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Strange specular with normal map (BlinnPhong)


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#1 JackShannon   Members   -  Reputation: 484

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Posted 25 April 2013 - 08:21 AM

SOLVED

 

Please can someone take a look at my normal map code, the diffuse is fine.

 

Without normal map:

2GiIt.png

 

With normal map:

2GiCw.png

 

Vertex shader:

/* The following can be defined:
 *      TEXTURED
 *      NORMALMAPPED
 */

in vec3 v_position;
#if defined(TEXTURED) || defined(NORMALMAPPED)
in vec2 v_uv;
#endif
in vec3 v_normal;
#ifdef NORMALMAPPED
in vec4 v_tangent;
#endif

layout(std140) uniform Transform
{
	mat4 t_model_view_proj;
	mat4 t_model_view;
	mat3 t_normal;
};

#if defined(TEXTURED) || defined(NORMALMAPPED)
out vec2 f_uv;
#endif

#ifdef NORMALMAPPED
layout(std140) uniform Light
{
    int l_type;
    vec3 l_orientation;
    float l_attenuation;
    vec3 l_ambient;
    vec3 l_diffuse;
    vec3 l_specular;
};
out vec3 tbn_lightDirection;
out vec3 tbn_viewDirection;
#else
out vec3 f_position;
out vec3 f_normal;
out vec3 f_viewDirection;
#endif

void main()
{
    gl_Position = t_model_view_proj * vec4(v_position, 1.0);

    #if defined(TEXTURED) || defined(NORMALMAPPED)
    f_uv = v_uv;
    #endif

    #ifdef NORMALMAPPED
    vec3 v_bitangent = v_tangent.z * cross(v_normal, v_tangent.xyz); // tangent.z stores m value which is the determinant of the object space to tangent space matrix

    mat3 TBN = transpose(mat3(v_tangent.xyz,
                              v_bitangent,
                              v_normal));

    tbn_lightDirection = normalize(TBN * l_orientation);
    tbn_viewDirection = -normalize(TBN * v_position);
    #else
    f_position = (t_model_view * vec4(v_position, 1.0)).xyz;
    f_normal = normalize(t_normal * v_normal);
    f_viewDirection = -normalize(t_model_view * vec4(v_position, 1.0)).xyz;
    #endif
}

 

Fragment shader:

/* The following can be defined:
 *      TEXTURED
 *      NORMALMAPPED
 */

#define LTYPE_DIRECTIONAL 0
#define LTYPE_POINT 1

#if defined(TEXTURED) || defined(NORMALMAPPED)
in vec2 f_uv;
#endif
#ifdef TEXTURED
uniform sampler2D diffuseTexture;
#endif

#ifdef NORMALMAPPED
uniform sampler2D normalTexture;
in vec3 tbn_lightDirection;
in vec3 tbn_viewDirection;
#else
in vec3 f_position;
in vec3 f_normal;
in vec3 f_viewDirection;
#endif

layout(std140) uniform Light
{
    int l_type;
    vec3 l_orientation;
    float l_attenuation;
    vec3 l_ambient;
    vec3 l_diffuse;
    vec3 l_specular;
};

layout(std140) uniform Material
{
    vec3 m_ambient;
    vec3 m_diffuse;
    vec3 m_specular; // scale specular by shininess strength in external tool
    float m_shininess;
};

out vec4 fragment;

float lambert(vec3 lightDirection, vec3 normal)
{
    float lambertTerm = dot(lightDirection, normal);
    lambertTerm = clamp(lambertTerm, 0, 1);
    return lambertTerm;
}

float blinnPhong(vec3 lightDirection, vec3 normal, vec3 viewDirection)
{
    vec3 halfwayDirection = normalize(lightDirection + viewDirection);
    float blinnTerm = dot(normal, halfwayDirection);
    blinnTerm = clamp(blinnTerm, 0, 1);
    blinnTerm = pow(blinnTerm, m_shininess);
    return blinnTerm;
}

// not normalized
vec3 getL()
{
    #ifdef NORMALMAPPED
        return normalize(tbn_lightDirection);
    #else
    if (l_type == LTYPE_DIRECTIONAL) {
        return l_orientation;
    }
    else if (l_type == LTYPE_POINT) {
        return l_orientation - f_position;
    }
    #endif
}

vec3 getN()
{
    #ifdef NORMALMAPPED
    vec3 tbnNormal = texture(normalTexture, f_uv).rgb * 2.0 - 1.0;
    return normalize(tbnNormal);
    #else
    return normalize(f_normal);
    #endif
}

vec3 getV()
{
    #ifdef NORMALMAPPED
        return normalize(tbn_viewDirection);
    #else
    return normalize(f_viewDirection);
    #endif
}

void main()
{
    vec3 lightDiffuse, lightSpecular = vec3(0);

    vec3 lightVector = getL();
    vec3 l = normalize(lightVector);
    vec3 n = getN();

    float lambertTerm = lambert(l, n);

    lightDiffuse = l_diffuse * lambertTerm;
    if (lambertTerm > 0) {
        vec3 v = getV();
        lightSpecular = l_specular * blinnPhong(l, n, v);
    }

    #ifdef TEXTURED
    vec3 diffuse = texture(diffuseTexture, f_uv).xyz * lightDiffuse;
    #else
    vec3 diffuse = m_diffuse * lightDiffuse;
    #endif
    vec3 specular = m_specular * lightSpecular;

    float attenuation;
    if (l_type == LTYPE_DIRECTIONAL) {
        attenuation = 1;
    }
    else if (l_type == LTYPE_POINT) {
        float distanceToLight = length(lightVector);
        float attenuation = 1.0 / (1.0 + l_attenuation * pow(distanceToLight, 2));
    }

    fragment = vec4(m_ambient + attenuation * (diffuse + specular), 1.0);
    //fragment = vec4(diffuse + specular, 1.0);
}

Edited by JackShannon, 25 April 2013 - 04:00 PM.


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#2 JackShannon   Members   -  Reputation: 484

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Posted 25 April 2013 - 03:37 PM

It turns out that the speculars are correct, but are only being rendered on half of the pane. This demonstrates it more clearly: 2H4q0.png

 

Why could this be?

 

 

EDIT: solved! It turned out that I shouldn't have normalised tbn_viewDirection, this fixed it:

2H5bl.png


Edited by JackShannon, 27 April 2013 - 09:54 AM.





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