Minimal D3D11 bonus material: extra minimal triangle

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Minimal D3D11 bonus material: extra minimal triangle

A quick side exercise to see how little code one can get away with to put that RGB triangle on screen using D3D11 (without bending over backwards with trickery). This is a complete app in < 40 LOC (including the HLSL).

For more.. useful.. D3D11 reference code, see the original Minimal D3D11, Minimal D3D11 pt2 and Minimal D3D11 pt3

code.cpp

#pragma comment(lib, "user32")
#pragma comment(lib, "d3d11")
#pragma comment(lib, "d3dcompiler")

///////////////////////////////////////////////////////////////////////////////////////////////////

#include <windows.h>
#include <d3d11.h>
#include <d3dcompiler.h>

///////////////////////////////////////////////////////////////////////////////////////////////////

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
{
    WNDCLASSA wndClass = { 0, DefWindowProcA, 0, 0, 0, 0, 0, 0, 0, "d7" };

    RegisterClassA(&wndClass);

    HWND window = CreateWindowExA(0, "d7", 0, 0x91000000, 0, 0, 0, 0, 0, 0, 0, 0);

    ///////////////////////////////////////////////////////////////////////////////////////////////

    D3D_FEATURE_LEVEL featureLevels[] = { D3D_FEATURE_LEVEL_11_0 };

    DXGI_SWAP_CHAIN_DESC swapChainDesc = { { 0, 0, {}, DXGI_FORMAT_B8G8R8A8_UNORM }, { 1 }, 32, 2, window, 1 };

    IDXGISwapChain* swapChain;

    ID3D11Device* device;
    ID3D11DeviceContext* deviceContext;

    D3D11CreateDeviceAndSwapChain(0, D3D_DRIVER_TYPE_HARDWARE, 0, D3D11_CREATE_DEVICE_BGRA_SUPPORT, featureLevels, 1, 7, &swapChainDesc, &swapChain, &device, 0, &deviceContext);

    swapChain->GetDesc(&swapChainDesc);
	
    ///////////////////////////////////////////////////////////////////////////////////////////////

    ID3D11Texture2D* renderTarget;

    swapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (void**)&renderTarget);

    ID3D11RenderTargetView* renderTargetView;

    device->CreateRenderTargetView(renderTarget, 0, &renderTargetView);

    ///////////////////////////////////////////////////////////////////////////////////////////////

    ID3DBlob* cso;

    D3DCompileFromFile(L"shaders.hlsl", 0, 0, "vs", "vs_5_0", 0, 0, &cso, 0);

    ID3D11VertexShader* vertexShader;

    device->CreateVertexShader(cso->GetBufferPointer(), cso->GetBufferSize(), 0, &vertexShader);

    ///////////////////////////////////////////////////////////////////////////////////////////////

    D3DCompileFromFile(L"shaders.hlsl", 0, 0, "ps", "ps_5_0", 0, 0, &cso, 0);

    ID3D11PixelShader* pixelShader;

    device->CreatePixelShader(cso->GetBufferPointer(), cso->GetBufferSize(), 0, &pixelShader);

    ///////////////////////////////////////////////////////////////////////////////////////////////

    D3D11_VIEWPORT viewport = { 0, 0, (float)swapChainDesc.BufferDesc.Width, (float)swapChainDesc.BufferDesc.Height, 0, 1 };

    ///////////////////////////////////////////////////////////////////////////////////////////////

    deviceContext->VSSetShader(vertexShader, 0, 0);
    deviceContext->RSSetViewports(1, &viewport);
    deviceContext->PSSetShader(pixelShader, 0, 0);
    deviceContext->OMSetRenderTargets(1, &renderTargetView, 0);

    deviceContext->Draw(3, 0);

    ///////////////////////////////////////////////////////////////////////////////////////////////

    swapChain->Present(1, 0);

    ///////////////////////////////////////////////////////////////////////////////////////////////

    MSG msg;

    GetMessageA(&msg, 0, WM_KEYFIRST, WM_KEYLAST);
}

shaders.hlsl

struct vs_out
{
    float4 pos : SV_POSITION;
    float4 col : COL;
};

vs_out vs(uint vid : SV_VERTEXID)
{
    vs_out output = { float4(vid * 0.5f, vid & 1, 1, 1.5f) - 0.5f, float4(vid == 0, vid == 1, vid == 2, 1) };
    return output;
}

float4 ps(vs_out input) : SV_TARGET
{
    return input.col;
}