Rainbow trianglegit add .

shaders/simple_shader.vert

@@ -1,7 +1,11 @@
 #version 450
 
 layout(location = 0) in vec2 position;
+layout(location = 1) in vec3 color;
+
+layout(location = 0) out vec3 fragColor;
 
 void main() {
   gl_Position = vec4(position, 0.0, 1.0);
+  fragColor = color;
 }