Unity3d《Shader篇》绘制圆角图片

Pass
        {
            CGPROGRAM
// Upgrade NOTE: excluded shader from OpenGL ES 2.0 because it does not contain a surface program or both vertex and fragment programs.
#pragma exclude_renderers gles

            #pragma fragment frag
            #include "UnityCG.cginc"

            sampler2D _MainTex;
            float4 _MainColor;
            float _RoundRadius;

            struct texCoord
            {
                float2 inputTexCoord : TEXCOORD0;
            };

            float4 frag(texCoord input) : COLOR
            {
                float x = input.inputTexCoord.x;
                float y = input.inputTexCoord.y;
                float4 col = tex2D(_MainTex,input.inputTexCoord)*_MainColor;

                float radius = _RoundRadius;

                if(x<radius && y<radius)
                {
                    if(pow(x-radius,2)+pow(y-radius,2)>radius*radius)
                    {
                        discard;
                    }
                }
                else if(x>1-radius && y>1-radius)
                {
                    if(pow(x-(1-radius),2)+pow(y-(1-radius),2)>radius*radius)
                    {
                        discard;
                    }
                }
                else if(x<radius && y>1-radius)
                {
                    if(pow(x-radius,2)+pow(y-(1-radius),2)>radius*radius)
                    {
                        discard;
                    }
                }

                else if(x>1-radius && y<radius)
                {
                    if(pow(x-(1-radius),2)+pow(y-radius,2)>radius*radius)
                    {
                        discard;
                    }
                }

                return col;
            }

            ENDCG
        }

效果图