffuseColor).rgb;
                    #else
                        diffuseColor.rgb = texelColor.rgb;
                    #endif
                #endif
            #endif
        #else
            #ifdef NEED_ADJUST_COLOR
                diffuseColor.rgb = changeColorV130(texelColor, gradationInputBlack, gradationInputWhite, gradationGamma, gradationOutputBlack, gradationOutputWhite, diffuseColor).rgb;
            #else
                #ifdef USE_GRADIENT
                    diffuseColor.rgb = colorGradient();
                    diffuseColor.rgb = changeColorV130(texelColor, gradationInputBlack, gradationInputWhite, gradationGamma, gradationOutputBlack, gradationOutputWhite, diffuseColor).rgb;
                #else
                    diffuseColor.rgb = texelColor.rgb;
                #endif
            #endif
        #endif
        diffuseColor.a *= texelColor.a;
        #ifdef MAP_CLAMP_TO_EDGE 
            if (vUv.x >= 0.0 && vUv.x <= 1.0 && vUv.y >= 0.0 && vUv.y <= 1.0) {
            }
            else {
                diffuseColor.a = 0.0;
            }
        #endif 
        #ifdef DISCARD_MAP_ALPHA
            if(texelColor.a<0.001) discard; 
        #endif
    #else 
        diffuseColor *= texelColor; //颜色的乘值
    #endif
#endif