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Texture-based thick lines: Remove unnecessary indirection in fetching UV data, removed lerp call, renames, tweaks.

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This commit is contained in:
omar
2020-05-16 16:55:05 +02:00
parent a07c8b6999
commit 78d6bdf080
5 changed files with 58 additions and 60 deletions
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84
imgui_draw.cpp
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@ -668,7 +668,6 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
const ImVec2 opaque_uv = _Data->TexUvWhitePixel;
const int count = closed ? points_count : points_count - 1; // The number of line segments we need to draw
const bool thick_line = (thickness > 1.0f);
if (Flags & ImDrawListFlags_AntiAliasedLines)
@ -679,12 +678,11 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
// Thicknesses <1.0 should behave like thickness 1.0
thickness = ImMax(thickness, 1.0f);
const int integer_thickness = (int)thickness ;
const float fractional_thickness = (thickness) - integer_thickness;
const int integer_thickness = (int)thickness;
const float fractional_thickness = thickness - integer_thickness;
// Do we want to draw this line using a texture?
const bool use_texture = (Flags & ImDrawListFlags_AntiAliasedLinesUseTexData) && (integer_thickness < IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX);
const bool use_texture = (Flags & ImDrawListFlags_AntiAliasedLinesUseTex) && (integer_thickness < IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX);
// We should never hit this, because NewFrame() doesn't set ImDrawListFlags_AntiAliasedLinesUseTexData unless ImFontAtlasFlags_NoAALines is off
IM_ASSERT_PARANOID((!use_texture) || (!(_Data->Font->ContainerAtlas->Flags & ImFontAtlasFlags_NoAALines)));
@ -712,8 +710,11 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
temp_normals[points_count - 1] = temp_normals[points_count - 2];
// If we are drawing a one-pixel-wide line without a texture, or a textured line of any width, we only need 2 or 3 vertices per point
if (!thick_line || use_texture)
if (use_texture || !thick_line)
{
// [PATH 1] Texture-based lines (thick or non-thick)
// [PATH 2] Non texture-based lines (non-thick)
// The width of the geometry we need to draw - this is essentially <thickness> pixels for the line itself, plus one pixel for AA
// We don't use AA_SIZE here because the +1 is tied to the generated texture and so alternate values won't work without changes to that code
const float half_draw_size = use_texture ? ((thickness * 0.5f) + 1) : 1.0f;
@ -734,7 +735,7 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
for (int i1 = 0; i1 < count; i1++) // i1 is the first point of the line segment
{
const int i2 = (i1 + 1) == points_count ? 0 : i1 + 1; // i2 is the second point of the line segment
unsigned int idx2 = ((i1 + 1) == points_count) ? _VtxCurrentIdx : (idx1 + (use_texture ? 2 : 3)); // Vertex index for end of segment
const unsigned int idx2 = ((i1 + 1) == points_count) ? _VtxCurrentIdx : (idx1 + (use_texture ? 2 : 3)); // Vertex index for end of segment
// Average normals
float dm_x = (temp_normals[i1].x + temp_normals[i2].x) * 0.5f;
@ -774,32 +775,30 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
if (use_texture)
{
// If we're using textures we only need to emit the left/right edge vertices
ImVec4 tex_uvs;
if (fractional_thickness == 0.0f) // Fast path for pure integer widths
tex_uvs = (*_Data->TexUvAALines)[integer_thickness];
else
ImVec4 tex_uvs = _Data->TexUvAALines[integer_thickness];
if (fractional_thickness != 0.0f)
{
// Calculate UV by interpolating between the two nearest integer line widths
const ImVec4 tex_uvs_0 = (*_Data->TexUvAALines)[integer_thickness];
const ImVec4 tex_uvs_1 = (*_Data->TexUvAALines)[integer_thickness + 1];
tex_uvs = ImLerp(tex_uvs_0, tex_uvs_1, fractional_thickness);
const ImVec4 tex_uvs_1 = _Data->TexUvAALines[integer_thickness + 1];
tex_uvs.x = tex_uvs.x + (tex_uvs_1.x - tex_uvs.x) * fractional_thickness; // inlined ImLerp()
tex_uvs.y = tex_uvs.y + (tex_uvs_1.y - tex_uvs.y) * fractional_thickness;
tex_uvs.z = tex_uvs.z + (tex_uvs_1.z - tex_uvs.z) * fractional_thickness;
tex_uvs.w = tex_uvs.w + (tex_uvs_1.w - tex_uvs.w) * fractional_thickness;
}
ImVec2 tex_uv0(tex_uvs.x, tex_uvs.y);
ImVec2 tex_uv1(tex_uvs.z, tex_uvs.w);
for (int i = 0; i < points_count; i++)
{
_VtxWritePtr[0].pos = temp_points[i * 2 + 0]; _VtxWritePtr[0].uv = ImVec2(tex_uvs.x, tex_uvs.y); _VtxWritePtr[0].col = col; // Left-side outer edge
_VtxWritePtr[1].pos = temp_points[i * 2 + 1]; _VtxWritePtr[1].uv = ImVec2(tex_uvs.z, tex_uvs.y); _VtxWritePtr[1].col = col; // Right-side outer edge
_VtxWritePtr[0].pos = temp_points[i * 2 + 0]; _VtxWritePtr[0].uv = tex_uv0; _VtxWritePtr[0].col = col; // Left-side outer edge
_VtxWritePtr[1].pos = temp_points[i * 2 + 1]; _VtxWritePtr[1].uv = tex_uv1; _VtxWritePtr[1].col = col; // Right-side outer edge
_VtxWritePtr += 2;
}
}
else
{
// If we're not using a texture, we need the centre vertex as well
// If we're not using a texture, we need the center vertex as well
for (int i = 0; i < points_count; i++)
{
_VtxWritePtr[0].pos = points[i]; _VtxWritePtr[0].uv = opaque_uv; _VtxWritePtr[0].col = col; // Centre of line
_VtxWritePtr[0].pos = points[i]; _VtxWritePtr[0].uv = opaque_uv; _VtxWritePtr[0].col = col; // Center of line
_VtxWritePtr[1].pos = temp_points[i * 2 + 0]; _VtxWritePtr[1].uv = opaque_uv; _VtxWritePtr[1].col = col_trans; // Left-side outer edge
_VtxWritePtr[2].pos = temp_points[i * 2 + 1]; _VtxWritePtr[2].uv = opaque_uv; _VtxWritePtr[2].col = col_trans; // Right-side outer edge
_VtxWritePtr += 3;
@ -808,7 +807,7 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
}
else
{
// For untextured lines that are greater than a pixel in width, we need to draw the solid line core and thus require four vertices per point
// [PATH 2] Non texture-based lines (thick): we need to draw the solid line core and thus require four vertices per point
const float half_inner_thickness = (thickness - AA_SIZE) * 0.5f;
// If line is not closed, the first and last points need to be generated differently as there are no normals to blend
@ -880,7 +879,7 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
}
else
{
// Non texture-based, Non anti-aliased lines
// [PATH 4] Non texture-based, Non anti-aliased lines
const int idx_count = count * 6;
const int vtx_count = count * 4; // FIXME-OPT: Not sharing edges
PrimReserve(idx_count, vtx_count);
@ -1720,7 +1719,7 @@ ImFontAtlas::ImFontAtlas()
TexWidth = TexHeight = 0;
TexUvScale = ImVec2(0.0f, 0.0f);
TexUvWhitePixel = ImVec2(0.0f, 0.0f);
PackIdMouseCursors = -1;
PackIdMouseCursors = PackIdAALines = -1;
}
ImFontAtlas::~ImFontAtlas()
@ -1748,7 +1747,7 @@ void ImFontAtlas::ClearInputData()
}
ConfigData.clear();
CustomRects.clear();
PackIdMouseCursors = -1;
PackIdMouseCursors = PackIdAALines = -1;
}
void ImFontAtlas::ClearTexData()
@ -2390,41 +2389,38 @@ static void ImFontAtlasBuildRenderDefaultTexData(ImFontAtlas* atlas)
static void ImFontAtlasBuildRegisterAALineCustomRects(ImFontAtlas* atlas)
{
if ((atlas->Flags & ImFontAtlasFlags_NoAALines))
if (atlas->Flags & ImFontAtlasFlags_NoAntiAliasedLines)
return;
// The "max_width + 2" here is to give space for the end caps, whilst height (IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX+1) is to accommodate the fact we have a zero-width row
const int max_width = IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX; // The maximum line width we want to generate
atlas->AALineRectId = atlas->AddCustomRectRegular(max_width + 2, IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX + 1);
// The +2 here is to give space for the end caps, whilst height +1 is to accommodate the fact we have a zero-width row
atlas->PackIdAALines = atlas->AddCustomRectRegular(IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX + 2, IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX + 1);
}
static void ImFontAtlasBuildRenderAALinesTexData(ImFontAtlas* atlas)
{
IM_ASSERT(atlas->TexPixelsAlpha8 != NULL);
IM_ASSERT(atlas->TexUvAALines.Size == 0);
if (atlas->Flags & ImFontAtlasFlags_NoAALines)
if (atlas->Flags & ImFontAtlasFlags_NoAntiAliasedLines)
return;
ImFontAtlasCustomRect& r = atlas->CustomRects[atlas->AALineRectId];
IM_ASSERT(r.IsPacked());
ImFontAtlasCustomRect* r = atlas->GetCustomRectByIndex(atlas->PackIdAALines);
IM_ASSERT(r->IsPacked());
// This generates a triangular shape in the texture, with the various line widths stacked on top of each other to allow interpolation between them
const int w = atlas->TexWidth;
for (unsigned int n = 0; n < (IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX + 1); n++) // +1 because of the zero-width row
for (unsigned int n = 0; n < IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX + 1; n++) // +1 because of the zero-width row
{
// Each line consists of at least two empty pixels at the ends, with a line of solid pixels in the middle
unsigned int y = n;
unsigned int line_width = n;
// Each line consists of at least two empty pixels at the ends, with a line of solid pixels in the middle
unsigned int pad_left = (r.Width - line_width) / 2;
unsigned int pad_right = r.Width - (pad_left + line_width);
unsigned int pad_left = (r->Width - line_width) / 2;
unsigned int pad_right = r->Width - (pad_left + line_width);
// Make sure we're inside the texture bounds before we start writing pixels
IM_ASSERT_PARANOID(pad_left + line_width + pad_right == r.Width);
IM_ASSERT_PARANOID(y < r.Height);
// Write each slice
unsigned char* write_ptr = &atlas->TexPixelsAlpha8[r.X + ((r.Y + y) * w)];
unsigned char* write_ptr = &atlas->TexPixelsAlpha8[r->X + ((r->Y + y) * w)];
for (unsigned int x = 0; x < pad_left; x++)
*(write_ptr++) = 0;
for (unsigned int x = 0; x < line_width; x++)
@ -2433,16 +2429,16 @@ static void ImFontAtlasBuildRenderAALinesTexData(ImFontAtlas* atlas)
*(write_ptr++) = 0;
// Calculate UVs for this line
ImFontAtlasCustomRect line_rect = r;
ImFontAtlasCustomRect line_rect = *r;
line_rect.X += (unsigned short)(pad_left - 1);
line_rect.Width = (unsigned short)(line_width + 2);
line_rect.Y += (unsigned short)y;
line_rect.Width = (unsigned short)(line_width + 2);
line_rect.Height = 1;
ImVec2 uv0, uv1;
atlas->CalcCustomRectUV(&line_rect, &uv0, &uv1);
float halfV = (uv0.y + uv1.y) * 0.5f; // Calculate a constant V in the middle of the row to avoid sampling artifacts
atlas->TexUvAALines.push_back(ImVec4(uv0.x, halfV, uv1.x, halfV));
float half_v = (uv0.y + uv1.y) * 0.5f; // Calculate a constant V in the middle of the row to avoid sampling artifacts
atlas->TexUvAALines[n] = ImVec4(uv0.x, half_v, uv1.x, half_v);
}
}