From 1cada85e6bd7135905199e82d6606da246aa902a Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Mon, 15 Jan 2018 12:20:27 +0100
Subject: [PATCH] ShaderGenerator: fixes for combine alpha blending

---
 panda/src/pgraphnodes/shaderGenerator.cxx | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/panda/src/pgraphnodes/shaderGenerator.cxx b/panda/src/pgraphnodes/shaderGenerator.cxx
index 6b83c3ef14..3546af732d 100644
--- a/panda/src/pgraphnodes/shaderGenerator.cxx
+++ b/panda/src/pgraphnodes/shaderGenerator.cxx
@@ -1444,7 +1444,7 @@ synthesize_shader(const RenderState *rs, const GeomVertexAnimationSpec &anim) {
         text << "\t result.rgb = ";
         text << combine_mode_as_string(tex, combine_rgb, false, i);
         text << ";\n\t result.a = ";
-        text << combine_mode_as_string(tex, combine_alpha, false, i);
+        text << combine_mode_as_string(tex, combine_alpha, true, i);
         text << ";\n";
       }
       if (tex._flags & ShaderKey::TF_rgb_scale_2) {
@@ -1667,6 +1667,7 @@ combine_source_as_string(const ShaderKey::TextureInfo &info, short num, bool alp
     csource << "saturate(1.0f - ";
   }
   switch (c_src) {
+    case TextureStage::CS_undefined:
     case TextureStage::CS_texture:
       csource << "tex" << texindex;
       break;
@@ -1685,8 +1686,6 @@ combine_source_as_string(const ShaderKey::TextureInfo &info, short num, bool alp
     case TextureStage::CS_last_saved_result:
       csource << "last_saved_result";
       break;
-    case TextureStage::CS_undefined:
-      break;
   }
   if (c_op == TextureStage::CO_one_minus_src_color ||
       c_op == TextureStage::CO_one_minus_src_alpha) {