Shader cleanup

A couple of class members from PixelShader and VertexShader
were still public. Fixed that in this cleanup.

Change-Id: I2dfaac7fd4cecdc791f1ef7236148e74c4b5b486
Reviewed-on: https://swiftshader-review.googlesource.com/5850
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
diff --git a/src/Shader/VertexProgram.cpp b/src/Shader/VertexProgram.cpp
index 5fda7e7..20caa49 100644
--- a/src/Shader/VertexProgram.cpp
+++ b/src/Shader/VertexProgram.cpp
@@ -50,7 +50,7 @@
 			enableContinue = Int4(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF);
 		}
 
-		if(shader->instanceIdDeclared)
+		if(shader->isInstanceIdDeclared())
 		{
 			instanceID = *Pointer<Int>(data + OFFSET(DrawData,instanceID));
 		}
@@ -596,7 +596,7 @@
 		{
 			for(int i = 0; i < MAX_VERTEX_OUTPUTS; i++)
 			{
-				unsigned char usage = shader->output[i][0].usage;
+				unsigned char usage = shader->getOutput(i, 0).usage;
 
 				switch(usage)
 				{