Simple normal map implementation

shaders/triangle.vert

@@ -16,21 +16,35 @@ layout(binding = 0) uniform ObjectUniformData {
 layout(location = 0) in vec3 position;
 layout(location = 1) in vec2 uv;
 layout(location = 2) in vec3 normal;
-layout(location = 3) in ivec4 bone_index;
-layout(location = 4) in vec4 bone_weight;
+layout(location = 3) in vec4 tangent;
+layout(location = 4) in ivec4 bone_index;
+layout(location = 5) in vec4 bone_weight;
 
 layout(location = 0) out vec2 tex_coords;
 layout(location = 1) out vec3 normal_wld;
 layout(location = 2) out vec3 position_wld;
+layout(location = 3) out mat3 tbn;
 
 out gl_PerVertex {
     vec4 gl_Position;
 };
 
 void main() {
+    // Vertex position
     gl_Position = ubo.projection * ubo.view * push.model * vec4(position, 1.0);
+    position_wld = vec3(push.model * vec4(position, 1.0));
+
+    // Just interpolate UV coords, no transformation needed
     tex_coords = uv;
 
-    position_wld = vec3(push.model * vec4(position, 1.0));
+    // This should probably be in object space? idk
     normal_wld = vec3(mat3(transpose(inverse(push.model))) * normal);
+
+    // Tangent->object space matrix
+    vec3 tangent3 = vec3(tangent.xy, 1.0);
+    vec3 bitangent = -cross(tangent3, normal_wld);
+    vec3 t = normalize(vec3(push.model * vec4(tangent3, 0.0)));
+    vec3 b = normalize(vec3(push.model * vec4(bitangent, 0.0)));
+    vec3 n = normalize(vec3(push.model * vec4(normal_wld, 0.0)));
+    tbn = mat3(t, b, n);
 }