directx programming - computer graphics and -...

DirectX Programming

Computer Graphics, 2012 Spring

Jihye Yun

Programming with GPU

• Various APIs and technologies

– Graphics programming

– General-purpose GPU programming

Applications

DirectX OpenGL CUDA OpenCL

GPU

DirectX

• Components

• DirectX SDK (Software Development Kit) – Libraries, header files, utilities, sample codes and docs

DirectX 1.0

1995 1996 1998 1999 2000 2001 2003 2004 2006 2008

DirectX 2.0

DirectX 5.0

DirectX 6.0

2002

DirectX 7.0

DirectX 8.0

DirectX 9.0

DirectX 9.0c

DirectX 10.0

2009

DirectX 11.0

2D and 3D graphics Direct3D

Sound XAudio2, X3DAudio, XACT

Input XInput

Installation

• You can download from Microsoft’s homepage

– Latest version: June 2010

– http://www.microsoft.com/download/en/details.aspx?id=6812

http://www.microsoft.com/download/en/details.aspx?id=6812

http://www.microsoft.com/download/en/details.aspx?id=6812

Visual Studio Settings

• Add DirectX include and library directories

– Tools > Options > Projects and Solutions >

VC++ Directories

Sample and Tutorial Codes

• Sample codes

– [DX directory]/Samples/C++/Direct3D11

• Tutorial codes

– [DX directory]/Samples/C++/Direct3D11/Tutorials

Sample and Tutorial Codes

• Using Sample Browser

Graphics Pipeline

Modeling Transformation

Viewing Transformation

Clipping

Projection (to screen space)

Scan Conversion (Rasterization)

Display

Direct3D Pipeline

• Stages

– Configured using API

• Shader stages

– Programmable using HLSL

Input-Assembler Stage

Rasterizer Stage

Stream-Output Stage

Output-Merger Stage

Vertex-Shader Stage

Geometry-Shader Stage

Pixel-Shader Stage

Memory Resources (Buffer, Texture, Constant Buffer)

Stage Abbr. Description

Input-Assembler IA Supply data to pipeline

Vertex-Shader VS Process vertices

Rasterizer RS Convert vector data to pixels

Pixel-Shader PS Generate per-pixel data

Output-Merger OM Generate final pipeline result


• Vertices

• Indices

• Primitive

– Composed of one or more vertices

– Point, line and triangle

– Primitive types • Point list, line list, line strip,

triangle list, triangle strip, …


Rasterizer Stage

Stream-Output Stage

Output-Merger Stage

Vertex-Shader Stage


Pixel-Shader Stage


Shader Stages

• Vertex/hull/domain/geometry/pixel-shader

• Programmable with HLSL


Rasterizer Stage

Stream-Output Stage

Output-Merger Stage

Vertex-Shader Stage


Pixel-Shader Stage


Ex. Tessellation using hull & domain shader

Shader Stages

• Vertex/hull/domain/geometry/pixel-shader

• Programmable with HLSL


Rasterizer Stage

Stream-Output Stage

Output-Merger Stage

Vertex-Shader Stage


Pixel-Shader Stage


Function Description

Creating shader object ID3D11Device::CreateVertexShader

Setting shader to use ID3D11DeviceContext::VSSetShader

Setting up each shader stage

ID3D11DeviceContext::VSSetConstantBuffer ID3D11DeviceContext::VSSetShaderResources ID3D11DeviceContext::VSSetSamplers

HLSL

• High Level Shading Language for DirectX

• For writing codes for programmable shaders in Direct3D pipeline

• Implements series of shader models

Shader Model Shader Profiles Direct3D support

Shader model 1 vs_1_1 Direct3D 9

Shader model 2 ps_2_0, ps_2_x, vs_2_0, vs_2_x

Shader model 3 ps_3_0, vs_3_0

Shader model 4 gs_4_0, ps_4_0, vs_4_0, gs_4_1, ps_4_1, vs_4_1 Direct3D 10

Shader model 5 cs_4_0, cs_4_1, cs_5_0, ds_5_0, gs_5_0, hs_5_0, ps_5_0, vs_5_0 Direct3D 11

Vertex-Shader Stage

• Process each vertex of primitives from IA

– Performs per-vertex operations (transformations, morphing, per-vertex lighting, …)

• Single input vertex, single

output vertex

– Always run on all vertices

• Mandatory stage


Rasterizer Stage

Stream-Output Stage

Output-Merger Stage

Vertex-Shader Stage


Pixel-Shader Stage


Rasterizer Stage

• Convert each primitive into pixels

• Performed operations

– Clipping vertices to view frustum

– Culling out back faces

– Performing divided by z to provide

perspective

– Mapping primitives to 2D viewport


Rasterizer Stage

Stream-Output Stage

Output-Merger Stage

Vertex-Shader Stage


Pixel-Shader Stage


Pixel-Shader Stage

• Process each pixel from rasterizer stage

• Enable rich shading techniques and more

• Generated output

– Colors to be written to render

targets

– Optional depth value

• All texture methods available

• Mandatory Stage


Rasterizer Stage

Stream-Output Stage

Output-Merger Stage

Vertex-Shader Stage


Pixel-Shader Stage


Output-Merger Stage

• Generate final rendered pixel color

– Combine pipeline state, pixel data generated by PS, contents of the depth/stencil buffers

• Determine visibility of pixels

(depth-stencil testing)

• Blend final pixel colors


Rasterizer Stage

Stream-Output Stage

Output-Merger Stage

Vertex-Shader Stage


Pixel-Shader Stage


Tutorial 1: Creating Device

• Create device object and swap chain

– Device • Used to perform both rendering and resource creation

– Swap chain • Encapsulate two or more buffers used for rendering and

display

• Front buffer: presented to display device

• Back buffer: render target

• Presents back buffer by swapping two buffers

Creating Device

ID3D11Device* g_pd3dDevice = NULL;

IDXGISwapChain* g_pSwapChain = NULL;

ID3D11DeviceContext* g_pImmediateContext = NULL;

if ( FAILED ( D3D11CreateDeviceAndSwapChain ( NULL,

D3DDRIVER_TYPE_HARDWARE, NULL, 0, featureLevels,

numFeatureLevels, D3D11_SDK_VERSION, &sd,

&g_pSwapChain, &g_pd3dDevice, NULL, &g_pImmediateContext ) ) )

{

return FALSE; }

Creating Device

DXGI_SWAP_CHAIN_DESC sd;

Zeromemory( &sd, sizeof(sd) );

sd.BufferCount = 1;

sd.BufferDesc.Width = 640;

sd.BufferDesc.Height = 480;

sd.BufferDesc.Format = DXGI_FORMAT_R8G8B88_UNORM;

sd.BufferDesc.RefreshRate.Numerator = 60;

sd.BufferDesc.RefreshRate.Denominator = 1;

sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;

sd.OutputWindow = g_hWnd;

sd.SampleDesc.Count = 1;

sd.SampleDesc.Quality = 0;

sd.Windowed = TRUE;

Create a Render Target View

• Resource view

– Allow a resource to be bound to the graphics pipeline at a specific stage

• Render target view is a type of resource view

– Pixel shader can simultaneously render to at least eight separate render targets

Create a Render Target View

ID3D11RenderTargetView* g_pRenderTargetView;

ID3D11Texture2D* pBackBuffer;

if( FAILED ( g_pSwapChain->GetBuffer( 0, __uuidof(ID3D11Texture2D), (LPVOID*)&pBackBuffer ) ) )

return FALSE;

hr = g_pd3dDevice->CreateRenerTargetView( pBackBuffer, NULL, &g_pRenderTargetView );

pBackBuffer->Release( );

if ( FAILED ( hr ) )

return FALSE;

g_pImmediateContext->OMSetRenderTargets( 1,

&g_pRenderTargetView, NULL);

Modifying Message Loop

MSG msg = {0};

while ( WM_QUIT != msg.message )

{

if( PeekMessage ( &msg, NULL, 0, 0, PM_REMOVE ) )

{

TranslateMessage( &msg );

DispatchMessage( & msg ); }

else

{

Render(); // Do some rendering

} }

Rendering Code

void Render( )

{

//

// clear the backbuffer

//

float ClearColor[4] = { 0.0f, 0.125f, 0.6f, 1.0f };

g_pd3dDevice->ClearRenderTargetView( g_pRenderTargetView,

ClearColor);

g_pSwapChain->Present( 0, 0 );

}

Initialize Viewport

• Viewport – 2D rectangle into which 3D scene is projected

– In Direct3D 11, no viewport is set by default

Initialize Viewport

D3D11_VIEWPORT vp;

vp.Width = (FLOAT)width;

vp.Height = (FLOAT)height;

vp.MinDepth = 0.0f;

vp.MaxDepth = 1.0f;

vp.TopLeftX = 0;

vp.TopLeftY = 0;

g_pImmediateContext->RSSetViewports( 1, &vp );

Tutorial 1: Creating Device

• Result

Tutorial 2: Rendering a Triangle

• How do we pass the information to the GPU?

Input Layout

• Describe the structure of vertices in a way that can be understood by the GPU

• Each vertex attribute can be described with the D3D11_INPUT_ELEMENT_DESC structure

D3D11_INPUT_ELEMENT_DESC {

SemanticName, SemanticIndex, Format, InputSlot,

AlignedByteOffset, InputSlotClass,

InstanceDataStepRate

};

Input Layout

struct SimpleVertex{

XMFLOAT3 Pos; // Position };

// Define the input layout

D3D11_INPUT_ELEMENT_DESC layout[ ] = {

{ “POSITION”, 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0

D3D11_INPUT_PER_VERTEX_DATA, 0 },

};

UINT numElements = ARRAYSIZE( layout );

Input Layout

ID3D11InputLayout* g_pVertexLayout;

// Create the input layout

if( FAILED ( g_pd3dDevice->CreateInputLayout( layout, numElements,

pVSBlob->GetBufferPointer( ),

pVSBlob->GetBufferSize( ),

&g_pVertexLayout ) ) )

return FALSE;

// Set the input layout

g_pImmediateContext->IASetInputLayout( g_pVertexLayout );

Create Vertex Buffer

SimpleVertex vertices[ ] = {

XMFLOAT3( 0.0f, 0.5f, 0.5f );

XMFLOAT3( 0.5f, -0.5f, 0.5f );

XMFLOAT3( -0.5f, -0.5f, 0.5f );

};

D3D11_BUFFER_DESC bd;

ZeroMemory( &bd);

bd.Usage = D3D11_USAGE_DEFAULT;

bd.ByteWidth = sizeof( SimpleVertex ) * 3;

bd.BindFlags = D3D_BIND_VERTEX_BUFFER;

bd.CPUAccessFlags = 0;

bd.MiscFlags = 0;

Create Vertex Buffer

D3D11_SUBRESOURCE_DATA InitData;

ZeroMemory( & InitData, sizeof( InitData ) );

InitData.pSystem = vertices;

// Create vertex buffer

ID3D11Buffer* g_pVertexBuffer = NULL;

if( FAILED( g_pd3dDevice->CreateBuffer( &bd, &InitData,

&g_pVertexBuffer ) ) )

return FALSE;

// Set vertex buffer

UINT stride = sizeof( SimpleVertex );

UINT offset = 0;

g_ImmediateContext->IASetVertexBuffers( 0, 1, &g_pVertexBuffer,

&stride, &offset);

Primitive Topology

// Set primitive topology

g_pImmediateContext->IASetPrimitiveTopology(

D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);

D3D_PRIMITIVE_TOPOLOGY_POINTLIST

D3D_PRIMITIVE_TOPOLOGY_LINELIST

D3D_PRIMITIVE_TOPOLOGY_LINESTRIP

D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST

D3D_PRIMITIVE_TOPOLOGY_TRIANGLESTRIP

….

Rendering Triangle

ID3D11VertexShader* g_pVertexShader = NULL;

ID3D11PixelShader* g_pPixelShader = NULL;

// Render a triangle

g_pImmediateContext->VSSetShader( g_pVertexShader, NULL, 0 );

g_pImmediateContext->PSSetShader( g_pPixelShader, NULL, 0 );

g_pImmediateContext->Draw( 3, 0 );

Tutorial 2: Rendering a Triangle

• Result

Tutorial 3: Shaders

• Shaders – Short programs that, executed by the GPU, take

certain input data, process that data, and then output the result to the next stage of pipeline • Vertex shader

• Pixel shader

• Geometry shader

• Hull/domain shader

• When rendering with Direct3D 11,

– The GPU must have a valid vertex shader and pixel shader

Vertex Shader

• The application passes vertex data to the GPU in the form of a vertex buffer

• GPU iterates through the vertices in the vertex buffer, executes the active vertex shader once for each vertex

float4 VS( float4 Pos : POSITION ) : SV_POSITION

{

return Pos; }

Pixel Shader

• Rasterization

float4 PS( float4 Pos : SV_POSITION ) : SV_Target

{

return float4( 1.0f, 1.0f, 0.0f, 1.f ); // Yellow with alpha = 1 }

Creating Shaders

ID3DBlob* pVSBlob = NULL, *pPSBlob = NULL, *pErrorBlob = NULL;

// Compile the vertex shader

if( FAILED( D3DX11CompileFromFile( “Tutorial03.fx”, NULL, NULL,

“VS”, “vs_4_0”, D3DCOMPILE_ENABLE_STRICNESS,

NULL, NULL, &pVSBlob, &pErrorBlob, NULL ) ) )

return FALSE;

// Compile the pixel shader

if( FAILED( D3DX11CompileFromFile( “Tutorial03.fx”, NULL, NULL,

“PS”, “ps_4_0”, D3DCOMPILE_ENABLE_STRICNESS,

NULL, NULL, &pPSBlob, &pErrorBlob, NULL ) ) )

return FALSE;

Creating Shaders

ID3D11VertexShader* g_pVertexShader = NULL;

ID3D11PixelShader* g_pPixelShader = NULL;

// Create the vertex shader

if( FAILED( g_pd3dDevice->CreateVertexShader(

pVSBlob->GetBufferPointer(), pVSBlob->GetBufferSize(),

NULL, &g_pVertexShader ) ) )

return FALSE;

// Create the pixel shader

if( FAILED( g_pd3dDevice->CreatePixelShader(

pPSBlob->GetBufferPointer(), pPSBlob->GetBufferSize(),

NULL, &g_pPixelShader ) ) )

return FALSE;

Rendering Triangle

// Render a triangle

g_pImmediateContext->VSSetShader( g_pVertexShader, NULL, 0 );

g_pImmediateContext->PSSetShader( g_pPixelShader, NULL, 0 );

g_pImmediateContext->Draw( 3, 0 );

Tutorial 3: Shaders

• Result

directx programming - computer graphics and -...

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