X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=init.h;h=7cee8587758331566d1b5b7e57db20e6f25aa2ab;hp=a1e71dd54053b3f168f3c47267eba1512bd2096b;hb=7702ea7f05b7a3ffc625e054b14b784d0029f561;hpb=38fca90c6ffde05e3459c7021e823cef0b3b27ac

diff --git a/init.h b/init.h
index a1e71dd..7cee858 100644
--- a/init.h
+++ b/init.h
@@ -1,21 +1,47 @@
 #ifndef _INIT_H
 #define _INIT_H
 
+#include <string>
+
+enum MovitDebugLevel {
+	MOVIT_DEBUG_OFF = 0,
+	MOVIT_DEBUG_ON = 1,
+};
+
 // Initialize the library; in particular, will query the GPU for information
 // that is needed by various components. For instance, it verifies that
 // we have all the OpenGL extensions we need.
-void init_movit();
+//
+// The first parameter gives which directory to read .frag files from.
+// This is a temporary hack until we add something more solid.
+//
+// The second parameter specifies whether debugging is on or off.
+// If it is on, Movit will write intermediate graphs and the final
+// generated shaders to the current directory.
+//
+// If you call init_movit() twice with different parameters,
+// only the first will count.
+void init_movit(const std::string& data_directory, MovitDebugLevel debug_level);
 
 // GPU features. These are not intended for end-user use.
 
 // Whether init_movit() has been called.
 extern bool movit_initialized;
 
-// An estimate on the number of different levels the linear texture interpolation
-// of the GPU can deliver. My Intel card seems to be limited to 2^6 levels here,
-// while a modern nVidia card (GTX 550 Ti) seem to use 2^8.
+// The current debug level.
+extern MovitDebugLevel movit_debug_level;
+
+// An estimate on the smallest values the linear texture interpolation
+// of the GPU can distinguish between, i.e., for a GPU with N-bit
+// texture subpixel precision, this value will be 2^-N.
+//
+// From reading the little specs that exist and through practical tests,
+// the broad picture seems to be that Intel cards have 6-bit precision,
+// nVidia cards have 8-bit, and Radeon cards have 6-bit before R6xx
+// (at least when not using trilinear sampling), but can reach
+// 8-bit precision on R6xx or newer in some (unspecified) cases.
 //
-// We currently don't bother to test above 2^10.
+// We currently don't bother to test for more than 1024 levels.
 extern float movit_texel_subpixel_precision;
 
 // Whether the GPU in use supports GL_EXT_texture_sRGB.