From add171b6faa52d29accf939521bc945aeeda73ba Mon Sep 17 00:00:00 2001
From: Hleb Valoshka <375gnu@gmail.com>
Date: Sat, 9 Nov 2019 23:42:21 +0300
Subject: [PATCH] Fix error reporting when shader linking failed

---
 src/celengine/glshader.cpp | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/src/celengine/glshader.cpp b/src/celengine/glshader.cpp
index 802af8b1..77647fe2 100644
--- a/src/celengine/glshader.cpp
+++ b/src/celengine/glshader.cpp
@@ -381,13 +381,36 @@ GetInfoLog(GLuint obj)
     GLint logLength = 0;
     GLsizei charsWritten = 0;
 
-    glGetShaderiv(obj, GL_INFO_LOG_LENGTH, &logLength);
+    enum { Unknown, Shader, Program } kind;
+
+    if (glIsShader(obj))
+    {
+        kind = Shader;
+    }
+    else if (glIsProgram(obj))
+    {
+        kind = Program;
+    }
+    else
+    {
+        cerr << "Unknown object passed to GetInfoLog()!\n";
+        return string();
+    }
+
+    if (kind == Shader)
+        glGetShaderiv(obj, GL_INFO_LOG_LENGTH, &logLength);
+    else
+        glGetProgramiv(obj, GL_INFO_LOG_LENGTH, &logLength);
+
     if (logLength <= 0)
         return string();
 
     auto* log = new char[logLength];
 
-    glGetShaderInfoLog(obj, logLength, &charsWritten, log);
+    if (kind == Shader)
+        glGetShaderInfoLog(obj, logLength, &charsWritten, log);
+    else
+        glGetProgramInfoLog(obj, logLength, &charsWritten, log);
 
     string s(log, charsWritten);
     delete[] log;