MAINT-2242 Fix for shader compilation errors on Intel HD graphics chips.

indra/newview/app_settings/shaders/class1/objects/previewV.glsl

@@ -23,9 +23,6 @@
  * $/LicenseInfo$
  */
 
-float calcDirectionalLight(vec3 n, vec3 l);
-float calcPointLightOrSpotLight(vec3 v, vec3 n, vec4 lp, vec3 ln, float la, float is_pointlight);
-
 uniform mat3 normal_matrix;
 uniform mat4 texture_matrix0;
 uniform mat4 modelview_matrix;
@@ -45,6 +42,42 @@ uniform vec3 light_direction[8];
 uniform vec3 light_attenuation[8]; 
 uniform vec3 light_diffuse[8];
 
+//===================================================================================================
+//declare these here explicitly to separate them from atmospheric lighting elsewhere to work around
+//drivers that are picky about functions being declared but not defined even if they aren't called
+float calcDirectionalLight(vec3 n, vec3 l)
+{
+	float a = max(dot(n,l),0.0);
+	return a;
+}
+
+
+float calcPointLightOrSpotLight(vec3 v, vec3 n, vec4 lp, vec3 ln, float la, float is_pointlight)
+{
+	//get light vector
+	vec3 lv = lp.xyz-v;
+	
+	//get distance
+	float d = length(lv);
+	
+	//normalize light vector
+	lv *= 1.0/d;
+	
+	//distance attenuation
+	float da = clamp(1.0/(la * d), 0.0, 1.0);
+	
+	// spotlight coefficient.
+	float spot = max(dot(-ln, lv), is_pointlight);
+	da *= spot*spot; // GL_SPOT_EXPONENT=2
+
+	//angular attenuation
+	da *= calcDirectionalLight(n, lv);
+
+	return da;	
+}
+//====================================================================================================
+
+
 void main()
 {
 	//transform vertex

indra/newview/llviewershadermgr.cpp

@@ -2025,11 +2025,11 @@ BOOL LLViewerShaderMgr::loadShadersObject()
 	if (success)
 	{
 		gObjectPreviewProgram.mName = "Simple Shader";
-		gObjectPreviewProgram.mFeatures.calculatesLighting = true;
+		gObjectPreviewProgram.mFeatures.calculatesLighting = false;
 		gObjectPreviewProgram.mFeatures.calculatesAtmospherics = false;
-		gObjectPreviewProgram.mFeatures.hasGamma = true;
+		gObjectPreviewProgram.mFeatures.hasGamma = false;
 		gObjectPreviewProgram.mFeatures.hasAtmospherics = false;
-		gObjectPreviewProgram.mFeatures.hasLighting = true;
+		gObjectPreviewProgram.mFeatures.hasLighting = false;
 		gObjectPreviewProgram.mFeatures.mIndexedTextureChannels = 0;
 		gObjectPreviewProgram.mFeatures.disableTextureIndex = true;
 		gObjectPreviewProgram.mShaderFiles.clear();
@@ -2037,6 +2037,7 @@ BOOL LLViewerShaderMgr::loadShadersObject()
 		gObjectPreviewProgram.mShaderFiles.push_back(make_pair("objects/previewF.glsl", GL_FRAGMENT_SHADER_ARB));
 		gObjectPreviewProgram.mShaderLevel = mVertexShaderLevel[SHADER_OBJECT];
 		success = gObjectPreviewProgram.createShader(NULL, NULL);
+		gObjectPreviewProgram.mFeatures.hasLighting = true;
 	}
 
 	if (success)