I have a simple Vulkan installation that downloads a fairly large grid file (female) and also applies diffuse and normal map textures.
Vertex Shader:
#version 450 core layout (set = 0, binding = 0) uniform ModelMatrix { mat4 model; } modelMatrix; layout (push_constant) uniform ViewProjection { mat4 view; mat4 projection; } viewProjection; layout (location = 0) in vec3 inPos; layout (location = 1) in vec3 inNor; layout (location = 2) in vec2 inUV; layout (location = 3) in vec3 inTan; layout (location = 4) in vec3 inBitan; layout (location = 0) out vec3 fragPos; layout (location = 1) out vec2 fragUV; layout (location = 2) out vec3 fragNor; layout (location = 3) out vec3 fragTan; layout (location = 4) out vec3 fragBitan; void main() { fragPos = vec3(viewProjection.view * modelMatrix.model * vec4(inPos, 1.0)); fragNor = mat3(viewProjection.view * modelMatrix.model) * inNor; fragUV = inUV; fragTan = mat3(viewProjection.view * modelMatrix.model) * inTan; fragBitan = mat3(viewProjection.view * modelMatrix.model) * inBitan; gl_Position = viewProjection.projection * vec4(fragPos, 1.0); }
Fragment Shader:
#version 450 core layout (location = 0) in vec3 fragPos; layout (location = 1) in vec2 fragUV; layout (location = 2) in vec3 fragNor; layout (location = 3) in vec3 fragTan; layout (location = 4) in vec3 fragBitan; layout (location = 0) out vec4 outFragColor; layout (set = 0, binding = 0) uniform MVP { mat4 model; } mvp; layout (set = 0, binding = 1) uniform sampler2D textureSampler; layout (set = 0, binding = 2) uniform sampler2D normalSampler; layout (set = 0, binding = 3) uniform sampler2D specSampler; layout (push_constant) uniform VP { mat4 view; mat4 projection; } vp; const vec3 lightPos = vec3(0.0, 0.0, 300.0); const float lightIntensity = 1.0f; const float shininess = 50.0; void main() { mat3 TBN = transpose(mat3( fragTan, fragBitan, fragNor )); vec3 normapFragNor = normalize(texture(normalSampler, fragUV).rgb * 2.0 - 1.0); vec3 lightDirectionTangSpace = TBN * (lightPos - fragPos); float dotProduct = dot(normalize(lightDirectionTangSpace), normalize(normapFragNor)); float meshNormalDotProduct = dot(normalize(lightDirectionTangSpace), normalize(fragNor)); float diffuse = min(max(dotProduct, 0.0), 1.0); float specular = pow(diffuse, shininess); vec4 texelColor = texture(textureSampler, fragUV); vec3 specularColor = vec3(texture(specSampler, fragUV)); float specResultColorComponent = min(1.0, diffuse); outFragColor = vec4(diffuse * vec3(texelColor) , texelColor.a); // For Spec Map: diffuse * vec3(texelColor) + (specular * specularColor) }
Result: 
As you can see, the fragments on the entire grid are shaded a bit fuzzy and noisy, especially on the hands.
Whenever I load this mesh with the same textures into Unity3D, the result without the mentioned noise: 
Another model with a normal map + spec works like a charm, so it sounds paradoxical for me, since Unity3D can correctly display both of these models, but my program cannot generate lighting values only for a specific model, which implies that the shader can interpret the data in textures / patterns! 
What could be the source of this problem?
[UPDATE]
After visualizing normals with a geometric shader: 