feat: vertex colors

polygon.hpp

@@ -11,6 +11,7 @@ struct polygon {
 
     decimal bounding[4]; // min x, max x, min y, max y
     vec3 normals[3];
+    vec3 colors[3];
 
     polygon(const vec3 &v1, const vec3 &v2, const vec3 &v3)
         : points{v1, v2, v3}, delta{} {}
@@ -84,6 +85,11 @@ struct polygon {
         return result.normalize();
     }
 
+    vec3 calcColor(vec3 barycentrics) {
+        return colors[0] * barycentrics[0] + colors[1] * barycentrics[1] +
+               colors[2] * barycentrics[2];
+    }
+
     decimal calcDepth(vec3 barycentrics) {
         return points[0].z() * barycentrics[0] +
                points[1].z() * barycentrics[1] +