I tried to implement normal mapping in my opengl application but I can't get it to work.

This is the diffuse map (which I add a brown color to) and this is the normal map.

In order to get the tangent and bitangent (in other places called binormals?) vectors, I run this function for every triangle in my mesh:

```
void getTangent(const glm::vec3 &v0, const glm::vec3 &v1, const glm::vec3 &v2,
const glm::vec2 &uv0, const glm::vec2 &uv1, const glm::vec2 &uv2,
std::vector<glm::vec3> &vTangents, std::vector<glm::vec3> &vBiangents)
{
// Edges of the triangle : postion delta
glm::vec3 deltaPos1 = v1-v0;
glm::vec3 deltaPos2 = v2-v0;
// UV delta
glm::vec2 deltaUV1 = uv1-uv0;
glm::vec2 deltaUV2 = uv2-uv0;
float r = 1.0f / (deltaUV1.x * deltaUV2.y - deltaUV1.y * deltaUV2.x);
glm::vec3 tangent = (deltaPos1 * deltaUV2.y - deltaPos2 * deltaUV1.y)*r;
glm::vec3 bitangent = (deltaPos2 * deltaUV1.x - deltaPos1 * deltaUV2.x)*r;
for(int i = 0; i < 3; i++) {
vTangents.push_back(tangent);
vBiangents.push_back(bitangent);
}
}
```

After that, I call glBufferData to upload the vertices, normals, uvs, tangents and bitangents to the GPU. The vertex shader:

```
#version 430
uniform mat4 ProjectionMatrix;
uniform mat4 CameraMatrix;
uniform mat4 ModelMatrix;
in vec3 vertex;
in vec3 normal;
in vec2 uv;
in vec3 tangent;
in vec3 bitangent;
out vec2 fsCoords;
out vec3 fsVertex;
out mat3 TBNMatrix;
void main()
{
gl_Position = ProjectionMatrix * CameraMatrix * ModelMatrix * vec4(vertex, 1.0);
fsCoords = uv;
fsVertex = vertex;
TBNMatrix = mat3(tangent, bitangent, normal);
}
```

Fragment shader:

```
#version 430
uniform sampler2D diffuseMap;
uniform sampler2D normalMap;
uniform mat4 ModelMatrix;
uniform vec3 CameraPosition;
uniform struct Light {
float ambient;
vec3 position;
} light;
uniform float shininess;
in vec2 fsCoords;
in vec3 fsVertex;
in mat3 TBNMatrix;
out vec4 color;
void main()
{
//base color
const vec3 brownColor = vec3(153.0 / 255.0, 102.0 / 255.0, 51.0 / 255.0);
color = vec4(brownColor * (texture(diffuseMap, fsCoords).rgb + 0.25), 1.0);//add a fixed base color (0.25), because its dark as hell
//general vars
vec3 normal = texture(normalMap, fsCoords).rgb * 2.0 - 1.0;
vec3 surfacePos = vec3(ModelMatrix * vec4(fsVertex, 1.0));
vec3 surfaceToLight = normalize(TBNMatrix * (light.position - surfacePos)); //unit vector
vec3 eyePos = TBNMatrix * CameraPosition;
//diffuse
float diffuse = max(0.0, dot(normal, surfaceToLight));
//specular
float specular;
vec3 incidentVector = -surfaceToLight; //unit
vec3 reflectionVector = reflect(incidentVector, normal); //unit vector
vec3 surfaceToCamera = normalize(eyePos - surfacePos); //unit vector
float cosAngle = max(0.0, dot(surfaceToCamera, reflectionVector));
if(diffuse > 0.0)
specular = pow(cosAngle, shininess);
//add lighting to the fragment color (no attenuation for now)
color.rgb *= light.ambient;
color.rgb += diffuse + specular;
}
```

The image I get is completely incorrect. (light positioned on camera)

What am I doing wrong here?

`color`

and`intensities`

instead of`color*intensity`

but I could overlook someting. 3. try just normal/bump shading at first (ignore ambient,reflect,specular...) and then if it works add the rest one by one ... always check shaders compilation logs – Spektre`color.rgb=browncolor.rgb*fabs(dot(surface_normal,light_direction));`

also have added answer with mine shaders that do something similar to what you want to achieve. If you do not check the logs then you can easilly miss some things like optimized i/o variables, syntax errors etc ... – Spektre