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JackNJ

OpenGL Yet another per-pixel ligthing question (Cg)

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I realize this is a common topic, my apologies for bringing this up again. I've been trying to move my lighting from object-space to eye-space, my problem is that my diffuse ligthing is not constant when rotating around a given object: I expect the diffuse light to not change when doing this. I assume this is correct, seeing how diffuse is not dependent on eye position. In the code below my ambient/specular lighting has been commented out. VP: // data from application to vertex program struct vertexIn { float4 Position : POSITION; float4 Normal : NORMAL; }; // vertex shader to pixel shader struct vertexOut { float4 HPosition : POSITION; float4 EyeNormal : TEXCOORD2; float4 PosEye : TEXCOORD3; }; // vertex shader vertexOut main(vertexIn IN) { vertexOut OUT; float4x4 ModelView = glstate.matrix.modelview[0]; float4x4 ModelViewIT = glstate.matrix.invtrans.modelview[0]; float4x4 ModelViewProj = glstate.matrix.mvp; // normal in eye coords OUT.EyeNormal.xyz = normalize(mul((float3x3)ModelViewIT, IN.Normal.xyz)); // pos in eye coords OUT.PosEye = mul(ModelView, IN.Position); // pos in clip coords OUT.HPosition = mul(ModelViewProj, IN.Position); return OUT; } FP: // data from vertex shader struct vertexOut { float4 HPosition : POSITION; float4 EyeNormal : TEXCOORD2; float4 PosEye : TEXCOORD3; }; // output from pixel shader struct pixelOut { float4 Color : COLOR0; }; // input from application struct pixelAppData { float4 lightColor; float materialShininess; float4 materialAmbient; float4 materialDiffuse; float4 materialSpecular; }; pixelOut main(vertexOut IN, uniform pixelAppData AppIn) { pixelOut OUT; float3 N = normalize(IN.EyeNormal.xyz); float4 lightPosEye = glstate.light[0].position; float3 L = normalize((lightPosEye - IN.PosEye).xyz); // not used atm float3 V = normalize(-IN.PosEye).xyz; // eye's position is always 0,0,0 in eye space // not used atm float3 H = normalize(L+V); float4 lightCoffs = lit(dot(N,L), dot(N,H), AppIn.materialShininess); // OUT.Color = AppIn.materialAmbient * lightCoffs[0]; OUT.Color = AppIn.lightColor * AppIn.materialDiffuse * lightCoffs[1]; // OUT.Color += AppIn.lightColor * AppIn.materialSpecular * lightCoffs[2]; return OUT; } My assumption is that the light position is somehow not correctly transformed into eye-space, however I'm using glLightfv(GL_LIGHT0, GL_POSITION, ..) to do this and according to my OpenGL manual this position given is automatically transfered into eye-space. Any help is appreciated.

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