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ImFontAtlas: reduced number of temporary allocation when building lots of input ranges

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This commit is contained in:
ocornut 2015-01-18 11:55:58 +00:00
parent edcf2d3bf6
commit e685e49781
1 changed files with 22 additions and 15 deletions
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37
imgui.cpp
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@ -6484,7 +6484,7 @@ bool ImFontAtlas::Build()
}
// Start packing
TexWidth = (total_glyph_count > 3000) ? 2048 : (total_glyph_count > 1000) ? 1024 : 512; // Width doesn't actually matters.
TexWidth = (total_glyph_count > 1000) ? 1024 : 512; // Width doesn't actually matters.
TexHeight = 0;
const int max_tex_height = 1024*32;
stbtt_pack_context spc;
@ -6499,6 +6499,14 @@ bool ImFontAtlas::Build()
stbrp_pack_rects((stbrp_context*)spc.pack_info, &extra_rect, 1);
TexExtraDataPos = ImVec2(extra_rect.x, extra_rect.y);
// Allocate packing character data and flag as non-packed (x0=y0=x1=y1=0)
stbtt_packedchar* packed_chardata = (stbtt_packedchar*)ImGui::MemAlloc(total_glyph_count * sizeof(stbtt_packedchar));
int packed_chardata_n = 0;
memset(packed_chardata, 0, total_glyph_count * sizeof(stbtt_packedchar));
stbrp_rect* rectdata = (stbrp_rect*)ImGui::MemAlloc(total_glyph_count * sizeof(stbrp_rect));
int rectdata_n = 0;
// First pass: pack all glyphs (no rendering at this point, we are working with glyph sizes only)
int tex_height = extra_rect.y + extra_rect.h;
for (size_t input_i = 0; input_i < InputData.size(); input_i++)
@ -6521,17 +6529,13 @@ bool ImFontAtlas::Build()
const ImWchar* in_range = &data.GlyphRanges[i * 2];
range.first_unicode_char_in_range = in_range[0];
range.num_chars_in_range = (in_range[1] - in_range[0]) + 1;
// Allocate characters and flag as not packed
// FIXME-OPT: Loose ranges will incur lots of allocations. Allocate all contiguous in loop above.
range.chardata_for_range = (stbtt_packedchar*)ImGui::MemAlloc(range.num_chars_in_range * sizeof(stbtt_packedchar));
for (int j = 0; j < range.num_chars_in_range; ++j)
range.chardata_for_range[j].x0 = range.chardata_for_range[j].y0 = range.chardata_for_range[j].x1 = range.chardata_for_range[j].y1 = 0;
range.chardata_for_range = packed_chardata + packed_chardata_n;
packed_chardata_n += range.num_chars_in_range;
}
// Pack
data.Rects = (stbrp_rect*)ImGui::MemAlloc(sizeof(stbrp_rect) * glyph_count);
IM_ASSERT(data.Rects);
data.Rects = rectdata + rectdata_n;
rectdata_n += glyph_count;
const int n = stbtt_PackFontRangesGatherRects(&spc, &data.FontInfo, data.Ranges.begin(), data.Ranges.size(), data.Rects);
stbrp_pack_rects((stbrp_context*)spc.pack_info, data.Rects, n);
@ -6540,6 +6544,7 @@ bool ImFontAtlas::Build()
if (data.Rects[i].was_packed)
tex_height = ImMax(tex_height, data.Rects[i].y + data.Rects[i].h);
}
IM_ASSERT(packed_chardata_n == total_glyph_count);
// Create texture
TexHeight = ImUpperPowerOfTwo(tex_height);
@ -6553,12 +6558,13 @@ bool ImFontAtlas::Build()
{
ImFontAtlasData& data = *InputData[input_i];
ret = stbtt_PackFontRangesRenderIntoRects(&spc, &data.FontInfo, data.Ranges.begin(), data.Ranges.size(), data.Rects);
ImGui::MemFree(data.Rects);
data.Rects = NULL;
}
// End packing
stbtt_PackEnd(&spc);
ImGui::MemFree(rectdata);
rectdata = NULL;
// Third pass: setup ImFont and glyphs for runtime
for (size_t input_i = 0; input_i < InputData.size(); input_i++)
@ -6601,18 +6607,19 @@ bool ImFontAtlas::Build()
data.OutFont->BuildLookupTable();
// Cleanup temporary
for (size_t i = 0; i < data.Ranges.size(); i++)
ImGui::MemFree(data.Ranges[i].chardata_for_range);
// Cleanup temporaries
data.Ranges.clear();
}
// Cleanup temporaries
ClearInputData();
ImGui::MemFree(packed_chardata);
packed_chardata = NULL;
// Draw white pixel into texture and make UV points to it
TexPixelsAlpha8[0] = TexPixelsAlpha8[1] = TexPixelsAlpha8[TexWidth+0] = TexPixelsAlpha8[TexWidth+1] = 0xFF;
TexUvWhitePixel = ImVec2((TexExtraDataPos.x + 0.5f) / TexWidth, (TexExtraDataPos.y + 0.5f) / TexHeight);
ClearInputData();
return true;
}