i render a scene including a teapot and ambient light .Without using fbo the whole scene seems ok!When i using fbo to render the scene into a texture,the light become dim. Why?
glGenFramebuffersEXT(1, &fb);
glGenTextures(1, &tex);
glGenRenderbuffersEXT(1, &depth_rb);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb);
glBindTexture(texTarget, tex);
glTexImage2D(texTarget,0,GL_RGBA,texWidth,texHeight,0,GL_RGBA,GL_FLOAT,0);
glTexParameterf(texTarget, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(texTarget, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(texTarget, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(texTarget, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, depth_rb);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, texWidth, texHeight);
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, tex, 0);//new
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, depth_rb);//new
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);