/// <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 old API.
/// </summary>
private unsafe void BindVertexAttributesForBuffer_OldAPI(OpenGLVertexBuffer vbuffer, UInt32 binding, UInt32 frequency, UInt32?program, UInt32?offset)
{
OpenGLState.BindArrayBuffer(vbuffer.OpenGLName);
var position = offset ?? this.offset;
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)
{
if (program.HasValue)
{
if (gl.IsInstancedRenderingAvailable)
{
gl.VertexAttribDivisor(location, frequency);
gl.ThrowIfError();
}
else
{
if (frequency != 0)
{
throw new NotSupportedException(OpenGLStrings.InstancedRenderingNotSupported);
}
}
gl.EnableVertexAttribArray(location);
gl.ThrowIfError();
}
switch (category)
{
case OpenGLAttribCategory.Single:
{
gl.VertexAttribPointer(location, size, type, normalize, vbuffer.VertexDeclaration.VertexStride, (void *)(position));
gl.ThrowIfError();
}
break;
case OpenGLAttribCategory.Double:
{
if (!gl.IsDoublePrecisionVertexAttribAvailable)
{
throw new NotSupportedException(OpenGLStrings.DoublePrecisionVAttribsNotSupported);
}
gl.VertexAttribLPointer(location, size, type, vbuffer.VertexDeclaration.VertexStride, (void *)(position));
gl.ThrowIfError();
}
break;
case OpenGLAttribCategory.Integer:
{
if (!gl.IsIntegerVertexAttribAvailable)
{
throw new NotSupportedException(OpenGLStrings.IntegerVAttribsNotSupported);
}
gl.VertexAttribIPointer(location, size, type, vbuffer.VertexDeclaration.VertexStride, (void *)(position));
gl.ThrowIfError();
}
break;
}
}
position += (uint)stride;
}
}