X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=init.cpp;h=ac52aa2ce3d7eee956e6cc629912e699bb6553b1;hp=129ee4c894d91ea3d5072b35a9812338981707fc;hb=38fca90c6ffde05e3459c7021e823cef0b3b27ac;hpb=17195eb5da34f03778cde297eb77c486fa0c51bc

diff --git a/init.cpp b/init.cpp
index 129ee4c..ac52aa2 100644
--- a/init.cpp
+++ b/init.cpp
@@ -2,8 +2,12 @@
 #include "opengl.h"
 #include "util.h"
 
+#include <set>
+#include <string>
+
 bool movit_initialized = false;
 float movit_texel_subpixel_precision;
+bool movit_srgb_textures_supported;
 
 namespace {
 
@@ -119,6 +123,43 @@ void measure_texel_subpixel_precision()
 	check_error();
 }
 
+void get_extensions(std::set<std::string> *extensions)
+{
+	char *str = strdup(reinterpret_cast<const char *>(glGetString(GL_EXTENSIONS)));
+	for (char *ptr = strtok(str, " "); ptr != NULL; ptr = strtok(NULL, " ")) {
+		extensions->insert(ptr);
+	}
+	free(str);
+}
+
+void check_extensions()
+{
+	std::set<std::string> extensions;
+	get_extensions(&extensions);
+
+	// We fundamentally need FBOs and floating-point textures.
+	assert(extensions.count("GL_ARB_framebuffer_object") != 0);
+	assert(extensions.count("GL_ARB_texture_float") != 0);
+
+	// We assume that we can use non-power-of-two textures without restrictions.
+	assert(extensions.count("GL_ARB_texture_non_power_of_two") != 0);
+
+	// We also need GLSL fragment shaders.
+	assert(extensions.count("GL_ARB_fragment_shader") != 0);
+	assert(extensions.count("GL_ARB_shading_language_100") != 0);
+
+	// FlatInput and YCbCrInput uses PBOs. (They could in theory do without,
+	// but no modern card would really not provide it.)
+	assert(extensions.count("GL_ARB_pixel_buffer_object") != 0);
+
+	// ResampleEffect uses RG textures to encode a two-component LUT.
+	assert(extensions.count("GL_ARB_texture_rg") != 0);
+
+	// sRGB texture decode would be nice, but are not mandatory
+	// (GammaExpansionEffect can do the same thing if needed).
+	movit_srgb_textures_supported = extensions.count("GL_EXT_texture_sRGB");
+}
+
 }  // namespace
 
 void init_movit()
@@ -132,6 +173,7 @@ void init_movit()
 	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 
 	measure_texel_subpixel_precision();
+	check_extensions();
 
 	movit_initialized = true;
 }