Index: shader.h
===================================================================
--- shader.h	(revision 478)
+++ shader.h	(revision 479)
@@ -7,6 +7,8 @@
 #ifndef SHADER_H
 #define SHADER_H
 
+#define RAYDIUM_SHADER_TANGENT_ATTRIB_NAME "tangent"
+
 typedef struct raydium_shader_Shader
 {
     int id;
@@ -15,9 +17,10 @@
     GLhandleARB vert;
     GLhandleARB frag;
     GLhandleARB prog;
+    GLint attrib_tangent; // -1 means "no tangent info asked in this shader"
 } raydium_shader_Shader;
 
 __global raydium_shader_Shader raydium_shader_shaders[RAYDIUM_MAX_SHADERS];
 __global signed char raydium_shader_support;
-
+__global int raydium_shader_active;
 #endif