public Texture LoadTextureFromImage <T>(Image <T> image, string name = null,
TextureLoadParameters?loadParams = null) where T : unmanaged, IPixel <T>
{
DebugTools.Assert(_mainThread == Thread.CurrentThread);
var actualParams = loadParams ?? TextureLoadParameters.Default;
var pixelType = typeof(T);
// Flip image because OpenGL reads images upside down.
var copy = FlipClone(image);
var texture = new GLHandle((uint)GL.GenTexture());
GL.BindTexture(TextureTarget.Texture2D, texture.Handle);
ApplySampleParameters(actualParams.SampleParameters);
PixelInternalFormat internalFormat;
PixelFormat pixelDataFormat;
PixelType pixelDataType;
if (pixelType == typeof(Rgba32))
{
internalFormat = actualParams.Srgb ? PixelInternalFormat.Srgb8Alpha8 : PixelInternalFormat.Rgba8;
pixelDataFormat = PixelFormat.Rgba;
pixelDataType = PixelType.UnsignedByte;
}
else if (pixelType == typeof(Alpha8))
{
if (image.Width % 4 != 0 || image.Height % 4 != 0)
{
throw new ArgumentException("Alpha8 images must have multiple of 4 sizes.");
}
internalFormat = PixelInternalFormat.R8;
pixelDataFormat = PixelFormat.Red;
pixelDataType = PixelType.UnsignedByte;
// TODO: Does it make sense to default to 1 for RGB parameters?
// It might make more sense to pass some options to change swizzling.
var swizzle = new[] { (int)All.One, (int)All.One, (int)All.One, (int)All.Red };
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleRgba, swizzle);
}
else if (pixelType == typeof(Gray8) && !actualParams.Srgb)
{
// Can only use R8 for Gray8 if sRGB is OFF.
// Because OpenGL doesn't provide non-sRGB single/dual channel image formats.
// Vulkan when?
if (copy.Width % 4 != 0 || copy.Height % 4 != 0)
{
throw new ArgumentException("Gray8 non-sRGB images must have multiple of 4 sizes.");
}
internalFormat = PixelInternalFormat.R8;
pixelDataFormat = PixelFormat.Red;
pixelDataType = PixelType.UnsignedByte;
var swizzle = new[] { (int)All.Red, (int)All.Red, (int)All.Red, (int)All.One };
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleRgba, swizzle);
}
else
{
throw new NotImplementedException($"Unable to handle pixel type '{pixelType.Name}'");
}
unsafe
{
var span = copy.GetPixelSpan();
fixed(T *ptr = span)
{
GL.TexImage2D(TextureTarget.Texture2D, 0, internalFormat, copy.Width, copy.Height, 0,
pixelDataFormat, pixelDataType, (IntPtr)ptr);
}
}
return(GenTexture(texture, (copy.Width, copy.Height), name));
}
public Texture LoadTextureFromImage <T>(Image <T> image, string?name = null,
TextureLoadParameters?loadParams = null) where T : unmanaged, IPixel <T>
{
DebugTools.Assert(_mainThread == Thread.CurrentThread);
var actualParams = loadParams ?? TextureLoadParameters.Default;
var pixelType = typeof(T);
if (!_hasGLTextureSwizzle)
{
// If texture swizzle isn't available we have to pre-process the images to apply it ourselves
// and then upload as RGBA8.
// Yes this is inefficient but the alternative is modifying the shaders,
// which I CBA to do.
// Even 8 year old iGPUs support texture swizzle.
if (pixelType == typeof(A8))
{
// Disable sRGB so stuff doesn't get interpreter wrong.
actualParams.Srgb = false;
var img = ApplyA8Swizzle((Image <A8>)(object) image);
return(LoadTextureFromImage(img, name, loadParams));
}
if (pixelType == typeof(L8) && !actualParams.Srgb)
{
var img = ApplyL8Swizzle((Image <L8>)(object) image);
return(LoadTextureFromImage(img, name, loadParams));
}
}
// Flip image because OpenGL reads images upside down.
var copy = FlipClone(image);
var texture = new GLHandle((uint)GL.GenTexture());
CheckGlError();
GL.BindTexture(TextureTarget.Texture2D, texture.Handle);
CheckGlError();
ApplySampleParameters(actualParams.SampleParameters);
PixelInternalFormat internalFormat;
PixelFormat pixelDataFormat;
PixelType pixelDataType;
if (pixelType == typeof(Rgba32))
{
internalFormat = actualParams.Srgb ? PixelInternalFormat.Srgb8Alpha8 : PixelInternalFormat.Rgba8;
pixelDataFormat = PixelFormat.Rgba;
pixelDataType = PixelType.UnsignedByte;
}
else if (pixelType == typeof(A8))
{
if (image.Width % 4 != 0 || image.Height % 4 != 0)
{
throw new ArgumentException("Alpha8 images must have multiple of 4 sizes.");
}
internalFormat = PixelInternalFormat.R8;
pixelDataFormat = PixelFormat.Red;
pixelDataType = PixelType.UnsignedByte;
unsafe
{
// TODO: Does it make sense to default to 1 for RGB parameters?
// It might make more sense to pass some options to change swizzling.
var swizzle = stackalloc[] { (int)All.One, (int)All.One, (int)All.One, (int)All.Red };
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleRgba, swizzle);
}
}
else if (pixelType == typeof(L8) && !actualParams.Srgb)
{
// Can only use R8 for L8 if sRGB is OFF.
// Because OpenGL doesn't provide sRGB single/dual channel image formats.
// Vulkan when?
if (copy.Width % 4 != 0 || copy.Height % 4 != 0)
{
throw new ArgumentException("L8 non-sRGB images must have multiple of 4 sizes.");
}
internalFormat = PixelInternalFormat.R8;
pixelDataFormat = PixelFormat.Red;
pixelDataType = PixelType.UnsignedByte;
unsafe
{
var swizzle = stackalloc[] { (int)All.Red, (int)All.Red, (int)All.Red, (int)All.One };
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleRgba, swizzle);
}
}
else
{
throw new NotImplementedException($"Unable to handle pixel type '{pixelType.Name}'");
}
unsafe
{
var span = copy.GetPixelSpan();
fixed(T *ptr = span)
{
GL.TexImage2D(TextureTarget.Texture2D, 0, internalFormat, copy.Width, copy.Height, 0,
pixelDataFormat, pixelDataType, (IntPtr)ptr);
CheckGlError();
}
}
var pressureEst = EstPixelSize(internalFormat) * copy.Width * copy.Height;
return(GenTexture(texture, (copy.Width, copy.Height), name, pressureEst));
}
