From 8c1f64e086e3dd12be80a97b2e35ce3cffbff6d2 Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Mon, 14 Nov 2016 19:40:46 +0100
Subject: [PATCH] Fix for 1.9: fix errors when Cg-style matrix inputs are mat3

---
 doc/ReleaseNotes                          |  1 +
 panda/src/glstuff/glShaderContext_src.cxx | 12 ++++++++++--
 panda/src/glstuff/glShaderContext_src.h   |  2 +-
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/doc/ReleaseNotes b/doc/ReleaseNotes
index 157a20b2bf..b7462a97d6 100644
--- a/doc/ReleaseNotes
+++ b/doc/ReleaseNotes
@@ -47,6 +47,7 @@ This issue fixes several bugs that were still found in 1.9.2.
 * Fix compilation errors with Bullet 2.84
 * Fix exception when trying to pickle NodePathCollection objects
 * Fix error when trying to raise vectors to a power
+* GLSL: fix error when legacy matrix generator inputs are mat3
 
 ------------------------  RELEASE 1.9.2  ------------------------
 
diff --git a/panda/src/glstuff/glShaderContext_src.cxx b/panda/src/glstuff/glShaderContext_src.cxx
index df8ea97655..5ce322bfac 100644
--- a/panda/src/glstuff/glShaderContext_src.cxx
+++ b/panda/src/glstuff/glShaderContext_src.cxx
@@ -51,7 +51,7 @@ TypeHandle CLP(ShaderContext)::_type_handle;
 //               actually picked up and the appropriate ShaderMatSpec pushed onto _mat_spec.
 ////////////////////////////////////////////////////////////////////
 bool CLP(ShaderContext)::
-parse_and_set_short_hand_shader_vars(Shader::ShaderArgId &arg_id, Shader *objShader) {
+parse_and_set_short_hand_shader_vars(Shader::ShaderArgId &arg_id, GLenum param_type, Shader *objShader) {
   Shader::ShaderArgInfo p;
   p._id = arg_id;
   p._cat = GLCAT;
@@ -167,6 +167,14 @@ parse_and_set_short_hand_shader_vars(Shader::ShaderArgId &arg_id, Shader *objSha
     else if (pieces[0] == "col2")  bind._piece = Shader::SMP_col2;
     else if (pieces[0] == "col3")  bind._piece = Shader::SMP_col3;
 
+    if (param_type == GL_FLOAT_MAT3) {
+      if (bind._piece == Shader::SMP_whole) {
+        bind._piece = Shader::SMP_upper3x3;
+      } else if (bind._piece == Shader::SMP_transpose) {
+        bind._piece = Shader::SMP_transpose3x3;
+      }
+    }
+
     if (!objShader->cp_parse_coord_sys(p, pieces, next, bind, true)) {
       return false;
     }
@@ -614,7 +622,7 @@ CLP(ShaderContext)(CLP(GraphicsStateGuardian) *glgsg, Shader *s) : ShaderContext
         }
 
         //Tries to parse shorthand notations like mspos_XXX and trans_model_to_clip_of_XXX
-        if (parse_and_set_short_hand_shader_vars(arg_id, s)) {
+        if (parse_and_set_short_hand_shader_vars(arg_id, param_type, s)) {
           continue;
         }
 
diff --git a/panda/src/glstuff/glShaderContext_src.h b/panda/src/glstuff/glShaderContext_src.h
index 62d54ed675..51376e44f4 100644
--- a/panda/src/glstuff/glShaderContext_src.h
+++ b/panda/src/glstuff/glShaderContext_src.h
@@ -87,7 +87,7 @@ private:
   void glsl_report_program_errors(GLuint program, bool fatal);
   bool glsl_compile_shader(Shader::ShaderType type);
   bool glsl_compile_and_link();
-  bool parse_and_set_short_hand_shader_vars(Shader::ShaderArgId &arg_id, Shader *s);
+  bool parse_and_set_short_hand_shader_vars(Shader::ShaderArgId &arg_id, GLenum param_type, Shader *s);
   void release_resources();
 
 public: