ios - iOS-Metal: 深度バッファをクリアするには? OpenGL の glClear(GL_DEPTH_BUFFER_BIT) に似ています

Question

OpenGLで使用する深度バッファをクリアする必要がありglClear(GL_DEPTH_BUFFER_BIT)ますが、金属で行うにはどうすればよいですか? 私はアップルのドキュメントを調べましたが、それについてのヒントはありません。

Answer 1

サンプルコードでソリューションをより明確に説明するには

レンダリングを開始する前に:

void prepareRendering(){
    CMDBuffer = [_commandQueue commandBuffer]; // get command Buffer
    drawable = [_metalLayer nextDrawable]; // get drawable from metalLayer
    renderingTexture = drawable.texture; // set that as rendering te
    setupRenderPassDescriptorForTexture(drawable.texture); // set the depth and colour buffer properties
    RenderCMDBuffer = [CMDBuffer renderCommandEncoderWithDescriptor:_renderPassDescriptor];
    RenderCMDBuffer.label = @"MyRenderEncoder";
    setUpDepthState(CompareFunctionLessEqual,true,false); // 
    [RenderCMDBuffer setDepthStencilState:_depthState];
    [RenderCMDBuffer pushDebugGroup:@"DrawCube"];
}

void setupRenderPassDescriptorForTexture(id <MTLTexture> texture)
{
    if (_renderPassDescriptor == nil)
        _renderPassDescriptor = [MTLRenderPassDescriptor renderPassDescriptor];
        // set color buffer properties
        _renderPassDescriptor.colorAttachments[0].texture = texture;
        _renderPassDescriptor.colorAttachments[0].loadAction = MTLLoadActionClear;
        _renderPassDescriptor.colorAttachments[0].clearColor = MTLClearColorMake(1.0f, 1.0f,1.0f, 1.0f);
            _renderPassDescriptor.colorAttachments[0].storeAction = MTLStoreActionStore;
// set depth buffer properties
            MTLTextureDescriptor* desc = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat: MTLPixelFormatDepth32Float width: texture.width height: texture.height mipmapped: NO];
            _depthTex = [device newTextureWithDescriptor: desc];
            _depthTex.label = @"Depth";
            _renderPassDescriptor.depthAttachment.texture = _depthTex;
            _renderPassDescriptor.depthAttachment.loadAction = MTLLoadActionClear;
            _renderPassDescriptor.depthAttachment.clearDepth = 1.0f;
                _renderPassDescriptor.depthAttachment.storeAction = MTLStoreActionDontCare;
   }

ここにコンテンツをレンダリングします

Render();

レンダリング後

ogles2 メソッドと同様 [_context presentRenderbuffer:_colorRenderBuffer];

void endDisplay()
{
    [RenderCMDBuffer popDebugGroup];
    [RenderCMDBuffer endEncoding];
    [CMDBuffer presentDrawable:drawable];
    [CMDBuffer commit];
    _currentDrawable = nil;
}

上記のメソッドは、各フレームをレンダリングした後に深度とカラー バッファーをクリアします。

デプスバッファを途中でクリアするには

    void clearDepthBuffer(){
    // end encoding the render command buffer  
            [RenderCMDBuffer popDebugGroup];
            [RenderCMDBuffer endEncoding];

            // here MTLLoadActionClear will clear your last drawn depth values
            _renderPassDescriptor.depthAttachment.loadAction = MTLLoadActionClear;            _renderPassDescriptor.depthAttachment.clearDepth = 1.0f;
            _renderPassDescriptor.depthAttachment.storeAction = MTLStoreActionDontCare;

            // here MTLLoadActionLoad will reuse your last drawn color buffer
            _renderPassDescriptor.colorAttachments[0].loadAction = MTLLoadActionLoad;
            _renderPassDescriptor.colorAttachments[0].storeAction = MTLStoreActionStore;

            RenderCMDBuffer = [CMDBuffer renderCommandEncoderWithDescriptor:_renderPassDescriptor];
            RenderCMDBuffer.label = @"MyRenderEncoder";
            [RenderCMDBuffer pushDebugGroup:@"DrawCube"];
        }