fix: lower required OpenGL version + resolve offset bug

src/shader/pixelbuf.vert

@@ -1,4 +1,4 @@
-#version 450 core
+#version 330 core
 layout (location = 0) in vec3 aPos;
 layout (location = 1) in vec3 aColor;
 layout (location = 2) in vec2 aTexCoord;
@@ -6,9 +6,8 @@ layout (location = 2) in vec2 aTexCoord;
 out vec3 ourColor;
 out vec2 TexCoord;
 
-void main()
-{
+void main() {
 	gl_Position = vec4(aPos, 1.0);
 	ourColor = aColor;
-	TexCoord = vec2(aTexCoord.x, aTexCoord.y);
+	TexCoord = aTexCoord;
 }