added a program that just copies input to output

com/danitheskunk/skunkworks/backends/gl/ProgramCopy.java

@@ -0,0 +1,37 @@
+package com.danitheskunk.skunkworks.backends.gl;
+
+public class ProgramCopy extends Program {
+	private static final String fragmentSource = """
+		#version 450
+		layout(location = 1) in vec2 texCoord;
+		layout(binding = 0) uniform sampler2D tex;
+		out vec4 color;
+		void main() {
+			vec4 col = texture(tex, texCoord);
+			if(col.a > 0.0) {
+				color = col;
+			}
+		}
+		""";
+	private static final String vertexSource = """
+		#version 450
+		layout(location = 0) in vec2 pos;
+		layout(location = 1) out vec2 out_texCoord;
+		void main() {
+			gl_Position = vec4(pos, 0.0f, 1.0f);
+			out_texCoord = vec2(pos.x * 0.5 + 0.5, pos.y * 0.5 + 0.5);
+		}
+		""";
+	private ProgramCopy() {
+		super(vertexSource, fragmentSource);
+	}
+
+	private static ProgramCopy instance;
+
+	public static ProgramCopy getInstance() {
+		if(instance == null) {
+			instance = new ProgramCopy();
+		}
+		return instance;
+	}
+}