Flip normal if a surface faces away from the camera

[libs/gl.git] / shaderlib / common.glsl

diff --git a/shaderlib/common.glsl b/shaderlib/common.glsl
index 35d5a87eafb8bf8c83e8fe877cdf5e90b0a3d724..557d4d76a17cff24ef538946d8d95e531d5c099d 100644 (file)
--- a/shaderlib/common.glsl
+++ b/shaderlib/common.glsl
@@ -42,11 +42,11 @@ void standard_transform()
        vec4 eye_vertex = eye_world_matrix*world_vertex;
        gl_Position = clip_eye_matrix*eye_vertex;
 
-       out vec3 world_normal = normal_tf*get_vertex_normal();
+       out vec3 world_normal = normalize(normal_tf*get_vertex_normal());
        if(use_normal_map)
        {
-               vec3 world_tangent = normal_tf*tangent;
-               vec3 world_binormal = cross(world_normal, world_tangent);
+               vec3 world_tangent = normalize(normal_tf*tangent);
+               vec3 world_binormal = normalize(cross(world_normal, world_tangent));
                out mat3 world_tbn_matrix = mat3(world_tangent, world_binormal, world_normal);
        }
 
@@ -78,10 +78,12 @@ layout(location=0) out vec4 frag_color;
 
 virtual vec3 get_fragment_normal()
 {
+       vec3 normal;
+       float sgn = (gl_FrontFacing ? 1.0 : -1.0);
        if(use_normal_map)
-               return normalize(world_tbn_matrix*(texture(normal_map, texcoord.xy).xyz*2.0-1.0));
+               return sgn*normalize(world_tbn_matrix*(texture(normal_map, texcoord.xy).xyz*2.0-1.0));
        else
-               return normalize(world_normal);
+               return sgn*normalize(world_normal);
 }
 
 virtual IncomingLight get_incoming_light(int index, vec3 world_pos)