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Texture-based thick lines: Tweaks, fix for truetype builder.

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This commit is contained in:
omar
2020-01-23 15:23:23 +01:00
parent 741ab74b55
commit 222b7ddbfa
5 changed files with 74 additions and 83 deletions
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140
imgui_draw.cpp
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@ -358,6 +358,7 @@ ImDrawListSharedData::ImDrawListSharedData()
ArcFastVtx[i] = ImVec2(ImCos(a), ImSin(a));
}
memset(CircleSegmentCounts, 0, sizeof(CircleSegmentCounts)); // This will be set by SetCircleSegmentMaxError()
TexUvAALines = NULL;
}
void ImDrawListSharedData::SetCircleSegmentMaxError(float max_error)
@ -680,18 +681,18 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
const int integer_thickness = ImMax((int)(thickness - 0.5f), 1);
// Do we want to draw this line using a texture?
bool use_textures = (Flags & ImDrawListFlags_TexturedAALines) && (integer_thickness <= IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX);
const bool use_texture = (Flags & ImDrawListFlags_AntiAliasedLinesUseTexData) && (integer_thickness <= IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX);
// We should never hit this, because NewFrame() doesn't set ImDrawListFlags_TexturedAALines unless ImFontAtlasFlags_NoAALines is off
IM_ASSERT_PARANOID((!use_textures) || (!(_Data->Font->ContainerAtlas->Flags & ImFontAtlasFlags_NoAALines)));
// 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)));
const int idx_count = use_textures ? (count * 6) : (thick_line ? count * 18 : count * 12);
const int vtx_count = use_textures ? (points_count * 2) : (thick_line ? points_count * 4 : points_count * 3);
const int idx_count = use_texture ? (count * 6) : (thick_line ? count * 18 : count * 12);
const int vtx_count = use_texture ? (points_count * 2) : (thick_line ? points_count * 4 : points_count * 3);
PrimReserve(idx_count, vtx_count);
// Temporary buffer
// The first <points_count> items are normals at each line point, then after that there are either 2 or 4 temp points for each line point
ImVec2* temp_normals = (ImVec2*)alloca(points_count * ((thick_line && !use_textures) ? 5 : 3) * sizeof(ImVec2)); //-V630
ImVec2* temp_normals = (ImVec2*)alloca(points_count * ((thick_line && !use_texture) ? 5 : 3) * sizeof(ImVec2)); //-V630
ImVec2* temp_points = temp_normals + points_count;
// Calculate normals (tangents) for each line segment
@ -708,7 +709,7 @@ 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_textures))
if (!thick_line || use_texture)
{
// The width of the geometry we need to draw
const float half_draw_size = (!thick_line) ? AA_SIZE : (AA_SIZE + (thickness * 0.5f));
@ -729,7 +730,7 @@ 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_textures ? 2 : 3)); // Vertex index for end of segment
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;
@ -745,7 +746,7 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
out_vtx[1].x = points[i2].x - dm_x;
out_vtx[1].y = points[i2].y - dm_y;
if (use_textures)
if (use_texture)
{
// Add indices for two triangles
_IdxWritePtr[0] = (ImDrawIdx)(idx2 + 0); _IdxWritePtr[1] = (ImDrawIdx)(idx1 + 0); _IdxWritePtr[2] = (ImDrawIdx)(idx1 + 1); // Right tri
@ -766,7 +767,7 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
}
// Add vertexes for each point on the line
if (use_textures)
if (use_texture)
{
// If we're using textures we only need to emit the left/right edge vertices
const ImVec4 tex_uvs = (*_Data->TexUvAALines)[integer_thickness - 1];
@ -2051,7 +2052,6 @@ bool ImFontAtlasBuildWithStbTruetype(ImFontAtlas* atlas)
IM_ASSERT(atlas->ConfigData.Size > 0);
ImFontAtlasBuildInit(atlas);
ImFontAtlasBuildRegisterAALineCustomRects(atlas);
// Clear atlas
atlas->TexID = (ImTextureID)NULL;
@ -2373,6 +2373,59 @@ static void ImFontAtlasBuildRenderDefaultTexData(ImFontAtlas* atlas)
atlas->TexUvWhitePixel = ImVec2((r->X + 0.5f) * atlas->TexUvScale.x, (r->Y + 0.5f) * atlas->TexUvScale.y);
}
// This is called/shared by both the stb_truetype and the FreeType builder.
const unsigned int FONT_ATLAS_AA_LINE_TEX_HEIGHT = 1; // Technically we only need 1 pixel in the ideal case but this can be increased if necessary to give a border to avoid sampling artifacts
static void ImFontAtlasBuildRegisterAALineCustomRects(ImFontAtlas* atlas)
{
if (atlas->AALineRectIds.Size > 0)
return;
if ((atlas->Flags & ImFontAtlasFlags_NoAALines))
return;
for (int n = 0; n < IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX; n++)
{
// The "width + 3" here is interesting. +2 is to give space for the end caps, but the remaining +1 is
// because (empirically) to match the behavior of the untextured render path we need to draw lines one pixel wider.
const int width = n + 1; // The line width this entry corresponds to
atlas->AALineRectIds.push_back(atlas->AddCustomRectRegular(width + 3, FONT_ATLAS_AA_LINE_TEX_HEIGHT));
}
}
static void ImFontAtlasBuildRenderAALinesTexData(ImFontAtlas* atlas)
{
IM_ASSERT(atlas->TexPixelsAlpha8 != NULL);
IM_ASSERT(atlas->TexUvAALines.Size == 0);
if (atlas->Flags & ImFontAtlasFlags_NoAALines)
return;
const int w = atlas->TexWidth;
for (unsigned int n = 0; n < IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX; n++)
{
IM_ASSERT(atlas->AALineRectIds.Size > (int)n);
ImFontAtlasCustomRect& r = atlas->CustomRects[atlas->AALineRectIds[n]];
IM_ASSERT(r.IsPacked());
// We fill as many lines as we were given, to allow for >1 lines being used to work around sampling weirdness
for (unsigned int y = 0; y < r.Height; y++)
{
// Each line consists of two empty pixels at the ends, with a line of solid pixels in the middle
unsigned char* write_ptr = &atlas->TexPixelsAlpha8[r.X + ((r.Y + y) * w)];
*(write_ptr++) = 0;
for (unsigned short x = 0; x < (r.Width - 2U); x++)
*(write_ptr++) = 0xFF;
*(write_ptr++) = 0;
}
ImVec2 uv0, uv1;
atlas->CalcCustomRectUV(&r, &uv0, &uv1);
float halfV = (uv0.y + uv1.y) * 0.5f; // Calculate a constant V in the middle of the texture as we want a horizontal slice (with some padding either side to avoid sampling artifacts)
atlas->TexUvAALines.push_back(ImVec4(uv0.x, halfV, uv1.x, halfV));
}
}
// Note: this is called / shared by both the stb_truetype and the FreeType builder
void ImFontAtlasBuildInit(ImFontAtlas* atlas)
{
@ -2384,75 +2437,16 @@ void ImFontAtlasBuildInit(ImFontAtlas* atlas)
else
atlas->PackIdMouseCursors = atlas->AddCustomRectRegular(2, 2);
}
ImFontAtlasBuildRegisterAALineCustomRects(atlas);
}
// This is called/shared by both the stb_truetype and the FreeType builder.
const unsigned int FONT_ATLAS_AA_LINE_TEX_HEIGHT = 1; // Technically we only need 1 pixel in the ideal case but this can be increased if necessary to give a border to avoid sampling artifacts
void ImFontAtlasBuildRegisterAALineCustomRects(ImFontAtlas* atlas)
{
if (atlas->AALineRectIds.size() > 0)
return;
if ((atlas->Flags & ImFontAtlasFlags_NoAALines))
return;
const int max = IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX;
for (int n = 0; n < max; n++)
{
const int width = n + 1; // The line width this entry corresponds to
// The "width + 3" here is interesting - +2 is to give space for the end caps, but the remaining +1 is because (empirically) to match the behaviour of the untextured render path we need to draw lines one pixel wider
atlas->AALineRectIds.push_back(atlas->AddCustomRectRegular(width + 3, FONT_ATLAS_AA_LINE_TEX_HEIGHT));
}
}
void ImFontAtlasBuildAALinesTexData(ImFontAtlas* atlas)
{
IM_ASSERT(atlas->TexPixelsAlpha8 != NULL);
IM_ASSERT(atlas->TexUvAALines.size() == 0);
if (atlas->Flags & ImFontAtlasFlags_NoAALines)
return;
const int w = atlas->TexWidth;
const unsigned int max = IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX;
for (unsigned int n = 0; n < max; n++)
{
IM_ASSERT(atlas->AALineRectIds.size() > (int)n);
ImFontAtlas::CustomRect& r = atlas->CustomRects[atlas->AALineRectIds[n]];
IM_ASSERT(r.IsPacked());
// We fill as many lines as we were given, to allow for >1 lines being used to work around sampling weirdness
for (unsigned int y = 0; y < r.Height; y++)
{
unsigned char* write_ptr = &atlas->TexPixelsAlpha8[r.X + ((r.Y + y) * w)];
// Each line consists of two empty pixels at the ends, with a line of solid pixels in the middle
*(write_ptr++) = 0;
for (unsigned short x = 0; x < (r.Width - 2U); x++)
{
*(write_ptr++) = 0xFF;
}
*(write_ptr++) = 0;
}
ImVec2 uv0, uv1;
atlas->CalcCustomRectUV(&r, &uv0, &uv1);
float halfV = (uv0.y + uv1.y) * 0.5f; // Calculate a constant V in the middle of the texture as we want a horizontal slice (with some padding either side to avoid sampling artifacts)
atlas->TexUvAALines.push_back(ImVec4(uv0.x, halfV, uv1.x, halfV));
}
}
void ImFontAtlasBuildFinish(ImFontAtlas* atlas)
{
// Render into our custom data blocks
IM_ASSERT(atlas->TexPixelsAlpha8 != NULL);
ImFontAtlasBuildRenderDefaultTexData(atlas);
// Render anti-aliased line textures
ImFontAtlasBuildAALinesTexData(atlas);
ImFontAtlasBuildRenderAALinesTexData(atlas);
// Register custom rectangle glyphs
for (int i = 0; i < atlas->CustomRects.Size; i++)