+PixelFormat get_srgb_pixelformat(PixelFormat pf)
+{
+ switch(pf)
+ {
+ case RGB: return SRGB;
+ case RGBA: return SRGB_ALPHA;
+ case RGB8: return SRGB8;
+ case RGBA8: return SRGB8_ALPHA8;
+ case LUMINANCE: return SLUMINANCE;
+ case LUMINANCE8: return SLUMINANCE8;
+ case LUMINANCE_ALPHA: return SLUMINANCE_ALPHA;
+ case LUMINANCE_ALPHA8: return SLUMINANCE8_ALPHA8;
+ default: return pf;
+ }
+}
+
+unsigned get_component_count(PixelFormat pf)
+{
+ switch(get_base_pixelformat(pf))
+ {
+ case STENCIL_INDEX:
+ case DEPTH_COMPONENT:
+ case LUMINANCE:
+ case SLUMINANCE:
+ return 1;
+ case LUMINANCE_ALPHA:
+ case SLUMINANCE_ALPHA:
+ return 2;
+ case RGB:
+ case BGR:
+ return 3;
+ case RGBA:
+ case BGRA:
+ return 4;
+ default:
+ throw invalid_argument("get_component_count");
+ }
+}
+
+unsigned get_component_size(PixelFormat pf)
+{
+ switch(pf)
+ {
+ case RGB16F:
+ case RGBA16F:
+ case LUMINANCE16F:
+ case LUMINANCE_ALPHA16F:
+ return 2;
+ case RGB32F:
+ case RGBA32F:
+ case LUMINANCE32F:
+ case LUMINANCE_ALPHA32F:
+ return 4;
+ default:
+ return 1;
+ }
+}
+
+unsigned get_pixel_size(PixelFormat pf)
+{
+ return get_component_count(pf)*get_component_size(pf);
+}
+
+void require_pixelformat(PixelFormat pf)
+{
+ switch(pf)
+ {
+ case RGB16F:
+ case RGB32F:
+ case RGBA16F:
+ case RGBA32F:
+ case LUMINANCE16F:
+ case LUMINANCE32F:
+ case LUMINANCE_ALPHA16F:
+ case LUMINANCE_ALPHA32F:
+ { static Require _req(ARB_texture_float); }
+ break;
+ case SRGB:
+ case SRGB8:
+ case SRGB_ALPHA:
+ case SRGB8_ALPHA8:
+ case SLUMINANCE:
+ case SLUMINANCE8:
+ case SLUMINANCE_ALPHA:
+ case SLUMINANCE8_ALPHA8:
+ { static Require _req(EXT_texture_sRGB); }
+ break;
+ case BGR:
+ case BGRA:
+ { static Require _req(EXT_bgra); }
+ break;
+ default:
+ break;
+ }
+}
+