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 1d5819a1bfc812648cfb800587b5071ab776bd72..557d4d76a17cff24ef538946d8d95e531d5c099d 100644 (file)
--- a/shaderlib/common.glsl
+++ b/shaderlib/common.glsl
@@ -38,31 +38,22 @@ void standard_transform()
        mat4 vertex_tf = get_vertex_transform();
        mat3 normal_tf = get_normal_transform();
 
-       vec4 world_vertex = vertex_tf*get_vertex_position();
+       out vec4 world_vertex = vertex_tf*get_vertex_position();
        vec4 eye_vertex = eye_world_matrix*world_vertex;
        gl_Position = clip_eye_matrix*eye_vertex;
 
-       out vec3 world_normal = normal_tf*get_vertex_normal();
-       vec3 world_tangent = normal_tf*tangent;
-       vec3 world_binormal = cross(world_normal, world_tangent);
-       out mat3 world_tbn_matrix = mat3(world_tangent, world_binormal, world_normal);
+       out vec3 world_normal = normalize(normal_tf*get_vertex_normal());
+       if(use_normal_map)
+       {
+               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);
+       }
 
-       vec3 eye_pos = (inverse(eye_world_matrix)*vec4(0.0, 0.0, 0.0, 1.0)).xyz;
+       vec3 eye_pos = world_eye_matrix[3].xyz;
        out vec3 world_look_dir = normalize(world_vertex.xyz-eye_pos);
 
-       out vec3 world_light_dir = light_sources[0].position.xyz-world_vertex.xyz*light_sources[0].position.w;
-
-       out vec3 world_halfway_dir = normalize(world_light_dir-world_look_dir);
-
        out float fog_coord = eye_vertex.z;
-
-       if(use_clipping)
-       {
-               for(int i=0; i<max_clip_planes; ++i)
-                       gl_ClipDistance[i] = dot(world_vertex, clip_planes[i].equation);
-       }
-
-       shadow_transform(world_vertex);
 }
 
 virtual void custom_transform()
@@ -77,12 +68,31 @@ void main()
 }
 
 #pragma MSP stage(fragment)
+struct IncomingLight
+{
+       vec3 direction;
+       vec3 color;
+};
+
+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)
+{
+       vec4 light_pos = light_sources[index].position;
+       vec3 rel_pos = light_pos.xyz-world_pos*light_pos.w;
+       float d = length(rel_pos);
+       float attenuation = 1.0/dot(vec3(1.0, d, d*d), light_sources[index].attenuation);
+       return IncomingLight(rel_pos/d, light_sources[index].color*attenuation);
 }
 
 virtual vec3 get_environment_sample(vec3 direction, float roughness)