// NB: vertexColor needs to be as srgb when in gamma space, and in linear otherwise
public static unsafe void LayoutString(char *text, int textLength, float fontSize, HorizontalAlignment hAlign,
VerticalAlignment vAlign, float4 vertexColor,
ref FontData font, DynamicBuffer <DynamicSimpleVertex> dynMesh, DynamicBuffer <DynamicIndex> dynTriangles,
out AABB aabb)
{
LayoutString(text, textLength, fontSize, hAlign, vAlign, vertexColor, ref font,
dynMesh.Reinterpret <SimpleVertex>(),
dynTriangles.Reinterpret <ushort>(),
out aabb);
}
// NB: vertexColor needs to be as srgb when in gamma space, and in linear otherwise
public static unsafe void LayoutString <T1, T2>(char *text, int textLength, float fontSize,
HorizontalAlignment hAlign, VerticalAlignment vAlign, float4 vertexColor,
ref FontData font, T1 mesh, T2 triangles,
out AABB aabb)
where T1 : INativeList <SimpleVertex>
where T2 : INativeList <ushort>
{
// TODO -- unicode code points may map to 0..N glyphs. We just assume 1:1 right now because we're not shaping
int *glyphIndices = stackalloc int[textLength];
// figure out the glyph indices
int gi = 0;
for (int ci = 0; ci < textLength; ci++)
{
var charUnicode = text[ci];
int glyphIndex = font.FindGlyphIndexForCodePoint(charUnicode);
// TODO handle tofu
if (glyphIndex == -1)
{
continue;
}
glyphIndices[gi++] = glyphIndex;
}
int numGlyphs = gi;
// font base calcs
bool isOrtho = false; // ???
float baseScale = fontSize / font.Face.PointSize * font.Face.Scale * (isOrtho ? 1 : 0.1f);
float currentElementScale = baseScale;
// allocate space in the mesh
mesh.Length = numGlyphs * 4;
int numLines = CountLines(text, textLength);
float fontBaseLineOffset = font.Face.Baseline * currentElementScale;
if (vAlign == VerticalAlignment.Top)
{
fontBaseLineOffset -= font.Face.Ascent * currentElementScale;
}
else if (vAlign == VerticalAlignment.Bottom)
{
fontBaseLineOffset += (-(font.Face.Descent) * currentElementScale);
fontBaseLineOffset += (font.Face.Ascent + font.Face.Descent) * (numLines - 1);
}
else if (vAlign == VerticalAlignment.Center)
{
fontBaseLineOffset = (font.Face.Baseline - (font.Face.Ascent + font.Face.Descent) * 0.5f) *
currentElementScale;
fontBaseLineOffset += (font.Face.Ascent + font.Face.Descent) * (numLines - 1) * 0.5f;
}
// experimental multi line: wrap mesh generation into a while loop so we can change offset for each line
bool keepGoing = true;
int startIndex = 0;
int meshIndex = 0;
while (keepGoing)
{
int blockLength = StrTok('\n', text, textLength, out char *nextBlock, out int remainingTextLength);
float xAdvance = 0.0f;
float totalAdvance = 0.0f;
if (hAlign != HorizontalAlignment.Left)
{
for (int i = startIndex; i < startIndex + blockLength; ++i)
{
int glyphIndex = glyphIndices[i];
var glyph = font.Glyphs[glyphIndex];
totalAdvance += glyph.HorizontalAdvance * currentElementScale;
}
if (hAlign == HorizontalAlignment.Center)
{
xAdvance = -(totalAdvance / 2.0f);
}
else if (hAlign == HorizontalAlignment.Right)
{
xAdvance = -totalAdvance;
}
}
for (gi = startIndex; gi < startIndex + blockLength; ++gi)
{
int glyphIndex = glyphIndices[gi];
var glyph = font.Glyphs[glyphIndex];
var glyphRect = font.GlyphRects[glyphIndex];
SimpleVertex topLeft = new SimpleVertex();
SimpleVertex bottomLeft = new SimpleVertex();
SimpleVertex topRight = new SimpleVertex();
SimpleVertex bottomRight = new SimpleVertex();
// TODO store this in the asset data per glyph
float2 tl = new float2(glyph.HorizontalBearing.x, glyph.HorizontalBearing.y);
float2 br = new float2(glyph.HorizontalBearing.x + glyph.Size.x,
glyph.HorizontalBearing.y - glyph.Size.y);
float2 advance = new float2(xAdvance, fontBaseLineOffset);
topLeft.Position = new float3(advance + tl * currentElementScale, 0.0f);
bottomLeft.Position = new float3(advance + new float2(tl.x, br.y) * currentElementScale, 0.0f);
topRight.Position = new float3(advance + new float2(br.x, tl.y) * currentElementScale, 0.0f);
bottomRight.Position.x = topRight.Position.x;
bottomRight.Position.y = bottomLeft.Position.y;
bottomRight.Position.z = 0.0f;
topLeft.TexCoord0 = glyphRect.TopLeftUV;
bottomLeft.TexCoord0 = new float2(glyphRect.TopLeftUV.x, glyphRect.BottomRightUV.y);
bottomRight.TexCoord0 = glyphRect.BottomRightUV;
topRight.TexCoord0 = new float2(glyphRect.BottomRightUV.x, glyphRect.TopLeftUV.y);
topLeft.Color = vertexColor;
bottomLeft.Color = vertexColor;
topRight.Color = vertexColor;
bottomRight.Color = vertexColor;
mesh[meshIndex + 0] = bottomLeft;
mesh[meshIndex + 1] = topLeft;
mesh[meshIndex + 2] = topRight;
mesh[meshIndex + 3] = bottomRight;
meshIndex += 4;
xAdvance += glyph.HorizontalAdvance * currentElementScale;
}
keepGoing = remainingTextLength > 0;
fontBaseLineOffset -= (font.Face.Ascent + font.Face.Descent);
textLength = remainingTextLength;
text = nextBlock;
startIndex += blockLength;
}
// mesh bounds
MinMaxAABB bounds = MinMaxAABB.Empty;
for (int i = 0; i < numGlyphs * 4; ++i)
{
bounds.Encapsulate(mesh[i].Position);
}
aabb = bounds;
// Then make the index buffer
triangles.Length = numGlyphs * 6;
int index4 = 0;
int index6 = 0;
for (int i = 0; i < numGlyphs; i++)
{
triangles[index6 + 0] = (ushort)(index4 + 0);
triangles[index6 + 1] = (ushort)(index4 + 1);
triangles[index6 + 2] = (ushort)(index4 + 2);
triangles[index6 + 3] = (ushort)(index4 + 2);
triangles[index6 + 4] = (ushort)(index4 + 3);
triangles[index6 + 5] = (ushort)(index4 + 0);
index4 += 4;
index6 += 6;
}
}
