public VAO(ShaderProgram program, VBO <T1> vbo1, string attribName, VBO <int> elementArray)
: base(program)
{
IGenericVBO[] vbos = new IGenericVBO[2];
vbos[0] = new GenericVBO <T1>(vbo1, attribName);
vbos[1] = new GenericVBO <int>(elementArray);
Init(vbos);
}
public VAO(ShaderProgram program, VBO <T1> vbo1, string[] attribNames, VBO <int> elementArray)
: base(program)
{
if (attribNames.Length != 1)
{
throw new Exception(string.Format("Expected an array of 1 name, but instead got {0}.", attribNames.Length));
}
IGenericVBO[] vbos = new IGenericVBO[2];
vbos[0] = new GenericVBO <T1>(vbo1, attribNames[0]);
vbos[1] = new GenericVBO <int>(elementArray);
Init(vbos);
}
public void BindAttributes(ShaderProgram program)
{
IGenericVBO elementArray = null;
for (int i = 0; i < vbos.Length; i++)
{
if (vbos[i].BufferTarget == BufferTarget.ElementArrayBuffer)
{
elementArray = vbos[i];
// To not break compatibility with previous versions of this call,
// int is allowed as an element type even though the specs don't allow it.
// All cases where int is used as the default element type have been marked obsolete
// but until it's completely removed, this will serve to support that use case.
if (allowIntAsElementType && vbos[i].PointerType == VertexAttribPointerType.Int)
{
elementType = DrawElementsType.UnsignedInt;
}
else
{
// Check if the element array can be used as an indice buffer.
if (!ValidElementTypes.ContainsKey(vbos[i].PointerType))
{
throw new Exception($"The element buffer must be an unsigned integral type. See {nameof(DrawElementsType)} enum for valid types.");
}
elementType = ValidElementTypes[vbos[i].PointerType];
}
continue;
}
// According to OGL spec then, if there is no location for an attribute, -1 is returned.
// The same error representation is used here.
int loc = program[vbos[i].Name]?.Location ?? -1;
if (loc == -1)
{
throw new Exception(string.Format("Shader did not contain '{0}'.", vbos[i].Name));
}
Gl.EnableVertexAttribArray((uint)loc);
Gl.BindBuffer(vbos[i].BufferTarget, vbos[i].ID);
if (vbos[i].CastToFloat)
{
Gl.VertexAttribPointer((uint)loc, vbos[i].Size, vbos[i].PointerType, vbos[i].Normalize, 0, IntPtr.Zero);
}
else if (vbos[i].IsIntegralType)
{
Gl.VertexAttribIPointer((uint)loc, vbos[i].Size, vbos[i].PointerType, 0, IntPtr.Zero);
}
else if (vbos[i].PointerType == VertexAttribPointerType.Double)
{
Gl.VertexAttribLPointer((uint)loc, vbos[i].Size, vbos[i].PointerType, 0, IntPtr.Zero);
}
else
{
throw new Exception("VBO shouldn't be cast to float, isn't an integral type and is not a float. No vertex attribute support this combination.");
}
// 0 is the divisors default value.
// No need to set the divisor to its default value.
if (vbos[i].Divisor != 0)
{
Gl.VertexAttribDivisor((uint)loc, vbos[i].Divisor);
}
}
if (elementArray != null)
{
Gl.BindBuffer(BufferTarget.ElementArrayBuffer, elementArray.ID);
VertexCount = elementArray.Length;
}
}
