Shader Problem

I have this error whit my shader: Number of Fragment Texture Image Units exceeds HW limits. and here is the shader code: shader_type spatial; render_mode blend_mix; uniform vec4 albedo : hint_color; uniform sampler2D texture_albedo : hint_albedo; uniform sampler2D grassTex : hint_albedo; uniform sampler2D grass2Tex : hint_albedo; uniform sampler2D grass3Tex : hint_albedo; uniform sampler2D grass4Tex : hint_albedo; uniform sampler2D cliffTex : hint_albedo; uniform sampler2D cliff2Tex : hint_albedo; uniform sampler2D cliff3Tex : hint_albedo; uniform sampler2D cliff4Tex : hint_albedo; uniform sampler2D sandTex : hint_albedo; uniform sampler2D sand2Tex : hint_albedo; uniform sampler2D sand3Tex : hint_albedo; uniform sampler2D sand4Tex : hint_albedo; uniform float offset : hint_range(5,35); vec3 splating(vec2 uv,float channel,sampler2D tex1,sampler2D tex2, sampler2D tex3, sampler2D tex4) { vec3 result; if (channel == 100.0) { result = texture(tex1,uv).rgb * channel; } else if (channel == 50.0) { result = texture(tex2,uv).rgb * channel; } else if (channel == 25.0) { result = texture(tex3,uv).rgb * channel; } else if (channel == 12.0) { result = texture(tex4,uv).rgb * channel; } else { result = texture(tex1,uv).rgb * channel; } return result; } void fragment() { float redchannel = texture(texture_albedo,UV).r; float greenchannel = texture(texture_albedo,UV).g; float bluechannel = texture(texture_albedo,UV).b; float alphachannel = texture(texture_albedo,UV).a; vec3 red_level = splating(UV*offset,redchannel,cliffTex,cliff2Tex,cliff3Tex,cliff4Tex); vec3 green_level = splating(UV*offset,greenchannel,grassTex,grass2Tex,grass3Tex,grass4Tex); vec3 blue_level = splating(UV*offset,bluechannel,sandTex,sand2Tex,sand3Tex,sand4Tex); vec3 result = red_level + green_level + blue_level; ALBEDO = albedo.rgb * result; }