/// <summary>
/// Initializes a portion of the buffer's data with the specified data.
/// </summary>
/// <typeparam name="T">The type of each item.</typeparam>
/// <param name="data">The data used to initialize the buffer's data.</param>
/// <param name="offsetInBytes">The offset where data replacement will begin</param>
/// <exception cref="ArgumentOutOfRangeException">The specified range includes data
/// outside the buffer's current capacity.</exception>
public void SetSubData <T>(T data, int offsetInBytes) where T : struct
{
int itemSizeInBytes = System.Runtime.InteropServices.Marshal.SizeOf(typeof(T));
if (!BufferValidation.IsValidAccess(offsetInBytes, itemSizeInBytes, 1, SizeInBytes))
{
throw new ArgumentOutOfRangeException("", BufferExceptionMessages.outOfRange);
}
Bind();
GL.BufferSubData(Target, new IntPtr(offsetInBytes), itemSizeInBytes, ref data);
}
/// <summary>
/// Binds the buffer and reads <paramref name="itemCount"/> elements of type <typeparamref name="T"/>
/// starting at <paramref name="offsetInBytes"/>.
/// </summary>
/// <typeparam name="T">The type of each item. This includes arithmetic types like <see cref="int"/>.</typeparam>
/// <param name="offsetInBytes">The starting offset for reading</param>
/// <param name="itemCount">The number of items of type <typeparamref name="T"/> to read.</param>
/// <returns>An array of size <paramref name="itemCount"/></returns>
/// <exception cref="ArgumentOutOfRangeException">The specified range includes data outside the buffer's current capacity.</exception>
public T[] GetSubData <T>(int offsetInBytes, int itemCount) where T : struct
{
int itemSizeInBytes = System.Runtime.InteropServices.Marshal.SizeOf(typeof(T));
if (!BufferValidation.IsValidAccess(offsetInBytes, itemSizeInBytes, itemCount, SizeInBytes))
{
throw new ArgumentOutOfRangeException("", BufferExceptionMessages.outOfRange);
}
Bind();
T[] data = new T[itemCount];
GL.GetBufferSubData(Target, new IntPtr(offsetInBytes), itemCount * itemSizeInBytes, data);
return(data);
}
/// <summary>
/// Configures the data source for a floating point vertex attribute.
/// An exception is thrown if the specified parameters would result in an invalid buffer access.
/// </summary>
/// <param name="vertexAttribute">The vertex attribute information></param>
/// <param name="bufferName">The name of the buffer used for <see cref="AddBuffer{T}(string, T[])"/></param>
/// <param name="offsetInBytes">The offset in bytes for the start of the vertex data in the buffer</param>
/// <param name="strideInBytes">The stride in bytes for the buffer data</param>
/// <exception cref="ArgumentOutOfRangeException">The specified parameters would result in an invalid buffer access.</exception>
public void ConfigureAttribute(VertexAttribute vertexAttribute, string bufferName, int offsetInBytes, int strideInBytes)
{
if (strideInBytes < 0)
{
throw new ArgumentOutOfRangeException(nameof(strideInBytes), invalidAccessMessage);
}
if (!bufferByName.ContainsKey(bufferName))
{
throw new ArgumentException($"The buffer {bufferName} has not been added.", nameof(bufferName));
}
var buffer = bufferByName[bufferName];
var elementSize = AttribPointerUtils.GetSizeInBytes(vertexAttribute.Type) * (int)vertexAttribute.ValueCount;
if (!BufferValidation.IsValidAccess(offsetInBytes, strideInBytes, elementSize, VertexCount, buffer.SizeInBytes))
{
throw new ArgumentOutOfRangeException("", invalidAccessMessage);
}
// Associate attributes with the appropriate buffer, so the buffer can be bound later.
attributesByBuffer[buffer].Add(new VertexAttributeExtended(vertexAttribute, offsetInBytes, strideInBytes));
}
public void NegativeElementSize()
{
Assert.IsFalse(BufferValidation.IsValidAccess(0, 4, -4, 4, 16));
}
public void ValidWriteEmptyBuffer()
{
Assert.IsTrue(BufferValidation.IsValidAccess(0, 0, 0, 0));
}
public void ElementSizeLessThanStride()
{
// The difference between stride and element size is just padding and won't actually be read for the last element.
// Read: element + pad 1 + element + pad 1 + element + pad 1 + element + *skip padding* = 19 bytes
Assert.IsTrue(BufferValidation.IsValidAccess(0, 5, 4, 4, 19));
}
public void ElementSizeGreaterThanStride()
{
// The element size is valid but the stride is not.
Assert.IsFalse(BufferValidation.IsValidAccess(0, 3, 4, 4, 16));
}
public void NegativeElementCountNegativeStride()
{
// This may work for a naive implementation.
Assert.IsFalse(BufferValidation.IsValidAccess(0, -4, -4, 16));
}
public void NegativeLength()
{
// This may work for a naive implementation.
Assert.IsFalse(BufferValidation.IsValidAccess(0, -4, 4, -16));
}
public void NegativeStride()
{
Assert.IsFalse(BufferValidation.IsValidAccess(0, -4, 4, 16));
}
public void ReadOnePastEnd()
{
Assert.IsFalse(BufferValidation.IsValidAccess(1, 4, 4, 16));
}
public void ReadHalfBuffer()
{
Assert.IsTrue(BufferValidation.IsValidAccess(8, 4, 2, 16));
}
public void ReadWholeBuffer()
{
Assert.IsTrue(BufferValidation.IsValidAccess(0, 4, 4, 16));
}
public void NegativeOffset()
{
Assert.IsFalse(BufferValidation.IsValidAccess(-4, 4, 4, 32));
}
