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# Directional Light

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36 replies to this topic

### #1Medo3337  Members

Posted 18 July 2013 - 12:59 PM

I'm trying to get directional light to work (for sun light), unfortunately I'm seeing static light on the mesh, what's wrong with the following code?
//-----------------------------------------------------------------------
// Pixel shader function (DIRECTIONAL LIGHT)
//-----------------------------------------------------------------------
float4 PS( VS_OUTPUT IN ) : COLOR
{
float3 viewDir = cameraPos - IN.worldPos;
float3 lightDir = -lightDirection;
float3 halfVector = normalize(normalize(lightDir) + normalize(viewDir));

float3 n = normalize(IN.Normal);
float3 h = normalize(halfVector);
float3 l = normalize(lightDir);

float nDotL = saturate(dot(n, l));
float nDotH = saturate(dot(n, h));
float power = (nDotL == 0.0f) ? 0.0f : pow(nDotH, materialPower);

float4 FinalDiffuse = materialDiffuse * lightDiffuse;
float4 FinalSpecular = materialSpecular * lightSpecular;

float4 color = (materialAmbient + globalAmbient) +
(FinalDiffuse * nDotL) + (FinalSpecular * power);
return color * tex2D(colorMap, IN.UV);
}

### #2menohack  Members

Posted 18 July 2013 - 03:02 PM

Are you transforming cameraPos?

If you were using visual studio 2012 you could debug the shader and inspect values after it runs.

### #3Medo3337  Members

Posted 18 July 2013 - 04:10 PM

@menohack: I'm using Visual Studio 2010

Yes I'm updating cameraPos value each render.

Here is a part of the C++ code:

// Light
float lightDiffuse[4] = {1.0f, 1.0f, 1.0f, 0.01f};
float lightSpecular[4] = {0.5f, 0.5f, 0.5f, 0.5f};
pEffect->SetValue("lightDiffuse", &lightDiffuse, sizeof(lightDiffuse));
pEffect->SetValue("lightSpecular", &lightSpecular, sizeof(lightSpecular));

// Material
float materialDiffuse[4] = {1.0f, 1.0f, 1.0f, 1.0f};
float materialAmbient[4] = {0.15f, 0.15f, 0.15f, 1.0f};
float materialSpecular[4] = {1.0f, 1.0f, 1.0f, 1.0f};
float materialPower = 10.0f;

float gAmbient[4] = { 1.0f, 1.0f, 1.0f, 1.0f };
pEffect->SetValue("globalAmbient", &gAmbient, sizeof(gAmbient));

D3DXVECTOR3 lightDirection(0.0f, 10.0f, 1.0f);
pEffect->SetValue("lightDirection", &lightDirection, sizeof(D3DXVECTOR3));
pEffect->SetValue("cameraPos", &getCameraPosition(), sizeof(D3DXVECTOR3));

pEffect->SetTexture("colorMapTexture", texture);

Edited by Medo3337, 18 July 2013 - 11:12 PM.

### #4Medo3337  Members

Posted 19 July 2013 - 12:14 AM

I got the directional light to work, but now, I don't see the specular light unless I set a very low number for specular power.

And when I set a very low number such as 1 or 2 I get high specular color.

### #5NightCreature83  Members

Posted 19 July 2013 - 02:07 AM

As long as you aren't running on Win 8 you can use PIX from the the D3D SDK folder it also allows you to debug the shader. Or use the NVidia or AMD tools.

Worked on titles: CMR:DiRT2, DiRT 3, DiRT: Showdown, GRID 2, theHunter, theHunter: Primal, Mad Max

### #6BornToCode  Members

Posted 19 July 2013 - 09:15 AM

How many vertices are in your mesh. If you have a model that is not dense enough when you apply specular to it, it will spread across the whole model which makes sense. An good example to test specular on is a sphere for example.

Edited by BornToCode, 19 July 2013 - 09:16 AM.

Posted 19 July 2013 - 11:03 AM

I'd recommend trying to implement bump mapping before implementing any specular lighting. It will show the specular light in much better detail.

Here is a tutorial for bumpmapping http://www.rastertek.com/dx10tut20.html.

Co-Founder of Tesseract Interactive.

Check out our project Excubitor on http://excubitorgame.com and http://www.indiedb.com/games/excubitor

### #8Medo3337  Members

Posted 20 July 2013 - 01:15 AM

Even the specular light sometimes look weird, here is a screenshot of the specular light (red light):

Here is the Vertex Shader code:

VS_OUTPUT VS( VS_INPUT IN )
{
VS_OUTPUT Out;
Out = (VS_OUTPUT)0;
float4x4 WVP = mul(World, mul(View, Projection));
Out.Pos = mul(float4(IN.Pos, 1.0f), WVP);
Out.UV = IN.UV;
Out.Normal = mul(IN.Normal, (float3x3)World);
Out.worldPos = mul(float4(IN.Pos, 1.0f), World).xyz;
return Out;
}

### #9Medo3337  Members

Posted 20 July 2013 - 12:01 PM

Any idea what's going on?

### #10LancerSolurus  Members

Posted 20 July 2013 - 04:39 PM

Couple of things not mention, 1) where is the light, 2) did you multiply the specular using the dot product

I saw in the previous posting of your PS code that you did not do #2 properly, the specular reflection looks like it's on the wrong side of the wall. Without knowing #1 I can't be sure. Plus the way you did the specular power nDotL check, it should be nDotL <= 0, not == which would set the power to 0 only along the light/dark border.

******************************************************************************************

### #11Medo3337  Members

Posted 20 July 2013 - 08:48 PM

@LancerSolurus:

1) I'm setting the light direction to (1, 0, 1), it's a directional light (no position).

2) Not sure what you mean exactly

Here is the entire effect file:

float4x4 World;
float4x4 View;
float4x4 Projection;

// Light
float3 lightDirection;  // Directional light
float4 lightDiffuse;
float4 lightAmbient;
float4 lightSpecular;

// Material
float4 materialDiffuse;
float4 materialAmbient;
float4 materialSpecular;
float materialPower;

float4 globalAmbient;

// Camera position
float3 cameraPos;

// Texture
texture colorMapTexture;
sampler2D colorMap = sampler_state
{
Texture = <colorMapTexture>;
MagFilter = Linear;
MinFilter = Anisotropic;
MipFilter = Linear;
MaxAnisotropy = 16;
};

struct VS_INPUT
{
float3 Pos : POSITION;
float2 UV : TEXCOORD0;
float3 Normal : NORMAL;
};

struct VS_OUTPUT
{
float4 Pos : POSITION;
float3 worldPos : TEXCOORD1;
float2 UV : TEXCOORD0;
float3 Normal : NORMAL;
};

//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
VS_OUTPUT VS( VS_INPUT IN )
{
VS_OUTPUT Out;
Out = (VS_OUTPUT)0;
float4x4 WVP = mul(World, mul(View, Projection));
Out.Pos = mul(float4(IN.Pos, 1.0f), WVP);
Out.UV = IN.UV;
Out.Normal = mul(IN.Normal, (float3x3)World).xyz;
Out.worldPos = mul(float4(IN.Pos, 1.0f), World).xyz;
return Out;
}

//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
float4 PS( VS_OUTPUT IN ) : COLOR
{
float3 viewDir = normalize(cameraPos - IN.worldPos);
float3 lightDir = normalize(-lightDirection);
float3 halfVector = normalize(lightDir + viewDir);

float3 n = normalize(IN.Normal);
float3 h = normalize(halfVector);
float3 l = normalize(lightDir);

float nDotL = saturate(dot(n, l));
float nDotH = saturate(dot(n, h));
float power = (nDotL <= 0.0f) ? 0.0f : pow(nDotH, materialPower);

float4 FinalDiffuse = materialDiffuse * lightDiffuse;
float4 FinalSpecular = materialSpecular * lightSpecular;

float4 color = (materialAmbient + globalAmbient) + (FinalDiffuse * nDotL) + (FinalSpecular * power);
return color * tex2D(colorMap, IN.UV);
}

//-----------------------------------------------------------------------------
// Techniques.
//-----------------------------------------------------------------------------
technique DirectionalLight
{
pass
{
AlphaBlendEnable = false;
ZEnable = true;
}
}

### #12belfegor  Members

Posted 21 July 2013 - 03:04 AM

nDotL and nDotH are saturated (clamped to 0 - 1 range) so i see no reason to check anything as it will return valid number, just make sure that your "materialPower" > 0

//float power = (nDotL <= 0.0f) ? 0.0f : pow(nDotH, materialPower);
float power = pow(nDotH, materialPower);


### #13Medo3337  Members

Posted 21 July 2013 - 01:00 PM

@belfegor: That won't really help, I still have the same problem, you might want to check my shader code to see yourself what's going on

### #14belfegor  Members

Posted 21 July 2013 - 01:20 PM

Copy/paste your cpp and whole shader again so i can see everything involved, try not to remove/edit something out.

Edited by belfegor, 21 July 2013 - 01:21 PM.

### #15Medo3337  Members

Posted 21 July 2013 - 01:42 PM

@belfegor:

C++:

D3DXHANDLE hTechnique;
hTechnique = pEffect->GetTechniqueByName("DirectionalLighting");
if (FAILED(pEffect->SetTechnique(hTechnique)))
return;

D3DXMATRIX view = camera->viewMatrix();
D3DXMATRIX proj = camera->projectionMatrix();

pEffect->SetMatrix("View", &view);
pEffect->SetMatrix("Projection", &proj);

// Light
float lightDiffuse[4] = {0.9f, 0.9f, 0.9f, 1.0f};
float lightSpecular[4] = {1.0f, 0.0f, 0.0f, 0.0f};
pEffect->SetValue("lightDiffuse", &lightDiffuse, sizeof(lightDiffuse));
pEffect->SetValue("lightSpecular", &lightSpecular, sizeof(lightSpecular));

// Material
float materialDiffuse[4] = {1.0f, 1.0f, 1.0f, 1.0f};
float materialAmbient[4] = {0.15f, 0.15f, 0.15f, 1.0f};
float materialSpecular[4] = {1.0f, 1.0f, 1.0f, 1.0f};
float materialPower = 20.0f;

pEffect->SetValue("materialDiffuse", &materialDiffuse, sizeof(materialDiffuse));
pEffect->SetValue("materialAmbient", &materialAmbient, sizeof(materialAmbient));
pEffect->SetValue("materialSpecular", &materialSpecular, sizeof(materialSpecular));
pEffect->SetValue("materialPower", &materialPower, sizeof(materialPower));

float gAmbient[4] = { 0.2f, 0.2f, 0.2f, 0.0f };
pEffect->SetValue("globalAmbient", &gAmbient, sizeof(gAmbient));

float lightDirection[3] = {1.0f, 0.0f, 1.0f};
pEffect->SetValue("lightDirection", &lightDirection, sizeof(lightDirection));

float cameraPos[3] = {camera->position().x, camera->position().y, camera->position().z};
pEffect->SetValue("cameraPos", cameraPos, sizeof(cameraPos));

pEffect->SetTexture("colorMapTexture", texture);

UINT passes = 0;
pEffect->Begin(&passes, 0);
pEffect->BeginPass(0);

D3DXMATRIX mWorld = model->worldMatrix();
pEffect->SetMatrix("World", &mWorld);

model->render(dt);

pEffect->EndPass();
pEffect->End();

float4x4 World;
float4x4 View;
float4x4 Projection;

// Light
float4 lightDiffuse;
float4 lightSpecular;
float3 lightDirection;  // Directional light

// Material
float4 materialDiffuse;
float4 materialAmbient;
float4 materialSpecular;
float materialPower;

float4 globalAmbient;

// Camera position
float3 cameraPos;

// Texture
texture colorMapTexture;
sampler2D colorMap = sampler_state
{
Texture = <colorMapTexture>;
MagFilter = Linear;
MinFilter = Anisotropic;
MipFilter = Linear;
MaxAnisotropy = 16;
};

struct VS_INPUT
{
float3 Pos : POSITION;
float2 UV : TEXCOORD0;
float3 Normal : NORMAL;
};

struct VS_OUTPUT
{
float4 Pos : POSITION;
float2 UV : TEXCOORD0;
float3 Normal : NORMAL;
float3 worldPos : TEXCOORD4;
};

//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
VS_OUTPUT VS( VS_INPUT IN )
{
VS_OUTPUT Out;
Out = (VS_OUTPUT)0;
float4x4 WVP = mul(World, mul(View, Projection));
Out.Pos = mul(float4(IN.Pos, 1.0f), WVP);
Out.UV = IN.UV;
Out.Normal = mul(IN.Normal, (float3x3)World).xyz;
Out.worldPos = mul(float4(IN.Pos, 1.0f), World).xyz;
return Out;
}

//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
float4 PS( VS_OUTPUT IN ) : COLOR
{
float3 viewDir = normalize(cameraPos - IN.worldPos);

float3 lightDir = normalize(-lightDirection);
float3 halfVector = normalize(lightDir + viewDir);

float3 n = normalize(IN.Normal);
float3 h = normalize(halfVector);
float3 l = normalize(lightDir);

float nDotL = saturate(dot(n, l));
float nDotH = saturate(dot(n, h));
float power = pow(nDotH, materialPower);

float4 FinalDiffuse = materialDiffuse * lightDiffuse;
float4 FinalSpecular = materialSpecular * lightSpecular;

float4 color = (materialAmbient + globalAmbient) + (FinalDiffuse * nDotL) + (FinalSpecular * power);
return color * tex2D(colorMap, IN.UV);
}

//-----------------------------------------------------------------------------
// Techniques.
//-----------------------------------------------------------------------------
technique DirectionalLighting
{
pass
{
AlphaBlendEnable = false;
ZEnable = true;
}
}

### #16belfegor  Members

Posted 21 July 2013 - 02:26 PM

I have just plugged your code and shader in some of my project, changed only light specular to pure white:

### #17Medo3337  Members

Posted 21 July 2013 - 06:37 PM

@belfegor: Have you tried to scale and move the teapot?

It works much better with the teapot, but when I scale and move it sometimes I see weird specular (Like the one I posted in the screenshot).

Generally, the diffuse light works well with any mesh, but the specular disappear with my box mesh, sometimes it show up, but it looks weird.

I believe there is a problem with the shader code.

### #18Medo3337  Members

Posted 22 July 2013 - 06:04 AM

@belfegor: Okay, after testing for sometime

I notice that the shapes I create manually works much better with the shader light (D3DXCreateTeapot, D3DXCreateBox, D3DXCreateSphere, etc...) All works very well with the light.

However, when I load a mesh using D3DXLoadMeshFromX(), the specular light get messed up.

### #19Medo3337  Members

Posted 22 July 2013 - 03:29 PM

Up

### #20Anddos  Members

Posted 22 July 2013 - 08:05 PM

@belfegor: Okay, after testing for sometime

I notice that the shapes I create manually works much better with the shader light (D3DXCreateTeapot, D3DXCreateBox, D3DXCreateSphere, etc...) All works very well with the light.

However, when I load a mesh using D3DXLoadMeshFromX(), the specular light get messed up.

did you clone the mesh so it has NORMALS?

Edited by Anddos, 22 July 2013 - 08:06 PM.

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