Shader MyCustom/BlendMode { Properties { // A图 _TexTop (_TexTop, 2D) white {} // B图 _TexBottom (_TexBottom, 2D) white {} } SubShader { CGINCLUDE // 适配unity Gamma空间 和 linear空间 的宏 #ifdef UNITY_COLORSPACE_GAMMA #define _ColorLinear2Gamma(c) c #define _ColorGamma2Linear(c) c #else #define _ColorLinear2Gamma(c) pow(c, 0.455) #define _ColorGamma2Linear(c) pow(c, 2.2) #endif // 用于色向转换的公式 const float EPSILON 1e-10; float3 _hue2rgb(float hue) { // Hue [0..1] to RGB [0..1] // See http://www.chilliant.com/rgb2hsv.html float3 rgb abs(hue * 6. - float3(3, 2, 4)) * float3(1, -1, -1) float3(-1, 2, 2); return clamp(rgb, 0., 1.); } float3 _rgb2hcv(float3 rgb) { // RGB [0..1] to Hue-Chroma-Value [0..1] // Based on work by Sam Hocevar and Emil Persson float4 p (rgb.g rgb.b) ? float4(rgb.bg, -1., 2. / 3.) : float4(rgb.gb, 0., -1. / 3.); float4 q (rgb.r p.x) ? float4(p.xyw, rgb.r) : float4(rgb.r, p.yzx); float c q.x - min(q.w, q.y); float h abs((q.w - q.y) / (6. * c EPSILON) q.z); return float3(h, c, q.x); } float3 _hsb2rgb(float3 hsl) { // Hue-Saturation-Lightness [0..1] to RGB [0..1] float3 rgb _hue2rgb(hsl.x); float c (1. - abs(2. * hsl.z - 1.)) * hsl.y; return (rgb - 0.5) * c hsl.z; } float3 _rgb2hsb(float3 rgb) { // RGB [0..1] to Hue-Saturation-Lightness [0..1] float3 hcv _rgb2hcv(rgb); float z hcv.z - hcv.y * 0.5; float s hcv.y / (1. - abs(z * 2. - 1.) EPSILON); return float3(hcv.x, s, z); } // 正常 float3 _normal(float3 srcColor, float3 dstColor) { float3 col srcColor; return col; } // 变暗 float3 _darken(float3 srcColor, float3 dstColor) { float3 col min(srcColor, dstColor); return col; } // 正片叠底 float3 _multiply(float3 srcColor, float3 dstColor) { float3 col srcColor * dstColor; return col; } // 颜色加深 float3 _colorBurn(float3 srcColor, float3 dstColor) { float3 col 1 - (1 - dstColor) / srcColor; col saturate(col); return col; } // 线性加深 float3 _linearBurn(float3 srcColor, float3 dstColor) { float3 col srcColor dstColor - 1; col saturate(col); return col; } // 深色 float3 _darkerColor(float3 srcColor, float3 dstColor) { // step(a, x): 如果 x a返回 0, 如果 x a返回 1 float flag step(srcColor.r * 0.22 srcColor.g * 0.707 srcColor.b * 0.071, dstColor.r * 0.22 dstColor.g * 0.707 dstColor.b * 0.071); float3 col flag * srcColor (1 - flag) * dstColor; return col; } // Lighten变亮组 // 变亮 float3 _lighten(float3 srcColor, float3 dstColor) { float3 col max(srcColor, dstColor); return col; } // 滤色, screen是multiply的相反值 float3 _screen(float3 srcColor, float3 dstColor) { float3 col srcColor dstColor - srcColor * dstColor; return col; } // 颜色减淡, 与_colorBurn的实现相反 float3 _colorDodge(float3 srcColor, float3 dstColor) { float3 col dstColor / (1 - srcColor); col saturate(col); return col; } // 线性减淡添加 float3 _linearDodgeAdd(float3 srcColor, float3 dstColor) { float3 col srcColor dstColor; return col; } // 浅色, 灰度计算同“深色”但是取值交换 float3 _ligherColor(float3 srcColor, float3 dstColor) { // step(a, x): 如果 x a返回 0, 如果 x a返回 1 float flag step(srcColor.r * 0.22 srcColor.g * 0.707 srcColor.b * 0.071, dstColor.r * 0.22 dstColor.g * 0.707 dstColor.b * 0.071); float3 col flag * dstColor (1 - flag) * srcColor; return col; } // 对比融合组 // 叠加 float3 _overlay(float3 srcColor, float3 dstColor) { float3 flag step(0.5, dstColor); float3 col flag * (1 - 2 * (1 - srcColor) * (1 - dstColor)) (1- flag) * (2 * srcColor * dstColor); return col; } // 柔光 float3 _softLight(float3 srcColor, float3 dstColor) { float3 flag step(0.5, srcColor); float3 col flag * (1 - (1 - dstColor) * (1 - (srcColor - 0.5))) (1 - flag) * (dstColor * (srcColor 0.5)); return col; } // 强光 float3 _hardLight(float3 srcColor, float3 dstColor) { float3 flag step(0.5, srcColor); float3 col flag * (1 - (1 - dstColor) * (1 - 2 * (srcColor - 0.5))) (1 - flag) * (dstColor * (2 * srcColor)); return col; } // 亮光 float3 _vividLight(float3 srcColor, float3 dstColor) { float3 flag step(0.5, srcColor); float3 col flag * (dstColor / (1 - 2 * (srcColor - 0.5))) (1 - flag) * (dstColor * (2 * srcColor)); return col; } // 线性光 float3 _linearLight(float3 srcColor, float3 dstColor) { //float3 flag step(0.5, srcColor); //float3 col flag * (dstColor 2 * srcColor - 1) (1 - flag) * (dstColor 2 * srcColor - 1); float3 col dstColor 2 * srcColor - 1; col saturate(col); return col; } // 点光 float3 _pinLight(float3 srcColor, float3 dstColor) { float3 flag step(0.5, srcColor); float3 col flag * (max(dstColor, 2 * (srcColor - 0.5))) (1 - flag) * (min(dstColor, 2 * srcColor)); return col; } // 实色混合 float3 _hardMix(float3 srcColor, float3 dstColor) { float3 flag step(1 - dstColor, srcColor); float3 col flag; return col; } // 差集组 // 差集 float3 _difference(float3 srcColor, float3 dstColor) { float3 col abs(dstColor - srcColor); return col; } // 排除 float3 _exclusion(float3 srcColor, float3 dstColor) { float3 col srcColor dstColor - 2 * srcColor * dstColor; return col; } // 减去 float3 _subtract(float3 srcColor, float3 dstColor) { float3 col dstColor - srcColor; col saturate(col); return col; } // 划分 float3 _divide(float3 srcColor, float3 dstColor) { float3 col dstColor / srcColor; return col; } // 色彩组 // 色相 float3 _hue(float3 srcColor, float3 dstColor) { float3 col _rgb2hsb(dstColor); col.x _rgb2hsb(srcColor).x; col _hsb2rgb(col); col saturate(col); return col; } // 饱和度 float3 _saturate(float3 srcColor, float3 dstColor) { float3 col _rgb2hsb(dstColor); col.y _rgb2hsb(srcColor).y; col _hsb2rgb(col); col saturate(col); return col; } // 饱和度 float3 _luminosity(float3 srcColor, float3 dstColor) { float3 col _rgb2hsb(dstColor); col.z _rgb2hsb(srcColor).z; col _hsb2rgb(col); col saturate(col); return col; } // 颜色 float3 _color(float3 srcColor, float3 dstColor) { float3 col _rgb2hsb(dstColor); col.xy _rgb2hsb(srcColor).xy; col _hsb2rgb(col); col saturate(col); return col; } ENDCG Pass { Tags { RenderTypeTransparent QueueTransparent } ZWrite Off Blend SrcAlpha OneMinusSrcAlpha CGPROGRAM #pragma vertex vert #pragma fragment frag // 引入宏定义 #pragma shader_feature PS_NORMAL PS_DARKEN PS_MULTIPLY PS_COLORBURN PS_LINEARBURN PS_DARKERCOLOR PS_LIGHTEN PS_SCREEN PS_COLORDODGE PS_LINEARDODGEADD PS_LIGHTERCOLOR PS_OVERLAY PS_SOFTLIGHT PS_HARDLIGHT PS_VIVIDLIGHT PS_LINEARLIGHT PS_PINLIGHT PS_HARDMIX PS_DIFFERENCE PS_EXCLUSION PS_SUBTRACT PS_DIVIDE PS_HUE PS_SATURATION PS_COLOR PS_LUMINOSITY #include UnityCG.cginc struct appdata { float4 vertex : POSITION; float2 uv : TEXCOORD0; }; struct v2f { float2 uv : TEXCOORD0; float4 vertex : SV_POSITION; }; sampler2D _TexTop; sampler2D _TexBottom; float4 _TexTop_ST; v2f vert (appdata v) { v2f o; o.vertex UnityObjectToClipPos(v.vertex); o.uv v.uv; return o; } fixed4 frag (v2f i) : SV_Target { // 采集图片 float4 topColor tex2D(_TexTop, i.uv); float4 bottomColor tex2D(_TexBottom, i.uv); // 由于Photoshop采用Gamma空间转换Linear到Gamma float3 srcColor _ColorLinear2Gamma(topColor.rgb); float3 dstColor _ColorLinear2Gamma(bottomColor.rgb); float3 blend 0; // 根据模式继续混合 #ifdef PS_NORMAL blend _normal(srcColor, dstColor); #elif PS_DARKEN blend _darken(srcColor, dstColor); #elif PS_MULTIPLY blend _multiply(srcColor, dstColor); #elif PS_COLORBURN blend _colorBurn(srcColor, dstColor); #elif PS_LINEARBURN blend _linearBurn(srcColor, dstColor); #elif PS_DARKERCOLOR blend _darkerColor(srcColor, dstColor); #elif PS_LIGHTEN blend _lighten(srcColor, dstColor); #elif PS_SCREEN blend _screen(srcColor, dstColor); #elif PS_COLORDODGE blend _colorDodge(srcColor, dstColor); #elif PS_LINEARDODGEADD blend _linearDodgeAdd(srcColor, dstColor); #elif PS_LIGHTERCOLOR blend _lighterColor(srcColor, dstColor); #elif PS_OVERLAY blend _overlay(srcColor, dstColor); #elif PS_SOFTLIGHT blend _softLight(srcColor, dstColor); #elif PS_HARDLIGHT blend _hardLight(srcColor, dstColor); #elif PS_VIVIDLIGHT blend _vividLight(srcColor, dstColor); #elif PS_LINEARLIGHT blend _linearLight(srcColor, dstColor); #elif PS_PINLIGHT blend _pinLight(srcColor, dstColor); #elif PS_HARDMIX blend _hardMix(srcColor, dstColor); #elif PS_DIFFERENCE blend _difference(srcColor, dstColor); #elif PS_EXCLUSION blend _exclusion(srcColor, dstColor); #elif PS_SUBTRACT blend _subtract(srcColor, dstColor); #elif PS_DIVIDE blend _divide(srcColor, dstColor); #elif PS_HUE blend _hue(srcColor, dstColor); #elif PS_SATURATION blend _saturation(srcColor, dstColor); #elif PS_COLOR blend _color(srcColor, dstColor); #elif PS_LUMINOSITY blend _luminosity(srcColor, dstColor); #else blend 0; #endif // 转换回linear空间适配Unity输出 blend _ColorGamma2Linear(blend); // Alpha通道混合交集为1为混合部分 float blendPart min(topColor.a, bottomColor.a); // 贴图都带有alpha float4 finalColor 1; // 图片其他部分采用原色 finalColor.rgb topColor.rgb * (topColor.a - blendPart) bottomColor.rgb * (bottomColor.a - blendPart) blend * blendPart; finalColor.a max(topColor.a, bottomColor.a); //// photoshop图片做混合 //finalColor.rgb blend; //finalColor.a 1; return finalColor; } ENDCG } } CustomEditor GUIExtension.MyCustomBlendModeShaderGUI }前言本节介绍了各种Blending混合方式是如何工作的并使用它们完成Photoshop中对应的效果混合模式shader中定义Blend SrcFactor Dstsactor最终的颜色(shader计算的颜色*SrcFactor)(屏幕已有的颜色*DstFactor)One // 1Zero // 0SrcColor // shader计算后的rgb值SrcAlpha // shader计算后alpha值DrcColor // 帧缓冲区的源rgb值(屏幕已有颜色)DrcAlpha // 帧缓冲区的源alpha值(屏幕已有颜色的alpha值)OneMinusSrcColor // 1 - SrcColorOneMinusSrcAlpha // 1 - SrcAlphaOneMinusDstColor // 1 - DstColorOneMinusDstAlpha // 1 - DstAlphaPhotoshop效果对比代码实现原图片A及Alpha通道原图片B及Alpha通道
TA不一样(十)
Shader MyCustom/BlendMode { Properties { // A图 _TexTop (_TexTop, 2D) white {} // B图 _TexBottom (_TexBottom, 2D) white {} } SubShader { CGINCLUDE // 适配unity Gamma空间 和 linear空间 的宏 #ifdef UNITY_COLORSPACE_GAMMA #define _ColorLinear2Gamma(c) c #define _ColorGamma2Linear(c) c #else #define _ColorLinear2Gamma(c) pow(c, 0.455) #define _ColorGamma2Linear(c) pow(c, 2.2) #endif // 用于色向转换的公式 const float EPSILON 1e-10; float3 _hue2rgb(float hue) { // Hue [0..1] to RGB [0..1] // See http://www.chilliant.com/rgb2hsv.html float3 rgb abs(hue * 6. - float3(3, 2, 4)) * float3(1, -1, -1) float3(-1, 2, 2); return clamp(rgb, 0., 1.); } float3 _rgb2hcv(float3 rgb) { // RGB [0..1] to Hue-Chroma-Value [0..1] // Based on work by Sam Hocevar and Emil Persson float4 p (rgb.g rgb.b) ? float4(rgb.bg, -1., 2. / 3.) : float4(rgb.gb, 0., -1. / 3.); float4 q (rgb.r p.x) ? float4(p.xyw, rgb.r) : float4(rgb.r, p.yzx); float c q.x - min(q.w, q.y); float h abs((q.w - q.y) / (6. * c EPSILON) q.z); return float3(h, c, q.x); } float3 _hsb2rgb(float3 hsl) { // Hue-Saturation-Lightness [0..1] to RGB [0..1] float3 rgb _hue2rgb(hsl.x); float c (1. - abs(2. * hsl.z - 1.)) * hsl.y; return (rgb - 0.5) * c hsl.z; } float3 _rgb2hsb(float3 rgb) { // RGB [0..1] to Hue-Saturation-Lightness [0..1] float3 hcv _rgb2hcv(rgb); float z hcv.z - hcv.y * 0.5; float s hcv.y / (1. - abs(z * 2. - 1.) EPSILON); return float3(hcv.x, s, z); } // 正常 float3 _normal(float3 srcColor, float3 dstColor) { float3 col srcColor; return col; } // 变暗 float3 _darken(float3 srcColor, float3 dstColor) { float3 col min(srcColor, dstColor); return col; } // 正片叠底 float3 _multiply(float3 srcColor, float3 dstColor) { float3 col srcColor * dstColor; return col; } // 颜色加深 float3 _colorBurn(float3 srcColor, float3 dstColor) { float3 col 1 - (1 - dstColor) / srcColor; col saturate(col); return col; } // 线性加深 float3 _linearBurn(float3 srcColor, float3 dstColor) { float3 col srcColor dstColor - 1; col saturate(col); return col; } // 深色 float3 _darkerColor(float3 srcColor, float3 dstColor) { // step(a, x): 如果 x a返回 0, 如果 x a返回 1 float flag step(srcColor.r * 0.22 srcColor.g * 0.707 srcColor.b * 0.071, dstColor.r * 0.22 dstColor.g * 0.707 dstColor.b * 0.071); float3 col flag * srcColor (1 - flag) * dstColor; return col; } // Lighten变亮组 // 变亮 float3 _lighten(float3 srcColor, float3 dstColor) { float3 col max(srcColor, dstColor); return col; } // 滤色, screen是multiply的相反值 float3 _screen(float3 srcColor, float3 dstColor) { float3 col srcColor dstColor - srcColor * dstColor; return col; } // 颜色减淡, 与_colorBurn的实现相反 float3 _colorDodge(float3 srcColor, float3 dstColor) { float3 col dstColor / (1 - srcColor); col saturate(col); return col; } // 线性减淡添加 float3 _linearDodgeAdd(float3 srcColor, float3 dstColor) { float3 col srcColor dstColor; return col; } // 浅色, 灰度计算同“深色”但是取值交换 float3 _ligherColor(float3 srcColor, float3 dstColor) { // step(a, x): 如果 x a返回 0, 如果 x a返回 1 float flag step(srcColor.r * 0.22 srcColor.g * 0.707 srcColor.b * 0.071, dstColor.r * 0.22 dstColor.g * 0.707 dstColor.b * 0.071); float3 col flag * dstColor (1 - flag) * srcColor; return col; } // 对比融合组 // 叠加 float3 _overlay(float3 srcColor, float3 dstColor) { float3 flag step(0.5, dstColor); float3 col flag * (1 - 2 * (1 - srcColor) * (1 - dstColor)) (1- flag) * (2 * srcColor * dstColor); return col; } // 柔光 float3 _softLight(float3 srcColor, float3 dstColor) { float3 flag step(0.5, srcColor); float3 col flag * (1 - (1 - dstColor) * (1 - (srcColor - 0.5))) (1 - flag) * (dstColor * (srcColor 0.5)); return col; } // 强光 float3 _hardLight(float3 srcColor, float3 dstColor) { float3 flag step(0.5, srcColor); float3 col flag * (1 - (1 - dstColor) * (1 - 2 * (srcColor - 0.5))) (1 - flag) * (dstColor * (2 * srcColor)); return col; } // 亮光 float3 _vividLight(float3 srcColor, float3 dstColor) { float3 flag step(0.5, srcColor); float3 col flag * (dstColor / (1 - 2 * (srcColor - 0.5))) (1 - flag) * (dstColor * (2 * srcColor)); return col; } // 线性光 float3 _linearLight(float3 srcColor, float3 dstColor) { //float3 flag step(0.5, srcColor); //float3 col flag * (dstColor 2 * srcColor - 1) (1 - flag) * (dstColor 2 * srcColor - 1); float3 col dstColor 2 * srcColor - 1; col saturate(col); return col; } // 点光 float3 _pinLight(float3 srcColor, float3 dstColor) { float3 flag step(0.5, srcColor); float3 col flag * (max(dstColor, 2 * (srcColor - 0.5))) (1 - flag) * (min(dstColor, 2 * srcColor)); return col; } // 实色混合 float3 _hardMix(float3 srcColor, float3 dstColor) { float3 flag step(1 - dstColor, srcColor); float3 col flag; return col; } // 差集组 // 差集 float3 _difference(float3 srcColor, float3 dstColor) { float3 col abs(dstColor - srcColor); return col; } // 排除 float3 _exclusion(float3 srcColor, float3 dstColor) { float3 col srcColor dstColor - 2 * srcColor * dstColor; return col; } // 减去 float3 _subtract(float3 srcColor, float3 dstColor) { float3 col dstColor - srcColor; col saturate(col); return col; } // 划分 float3 _divide(float3 srcColor, float3 dstColor) { float3 col dstColor / srcColor; return col; } // 色彩组 // 色相 float3 _hue(float3 srcColor, float3 dstColor) { float3 col _rgb2hsb(dstColor); col.x _rgb2hsb(srcColor).x; col _hsb2rgb(col); col saturate(col); return col; } // 饱和度 float3 _saturate(float3 srcColor, float3 dstColor) { float3 col _rgb2hsb(dstColor); col.y _rgb2hsb(srcColor).y; col _hsb2rgb(col); col saturate(col); return col; } // 饱和度 float3 _luminosity(float3 srcColor, float3 dstColor) { float3 col _rgb2hsb(dstColor); col.z _rgb2hsb(srcColor).z; col _hsb2rgb(col); col saturate(col); return col; } // 颜色 float3 _color(float3 srcColor, float3 dstColor) { float3 col _rgb2hsb(dstColor); col.xy _rgb2hsb(srcColor).xy; col _hsb2rgb(col); col saturate(col); return col; } ENDCG Pass { Tags { RenderTypeTransparent QueueTransparent } ZWrite Off Blend SrcAlpha OneMinusSrcAlpha CGPROGRAM #pragma vertex vert #pragma fragment frag // 引入宏定义 #pragma shader_feature PS_NORMAL PS_DARKEN PS_MULTIPLY PS_COLORBURN PS_LINEARBURN PS_DARKERCOLOR PS_LIGHTEN PS_SCREEN PS_COLORDODGE PS_LINEARDODGEADD PS_LIGHTERCOLOR PS_OVERLAY PS_SOFTLIGHT PS_HARDLIGHT PS_VIVIDLIGHT PS_LINEARLIGHT PS_PINLIGHT PS_HARDMIX PS_DIFFERENCE PS_EXCLUSION PS_SUBTRACT PS_DIVIDE PS_HUE PS_SATURATION PS_COLOR PS_LUMINOSITY #include UnityCG.cginc struct appdata { float4 vertex : POSITION; float2 uv : TEXCOORD0; }; struct v2f { float2 uv : TEXCOORD0; float4 vertex : SV_POSITION; }; sampler2D _TexTop; sampler2D _TexBottom; float4 _TexTop_ST; v2f vert (appdata v) { v2f o; o.vertex UnityObjectToClipPos(v.vertex); o.uv v.uv; return o; } fixed4 frag (v2f i) : SV_Target { // 采集图片 float4 topColor tex2D(_TexTop, i.uv); float4 bottomColor tex2D(_TexBottom, i.uv); // 由于Photoshop采用Gamma空间转换Linear到Gamma float3 srcColor _ColorLinear2Gamma(topColor.rgb); float3 dstColor _ColorLinear2Gamma(bottomColor.rgb); float3 blend 0; // 根据模式继续混合 #ifdef PS_NORMAL blend _normal(srcColor, dstColor); #elif PS_DARKEN blend _darken(srcColor, dstColor); #elif PS_MULTIPLY blend _multiply(srcColor, dstColor); #elif PS_COLORBURN blend _colorBurn(srcColor, dstColor); #elif PS_LINEARBURN blend _linearBurn(srcColor, dstColor); #elif PS_DARKERCOLOR blend _darkerColor(srcColor, dstColor); #elif PS_LIGHTEN blend _lighten(srcColor, dstColor); #elif PS_SCREEN blend _screen(srcColor, dstColor); #elif PS_COLORDODGE blend _colorDodge(srcColor, dstColor); #elif PS_LINEARDODGEADD blend _linearDodgeAdd(srcColor, dstColor); #elif PS_LIGHTERCOLOR blend _lighterColor(srcColor, dstColor); #elif PS_OVERLAY blend _overlay(srcColor, dstColor); #elif PS_SOFTLIGHT blend _softLight(srcColor, dstColor); #elif PS_HARDLIGHT blend _hardLight(srcColor, dstColor); #elif PS_VIVIDLIGHT blend _vividLight(srcColor, dstColor); #elif PS_LINEARLIGHT blend _linearLight(srcColor, dstColor); #elif PS_PINLIGHT blend _pinLight(srcColor, dstColor); #elif PS_HARDMIX blend _hardMix(srcColor, dstColor); #elif PS_DIFFERENCE blend _difference(srcColor, dstColor); #elif PS_EXCLUSION blend _exclusion(srcColor, dstColor); #elif PS_SUBTRACT blend _subtract(srcColor, dstColor); #elif PS_DIVIDE blend _divide(srcColor, dstColor); #elif PS_HUE blend _hue(srcColor, dstColor); #elif PS_SATURATION blend _saturation(srcColor, dstColor); #elif PS_COLOR blend _color(srcColor, dstColor); #elif PS_LUMINOSITY blend _luminosity(srcColor, dstColor); #else blend 0; #endif // 转换回linear空间适配Unity输出 blend _ColorGamma2Linear(blend); // Alpha通道混合交集为1为混合部分 float blendPart min(topColor.a, bottomColor.a); // 贴图都带有alpha float4 finalColor 1; // 图片其他部分采用原色 finalColor.rgb topColor.rgb * (topColor.a - blendPart) bottomColor.rgb * (bottomColor.a - blendPart) blend * blendPart; finalColor.a max(topColor.a, bottomColor.a); //// photoshop图片做混合 //finalColor.rgb blend; //finalColor.a 1; return finalColor; } ENDCG } } CustomEditor GUIExtension.MyCustomBlendModeShaderGUI }前言本节介绍了各种Blending混合方式是如何工作的并使用它们完成Photoshop中对应的效果混合模式shader中定义Blend SrcFactor Dstsactor最终的颜色(shader计算的颜色*SrcFactor)(屏幕已有的颜色*DstFactor)One // 1Zero // 0SrcColor // shader计算后的rgb值SrcAlpha // shader计算后alpha值DrcColor // 帧缓冲区的源rgb值(屏幕已有颜色)DrcAlpha // 帧缓冲区的源alpha值(屏幕已有颜色的alpha值)OneMinusSrcColor // 1 - SrcColorOneMinusSrcAlpha // 1 - SrcAlphaOneMinusDstColor // 1 - DstColorOneMinusDstAlpha // 1 - DstAlphaPhotoshop效果对比代码实现原图片A及Alpha通道原图片B及Alpha通道
