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DX11 Depth Buffer rendering nothing

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Hello, I'm completely new to Directx 11 and I'm trying to implement a depth buffer in my program. Currently this is the result I'm getting when trying to render:


I've followed 2 different tutorials for depth buffer and it results in the same thing, so I'm starting to think the issue is related to something elsewhere in the code. Problem is, I don't have enough experience to know where to look or where to begin, so attached is my complete main.cpp file and shaders.hlsl.



#include <windows.h>
#include <d3d11.h>
#include <d3dx11.h>
#include <dxerr.h>

#include <xnamath.h>

#include <windows.h>
#include <string>
#include <iostream>
#include <cstring>
using namespace std;;

//	Global Variables
HWND		g_hWnd = NULL;

ID3D11Buffer*			g_pVertexBuffer;                
ID3D11VertexShader*		g_pVertexShader;         
ID3D11PixelShader*		g_pPixelShader;          
ID3D11InputLayout*		g_pInputLayout; 

ID3D11DepthStencilView* depthStencilView;
ID3D11Texture2D* depthStencilBuffer;

// Define vertex structure

// Define vertices of a triangle - screen coordinates -1.0 to +1.0
    POS_COL_VERTEX vertices[] =
         {XMFLOAT3(0.0f, 0.5f, 0.0f), XMFLOAT4(1.0f, 0.0f, 0.0f, 1.0f)},
		 {XMFLOAT3(0.5f, -0.5f, -0.5f), XMFLOAT4(1.0f, 0.0f, 0.0f, 1.0f)},
         {XMFLOAT3(-0.5f, -0.5f, -0.5f), XMFLOAT4(1.0f, 0.0f, 0.0f, 1.0f)},

		 {XMFLOAT3(0.0f, 0.5f, 0.0f), XMFLOAT4(0.0f, 1.0f, 0.0f, 1.0f)},
         {XMFLOAT3(0.5f, -0.5f, 0.5f), XMFLOAT4(0.0f, 1.0f, 0.0f, 1.0f)},
         {XMFLOAT3(0.5f, -0.5f, -0.5f), XMFLOAT4(0.0f, 1.0f, 0.0f, 1.0f)},

		 {XMFLOAT3(0.0f, 0.5f, 0.0f), XMFLOAT4(0.0f, 0.0f, 1.0f, 1.0f)},
         {XMFLOAT3(-0.5f, -0.5f, 0.5f), XMFLOAT4(0.0f, 0.0f, 1.0f, 1.0f)},
		 {XMFLOAT3(0.5f, -0.5f, 0.5f), XMFLOAT4(0.0f, 0.0f, 1.0f, 1.0f)},

		 {XMFLOAT3(0.0f, 0.5f, 0.0f), XMFLOAT4(1.0f, 1.0f, 1.0f, 1.0f)},
		 {XMFLOAT3(-0.5f, -0.5f, -0.5f), XMFLOAT4(1.0f, 1.0f, 1.0f, 1.0f)},
		 {XMFLOAT3(-0.5f, -0.5f, 0.5f), XMFLOAT4(1.0f, 1.0f, 1.0f, 1.0f)},

		 {XMFLOAT3(0.5f, -0.5f, -0.5f), XMFLOAT4(0.5f, 0.5f, 0.5f, 1.0f)},
         {XMFLOAT3(0.5f, -0.5f, 0.5f), XMFLOAT4(0.5f, 0.5f, 0.5f, 1.0f)},
		 {XMFLOAT3(-0.5f, -0.5f, -0.5f), XMFLOAT4(0.5f, 0.5f, 0.5f, 1.0f)},

		 {XMFLOAT3(-0.5f, -0.5f, -0.5f), XMFLOAT4(0.5f, 0.5f, 0.5f, 1.0f)},
         {XMFLOAT3(0.5f, -0.5f, 0.5f), XMFLOAT4(0.5f, 0.5f, 0.5f, 1.0f)},
		 {XMFLOAT3(-0.5f, -0.5f, 0.5f), XMFLOAT4(0.5f, 0.5f, 0.5f, 1.0f)}

// Rename for each tutorial
char		g_TutorialName[100] = "SWD304 - Tutorial 06 Exercise 01\0";

D3D_DRIVER_TYPE         g_driverType = D3D_DRIVER_TYPE_NULL;
D3D_FEATURE_LEVEL       g_featureLevel = D3D_FEATURE_LEVEL_11_0;
ID3D11Device*           g_pD3DDevice = NULL;
ID3D11DeviceContext*    g_pImmediateContext = NULL;
IDXGISwapChain*         g_pSwapChain = NULL;

ID3D11RenderTargetView* g_pBackBufferRTView = NULL;

float g_clear_colour[4] = {0.8f, 0.8f, 0.8f, 1.0f};

int screen_res[] = {640, 480};

ID3D11Buffer*			g_pConstantBuffer0; 

float redUpdate = 0.0f;
float scaleUpdate = 1.0f;
float xMod = 0.0f;
float yMod = 0.0f;

// Const buffer structs. Pack to 16 bytes. Don't let any single element cross a 16 byte boundary
	float RedAmount;  	// 4 bytes
	float ScaleAmount; // 4 bytes
	float xModAmount; // 4 bytes
	float yModAmount; // 4 bytes
	XMMATRIX WorldViewProjection; // 64 bytes
	// Total 80

int buffer0_size = 80;

// World vars
float world_z = 2.00f;
float world_x = 0.00f;
float world_y = 0.00f;

float world_fieldOfView = 45.00f;
float world_z_min = 0.00f;
float world_z_max = 100.00f;

float x_degrees = 00.00f;
float y_degrees = 00.00f;
float z_degrees = 00.00f;

//	Forward declarations
HRESULT InitialiseWindow(HINSTANCE hInstance, int nCmdShow);

HRESULT InitialiseD3D();
void ShutdownD3D();
void RenderFrame(void);
static void Draw();

HRESULT InitialiseGraphics(void);

// Entry point to the program. Initializes everything and goes into a message processing 
// loop. Idle time is used to render the scene.
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)

	if(FAILED(InitialiseWindow(hInstance, nCmdShow)))
		DXTRACE_MSG("Failed to create Window");
		return 0;

 		DXTRACE_MSG("Failed to create Device");
		return 0;

		DXTRACE_MSG( "Failed to initialise graphics" );
		return 0;

	// Main message loop
	MSG msg = {0};

	while(msg.message != WM_QUIT)
		if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))


	return (int) msg.wParam;

// Register class and create window
HRESULT InitialiseWindow(HINSTANCE hInstance, int nCmdShow)
	// Give your app window your own name
	char Name[100] = "Kristian Thomson\0";

	// Register class
	WNDCLASSEX wcex={0};
	wcex.cbSize = sizeof(WNDCLASSEX); = CS_HREDRAW | CS_VREDRAW;
	wcex.lpfnWndProc = WndProc;
	wcex.hInstance = hInstance;
	wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
//   wcex.hbrBackground = (HBRUSH )( COLOR_WINDOW + 1); // Needed for non-D3D apps
	wcex.lpszClassName = Name;

	if(!RegisterClassEx(&wcex)) return E_FAIL;

	// Create window
	g_hInst = hInstance;
	RECT rc = {0, 0, screen_res[0], screen_res[1]}; 
	g_hWnd = CreateWindow(	Name, g_TutorialName, WS_OVERLAPPEDWINDOW,
				CW_USEDEFAULT, CW_USEDEFAULT, rc.right - rc.left, 
				rc.bottom -, NULL, NULL, hInstance, NULL);
		return E_FAIL;

	ShowWindow(g_hWnd, nCmdShow);

	return S_OK;

// Called every time the application receives a message
	HDC hdc;

	int mouse_x = LOWORD(lParam);
	int mouse_y = HIWORD(lParam);

	float pointX = ((2.0f * (float)mouse_x) / (float) screen_res[0]) - 1.0f;
	float pointY = (((2.0f * (float)mouse_y) / (float) screen_res[1]) - 1.0f) * -1.0f;

		case WM_PAINT:
			hdc = BeginPaint(hWnd, &ps);
			EndPaint(hWnd, &ps);

		case WM_DESTROY:

			vertices[0].Pos.z -= 0.05f;
			vertices[1].Pos.z -= 0.05f;
			vertices[2].Pos.z -= 0.05f;

			//redUpdate += 0.05f;
			//scaleUpdate += 0.05f;

			vertices[0].Pos.z += 0.05f;
			vertices[1].Pos.z += 0.05f;
			vertices[2].Pos.z += 0.05f;

			//redUpdate -= 0.05f;
			//scaleUpdate -= 0.05f;
			//g_clear_colour[0] = pointX;
			//g_clear_colour[1] = pointY;
			//g_clear_colour[2] = (mouse_x/mouse_y)/2;

			//vertices[0].Pos.x = pointX;
			//vertices[0].Pos.y = pointY;

			//vertices[3].Pos.x = pointX;
			//vertices[3].Pos.y = pointY;

			/*if (pointX > 0.0f && pointY > 0.0f) {
				vertices[1].Pos.x = pointX + -0.5f;
				vertices[1].Pos.y = pointY + -0.5f;
			else {
				vertices[1].Pos.x = pointX + 0.5f;
				vertices[1].Pos.y = pointY + 0.5f;

			//float xxx = vertices[3].Pos.x;

		case WM_KEYDOWN: 
			if(wParam == VK_ESCAPE) {
				return 0;
			if(wParam == VK_DOWN) {
				yMod -= 0.05f;
				world_z += 0.05f;
			if(wParam == VK_UP) {
				yMod += 0.05f;
				world_z -= 0.05f;
			if(wParam == VK_LEFT) {
				xMod -= 0.05f;
				world_x += 0.05f;
			if(wParam == VK_RIGHT) {
				xMod += 0.05f;
				world_x -= 0.05f;

			if(wParam == 0x54) {
				xMod += 0.05f;
				x_degrees -= 1.50f;

			if(wParam == 0x59) {
				xMod += 0.05f;
				x_degrees += 1.50f;
			if(wParam == 0x47) {
				xMod += 0.05f;
				y_degrees -= 1.50f;

			if(wParam == 0x48) {
				xMod += 0.05f;
				y_degrees += 1.50f;
			if(wParam == 0x42) {
				xMod += 0.05f;
				z_degrees -= 1.50f;

			if(wParam == 0x4E) {
				xMod += 0.05f;
				z_degrees += 1.50f;
		case WM_SIZE:
        if (g_pSwapChain)
            g_pImmediateContext->OMSetRenderTargets(0, 0, 0);

            // Release all outstanding references to the swap chain's buffers.

            HRESULT hr;
            // Preserve the existing buffer count and format.
            // Automatically choose the width and height to match the client rect for HWNDs.
            hr = g_pSwapChain->ResizeBuffers(0, 0, 0, DXGI_FORMAT_UNKNOWN, 0);
            // Perform error handling here!

            // Get buffer and create a render-target-view.
            ID3D11Texture2D* pBuffer;
            hr = g_pSwapChain->GetBuffer(0, __uuidof( ID3D11Texture2D),
                                         (void**) &pBuffer );
            // Perform error handling here!

            hr = g_pD3DDevice->CreateRenderTargetView(pBuffer, NULL,
            // Perform error handling here!

            g_pImmediateContext->OMSetRenderTargets(1, &g_pBackBufferRTView, NULL );

            // Set up the viewport.
			//RECT rc;
			//UINT width = rc.right - rc.left;
			//UINT height = rc.bottom -;

            D3D11_VIEWPORT vp;
            vp.Width = mouse_x;
            vp.Height = mouse_y;
            vp.MinDepth = 0.0f;
            vp.MaxDepth = 1.0f;
            vp.TopLeftX = 0;
            vp.TopLeftY = 0;
            g_pImmediateContext->RSSetViewports( 1, &vp );

			return DefWindowProc(hWnd, message, wParam, lParam);

	return 0;

// Create D3D device and swap chain
HRESULT InitialiseD3D()

	RECT rc;
	GetClientRect(g_hWnd, &rc);
	UINT width = rc.right - rc.left;
	UINT height = rc.bottom -;

	UINT createDeviceFlags = 0;

#ifdef _DEBUG
	createDeviceFlags |= D3D11_CREATE_DEVICE_DEBUG;

	D3D_DRIVER_TYPE driverTypes[] =
		D3D_DRIVER_TYPE_HARDWARE, // comment out this line if you need to test D3D 11.0 functionality on hardware that doesn't support it
		D3D_DRIVER_TYPE_WARP, // comment this out also to use reference device
	UINT numDriverTypes = ARRAYSIZE(driverTypes);

	D3D_FEATURE_LEVEL featureLevels[] =
	UINT numFeatureLevels = ARRAYSIZE(featureLevels);

	ZeroMemory(&sd, sizeof(sd));
	sd.BufferCount = 1;
	sd.BufferDesc.Width = width;
	sd.BufferDesc.Height = height;
	sd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
	sd.BufferDesc.RefreshRate.Numerator = 60;
	sd.BufferDesc.RefreshRate.Denominator = 1;
	sd.OutputWindow = g_hWnd;
	sd.SampleDesc.Count = 1;
	sd.SampleDesc.Quality = 0;
	sd.Windowed = true;

	for(UINT driverTypeIndex = 0; driverTypeIndex < numDriverTypes; driverTypeIndex++)
		g_driverType = driverTypes[driverTypeIndex];
		hr = D3D11CreateDeviceAndSwapChain(NULL, g_driverType, NULL, 
			createDeviceFlags, featureLevels, numFeatureLevels, 
			D3D11_SDK_VERSION, &sd, &g_pSwapChain, 
			&g_pD3DDevice, &g_featureLevel, &g_pImmediateContext);

		return hr;

	// Get pointer to back buffer texture
	ID3D11Texture2D *pBackBufferTexture;
	hr = g_pSwapChain->GetBuffer(0, __uuidof(ID3D11Texture2D),

	if(FAILED(hr)) return hr;
	// Use the back buffer texture pointer to create the render target view
	hr = g_pD3DDevice->CreateRenderTargetView(pBackBufferTexture, NULL,

	if(FAILED(hr)) return hr;

	//Describe our Depth/Stencil Buffer
	D3D11_TEXTURE2D_DESC depthStencilDesc;

	depthStencilDesc.Width     = width;
	depthStencilDesc.Height    = height;
	depthStencilDesc.MipLevels = 1;
	depthStencilDesc.ArraySize = 1;
	depthStencilDesc.Format    = DXGI_FORMAT_D24_UNORM_S8_UINT;
	depthStencilDesc.SampleDesc.Count   = 1;
	depthStencilDesc.SampleDesc.Quality = 0;
	depthStencilDesc.Usage          = D3D11_USAGE_DEFAULT;
	depthStencilDesc.BindFlags      = D3D11_BIND_DEPTH_STENCIL;
	depthStencilDesc.CPUAccessFlags = 0; 
	depthStencilDesc.MiscFlags      = 0;

	g_pD3DDevice->CreateTexture2D(&depthStencilDesc, NULL, &depthStencilBuffer);
	g_pD3DDevice->CreateDepthStencilView(depthStencilBuffer, NULL, &depthStencilView);

	// Set the render target view
	g_pImmediateContext->OMSetRenderTargets(1, &g_pBackBufferRTView, depthStencilView);

	// Set the viewport
	D3D11_VIEWPORT viewport;

	viewport.TopLeftX = 0;
	viewport.TopLeftY = 0;
	viewport.Width = width;
	viewport.Height = height;
	viewport.MinDepth = 0.0f;
	viewport.MaxDepth = 1.0f;

	g_pImmediateContext->RSSetViewports(1, &viewport);

	return S_OK;

// Clean up D3D objects
void ShutdownD3D()
	if(g_pVertexBuffer) g_pVertexBuffer->Release();
	if(g_pInputLayout) g_pInputLayout->Release();
	if(g_pVertexShader) g_pVertexShader->Release();
	if(g_pPixelShader) g_pPixelShader->Release();
	if(g_pSwapChain) g_pSwapChain->Release();
	if(g_pImmediateContext) g_pImmediateContext->Release();
	if(g_pD3DDevice) g_pD3DDevice->Release();

	if(g_pBackBufferRTView) g_pBackBufferRTView->Release();

	if(g_pConstantBuffer0) g_pConstantBuffer0->Release();

	if(depthStencilView) depthStencilView->Release();
	if(depthStencilBuffer) depthStencilBuffer->Release();

// Render frame
void RenderFrame(void)
	g_pImmediateContext->ClearRenderTargetView(g_pBackBufferRTView, g_clear_colour);

	g_pImmediateContext->ClearDepthStencilView(depthStencilView, D3D11_CLEAR_DEPTH|D3D11_CLEAR_STENCIL, 1.0f, 0);

	CONSTANT_BUFFER0 cb0_values;

	// Update world view projection
	XMMATRIX projection, world, view;
	XMMATRIX world2;

	world = XMMatrixRotationX(XMConvertToRadians(45));
	world *= XMMatrixRotationY(XMConvertToRadians(45));
	world *= XMMatrixRotationZ(XMConvertToRadians(45));
	world *= XMMatrixTranslation(0, 0 , 5);

	projection = XMMatrixPerspectiveFovLH(XMConvertToRadians(world_fieldOfView), (float)screen_res[0]/(float)screen_res[1], world_z_min, world_z_max);
	view = XMMatrixIdentity();
	view *= XMMatrixTranslation(world_x, world_y , 0);
	cb0_values.WorldViewProjection = world * view * projection;

	// Set vertex buffer 
	UINT stride = sizeof(POS_COL_VERTEX);
	UINT offset = 0;
	g_pImmediateContext->IASetVertexBuffers(0, 1, &g_pVertexBuffer, &stride, &offset);

	// Select which primtive type to use

	// Draw the vertex buffer to the back buffer
	g_pImmediateContext->Draw(sizeof(vertices), 0);

	// upload the new values for the constant buffer
	g_pImmediateContext->UpdateSubresource(g_pConstantBuffer0, 0, 0, &cb0_values, 0, 0);

	world2 = XMMatrixRotationX(XMConvertToRadians(x_degrees));
	world2 *= XMMatrixRotationY(XMConvertToRadians(y_degrees));
	world2 *= XMMatrixRotationZ(XMConvertToRadians(z_degrees));
	world2 *= XMMatrixTranslation(0, 0.3f, world_z);

	cb0_values.WorldViewProjection = world2 * view * projection;

	g_pImmediateContext->UpdateSubresource(g_pConstantBuffer0, 0, 0, &cb0_values, 0, 0);

	// Draw the vertex buffer to the back buffer
	g_pImmediateContext->Draw(sizeof(vertices), 0);

	// Display what has just been rendered
	g_pSwapChain->Present(0, 0);


static void Draw() {
	g_pImmediateContext->Map(g_pVertexBuffer, NULL, D3D11_MAP_WRITE_DISCARD, NULL, &ms);	// Lock the buffer to allow writing
	memcpy(ms.pData, vertices, sizeof(vertices)); // Copy the data
	g_pImmediateContext->Unmap(g_pVertexBuffer, NULL);	// Unlock the buffer

HRESULT InitialiseGraphics()
    HRESULT hr = S_OK;

    // Set up and create vertex buffer
    D3D11_BUFFER_DESC bufferDesc;
    ZeroMemory(&bufferDesc, sizeof(bufferDesc));
    bufferDesc.Usage = D3D11_USAGE_DYNAMIC;		// Used by CPU and GPU
    bufferDesc.ByteWidth = sizeof(POS_COL_VERTEX) * sizeof(vertices);	// Total size of buffer, 3 vertices
    bufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;	// Use as a vertex buffer
    bufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;// Allow CPU access
    hr = g_pD3DDevice->CreateBuffer(&bufferDesc, NULL, &g_pVertexBuffer);//Create the buffer

    if(FAILED(hr)) // return error code on failure
         return hr;

	// Create constant buffer
	D3D11_BUFFER_DESC constant_buffer_desc;
	ZeroMemory(&constant_buffer_desc, sizeof(constant_buffer_desc));

	constant_buffer_desc.Usage = D3D11_USAGE_DEFAULT;	// Can use UpdateSubresource() to update
	constant_buffer_desc.ByteWidth = buffer0_size;	// MUST be a multiple of 16, calculate from CB struct
	constant_buffer_desc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;// Use as a constant buffer

	hr = g_pD3DDevice->CreateBuffer(&constant_buffer_desc, NULL, &g_pConstantBuffer0);

	if(FAILED(hr)) return hr;

    // Copy the vertices into the buffer

    // Load and compile pixel and vertex shaders - use vs_5_0 to target DX11 hardware only
    ID3DBlob *VS, *PS, *error;
    hr = D3DX11CompileFromFile("shaders.hlsl", 0, 0, "VShader", "vs_4_0", 0, 0, 0, &VS, &error, 0);

    if(error != 0) // check for shader compilation error
        if(FAILED(hr)) // don't fail if error is just a warning
            return hr;

    hr = D3DX11CompileFromFile("shaders.hlsl", 0, 0, "PShader", "ps_4_0", 0, 0, 0, &PS, &error, 0);

    if(error != 0)// check for shader compilation error
        if(FAILED(hr))// don't fail if error is just a warning
            return hr;

    // Create shader objects
    hr = g_pD3DDevice->CreateVertexShader(VS->GetBufferPointer(), VS->GetBufferSize(), NULL, &g_pVertexShader);

        return hr;
    hr = g_pD3DDevice->CreatePixelShader(PS->GetBufferPointer(), PS->GetBufferSize(), NULL, &g_pPixelShader);

        return hr;

    // Set the shader objects as active
    g_pImmediateContext->VSSetShader(g_pVertexShader, 0, 0);
    g_pImmediateContext->PSSetShader(g_pPixelShader, 0, 0);
	g_pImmediateContext->VSSetConstantBuffers(0, 1, &g_pConstantBuffer0);

    // Create and set the input layout object
    D3D11_INPUT_ELEMENT_DESC iedesc[] =

    hr = g_pD3DDevice->CreateInputLayout(iedesc, 2, VS->GetBufferPointer(), VS->GetBufferSize(), &g_pInputLayout);

        return hr;


    return S_OK;


cbuffer CBuffer0
	float red_fraction; // 4 bytes
	float scale_fraction; // 4 bytes
	float xmod_fraction; // 4 bytes
	float ymod_fraction; // 4 bytes
	matrix WVPMatrix;	// 64 bytes

struct VOut
     float4 position : SV_POSITION;
     float4 color : COLOR;

 VOut VShader(float4 position : POSITION, float4 color : COLOR)
     VOut output;

	 //color.r *= red_fraction;
	 //position.x *= scale_fraction;
	 //position.y *= scale_fraction;

	 //position.x += xmod_fraction;
	 //position.y += ymod_fraction;

     //output.position = position;
     output.color = color;

	 //output.color.g = output.position.y;
	 //output.color.b = output.position.x;

	 output.position = mul(WVPMatrix, position);

     return output;

 float4 PShader(float4 position : SV_POSITION, float4 color : COLOR) : SV_TARGET
	 //color.g = position.x;
	 //color.r = position.y;
	 return color;

Thank you very much in advance, I've been stuck on this all day and I have no idea what else to do to fix it.

Edited by Linkandzelda

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1. world_z_min cannot be 0. Use 0.1f or something similar.



g_pImmediateContext->Draw(sizeof(vertices), 0); 

sizeof() returns size in bytes, but Draw() call requires number of vertices, use ARRAYSIZE() macro.

Edited by Zaoshi Kaba

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1. world_z_min cannot be 0. Use 0.1f or something similar.



g_pImmediateContext->Draw(sizeof(vertices), 0); 

sizeof() returns size in bytes, but Draw() call requires number of vertices, use ARRAYSIZE() macro.


Hey, thanks so much! The min distance was the cause haha, can't believe I missed that one. As for the sizeof, good call, even though it's been working with that method so far.

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      2. I can draw 3D triangles using PCN (position, colored, normal) vertices just fine (even transparency and SpecularBlinnPhong shaders).
      However, if I'm using my 3D shader, and I want to draw my PC lines in the same scene how can I do that?
      If I change my lines to PCN and pass them to the 3D shader with my triangles, then the lighting screws them all up.  I only want the lighting for the 3D triangles, but no SpecularBlinnPhong/Lighting for the lines (just PC). 
      I am sure this is because if I change the lines to PNC there is not really a correct "normal" for the lines.  
      I assume I somehow need to draw the 3D triangles using one shader, and then "switch" to another shader and draw the lines?  But I have no clue how to use two different shaders in the same scene.  And then are the lines just drawn on top of the triangles, or vice versa (maybe draw order dependent)?  
      I must be missing something really basic, so if anyone can just point me in the right direction (or link to an example showing the implementation of multiple shaders) that would be REALLY appreciated.
      I'm also more than happy to post my simple test code if that helps as well!
    • By Reitano
      I am writing a linear allocator of per-frame constants using the DirectX 11.1 API. My plan is to replace the traditional constant allocation strategy, where most of the work is done by the driver behind my back, with a manual one inspired by the DirectX 12 and Vulkan APIs.
      In brief, the allocator maintains a list of 64K pages, each page owns a constant buffer managed as a ring buffer. Each page has a history of the N previous frames. At the beginning of a new frame, the allocator retires the frames that have been processed by the GPU and frees up the corresponding space in each page. I use DirectX 11 queries for detecting when a frame is complete and the ID3D11DeviceContext1::VS/PSSetConstantBuffers1 methods for binding constant buffers with an offset.
      The new allocator appears to be working but I am not 100% confident it is actually correct. In particular:
      1) it relies on queries which I am not too familiar with. Are they 100% reliable ?
      2) it maps/unmaps the constant buffer of each page at the beginning of a new frame and then writes the mapped memory as the frame is built. In pseudo code:
 = device.Map(page.buffer)
          Alloc(size, initData)
              memcpy( + page.start, initData, size)
          Alloc(size, initData)
              memcpy( + page.start, initData, size)
      (Note: calling Unmap at the end of a frame prevents binding the mapped constant buffers and triggers an error in the debug layer)
      Is this valid ? 
      3) I don't fully understand how many frames I should keep in the history. My intuition says it should be equal to the maximum latency reported by IDXGIDevice1::GetMaximumFrameLatency, which is 3 on my machine. But, this value works fine in an unit test while on a more complex demo I need to manually set it to 5, otherwise the allocator starts overwriting previous frames that have not completed yet. Shouldn't the swap chain Present method block the CPU in this case ?
      4) Should I expect this approach to be more efficient than the one managed by the driver ? I don't have meaningful profile data yet.
      Is anybody familiar with the approach described above and can answer my questions and discuss the pros and cons of this technique based on his experience ? 
      For reference, I've uploaded the (WIP) allocator code at  Feel free to adapt it in your engine and please let me know if you spot any mistakes
      Stefano Lanza
    • By Matt Barr
      Hey all. I've been working with compute shaders lately, and was hoping to build out some libraries to reuse code. As a prerequisite for my current project, I needed to sort a big array of data in my compute shader, so I was going to implement quicksort as a library function. My implementation was going to use an inout array to apply the changes to the referenced array.

      I spent half the day yesterday debugging in visual studio before I realized that the solution, while it worked INSIDE the function, reverted to the original state after returning from the function.

      My hack fix was just to inline the code, but this is not a great solution for the future.  Any ideas? I've considered just returning an array of ints that represents the sorted indices.
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