Per-Pixel Point Light

Graphics and GPU Programming Programming

Started by Medo Mex July 15, 2013 11:50 PM

17 comments, last by Waaayoff 10 years, 9 months ago

2,836

July 16, 2013 07:26 PM

Color values should be in 0 - 1 range, ambients should be relatively small, so try this:

// Light
float lightDiffuse[4] = {1.0f, 1.0f, 1.0f, 1.0f};
//float lightAmbient[4] = {0.0f, 0.0f, 0.0f, 1.0f};
float lightSpecular[4] = {1.0f, 1.0f, 1.0f, 1.0f};
float lightRange = 100.0f;
...

// Material
float materialDiffuse[4] = {1.0f, 1.0f, 1.0f, 1.0f};
float materialAmbient[4] = {0.05f, 0.05f, 0.05f, 1.0f};
float materialSpecular[4] = {1.0f, 1.0f, 1.0f, 1.0f};
float materialPower = 8.0f;
...

and you are missing "globalAmbient":

float gAmbient[4] = { 0.15f, 0.15f, 0.15f, 1.0f };
pEffect->SetValue("globalAmbient", &gAmbient, sizeof(gAmbient));

Medo Mex

891

Author

July 16, 2013 08:07 PM

@belfegor: Now, the mesh is completely black all the time.

belfegor

2,836

July 16, 2013 08:13 PM

It should not be completely black, have you enabled dx debug runtime? Check any dx debug messages in output window!

Repost your cpp code and shader.

Medo Mex

891

Author

July 16, 2013 08:14 PM

@belfegor: Nothing really in the output window, the shader is working correctly, but the mesh is black all the time.

You might want to the check the shader code...

belfegor

2,836

July 16, 2013 08:19 PM

It can't be pure black, should have at least ambient of 0.2 no matter the view and light angles, unless you have done something wrong in cpp code and then it skips shader.

I ask you again have you enbled dx debug runtime and set proper options in dx control panel?

Repost your cpp and shader!

I see you have your camera position in shader as single float set it as float3.

Medo Mex

891

Author

July 16, 2013 08:39 PM

@belfegor: Now, the mesh is not black, however I see the texture and it's dark and I don't see any light affecting it when it's very close to the light position.

Shader:


float4x4 World;
float4x4 View;
float4x4 Projection;

// Point light
float4 lightPosition;
float4 lightDiffuse;
float4 lightAmbient;
float4 lightSpecular;
float lightRange;

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

float4 globalAmbient;

// Camera position
float3 eyePos;

// Texture
texture colorMapTexture;

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

struct PS_INPUT
{
   float3 Pos : POSITION;
   float2 UV : TEXCOORD0;
   float3 Normal : TEXCOORD1;
   float3 worldPos : TEXCOORD2;
};

struct VS_INPUT 
{
   float3 Pos : POSITION;
   float2 UV : TEXCOORD0;
   float3 Normal : TEXCOORD1;
};

struct VS_OUTPUT 
{
   float4 Pos : POSITION;
   float2 UV : TEXCOORD0;
   float3 Normal : TEXCOORD1;
   float3 worldPos : TEXCOORD2;
};

//-----------------------------------------------------------------------
// Vertex shader function
//-----------------------------------------------------------------------
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;
}

//-----------------------------------------------------------------------
// Pixel shader function
//-----------------------------------------------------------------------
float4 PS( PS_INPUT IN ) : COLOR
{
    float3 viewDir = eyePos - IN.worldPos;
    float3 lightDir = (lightPosition - IN.worldPos) / lightRange;

    float atten = saturate(1.0f - dot(lightDir, lightDir));


    float3 n = normalize(IN.Normal);
    float3 l = normalize(lightDir);
    float3 v = normalize(viewDir);
    float3 h = normalize(l + v);
    
    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 + (atten * lightAmbient))) +
    //             (FinalDiffuse * nDotL * atten) + (FinalSpecular * power * atten);
    
    float4 color = (materialAmbient + globalAmbient) + (FinalDiffuse * nDotL * atten) + (FinalSpecular * power * atten);
    return color * tex2D(colorMap, IN.UV);
}


//-----------------------------------------------------------------------------
// Techniques.
//-----------------------------------------------------------------------------
technique PointLighting
{
    pass
    {
        AlphaBlendEnable = false;
        ZEnable = true;
        VertexShader = compile vs_3_0 VS();
        PixelShader = compile ps_3_0 PS();
    }
}

Medo Mex

891

Author

July 16, 2013 10:25 PM

I notice that the global ambient color is the only color that affect the mesh, there is no light at all.

The weird thing is that the light works perfectly when I change this line:


float3 n = normalize(IN.Normal);

To the old invalid value:


float3 n = normalize(tex2D(colorMap, IN.UV).rgb * 2.0f - 1.0f);

What's going on?

Medo Mex

891

Author

July 17, 2013 09:37 AM

Bump

Waaayoff

952

July 18, 2013 05:52 PM

Output the normals from the pixel shader as colour. Do they look correct?

"Spending your life waiting for the messiah to come save the world is like waiting around for the straight piece to come in Tetris...even if it comes, by that time you've accumulated a mountain of shit so high that you're fucked no matter what you do. "

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