+ case GL_DST_COLOR: a |= SDM_SRC_DST_COLOR; break;
+ case GL_ONE_MINUS_DST_COLOR: a |= SDM_SRC_INV_DST_COLOR; break;
+
+ /* (f, f, f, 1), f = min(As, 1 - Ad) = min(As, 1 - 1) = 0
+ * So (f, f, f, 1) = (0, 0, 0, 1). Since there is no destination alpha and
+ * the only supported alpha operation is GL_FUNC_ADD, the result modulating
+ * the source alpha with the alpha factor is largely irrelevant.
+ */
+ case GL_SRC_ALPHA_SATURATE: a |= SDM_SRC_ZERO; break;
+