- depth_buf.parameter(GL_DEPTH_TEXTURE_MODE, GL_LUMINANCE);
- depth_buf.parameter(GL_TEXTURE_COMPARE_MODE, GL_COMPARE_R_TO_TEXTURE);
- depth_buf.parameter(GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
- depth_buf.parameter(GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
- depth_buf.parameter(GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);