display slice and wireframe simultaneously

vis/shaders/direct-ortho.vs.glsl

@@ -0,0 +1,24 @@
+#version 430
+
+layout(std430, binding=1) buffer Positions {
+    vec4 verts[];
+};
+
+layout(std140, binding=1) uniform Matrices {
+    mat4 proj;
+    mat4 view;
+};
+
+out gl_PerVertex {
+    vec4 gl_Position;
+    float gl_PointSize;
+};
+
+out vec4 vpos;
+
+void main() {
+    vec4 pos = verts[gl_VertexID];
+    vpos = view * pos;
+    gl_Position = proj * vec4(vpos.xyz / (1), 1);
+    gl_PointSize = 5;
+}