public static GlUniformBlockBinding Bind(int programId, string blockName)
{
GlUniformBlockBinding binding;
// Get the block index
var uniformBlockIndex = GL.GetUniformBlockIndex(programId, blockName);
GlDebug.ThrowIfGlError("getting uniform block index");
if (uniformBlockIndex == (int)All.InvalidIndex)
{
throw new ArgumentException($"Uniform block '{blockName}' not found.", nameof(blockName));
}
// Check if this block already has an assigned binding point.
GL.GetActiveUniformBlock(programId, uniformBlockIndex, ActiveUniformBlockParameter.UniformBlockBinding, out int bindingPointIndex);
GlDebug.ThrowIfGlError("getting uniform block binding");
if (bindingPointIndex != 0)
{
// Block already has a binding (might be specified in the shader), so..
// If we've already created a binding ref for this block index, use that.
// Otherwise create a new one.
if (!BindingsByBindingPoint.TryGetValue(bindingPointIndex, out binding))
{
binding = new GlUniformBlockBinding(bindingPointIndex, blockName);
}
}
else
{
// Block doesn't already have a binding, so..
// If we've already created a binding point for this block name, use that.
// Otherwise assign a brand new one.
if (!BindingsByBlockName.TryGetValue(blockName, out binding))
{
// TODO: Not right. should also skip bindings already in use in OpenGL (because theyre specified in shaders)
// that we aren't aware of yet. might be better to not maintain a record ourselves and always just query opengl
int firstUnusedBindingPoint = 1;
while (BindingsByBindingPoint.ContainsKey(firstUnusedBindingPoint))
{
firstUnusedBindingPoint++;
}
binding = new GlUniformBlockBinding(firstUnusedBindingPoint, blockName);
}
// Bind this block to the binding point
GL.UniformBlockBinding(programId, uniformBlockIndex, binding.BindingPoint);
GlDebug.ThrowIfGlError("setting uniform block binding");
}
return(binding);
}
/// <summary>
/// Initializes a new instance of the <see cref="GlUniformBlockBindingRef"/> class.
/// </summary>
/// <param name="programId"></param>
/// <param name="blockName"></param>
public GlUniformBlockBindingRef(int programId, string blockName)
{
binding = GlUniformBlockBinding.Bind(programId, blockName);
binding.Use();
}