Added test case for reading UBOs with companion objects

Author: davesmith00000

ultraviolet/test/src/ultraviolet/acceptance/GLSLUBOTests.scala

@@ -4,6 +4,7 @@ import ultraviolet.DebugAST
 import ultraviolet.syntax.*
 
 import scala.annotation.nowarn
+import ultraviolet.macros.UBOReader
 
 @nowarn("msg=unused")
 class GLSLUBOTests extends munit.FunSuite {
@@ -49,4 +50,46 @@ class GLSLUBOTests extends munit.FunSuite {
 
   }
 
+  test("Can define a UBO struct from a case class with a companion") {
+
+    case class UBO1(TIME: highp[Float], val VIEWPORT_SIZE: vec2)
+    object UBO1:
+      /** Because of the initialisation order of synthesized mirror instances in companion objects, this _must_ be a
+        * lazy val or def, or use `new UBO1(..)`.
+        *
+        * HOWEVER, in practice, only a def will do, because the macro can't read the member values correctly if you use
+        * lazy val or val with new.
+        */
+      def reference: UBO1 =
+        UBO1(1.0f, vec2(0.0f))
+
+    // println(UBOReader.readUBO[UBO1])
+
+    inline def fragment =
+      Shader[UBO1 & FragEnv, Unit] { env =>
+        ubo[UBO1]
+        env.COLOR = vec4(env.UV, env.TIME, 1.0f)
+      }
+
+    val actual =
+      fragment.toGLSL[WebGL2](Version300ES, PrecisionHighPFloat).toOutput.code
+
+    // DebugAST.toAST(fragment)
+    // println(actual)
+
+    assertEquals(
+      actual,
+      s"""
+      |#version 300 es
+      |precision highp float;
+      |layout (std140) uniform UBO1 {
+      |  highp float TIME;
+      |  vec2 VIEWPORT_SIZE;
+      |};
+      |COLOR=vec4(UV,TIME,1.0);
+      |""".stripMargin.trim
+    )
+
+  }
+
 }