Initial pipeline work

shaders/sprite.frag.glsl

@@ -0,0 +1,10 @@
+#version 450
+
+layout(set = 2, binding = 0) uniform sampler2D u_tex; // SDL_GPU fragment sampler slot 0
+
+layout(location = 0) in vec2 v_uv;
+layout(location = 0) out vec4 out_color;
+
+void main() {
+    out_color = texture(u_tex, v_uv);
+}