feat: add ui renderer

src/shaders/ui_v_shader.glsl

@@ -0,0 +1,18 @@
+#version 460
+
+layout (location = 0) in vec2 pos;
+layout (location = 1) in vec2 texCoord;
+layout (location = 2) in float layer;
+
+out vec2 tc;
+
+flat out int tex_layer;
+
+uniform mat4 m_matrix;
+uniform mat4 proj_matrix;
+
+void main(void) {
+    gl_Position = proj_matrix * m_matrix * vec4(pos, 0.0, 1.0);
+    tc = texCoord;
+    tex_layer = int(layer);
+}