-#ifndef _INIT_H
-#define _INIT_H
+#ifndef _MOVIT_INIT_H
+#define _MOVIT_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;
+// Some GPUs use very inaccurate fixed-function circuits for rounding
+// floating-point values to 8-bit outputs, leading to absurdities like
+// the roundoff point between 128 and 129 being 128.62 instead of 128.6.
+// We test, for every integer, x+0.48 and x+0.52 and check that they
+// round the right way (giving some leeway, but not a lot); the number
+// of errors are stored here.
+//
+// If this value is above 0, and you have enabled dithering, we will
+// round off explicitly at the very end of the shader.
+extern int movit_num_wrongly_rounded;
+
// Whether the GPU in use supports GL_EXT_texture_sRGB.
extern bool movit_srgb_textures_supported;
-#endif // !defined(_INIT_H)
+#endif // !defined(_MOVIT_INIT_H)
projects / movit / blobdiff