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molehill mountaineer

DX11 directx 11 problem switching textures in simple font engine

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Hi folks,

I'm trying to display the amount of seconds a program has been running using a simple font engine which samples 2 textures (one for numbers, one for letters). Displaying letters works fine but the numbers come out wrong. By changing the background colors of the textures I've come to the conclusion that I'm not switching shader resources correctly. Can somebody tell me what I'm doing wrong here? Relevant code will most likely be in the DrawString() method.

EDIT: I figure I'm not supposed to switch shader resources before callin Draw(). Comments & suggestion are welcome


[source lang="cpp"]#include "FontEngine.h"
#include "Graphics.h"
#include "D3DX11.h"
#include "xnamath.h"
struct vertexPos
XMFLOAT3 position;
XMFLOAT2 texCoord;

FontEngine::FontEngine(Graphics* p_parent)
: m_bInitialized(false),


//remove member objects
void FontEngine::cleanup()
m_pGraphics->log(_T("[CLEANING] subsystem FontEngine"));



bool FontEngine::initialize()
ID3DBlob* vertexShaderBuffer = NULL;
bool compileResult = m_pGraphics->CompileD3DShader(_T("Effects/FontTextureMap.fx"), "VS_Main", "vs_4_0", &vertexShaderBuffer);

if(!compileResult) //texture shader compilation failed
MessageBox(NULL, _T("Failed to compile font engine vertex shader"), _T("Fatal Error"), MB_OK);
return false;
HRESULT d3dResult;
d3dResult = m_pGraphics->getDevice()->CreateVertexShader(vertexShaderBuffer->GetBufferPointer(),
NULL, &m_pVertexShader);
MessageBox(NULL, _T("Failed to create font vertex shader"), _T("Fatal Error"), MB_OK);
return false;
D3D11_INPUT_ELEMENT_DESC solidColorLayout[] =
unsigned int totalLayoutElements = ARRAYSIZE( solidColorLayout );

d3dResult = m_pGraphics->getDevice()->CreateInputLayout(solidColorLayout,

MessageBox(NULL, _T("Failed to create input layout in fontengine"), _T("Fatal Error"), MB_OK);
return false;
//compile and create pixel shader
ID3DBlob* pixelShaderBuffer;
compileResult = m_pGraphics->CompileD3DShader(_T("Effects/FontTextureMap.fx"), "PS_Main", "ps_4_0", &pixelShaderBuffer);

if(!compileResult) //compilation of pixel shader failed
MessageBox(NULL, _T("Failed to compile pixel shader in fontengine"), _T("Fatal Error"), MB_OK);
return false;

d3dResult = m_pGraphics->getDevice()->CreatePixelShader(pixelShaderBuffer->GetBufferPointer(),
0, &m_pPixelShader);

//warn user if pixel shader could not be created
MessageBox(NULL, _T("Failed to create pixel shader in fontengine"), _T("Fatal Error"), MB_OK);
return false;

//create shader resource view for letters
d3dResult = D3DX11CreateShaderResourceViewFromFile(m_pGraphics->getDevice(), _T("Graphics/Fonts/"), 0, 0, &m_pLetterMap, 0);
MessageBox(NULL, _T("Failed to create shader resource view for letters in fontengine"), _T("Fatal Error"), MB_OK);
return false;

//create shader resource view for numbers
d3dResult = D3DX11CreateShaderResourceViewFromFile(m_pGraphics->getDevice(), _T("Graphics/Fonts/"), 0, 0, &m_pNumberMap, 0);
MessageBox(NULL, _T("Failed to create shader resource view for numbers in fontengine"), _T("Fatal Error"), MB_OK);
return false;

//create sampler state
D3D11_SAMPLER_DESC colorMapDesc;
ZeroMemory(&colorMapDesc, sizeof(colorMapDesc));
colorMapDesc.AddressU = D3D11_TEXTURE_ADDRESS_WRAP;
colorMapDesc.AddressV = D3D11_TEXTURE_ADDRESS_WRAP;
colorMapDesc.AddressW = D3D11_TEXTURE_ADDRESS_WRAP;
colorMapDesc.ComparisonFunc = D3D11_COMPARISON_NEVER;
colorMapDesc.Filter = D3D11_FILTER_MIN_MAG_MIP_LINEAR;
colorMapDesc.MaxLOD = D3D11_FLOAT32_MAX;

d3dResult = m_pGraphics->getDevice()->CreateSamplerState(&colorMapDesc, &m_pSampler);
MessageBox(NULL, _T("Failed to create sampler state in fontengine"), _T("Fatal Error"), MB_OK);
return false;

D3D11_BUFFER_DESC vertexDesc;
ZeroMemory(&vertexDesc, sizeof(vertexDesc));
vertexDesc.Usage = D3D11_USAGE_DYNAMIC;
vertexDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
vertexDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
const int sizeOfSprite = sizeof(vertexPos) * 6; //six points to a quad
const int maxLetters = 45; //45 quads to a string
vertexDesc.ByteWidth =sizeOfSprite * maxLetters;
//create dynamic buffer
d3dResult = m_pGraphics->getDevice()->CreateBuffer(&vertexDesc, NULL, &m_pDynamicVertexBuffer);
MessageBox(NULL, _T("Failed to create dynamic buffer in fontengine"), _T("Fatal Error"), MB_OK);
return false;

//all checks passed - return true
m_bInitialized = true;
return true;

void FontEngine::drawString(tstring p_message, float p_xPosition, float p_yPosition)
//TODO datamembers?
//size (in bytes) of a single sprite
const int sizeOfSprite = sizeof(vertexPos) * 6;
const int maxLetters = 45;

int length = p_message.length();

//clamp strings that are too long
if(length > maxLetters)
length = maxLetters;
//per quad two triangles, per triangle three vertices (3*2=6)
const int verticesPerLetter = 6;
HRESULT d3dResult = m_pGraphics->getContext()->Map(m_pDynamicVertexBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mapResource);
MessageBox(NULL, _T("Failed to map dynamic buffer in fontengine"), _T("Fatal Error"), MB_OK);

vertexPos* spritePtr = (vertexPos*) mapResource.pData;
//convert to array of characters
const wchar_t* cString = p_message.c_str();
const int indexA = static_cast<char>('A');
const int indexZ = static_cast<char>('Z');
const int index0 = static_cast<char>('0');
const int index9 = static_cast<char>('9');

for(int i = 0; i < length; ++i)
//TODO hardcoded!
float charWidth = 32.0f / 800.0f;
// Char's height on screen.
float charHeight = 32.0f / 640.0f;

// Char's texel width.
float texelWidth = 32.0f / 864.0f;

int texLookup = 0; //the "index" of the character in the texture
int letter = static_cast<char>( cString[i] ); //the "index" of the character in the ASCII table
//select letter texture by default because we use space as default when the character isn't found on the fontmap
m_pGraphics->getContext()->PSSetShaderResources( 0, 1, &amp;amp;m_pLetterMap);

if( letter < indexA || letter > indexZ ) //not an uppercase letter?
if(letter < index0 || letter > index9) //not a number?
texLookup = ( indexZ - indexA ) + 1; // Grab one index past Z, which is a blank space in the texture.
else //it's a number
// Char's texel width.
texelWidth = 32.0f / 333.0f;
texLookup = (letter - index0);
m_pGraphics->getContext()->PSSetShaderResources(1,1, &amp;amp;m_pNumberMap);

else //uppercase letter
//select letter texture by default because we use space as kind of an error character
m_pGraphics->getContext()->PSSetShaderResources( 0, 1, &amp;amp;m_pLetterMap);

// A = 0, B = 1, Z = 25, etc.
texLookup = ( letter - indexA );

float thisStartX = p_xPosition + ( charWidth * static_cast<float>( i ) );
float thisEndX = thisStartX + charWidth;
float thisEndY = p_yPosition + charHeight;
spritePtr[0].position = XMFLOAT3( thisEndX, thisEndY, 0.01f );
spritePtr[1].position = XMFLOAT3( thisEndX, p_yPosition, 0.01f );
spritePtr[2].position = XMFLOAT3( thisStartX, p_yPosition, 0.01f );
spritePtr[3].position = XMFLOAT3( thisStartX, p_yPosition, 0.01f );
spritePtr[4].position = XMFLOAT3( thisStartX, thisEndY, 0.01f );
spritePtr[5].position = XMFLOAT3( thisEndX, thisEndY, 0.01f );

float tuStart = 0.0f + ( texelWidth * static_cast<float>( texLookup ) );
float tuEnd = tuStart + texelWidth;
spritePtr[0].texCoord = XMFLOAT2( tuEnd, 0.0f );
spritePtr[1].texCoord = XMFLOAT2( tuEnd, 1.0f );
spritePtr[2].texCoord = XMFLOAT2( tuStart, 1.0f );
spritePtr[3].texCoord = XMFLOAT2( tuStart, 1.0f );
spritePtr[4].texCoord = XMFLOAT2( tuStart, 0.0f );
spritePtr[5].texCoord = XMFLOAT2( tuEnd, 0.0f );
//move forward the size of a single quad (6 vertices per quad)
spritePtr += 6;

m_pGraphics->getContext()->Unmap(m_pDynamicVertexBuffer, 0 );
m_pGraphics->getContext()->Draw( 6 * length, 0 );
void FontEngine::setupRender()
ID3D11DeviceContext* context = m_pGraphics->getContext();
if(context == 0 )

unsigned int stride = sizeof( vertexPos );
unsigned int offset = 0;
context->IASetInputLayout( m_pInputLayout );
context->IASetVertexBuffers( 0, 1, &amp;amp;m_pDynamicVertexBuffer, &amp;amp;stride, &amp;amp;offset );
context->IASetPrimitiveTopology( D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST );
context->VSSetShader( m_pVertexShader, 0, 0 );
context->PSSetShader( m_pPixelShader, 0, 0 );
context->PSSetSamplers( 0, 1, &amp;amp;m_pSampler );
bool FontEngine::isInitialized()
return m_bInitialized;
}[/source] Edited by molehill mountaineer

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[quote name='MJP' timestamp='1353290990' post='5002202']
Could you post your pixel shader as well?

Sure thing, code is copy-pasted from online source (I wanted to postpone writing pixel shaders for a bit).
In the drawstring() method above I switch shader resources in a for-loop (e.g. 4 quads with letters, 1 with a number, 4 with letters). Only after the loop has finished do I call Draw(). I think this may be what I'm doing wrong - am I supposed to hold two textures in the pixelshader?

Beginning DirectX 11 Game Programming
By Allen Sherrod and Wendy Jones
Texture Mapping Shader

Texture2D colorMap_ : register( t0 );
SamplerState colorSampler_ : register( s0 );

struct VS_Input
float4 pos : POSITION;
float2 tex0 : TEXCOORD0;
struct PS_Input
float4 pos : SV_POSITION;
float2 tex0 : TEXCOORD0;

PS_Input VS_Main( VS_Input vertex )
PS_Input vsOut = ( PS_Input )0;
vsOut.pos = vertex.pos;
vsOut.tex0 = vertex.tex0;
return vsOut;

float4 PS_Main( PS_Input frag ) : SV_TARGET
return colorMap_.Sample( colorSampler_, frag.tex0 );
[/code] Edited by molehill mountaineer

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Seems to me that part of your PSSetShaderResources calls use start slot 0 and part of them use start slot 1 (namely, the number texture is bound to slot 1).

You shader is using only the slot 0 (register t0) , so logically binding resources to slot 1 (register t1) doesn't have any effect.


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[quote name='kauna' timestamp='1353328982' post='5002325']
Seems to me that part of your PSSetShaderResources calls use start slot 0 and part of them use start slot 1 (namely, the number texture is bound to slot 1).

You shader is using only the slot 0 (register t0) , so logically binding resources to slot 1 (register t1) doesn't have any effect.


Oh okay, so I'd have to add "Texture2D numberMap_ : register( t1 );" in order to actually make this work? Guess I'll have to read up on pixel shaders - thanks!

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I'm not 100% of the logic of your code, but you could first try to bind the textures to the same slot. Then at least you should be able to see the numbers.

You pixel shader calls Sample with colorMap_ map which is using register t0. Adding "Texture2D numberMap_ : register( t1 );" Doesn't do anything alone, you'll need to call Sample with that texture also, but that doesn't really lead to anywhere in this case.


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