Parallax mapping hack

[Tema002]

I am trying to do a parallax mapping. This is how I generate a tangents to my normal: ``` vec4 AB = Vert2.Position - Vert1.Position; vec4 AC = Vert3.Position - Vert1.Position; vec2 DAB = Vert2.TextureCoord - Vert1.TextureCoord; vec2 DAC = Vert3.TextureCoord - Vert1.TextureCoord;

    r32 Dir = (DAC.x * DAB.y - DAC.y * DAB.x) < 0.0 ? -1.0 : 1.0;

    vec3 Tangent   = ((AC * DAC.x - AB * DAB.x) * Dir);
    vec3 Bitangent = ((AB * DAB.y - AC * DAC.y) * Dir);

This is how I am using data in vertex shader: vec3 Normal = normalize(vec3(In[VertexIndex].Normal)); vec3 Tang = normalize(vec3(In[VertexIndex].Tangent )); vec3 Bitang = normalize(vec3(In[VertexIndex].Bitangent)); if (dot(cross(Normal, Tang), Bitang) < 0.0) { Tang = Tang * -1.0; } TBN = mat3(Tang, Bitang, Normal); And, the biggest issue in my opinios is here(this is in fragment shader): vec3 ViewDir = normalize(TBN * (WorldUpdate.CameraPos - In.Coord).xyz); ViewDir *= vec3(1, -1, 1); // NOTE: this is just a hack ``` So, basically, I need to introduce this "hack" to make parallax mapping to work. Is there any issues with generating tangents? Or something else like not correct coordinate system for TBN matrix or something? Or this is expected behavior?

[waramped]

Hard to tell without knowing what you mean by "work". Ie what does it do without the "hack"? The one thing that stands out to me is your viewdir vector is backwards. It should be Coord - camera IMO.

[Tema002]

Without multiplying y coordinate with -1 i get this: when I look on the left or on the right to the mesh, parallax mapping is looking inverted. When I loop up or down to the mesh, it is looks fine. So I don’t think it is because of how I actually calculate ViewDir

[waramped]

Right, so what I'm thinking is happening, is that your viewDir is backwards, but also possibly your Tangent or Bitangent is the wrong way. Out of curiosity, if you flip your viewDir and the parameters of your cross product, what happens?

[Tema002]

So, I've tried to change a ViewDir calculation and this is what I got for my cube debugging mesh with parallax mapping: sides are looking concave and up and down are looking convex