[OpenTK] Moved RelaxGraphicsMode to Utilities

This functionality is useful for all platform backends and is not
specific to the X11 backend.
This commit is contained in:
thefiddler 2014-01-22 10:49:27 +01:00
parent 6f3951e825
commit 615df9201b
2 changed files with 110 additions and 43 deletions

View file

@ -307,5 +307,113 @@ namespace OpenTK.Platform
#endregion
#endregion
#region RelaxGraphicsMode
internal static bool RelaxGraphicsMode(ref GraphicsMode mode)
{
ColorFormat color = mode.ColorFormat;
int depth = mode.Depth;
int stencil = mode.Stencil;
int samples = mode.Samples;
ColorFormat accum = mode.AccumulatorFormat;
int buffers = mode.Buffers;
bool stereo = mode.Stereo;
bool success = RelaxGraphicsMode(
ref color, ref depth, ref stencil, ref samples,
ref accum, ref buffers, ref stereo);
mode = new GraphicsMode(
color, depth, stencil, samples,
accum, buffers, stereo);
return success;
}
/// \internal
/// <summary>
/// Relaxes graphics mode parameters. Use this function to increase compatibility
/// on systems that do not directly support a requested GraphicsMode. For example:
/// - user requested stereoscopic rendering, but GPU does not support stereo
/// - user requseted 16x antialiasing, but GPU only supports 4x
/// </summary>
/// <returns><c>true</c>, if a graphics mode parameter was relaxed, <c>false</c> otherwise.</returns>
/// <param name="color">Color bits.</param>
/// <param name="depth">Depth bits.</param>
/// <param name="stencil">Stencil bits.</param>
/// <param name="samples">Number of antialiasing samples.</param>
/// <param name="accum">Accumulator buffer bits.</param>
/// <param name="buffers">Number of rendering buffers (1 for single buffering, 2+ for double buffering, 0 for don't care).</param>
/// <param name="stereo">Stereoscopic rendering enabled/disabled.</param>
internal static bool RelaxGraphicsMode(ref ColorFormat color, ref int depth, ref int stencil, ref int samples, ref ColorFormat accum, ref int buffers, ref bool stereo)
{
// Parameters are relaxed in order of importance.
// - Accumulator buffers are way outdated as a concept,
// so they go first.
// - Triple+ buffering is generally not supported by the
// core WGL/GLX/AGL/CGL/EGL specs, so we clamp
// to double-buffering as a second step. (If this doesn't help
// we will also fall back to undefined single/double buffering
// as a last resort).
// - AA samples are an easy way to increase compatibility
// so they go next.
// - Stereoscopic is only supported on very few GPUs
// (Quadro/FirePro series) so it goes next.
// - The rest of the parameters then follow.
if (accum != 0)
{
accum = 0;
return true;
}
if (buffers > 2)
{
buffers = 2;
return true;
}
if (samples > 0)
{
samples = Math.Max(samples - 2, 0);
return true;
}
if (stereo)
{
stereo = false;
return true;
}
if (stencil != 0)
{
stencil = 0;
return true;
}
if (depth != 0)
{
depth = 0;
return true;
}
if (color != 24)
{
color = 24;
return true;
}
if (buffers != 0)
{
buffers = 0;
return true;
}
// no parameters left to relax, fail
return false;
}
#endregion
}
}

View file

@ -52,49 +52,8 @@ namespace OpenTK.Platform.X11
if (visual == IntPtr.Zero)
{
// Relax parameters and retry
if (stereo)
{
stereo = false;
continue;
}
if (accum != 0)
{
accum = 0;
continue;
}
if (samples > 0)
{
samples = Math.Max(samples - 2, 0);
continue;
}
if (stencil != 0)
{
stencil = 0;
continue;
}
if (depth != 0)
{
depth = 0;
continue;
}
if (color != 24)
{
color = 24;
continue;
}
if (buffers != 0)
{
buffers = 0;
continue;
}
throw new GraphicsModeException("Requested GraphicsMode not available.");
if (!Utilities.RelaxGraphicsMode(ref color, ref depth, ref stencil, ref samples, ref accum, ref buffers, ref stereo))
throw new GraphicsModeException("Requested GraphicsMode not available.");
}
}
while (visual == IntPtr.Zero);