***************
VERTEX
***************
void mainV (
float4 iPosition : POSITION,
float4 iNormal : NORMAL,
float3 iTexCoord1 : TEXCOORD0,
float3 iTexCoord2 : TEXCOORD1,
uniform float4x4 iModelViewProj,
out float4 oPosition : POSITION,
out float3 oTexCoord1 : TEXCOORD0,
out float3 oTexCoord2 : TEXCOORD1,
out float3 oVertexPos : TEXCOORD2,
out float3 oVertexNormal : TEXCOORD3
)
{
oPosition = mul(iModelViewProj, iPosition);
oTexCoord1 = iTexCoord1;
oTexCoord2 = iTexCoord2;
oVertexPos = iPosition.xyz;
oVertexNormal = iNormal.xyz;
}
******************
FRAGMENT
******************
float3 light(
float3 iLightPos,
float3 iLightCol,
float3 iMaterial[5],
float3 iFragmentPosition,
float3 iFragmentNormal,
float3 iEyePosition
)
{
float3 final = iMaterial[3];
final += iMaterial[0] * iLightCol;
float3 Normal = normalize(iFragmentNormal);
float3 L = normalize(iLightPos - iFragmentPosition);
float Diffuse = max(dot(Normal, L), 0);
final += iMaterial[1] * iLightCol * Diffuse;
float3 V = normalize(iEyePosition - iFragmentPosition);
float3 H = normalize(L + V);
float Specular = pow(max(dot(Normal, H), 0), iMaterial[4].x);
final += iMaterial[1] * iLightCol * Diffuse;
float d = distance(iLightPos, iFragmentPosition);
return final / ( d * 0.25);
}
void mainF (
float3 iTexCoord1 : TEXCOORD0,
float3 iTexCoord2 : TEXCOORD1,
float4 iFragmentPos : TEXCOORD2,
float3 iFragmentNormal : TEXCOORD3,
uniform float3 iEyePosition,
uniform float4 iLightPos[4],
uniform float4 iLightCol[4],
uniform float3 iMaterial[5],
uniform sampler2D iTexture1,
uniform sampler2D iTexture2,
out float4 oColor : COLOR
)
{
float4 Tex1 = tex2D(iTexture1, iTexCoord1.xy);
float4 Tex2 = tex2D(iTexture2, iTexCoord2.xy);
oColor = float4(lerp(Tex1.rgb, Tex2.rgb, Tex2.a), 1);
iFragmentPos *= 0.1;
float3 Light = float3(1,1,1);
if(iLightPos[0].w>0.0) Light = light(iLightPos[0].xyz, iLightCol[0].rgb, iMaterial, iFragmentPos.xyz, iFragmentNormal, iEyePosition);
if(iLightPos[1].w>0.0) Light += light(iLightPos[1].xyz, iLightCol[1].rgb, iMaterial, iFragmentPos.xyz, iFragmentNormal, iEyePosition);
if(iLightPos[2].w>0.0) Light += light(iLightPos[2].xyz, iLightCol[2].rgb, iMaterial, iFragmentPos.xyz, iFragmentNormal, iEyePosition);
if(iLightPos[3].w>0.0) Light += light(iLightPos[3].xyz, iLightCol[3].rgb, iMaterial, iFragmentPos.xyz, iFragmentNormal, iEyePosition);
oColor = float4(Light, 1);
}
Basic per-fragment lighting with cg shader
Author
hi,
i've made a vertex program and a fragment program to bring multitexturing and per-fragment lighting to my 3d-app. unfortunately there is a problem with the spaces. in the vertex program i compute the vertices' world space position by multiplying the vertices with the modelviewproj matrix which is currently
1 0 0 0
0 1 0 0
0 0 1 -5
0 0 0 0.
there are four vertices which represent two triangles formed to a quad(-1,-1,1,1).
for the per-pixel lighting i need the fragment's position in world space because the viewer's position and the light position is in world space, too.
so i specify an output variable with the semantic TEXCOORD2 in the vertex program and a corresponding input variable in the fragment program. when i set the positions for each vertex, the rasterizer should give me an interpolated position for each fragment. but this doesn't seep to work properly. the z value is clamped to [0..1].
i have done everything exactly like what is in the nvidia's cg tutorial book.
except that i use world space positions in the fragment shader.
here is my code:
[Edited by - Zische on August 21, 2005 6:16:29 PM]
don´t know anything about fragments, but I noticed something in your code:
shouldn´t
be
? It´s the last line of MainF()... perhaps that helps.
shouldn´t
oColor = float4(Light,1);be
oColor = oColor * float4(Light,1);? It´s the last line of MainF()... perhaps that helps.
Author
You are right. I changed it for debugging, but this doesn't create the error. It rather helps me by showing the light's color instead of a shaded texture.
Quote:Original post by Zische
[...]the modelviewproj matrix which is currently
1 0 0 0
0 1 0 0
0 0 1 -5
0 0 0 0.
How is it possible, that your matrix is singular (determinant==0)? Where did you get it from?
Quote:
for the per-pixel lighting i need the fragment's position in world space because the viewer's position and the light position is in world space, too.
So shouldn't it be:
[...]uniform float4x4 iModelViewProj,uniform float4x4 iModel,out float4 oPosition : POSITION,[...]oPosition = mul(iModelViewProj, iPosition);oTexCoord1 = iTexCoord1;oTexCoord2 = iTexCoord2;oVertexPos = mul( iModel, iPosition );oVertexNormal = mul( (float3x3)iModel, (float3)iNormal );Unless you're sure the model matrix is identity, which is usually not the case.
~def
Author
im not so familiar with all thos matrices. the determinatn 0 was a mistake while i wrote the thread. here is what i do to pass the modelviewproj matrix to the shader:
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glMultMatrix(m_Transformation);
cgGLSetStateMatrixParameter(m_modelViewMatrix, CG_GL_MODELVIEW_PROJECTION_MATRIX, CG_GL_MATRIX_IDENTITY);
there were several mistakes in my code due to "brute force" debugging. here is the code:
the diffuse color works. but the specular is 0.
[Edited by - Zische on August 22, 2005 11:16:48 AM]
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glMultMatrix(m_Transformation);
cgGLSetStateMatrixParameter(m_modelViewMatrix, CG_GL_MODELVIEW_PROJECTION_MATRIX, CG_GL_MATRIX_IDENTITY);
there were several mistakes in my code due to "brute force" debugging. here is the code:
***********VERTEX***********void main ( float4 iPosition : POSITION, float4 iNormal : NORMAL, float3 iTexCoord1 : TEXCOORD0, float3 iTexCoord2 : TEXCOORD1, uniform float4x4 iModelViewProj, uniform float4x4 iModel, out float4 oPosition : POSITION, out float3 oTexCoord1 : TEXCOORD0, out float3 oTexCoord2 : TEXCOORD1, out float3 oVertexPos : TEXCOORD2, out float3 oVertexNormal : TEXCOORD3 ){ oPosition = mul(iModelViewProj, iPosition); oTexCoord1 = iTexCoord1; oTexCoord2 = iTexCoord2; oVertexPos = mul(iModel, oPosition).xyz; oVertexNormal = mul((float3x3)iModel, iNormal.xyz);}***********Fragment***********float3 light( float3 iLightPos, float3 iLightCol, float3 iMaterial[5], float3 iFragmentPosition, float3 iFragmentNormal, float3 iEyePosition ){ float3 final = iMaterial[3]; final += iMaterial[0] * iLightCol; float3 Normal = normalize(iFragmentNormal); float3 L = normalize(iLightPos - iFragmentPosition); float Diffuse = max(dot(Normal, L), 0); final += iMaterial[1] * iLightCol * Diffuse; float3 V = normalize(iEyePosition - iFragmentPosition); float3 H = normalize(L + V); float Specular = pow(max(dot(Normal, H), 0), iMaterial[4].x); if(Diffuse<=0) Specular = 0; final += iMaterial[2] * iLightCol * Specular; float d = distance(iLightPos, iFragmentPosition); return final / ( d * 0.25);}void main ( float3 iTexCoord1 : TEXCOORD0, float3 iTexCoord2 : TEXCOORD1, float4 iFragmentPos : TEXCOORD2, float3 iFragmentNormal : TEXCOORD3, uniform float3 iEyePosition, uniform float4 iLightPos[4], uniform float4 iLightCol[4], uniform float3 iMaterial[5], uniform sampler2D iTexture1, uniform sampler2D iTexture2, out float4 oColor : COLOR ){ float3 Light = float3(1,1,1); Light = light(iLightPos[0].xyz, iLightCol[0].rgb, iMaterial, iFragmentPos.xyz, iFragmentNormal, iEyePosition); oColor = float4(Light, 1);}the diffuse color works. but the specular is 0.
[Edited by - Zische on August 22, 2005 11:16:48 AM]
Don't take me wrong, but your code is quite confusing, and thus hard to debug.
Material[0], Material[1], Material[2], Material[3]. There are plenty of letters in the alphabet and plenty of words in a dictionary [grin].
Now seriously, what's with the iModel matrix? Are you setting it properly? In GL, you do not have explicitly model matrix (only model*view), so you got to keep track of it by yourself.
And why can't you simply debug your shader step-by-step? Or is there no such option in CG?
~def
Material[0], Material[1], Material[2], Material[3]. There are plenty of letters in the alphabet and plenty of words in a dictionary [grin].
Now seriously, what's with the iModel matrix? Are you setting it properly? In GL, you do not have explicitly model matrix (only model*view), so you got to keep track of it by yourself.
And why can't you simply debug your shader step-by-step? Or is there no such option in CG?
~def
Author
i dont know how to use nvidia's IDE FX Composer and i don't know how to implement cg compiling in microsoft's visual c++, so it is hard to debug, because i have to run cgc.exe everytime i want to debug syntax errors. but i cant really see what values are in the variables at runtime.
the iMaterial array is to collect information like ambient, diffuse, specular, emissive, shininess, alpha.
thanks for your help. i made it work now.
the iMaterial array is to collect information like ambient, diffuse, specular, emissive, shininess, alpha.
thanks for your help. i made it work now.
This topic is closed to new replies.
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