/// <inheritdoc/>
public override void Attach(IndexBuffer ibuffer)
{
Contract.Require(ibuffer, nameof(ibuffer));
Contract.EnsureNot(HasIndices, UltravioletStrings.GeometryStreamAlreadyHasIndices);
Contract.EnsureNotDisposed(this, Disposed);
Ultraviolet.ValidateResource(ibuffer);
var sdlIndexBuffer = (OpenGLIndexBuffer)ibuffer;
var sdlIndexBufferName = sdlIndexBuffer.OpenGLName;
this.ibuffer = sdlIndexBuffer;
if (IsUsingVertexArrayObject)
{
using (OpenGLState.ScopedBindVertexArrayObject(vao, 0, 0, true))
{
gl.BindBuffer(gl.GL_ELEMENT_ARRAY_BUFFER, sdlIndexBufferName);
gl.ThrowIfError();
}
}
this.glElementArrayBufferBinding = sdlIndexBufferName;
this.indexBufferElementType = ibuffer.IndexElementType;
}
/// <summary>
/// Binds the geometry stream's buffers to the device in preparation for rendering.
/// </summary>
private void BindBuffers(UInt32?program, UInt32?offset)
{
unsafe
{
var previousBuffer = (uint)OpenGLState.GL_ARRAY_BUFFER_BINDING;
if (IsUsingVertexArrayObject)
{
using (OpenGLState.ScopedBindVertexArrayObject(vao, glElementArrayBufferBinding ?? 0, force: !gl.IsVertexAttribBindingAvailable))
{
if (program.HasValue)
{
DisableVertexAttributesOnCachedProgram();
}
if (gl.IsVertexAttribBindingAvailable)
{
for (int i = 0; i < vbuffers.Count; i++)
{
var binding = vbuffers[i];
BindVertexAttributesForBuffer_NewAPI(binding.VertexBuffer,
(UInt32)i, (UInt32)binding.InstanceFrequency, program, offset);
}
}
else
{
for (int i = 0; i < vbuffers.Count; i++)
{
var binding = vbuffers[i];
BindVertexAttributesForBuffer_OldAPI(binding.VertexBuffer,
(UInt32)i, (UInt32)binding.InstanceFrequency, program, offset);
}
}
}
}
else
{
if (program.HasValue)
{
DisableVertexAttributesOnCachedProgram();
}
for (int i = 0; i < vbuffers.Count; i++)
{
var binding = vbuffers[i];
BindVertexAttributesForBuffer_OldAPI(binding.VertexBuffer,
(UInt32)i, (UInt32)binding.InstanceFrequency, program, offset);
}
OpenGLState.BindArrayBuffer(previousBuffer);
}
}
}
/// <summary>
/// Binds the specified buffer's vertex attributes to the currently cached program using the new API.
/// </summary>
private unsafe void BindVertexAttributesForBuffer_NewAPI(OpenGLVertexBuffer vbuffer, UInt32 binding, UInt32 frequency, UInt32?program, UInt32?offset)
{
var caps = Ultraviolet.GetGraphics().Capabilities;
using (OpenGLState.ScopedBindVertexArrayObject(vao, glElementArrayBufferBinding ?? 0))
{
if (program.HasValue || offset.HasValue)
{
gl.VertexArrayVertexBuffer(vao, binding, vbuffer.OpenGLName, (IntPtr)(offset ?? 0), vbuffer.VertexDeclaration.VertexStride);
gl.ThrowIfError();
}
if (program.HasValue)
{
gl.VertexArrayBindingDivisor(vao, binding, frequency);
gl.ThrowIfError();
var position = 0u;
foreach (var element in vbuffer.VertexDeclaration)
{
var name = GetVertexAttributeNameFromUsage(element.Usage, element.Index);
var size = 0;
var stride = 0;
var normalize = false;
var type = GetVertexFormatGL(element.Format, out size, out stride, out normalize);
var category = OpenGLAttribCategory.Single;
var location = (UInt32)OpenGLState.CurrentProgram.GetAttribLocation(name, out category);
if (location >= 0)
{
gl.VertexArrayAttribBinding(vao, location, binding);
gl.ThrowIfError();
gl.EnableVertexArrayAttrib(vao, location);
gl.ThrowIfError();
unsafe
{
switch (category)
{
case OpenGLAttribCategory.Single:
{
gl.VertexArrayAttribFormat(vao, location, size, type, normalize, position);
gl.ThrowIfError();
}
break;
case OpenGLAttribCategory.Double:
{
if (!caps.SupportsDoublePrecisionVertexAttributes)
{
throw new NotSupportedException();
}
gl.VertexArrayAttribLFormat(vao, location, size, type, position);
gl.ThrowIfError();
}
break;
case OpenGLAttribCategory.Integer:
{
if (!caps.SupportsIntegerVertexAttributes)
{
throw new NotSupportedException();
}
gl.VertexArrayAttribIFormat(vao, location, size, type, position);
gl.ThrowIfError();
}
break;
}
}
}
position += (uint)stride;
}
}
}
}