Diffuse color texture using UV maps in GLSL shaders

I want to add diffuse color texture to my object in GLSL shader code.

import bge
cont = bge.logic.getCurrentController()
VertexShader = """
         uniform mat4 viewMatrix; // world to view transformation
         uniform mat4 viewMatrixInverse; 
            // view to world transformation
         varying vec3 viewDirection; // direction in world space 
            // in which the viewer is looking
         varying vec3 normalDirection; // normal vector in world space 
         varying vec3 normal;
         varying vec3 view;
         void main()
            vec4 positionInViewSpace = gl_ModelViewMatrix * gl_Vertex;
               // transformation of gl_Vertex from object coordinates 
               // to view coordinates
            vec4 viewDirectionInViewSpace = positionInViewSpace 
               - vec4(0.0, 0.0, 0.0, 1.0);
               // camera is always at (0,0,0,1) in view coordinates;
               // this is the direction in which the viewer is looking 
               // (not the direction to the viewer)
            viewDirection = 
               vec3(viewMatrixInverse * viewDirectionInViewSpace);
               // transformation from view coordinates 
               // to world coordinates
            vec3 normalDirectionInViewSpace = 
               gl_NormalMatrix * gl_Normal;
               // transformation of gl_Normal from object coordinates 
               // to view coordinates
            normalDirection = normalize(vec3(
               vec4(normalDirectionInViewSpace, 0.0) * viewMatrix));
               // transformation of normal vector from view coordinates 
               // to world coordinates with the transposed 
               // (multiplication of the vector from the left) of 
               // the inverse of viewMatrixInverse, which is viewMatrix
            normal = normalize(gl_NormalMatrix * gl_Normal);
            view = -normalize(vec3(gl_ModelViewMatrix * gl_Vertex)); 
            gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
FragmentShader = """
         varying vec3 viewDirection;
         varying vec3 normalDirection;
         varying vec3 normal;
         varying vec3 view;
         uniform samplerCube cubeMap;
         void main()
            float fP = 0.5;
            float metallic = 0.0;
            vec3 reflectedDirection = reflect(viewDirection, normalize(normalDirection));
            vec4 color = vec4(0.0, 0.5, 0.5, 1.0);
            float fresnel = dot(view, normal);
            float fresnelPower = pow(fresnel, fP);
            vec3 specularColor = textureCube(cubeMap, vec3(reflectedDirection.x, -reflectedDirection.z, reflectedDirection.y));
            vec4 specular = vec4(specularColor.xyz, 1.0);
            gl_FragColor = mix(specular, mix(color + (specular * 0.04), specular, metallic), fresnelPower);
mesh = cont.owner.meshes[0]
for mat in mesh.materials:
    shader = mat.getShader()
    if shader != None:
        if not shader.isValid():
            shader.setSource(VertexShader, FragmentShader, 1)
            shader.setSampler('cubeMap', 0)
        viewMatrix = bge.logic.getCurrentScene().active_camera.world_to_camera
        shader.setUniformMatrix4('viewMatrix', viewMatrix)
        viewMatrixInverse = bge.logic.getCurrentScene().active_camera.camera_to_world
        shader.setUniformMatrix4('viewMatrixInverse', viewMatrixInverse)

In the code you can see ‘color’ variable(vec4) that needs to be replaced with a texture in slot 1(not slot 0 as 0 is cubemap). How can I do it? It should use UVs as coordinates.

vec4 color = texture(YourTexture, gl_TexCoord[0])

So I uniform texture and do that thing? Doesn’t it require texture2D()?
I tried both ways and I get black diffuse color instead of the texture I use(bright brown sand).

Hey? Why it doesn’t work like that?

After doing all as accurate as possible, I get a problem - I get all the diffuse color single color instead of a texture.

So, I just need to know - what to input here texture2D(theTexture, HERENEEDHELP); so that it binds texture to UV coordinates? I have no idea and multiple ways were tried.

A fix was found.