Hi, I have a problem with combining a spot light with a textured triangle strip. The spot light and the textured triangle strip work well, as long as they are not combined, but as soon as I activate the texture with the glEnable(GL_TEXTURE_2D) command, the spotlight doesn't work anymore. Has anybody an idea, where I have made the mistake? I would be grateful for any hints. thanks a lot Heinz P.S. The actual code I use for texture and lightning is as follows: void __fastcall TFormMain::SetupLighting() { GLfloat MaterialAmbient[] = {0.5, 0.5, 0.5, 1.0}; GLfloat MaterialDiffuse[] = {1.0, 1.0, 1.0, 1.0}; GLfloat MaterialSpecular[] = {1.0, 1.0, 1.0, 1.0}; GLfloat MaterialShininess[] = {50.0}; glMaterialfv(GL_FRONT, GL_AMBIENT, MaterialAmbient); glMaterialfv(GL_FRONT, GL_DIFFUSE, MaterialDiffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, MaterialSpecular); glMaterialfv(GL_FRONT, GL_SHININESS, MaterialShininess); glEnable(GL_COLOR_MATERIAL); glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE); glShadeModel(GL_SMOOTH); // set ambient light intensity GLfloat ambientLight[]={0.5,0.5,0.5,1.0}; glLightfv(GL_LIGHT0,GL_AMBIENT,ambientLight); // set diffuse light intensity GLfloat diffuseLight[]={0.8,0.8,0.8,1.0}; glLightfv(GL_LIGHT0,GL_DIFFUSE,diffuseLight); // set specular light intensity GLfloat specularLight[]={0.5,0.5,0.5,1.0}; glLightfv(GL_LIGHT0,GL_SPECULAR,specularLight); // set light position GLfloat lightPos[]={0.0,0.0,60.0,1.0}; glLightfv(GL_LIGHT0,GL_POSITION,lightPos); // set material properties GLfloat specularReflection[]={1.0,1.0,1.0,1.0}; glMaterialfv(GL_FRONT, GL_SPECULAR, specularReflection); glMateriali(GL_FRONT,GL_SHININESS,128); // set spot light parameters GLfloat spotDir[]={0.0,0.0,-1.0}; // define spot direction glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, spotDir); glLightf(GL_LIGHT0, GL_SPOT_CUTOFF,40.0); // set cutoff angle glLightf(GL_LIGHT0, GL_SPOT_EXPONENT,7.0); // set focusing strength glEnable(GL_LIGHT0); // activate the defined light glEnable(GL_LIGHTING); // enable lighting glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambientLight); // set lighting model glEnable(GL_COLOR_MATERIAL); glColorMaterial(GL_FRONT,GL_AMBIENT_AND_DIFFUSE); glEnable(GL_NORMALIZE); // normalize normal vectors } //--------------------------------------------------------------------------- void __fastcall TFormMain::SetupTexture() { const int texturesize1=512; bitmap = new Graphics::TBitmap; bitmap->LoadFromFile("keller2.bmp"); GLubyte bits[texturesize1][texturesize1][4]; for(int i = 0; i < texturesize1; i++) { for(int j = 0; j < texturesize1; j++) { bits[j][0]= (GLbyte)GetRValue(bitmap->Canvas->Pixels[j]); bits[j][1]= (GLbyte)GetGValue(bitmap->Canvas->Pixels[j]); bits[j][2]= (GLbyte)GetBValue(bitmap->Canvas->Pixels[j]); bits[j][3]= (GLbyte)255; } } glPixelStorei(GL_UNPACK_ALIGNMENT, 4); // specify memory alignment glGenTextures(1, &texture1); glBindTexture(GL_TEXTURE_2D, texture1); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texturesize1, texturesize1, 0, GL_RGBA, GL_UNSIGNED_BYTE, bits); glEnable(GL_TEXTURE_2D); glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL); }

Hi Heinz,
i am havin the same prob, but not with spotlight. I am trying to gets some fonts workin but i cannot change the color of them once i initialize my textures.
somehow i think its the same prob.


hope it helped ;-)))
cherio Woltan

I think your problem is

glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);

Try switching it to
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

From what I understand from my problem ridden attempts to do opengl lighting and blending, the texture needs to be blended, in a sense, with the trangle it's being put on to show the lighting on that trangle. GL_DECAL puts the texture on the triangle, overwriting anything underneath. GL_MODULATE basically lights the texture based on the trangle "beneath". So, from what I've seen, a texture is never directly lit, the traingle beneath it is, then they are combined. If I'm off, maybe some kind soul will come on here and flame me...

THANKS A LOT!

I have changed it now to GL_MODULATE and everything works fine. Thank you to all of you for your kind help and the detailed explanations!

Heinz