I’ve already written some vertex programs but only with NV_vertex_program and i would try to code with the ARB_vertex_program after reading the nvopenglspec.pdf !

I tried to code a very simple program which was supposed to calculate diffuse lighting with only N dot L in model space and eye space by using the state.matrix.modelview but without success !

I’ve passed in “local param” or “env param” the light in model space and the illumination works well ! So my problem is the state.matrix.modelview.inverse which doesnt seem to do HER job !!!

here the vertex program :

!!ARBvp1.0

ATTRIB iPos = vertex.position;

ATTRIB iNrml = vertex.normal;

PARAM mvp[4] = { state.matrix.mvp };

PARAM inv_mv[4] = { state.matrix.modelview.inverse };

PARAM eLight = program.local[0]; # eye space light

TEMP mLight;

OUTPUT oPos = result.position;

OUTPUT oCol = result.color;

DP4 oPos.x, mvp[0], iPos;

DP4 oPos.y, mvp[1], iPos;

DP4 oPos.z, mvp[2], iPos;

DP4 oPos.w, mvp[3], iPos;

# light in model space

DP3 mLight.x, inv_mv[0], eLight;

DP3 mLight.y, inv_mv[1], eLight;

DP3 mLight.z, inv_mv[2], eLight;

# vector L = l - vertex

SUB mLight, mLight, iPos;

DP3 mLight.w, mLight, mLight;

RSQ mLight.w, mLight.w;

MUL mLight.xyz, mLight.w, mLight;

DP3 oCol, mLight, iNrml;

END

Please help me, i want to sleep !

[This message has been edited by ze.destroy (edited 02-11-2003).]