Gouraud Shading

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////////////////////VERTEX SHADER////////////////////
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#version 330

layout(location = 0) in vec3 inPosition;
layout(location = 1) in vec3 inNormal;
layout(location = 2) in vec2 inTexCoord;

out vec3 Gouraud;
out vec2 texCoord;

uniform mat4 viewMatrix;
uniform mat4 modelMatrix;
uniform mat4 projectionMatrix;
uniform mat3 normalMatrix;
uniform vec3 camPosIn;
uniform vec3 lightPosIn;
uniform vec3 lightColour;

void main()
{
    vec3 position = vec3(0.0);
    vec3 normals = vec3(0.0);
    vec3 diffuse = vec3(0.0);
    vec3 specular = vec3(0.0);
    vec3 ambientColour = vec3(0.0);

    position = vec3((viewMatrix * modelMatrix) * vec4(inPosition, 1.0));
    normals = normalize(normalMatrix * inNormal);
    texCoord = inTexCoord;

    vec3 camDir = normalize(camPosIn - position);

    for (int i = 0; i < 1; i++)
    {
        float radius = 50.0;

        vec3 lightDir = normalize(lightPosIn - position);
        vec3 halfAngle = normalize(camDir + lightDir);
        float NdotL = clamp(dot(normals, lightDir), 0.0, 1.0);
        float NdotH = clamp(dot(normals, halfAngle), 0.0, 1.0);

        float specularHighlight = pow(NdotH, 250);
        vec3 S = (lightColour * specularHighlight);
        vec3 D = (lightColour * NdotL);

        float dist = length(lightPosIn - position);
        float attenuation = 1.0 / (1.0 + ((2.0 / radius) * dist) + ((1.0 / (radius * radius)) * (dist * dist)));

        diffuse += D * attenuation;
        specular += S * attenuation;
        ambientColour += lightColour * attenuation;
    }
    vec3 ambience = 0.01 * ambientColour;

    Gouraud = ambience + diffuse + specular;
    gl_Position = (projectionMatrix * (viewMatrix * modelMatrix)) * vec4(inPosition, 1.0);
}
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////////////////////FRAGMENT SHADER////////////////////
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#version 330
precision mediump float;

in vec3 Gouraud;
in vec2 texCoord;

layout (location = 0) out vec4 FragColour;

uniform sampler2D textureMap;

void main()
{
    vec3 albedo = texture(textureMap, texCoord).rgb;
    vec3 final = albedo * Gouraud;
    final = pow(final, vec3(1.0 / 2.2));
    FragColour = vec4(final, 1.0);
}