Add support for compute shaders.

[movit] / init.h

diff --git a/init.h b/init.h
index 7cee8587758331566d1b5b7e57db20e6f25aa2ab..23055227a41fde49b91aed18fcb613e80c864428 100644 (file)
--- a/init.h
+++ b/init.h
@@ -1,8 +1,11 @@
-#ifndef _INIT_H
-#define _INIT_H
+#ifndef _MOVIT_INIT_H
+#define _MOVIT_INIT_H
 
+#include "defs.h"
 #include <string>
 
+namespace movit {
+
 enum MovitDebugLevel {
        MOVIT_DEBUG_OFF = 0,
        MOVIT_DEBUG_ON = 1,
@@ -10,7 +13,8 @@ enum MovitDebugLevel {
 
 // 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.
+// we have all the OpenGL extensions we need. Returns true if initialization
+// succeeded.
 //
 // The first parameter gives which directory to read .frag files from.
 // This is a temporary hack until we add something more solid.
@@ -20,8 +24,8 @@ enum MovitDebugLevel {
 // 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);
+// only the first will count, and the second will always return true.
+bool init_movit(const std::string& data_directory, MovitDebugLevel debug_level) MUST_CHECK_RESULT;
 
 // GPU features. These are not intended for end-user use.
 
@@ -44,7 +48,39 @@ extern MovitDebugLevel movit_debug_level;
 // 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.
-extern bool movit_srgb_textures_supported;
+// 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 128.5.
+// 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, we will round off explicitly at the very end
+// of the shader. Note the following limitations:
+//
+//   - The measurement is done on linear 8-bit, not any sRGB format,
+//     10-bit output, or the likes.
+//   - This only covers the final pass; intermediates are not covered
+//     (only relevant if you use e.g. GL_SRGB8 intermediates).
+extern int movit_num_wrongly_rounded;
+
+// Whether the OpenGL driver (or GPU) in use supports GL_ARB_timer_query.
+extern bool movit_timer_queries_supported;
+
+// Whether the OpenGL driver (or GPU) in use supports compute shaders.
+// Note that certain OpenGL implementations might only allow this in core mode.
+extern bool movit_compute_shaders_supported;
+
+// What shader model we are compiling for. This only affects the choice
+// of a few files (like header.frag); most of the shaders are the same.
+enum MovitShaderModel {
+       MOVIT_GLSL_110,  // No longer in use, but kept until next ABI break in order not to change the enums.
+       MOVIT_GLSL_130,
+       MOVIT_ESSL_300,
+       MOVIT_GLSL_150,
+};
+extern MovitShaderModel movit_shader_model;
+
+}  // namespace movit
 
-#endif  // !defined(_INIT_H)
+#endif  // !defined(_MOVIT_INIT_H)