+ * Choose the mipmap level to use when sampling from a depth texture.
+ */
+static int
+choose_depth_texture_level(const struct gl_texture_object *tObj, GLfloat lambda)
+{
+ GLint level;
+
+ if (tObj->MinFilter == GL_NEAREST || tObj->MinFilter == GL_LINEAR) {
+ /* no mipmapping - use base level */
+ level = tObj->BaseLevel;
+ }
+ else {
+ /* choose mipmap level */
+ lambda = CLAMP(lambda, tObj->MinLod, tObj->MaxLod);
+ level = (GLint) lambda;
+ level = CLAMP(level, tObj->BaseLevel, tObj->_MaxLevel);
+ }
+
+ return level;
+}
+
+
+/**
+ * Sample a shadow/depth texture. This function is incomplete. It doesn't
+ * check for minification vs. magnification, etc.