| x | The x coordinate of the pixel to set. The range is 0through the (texture width - 1). | 
| y | The y coordinate of the pixel to set. The range is 0through the (texture height - 1). | 
| z | The z coordinate of the pixel to set. The range is 0through the (texture depth - 1). | 
| color | The color to set. | 
| mipLevel | The mipmap level to write to. The range is 0through the texture's Texture.mipmapCount. The default value is0. | 
Sets the pixel color at coordinates (x, y, z).
        This method sets pixel data for the texture in CPU memory. Texture.isReadable must be true, and you must call Apply after SetPixel to upload the changed pixels to the GPU.
Apply is an expensive operation because it copies all the pixels in the texture even if you've only changed some of the pixels, so change as many pixels as possible before you call it.SetPixel might be slower than some other texture methods because it converts the Color struct into the format the texture uses. To set pixel data more quickly, use SetPixelData instead.
The lower left corner is (0, 0, 0). If the pixel coordinate is outside the texture's dimensions, Unity clamps or repeats it, depending on the texture's TextureWrapMode.
If you need to get a large block of pixels, it might be faster to use SetPixels32.
You can use SetPixel with the following texture formats:
        
          Alpha8
          ARGB32
          ARGB4444
          BGRA32
          R16
          R16_SIGNED
          R8
          R8_SIGNED
          RFloat
          RG16
          RG16_SIGNED
          RG32
          RG32_SIGNED
          RGB24
          RGB24_SIGNED
          RGB48
          RGB48_SIGNED
          RGB565
          RGB9e5Float
          RGBA32
          RGBA32_SIGNED
          RGBA4444
          RGBA64
          RGBA64_SIGNED
          RGBAFloat
          RGBAHalf
          RGFloat
          RGHalf
          RHalf
        
        For all other formats, Unity ignores SetPixel.
Additional resources: SetPixels, SetPixelData, GetPixel, Apply.