   Changing Color and Alpha of a Quad without locking vertexbuffer?
  I want to change the alpha value and color value of my Quad's.But i don't want to make any Lock() on vertexbuffer.   I know that i can gain a fade effect by changing the diffuse color's alpha values.But this  means i must lock the vertex buffer.I dont want to do that..is there another way.   Also it would be nice to change texture color (again not using locking())   One more questiong i want to show only some part of a texture in my Quad.But i dont want to change u,v values (which means locking).İs there another way for that  such as texture matrix etc..   Simply,I want to make every effect i can without touching my vertexbuffers?What should i do for that..   
  thnks ...   ;  Vertex shader.   