Add the shaders

tools/pdsg/shaders/shader.frag

@@ -0,0 +1,20 @@
+#version 460
+      
+layout(location = 0) in vec2 oUV;
+layout(location = 1) in vec4 oColor;
+
+uniform sampler2D tex;
+layout(push_constant) uniform PushData {
+  int alfa;
+} push;
+
+out vec4 FragColor;
+    
+void main() {
+  vec4 tc = texture(tex, oUV);
+  if (push.alfa != 0) {
+    FragColor = vec4(oColor.rgb, tc.a * oColor.a);
+  } else {
+    FragColor = tc * oColor;
+  }
+}