/*If the app draws many different kinds of models, reconfiguring the pipeline may become a bottleneck.
* Instead, use a vertex array object to store a complete attribute configuration.
* Each configuration is independent of the other; each vertex array object can reference a different set of vertex attributes,
* which can be stored in the same vertex buffer object or split across several vertex buffer objects.
* https://developer.apple.com/library/ios/documentation/3DDrawing/Conceptual/OpenGLES_ProgrammingGuide/TechniquesforWorkingwithVertexData/TechniquesforWorkingwithVertexData.html#//apple_ref/doc/uid/TP40008793-CH107-SW1
*/
public static void ConfigureVertexArrayObject(out int vao, VBOUtil.Vbo vbo)
{
if (vbo.VertexBufferID == 0 || vbo.ElementBufferID == 0)
{
vao = 0;
return;
}
// Create and bind the vertex array object.
GL.GenVertexArrays(1, out vao);
GL.BindVertexArray(vao);
// Vertex Array Buffer
{
// Bind to the Array Buffer ID
GL.BindBuffer(BufferTarget.ArrayBuffer, vbo.VertexBufferID);
GL.EnableVertexAttribArray(0); //Position
GL.VertexAttribPointer(0, 3, VertexAttribPointerType.Float, false, 8 * sizeof(float), IntPtr.Zero);
GL.EnableVertexAttribArray(1); //Texture Coordinates
GL.VertexAttribPointer(1, 2, VertexAttribPointerType.Float, false, 8 * sizeof(float), (IntPtr)(IntPtr.Zero + 3 * sizeof(float)));
GL.EnableVertexAttribArray(2); //Normal
GL.VertexAttribPointer(2, 3, VertexAttribPointerType.Float, false, 8 * sizeof(float), (IntPtr)(IntPtr.Zero + 3 * sizeof(float) + 2 * sizeof(float)));
//TO BE REMOVED WHEN SHADERS ARE INTRODUCED
/*
* // Set the Pointer to the current bound array describing how the data ia stored
* GL.TexCoordPointer(2, TexCoordPointerType.Float, 8 * sizeof(float), (IntPtr)(IntPtr.Zero + 3 * sizeof(float)));
*
* // Enable the client state so it will use this array buffer pointer
* GL.EnableClientState(ArrayCap.TextureCoordArray);
*
* // Set the Pointer to the current bound array describing how the data ia stored
* GL.NormalPointer(NormalPointerType.Float, 8 * sizeof(float), (IntPtr)(IntPtr.Zero + 3 * sizeof(float) + 2 * sizeof(float)));
*
* // Enable the client state so it will use this array buffer pointer
* GL.EnableClientState(ArrayCap.NormalArray);
*/
}
// Element Array Buffer
{
// Bind to the Array Buffer ID
GL.BindBuffer(BufferTarget.ElementArrayBuffer, vbo.ElementBufferID);
}
// Bind back to the default state.
GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
GL.BindVertexArray(0);
}
int vao; //array buffer object
//Constructor to be used with VBO concept. Only single texture used. DisplayList not neaded any longer.
public SkyBox(float aSize)
{
mSize = aSize;
if (skyBoxTexturePath != null)
{
skyBoxSingleTexture = TextureManager.LoadTexture(skyBoxTexturePath);
}
//Using VBO concept instead of DisplayList
// loading Vertex Buffers
Shape skyBoxShape = new SkyBoxShape(aSize);
vbo = VBOUtil.LoadVBO(skyBoxShape);
VBOUtil.ConfigureVertexArrayObject(out vao, vbo);
}
public static int labelVao; //VOA for file node's labels
public static void LoadVBOs()
{
//Using VBO concept instead of DisplayList
// loading Vertex Buffers
Shape fileNodeShape = new FileNodeShape();
Shape dirNodeShape = new DirNodeShape();
Shape driveNodeShape = new DriveNodeShape();
vbo[(int)Node.NodeType.FILE_NODE] = VBOUtil.LoadVBO(fileNodeShape);
VBOUtil.ConfigureVertexArrayObject(out vao [(int)Node.NodeType.FILE_NODE], vbo [(int)Node.NodeType.FILE_NODE]);
vbo[(int)Node.NodeType.DIR_NODE] = VBOUtil.LoadVBO(dirNodeShape);
VBOUtil.ConfigureVertexArrayObject(out vao [(int)Node.NodeType.DIR_NODE], vbo [(int)Node.NodeType.DIR_NODE]);
vbo[(int)Node.NodeType.DRIVE_NODE] = VBOUtil.LoadVBO(driveNodeShape);
VBOUtil.ConfigureVertexArrayObject(out vao [(int)Node.NodeType.DRIVE_NODE], vbo [(int)Node.NodeType.DRIVE_NODE]);
Shape labelShape = new LabelShape();
labelVbo = VBOUtil.LoadVBO(labelShape);
VBOUtil.ConfigureVertexArrayObjectForLabels(out labelVao, labelVbo);
}
//Draw using VAO and VBO, where VAO stores a complete set of attributes for the given VBO
public static void Draw(int vao, VBOUtil.Vbo vbo)
{
// Push current Array Buffer state so we can restore it later
//GL.PushClientAttrib(ClientAttribMask.ClientVertexArrayBit);
if (vao != previouslyUsedVao) //To eliminate unnecessary GL calls.
{
previouslyUsedVao = vao;
GL.BindVertexArray(vao);
}
// Draw the elements in the element array buffer
// Draws up items in the Color, Vertex, TexCoordinate, and Normal Buffers using indices in the ElementArrayBuffer
//GL.DrawElements(PrimitiveType.Triangles, vbo.NumElements, DrawElementsType.UnsignedInt, IntPtr.Zero);
//GL.DrawRangeElements is slightly better performance-wise than GL.DrawElements
GL.DrawRangeElements(PrimitiveType.Triangles, 0, vbo.NumElements - 1, vbo.NumElements, DrawElementsType.UnsignedInt, IntPtr.Zero);
// Could also call GL.DrawArrays which would ignore the ElementArrayBuffer and just use primitives
// Of course we would have to reorder our data to be in the correct primitive order
// Restore the state
//GL.PopClientAttrib();
}