From eccf1add8ad3f681621ca084bf05cdd5ae1c53f8 Mon Sep 17 00:00:00 2001
From: baldurk <baldurk@baldurk.org>
Date: Fri, 1 Feb 2019 15:55:47 +0000
Subject: [PATCH] Don't try to compile quadwrite shader if required extensions
 are missing

---
 renderdoc/driver/gl/gl_common.h    |  1 +
 renderdoc/driver/gl/gl_overlay.cpp | 18 ++++++++++--------
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/renderdoc/driver/gl/gl_common.h b/renderdoc/driver/gl/gl_common.h
index 133488bd3..1c7ae5038 100644
--- a/renderdoc/driver/gl/gl_common.h
+++ b/renderdoc/driver/gl/gl_common.h
@@ -689,6 +689,7 @@ extern bool IsGLES;
   EXT_TO_CHECK(44, 99, ARB_query_buffer_object)                  \
   EXT_TO_CHECK(45, 99, ARB_clip_control)                         \
   EXT_TO_CHECK(45, 99, ARB_direct_state_access)                  \
+  EXT_TO_CHECK(45, 99, ARB_derivative_control)                   \
   EXT_TO_CHECK(46, 99, ARB_polygon_offset_clamp)                 \
   EXT_TO_CHECK(46, 99, ARB_texture_filter_anisotropic)           \
   EXT_TO_CHECK(46, 99, ARB_pipeline_statistics_query)            \
diff --git a/renderdoc/driver/gl/gl_overlay.cpp b/renderdoc/driver/gl/gl_overlay.cpp
index ff93b19ee..f6839863f 100644
--- a/renderdoc/driver/gl/gl_overlay.cpp
+++ b/renderdoc/driver/gl/gl_overlay.cpp
@@ -258,7 +258,7 @@ ResourceId GLReplay::RenderOverlay(ResourceId texid, CompType typeHint, DebugOve
   {
     std::string defines = "";
 
-    if(GLCoreVersion < 45)
+    if(!HasExt[ARB_derivative_control])
     {
       // dFdx fine functions not available before GLSL 450. Use normal dFdx, which might be coarse,
       // so won't show quad overdraw properly
@@ -267,14 +267,16 @@ ResourceId GLReplay::RenderOverlay(ResourceId texid, CompType typeHint, DebugOve
 
       RDCWARN("Quad overdraw requires GLSL 4.50 for dFd(xy)fine, using possibly coarse dFd(xy).");
     }
-    else
-    {
-      glslVer = 450;
-    }
 
-    std::string source =
-        GenerateGLSLShader(GetEmbeddedResource(glsl_quadwrite_frag), shaderType, glslVer, defines);
-    DebugData.quadoverdrawFragShader = CreateShader(eGL_FRAGMENT_SHADER, source);
+    DebugData.quadoverdrawFragShader = 0;
+
+    // needs these extensions
+    if(HasExt[ARB_gpu_shader5] && HasExt[ARB_shader_image_load_store])
+    {
+      std::string source =
+          GenerateGLSLShader(GetEmbeddedResource(glsl_quadwrite_frag), shaderType, glslVer, defines);
+      DebugData.quadoverdrawFragShader = CreateShader(eGL_FRAGMENT_SHADER, source);
+    }
   }
   else
   {