/*

 Copyright (C) 2015-2016 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 Utility class for creating a render pass descriptor.

 */

#import "MetalNBodyRenderPassDescriptor.h"

@implementation MetalNBodyRenderPassDescriptor

{

@private

    BOOL _haveTexture;

    MTLLoadAction  _load;

    MTLStoreAction _store;

    MTLClearColor  _color;

    MTLRenderPassDescriptor* _descriptor;

}

- (nullable MTLRenderPassDescriptor *) _newDescriptor

{

    MTLRenderPassDescriptor* pDescriptor = [MTLRenderPassDescriptor renderPassDescriptor];

    if(pDescriptor)

    {

        pDescriptor.colorAttachments[0].loadAction  = _load;

        pDescriptor.colorAttachments[0].storeAction = _store;

        pDescriptor.colorAttachments[0].clearColor  = _color;

    } // if

    else

    {

        NSLog(@">> ERROR:  Failed to instantiate a Metal render pass decriptor!");

    } // else

    return pDescriptor;

} // _newDescriptor

- (instancetype) init

{

    self = [super init];

    if(self)

    {

        _load        = MTLLoadActionClear;

        _store       = MTLStoreActionStore;

        _color       = MTLClearColorMake(0.0f, 0.0f, 0.0f, 0.0f);

        _haveTexture = NO;

        _descriptor  = [self _newDescriptor];

    } // if

    return self;

} // init

- (void) setColor:(MTLClearColor)color

{

    _color = color;

    if(_descriptor)

    {

        _descriptor.colorAttachments[0].clearColor = _color;

    } // if

} // setColor

- (void) setDrawable:(nullable id<CAMetalDrawable>)drawable

{

    _haveTexture = NO;

    if(drawable && _descriptor)

    {

        id<MTLTexture> texture = drawable.texture;

        if(texture)

        {

            _descriptor.colorAttachments[0].texture = texture;

            _haveTexture = YES;

        } // if

    } // if

} // setDrawable

@end