Wireframe rendering.

shaders/shader.frag

@@ -1,9 +1,28 @@
 #version 450
 
-layout(location = 0) in vec3 fragColor;
+layout(location = 1) in vec3 in_normal;
+layout(location = 2) in vec3 in_color;
+layout(location = 3) in vec3 in_edge_dist;
 
-layout(location = 0) out vec4 outColor;
+layout(location = 0) out vec4 out_color;
 
 void main() {
-    outColor = vec4(fragColor, 1.0);
+    vec3 edge_dist = vec3(0.75) - in_edge_dist;
+    float edge = clamp(
+        max(edge_dist[0], max(edge_dist[1], edge_dist[2])),
+        0.0, 1.0
+    );
+
+    vec3 edge_color = vec3(1.0);
+    vec3 light_dir = normalize(vec3(-0.2, -0.1, -1.0));
+
+    vec3 color = in_color;
+
+    // vec3 normal = normalize(in_normal);
+    // color *= clamp(
+    //     dot(normal, light_dir),
+    //     0.0, 1.0
+    // );
+
+    out_color = vec4(mix(color, edge_color, edge), 1.0);
 }

shaders/shader.geom

@@ -0,0 +1,49 @@
+#version 450
+
+layout(triangles) in;
+layout(triangle_strip, max_vertices=3) out;
+
+layout(binding = 0) uniform Uniforms {
+    mat4 scene_from_model;
+    mat4 projection_from_scene;
+    vec2 half_screen_size;
+    float lod;
+} uniforms;
+
+layout(location = 0) in vec4 in_position[3];
+layout(location = 1) in vec3 in_normal[3];
+layout(location = 2) in vec3 in_color[3];
+
+layout(location = 0) out vec4 out_position;
+layout(location = 1) out vec3 out_normal;
+layout(location = 2) out vec3 out_color;
+layout(location = 3) noperspective out vec3 out_edge_dist;
+
+void main() {
+    vec2 positions[3] = {
+        uniforms.half_screen_size * gl_in[0].gl_Position.xy / gl_in[0].gl_Position.w,
+        uniforms.half_screen_size * gl_in[1].gl_Position.xy / gl_in[1].gl_Position.w,
+        uniforms.half_screen_size * gl_in[2].gl_Position.xy / gl_in[2].gl_Position.w,
+    };
+
+    for(int i = 0; i < 3; i += 1) {
+        gl_Position = gl_in[i].gl_Position;
+        out_position = in_position[i];
+        out_normal = in_normal[i];
+        out_color = in_color[i];
+        out_edge_dist = vec3(0.0);
+
+        vec2 p0 = positions[(i + 0) % 3];
+        vec2 p1 = positions[(i + 1) % 3];
+        vec2 p2 = positions[(i + 2) % 3];
+
+        // vec2 v21 = p2 - p1;
+        // out_edge_dist[i] = (p1.x * v21.x + p1.y * v21.y) / dot(v21, v21);
+
+        vec2 v0 = p0 - p2;
+        vec2 v1 = p1 - p2;
+        out_edge_dist[i] = determinant(mat2(v0, v1)) / length(v1);
+
+        EmitVertex();
+    }
+}

shaders/shader.vert

@@ -3,17 +3,31 @@
 layout(binding = 0) uniform Uniforms {
     mat4 scene_from_model;
     mat4 projection_from_scene;
+    vec2 screen_size;
+    float lod;
 } uniforms;
 
-layout(location = 0) in vec3 inPosition;
-layout(location = 1) in vec3 inColor;
+layout(location = 0) in vec3 in_position;
+layout(location = 1) in vec3 in_position2;
+layout(location = 2) in vec3 in_normal;
+layout(location = 3) in vec3 in_color;
 
-layout(location = 0) out vec3 fragColor;
+layout(location = 0) out vec4 out_position;
+layout(location = 1) out vec3 out_normal;
+layout(location = 2) out vec3 out_color;
 
 void main() {
-    gl_Position =
+    float lod = clamp(
+        2.0 * dot(transpose(uniforms.scene_from_model)[0].xyz, in_position) + 0.5,
+        0.0, 1.0
+    );
+    vec3 position = mix(in_position2, in_position, lod);
+    out_position =
         uniforms.projection_from_scene *
         uniforms.scene_from_model *
-        vec4(inPosition, 1.0);
-    fragColor = inColor;
+        vec4(position, 1.0);
+    out_normal = in_normal;
+    out_color = in_color;
+
+    gl_Position = out_position;
 }