brad/2744 handle shader errors (#3105)

* Partial solution to secondlife/viewer#2744 crash with better error handling.

Handles shader compile errors better, and should turn crash into an LL_ERRS assertion failure.
Strengthed more assertions and improved shader error line numbers

* Even more error handling to get a handle on crash secondlife/viewer#2744
* Improved GLSL correctness on Intel chips that lack OpenGL 4.6 support. secondlife/viewer#2744
* Removed non-working fallback code for gDeferredPostProgram
* Fixed incorrect llmax call

3 files changed, 10 insertions, 12 deletions

diff --git a/indra/llrender/llglslshader.cpp b/indra/llrender/llglslshader.cpp
index 6ba5463acd..45bb24a5b7 100644
--- a/indra/llrender/llglslshader.cpp
+++ b/indra/llrender/llglslshader.cpp
@@ -1046,7 +1046,7 @@ void LLGLSLShader::bind()
 {
     LL_PROFILE_ZONE_SCOPED_CATEGORY_SHADER;
 
-    llassert(mProgramObject != 0);
+    llassert_always(mProgramObject != 0);
 
     gGL.flush();
 
@@ -1069,6 +1069,9 @@ void LLGLSLShader::bind()
         LLShaderMgr::instance()->updateShaderUniforms(this);
         mUniformsDirty = false;
     }
+
+    llassert_always(sCurBoundShaderPtr != nullptr);
+    llassert_always(sCurBoundShader == mProgramObject);
 }
 
 void LLGLSLShader::bind(U8 variant)
diff --git a/indra/llrender/llrender.cpp b/indra/llrender/llrender.cpp
index c8a9fb4893..eb2cd560a6 100644
--- a/indra/llrender/llrender.cpp
+++ b/indra/llrender/llrender.cpp
@@ -1569,7 +1569,8 @@ void LLRender::flush()
     if (mCount > 0)
     {
         LL_PROFILE_ZONE_SCOPED_CATEGORY_PIPELINE;
-        llassert(LLGLSLShader::sCurBoundShaderPtr != nullptr);
+        llassert_always(LLGLSLShader::sCurBoundShaderPtr != nullptr);
+
         if (!mUIOffset.empty())
         {
             sUICalls++;
diff --git a/indra/llrender/llshadermgr.cpp b/indra/llrender/llshadermgr.cpp
index 150277c8df..e02dd4771e 100644
--- a/indra/llrender/llshadermgr.cpp
+++ b/indra/llrender/llshadermgr.cpp
@@ -559,17 +559,11 @@ GLuint LLShaderMgr::loadShaderFile(const std::string& filename, S32 & shader_lev
         }
         else if (major_version == 3)
         {
-            if (minor_version < 10)
+            if (minor_version <= 29)
             {
-                shader_code_text[shader_code_count++] = strdup("#version 300\n");
-            }
-            else if (minor_version <= 19)
-            {
-                shader_code_text[shader_code_count++] = strdup("#version 310\n");
-            }
-            else if (minor_version <= 29)
-            {
-                shader_code_text[shader_code_count++] = strdup("#version 320\n");
+                // OpenGL 3.2 had GLSL version 1.50.  anything after that the version numbers match.
+                // https://www.khronos.org/opengl/wiki/Core_Language_(GLSL)#OpenGL_and_GLSL_versions
+                shader_code_text[shader_code_count++] = strdup("#version 150\n");
             }
             else
             {