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Optimise rendering of scrollable text boxes by clipping

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Add optional clipping rectangle to CTextRenderer. Strings that are
printed
outside the vertical extent of the clipping rectangle will be
immediately
skipped. This greatly reduces the cost of large scrollable text boxes.

This was SVN commit r14019.
This commit is contained in:
Ykkrosh 2013-10-18 16:05:02 +00:00
parent 751558d894
commit 91169c82c7
5 changed files with 51 additions and 2 deletions
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13
source/graphics/Font.h
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@ -74,6 +74,13 @@ public:
int GetHeight() const { return m_Height; }
int GetCharacterWidth(wchar_t c) const;
void CalculateStringSize(const wchar_t* string, int& w, int& h) const;
void GetGlyphBounds(float& x0, float& y0, float& x1, float& y1) const
{
x0 = m_BoundsX0;
y0 = m_BoundsY0;
x1 = m_BoundsX1;
y1 = m_BoundsY1;
}
const GlyphMap& GetGlyphs() const { return m_Glyphs; }
CTexturePtr GetTexture() const { return m_Texture; }
@ -86,6 +93,12 @@ private:
int m_LineSpacing;
int m_Height; // height of a capital letter, roughly
// Bounding box of all glyphs
float m_BoundsX0;
float m_BoundsY0;
float m_BoundsX1;
float m_BoundsY1;
};
#endif // INCLUDED_FONT

10
source/graphics/FontManager.cpp
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@ -88,6 +88,11 @@ bool CFontManager::ReadFont(CFont* font, const CStrW& fontName)
FNTStream >> font->m_LineSpacing;
FNTStream >> font->m_Height;
font->m_BoundsX0 = FLT_MAX;
font->m_BoundsY0 = FLT_MAX;
font->m_BoundsX1 = -FLT_MAX;
font->m_BoundsY1 = -FLT_MAX;
for (int i = 0; i < NumGlyphs; ++i)
{
int Codepoint, TextureX, TextureY, Width, Height, OffsetX, OffsetY, Advance;
@ -106,6 +111,11 @@ bool CFontManager::ReadFont(CFont* font, const CStrW& fontName)
CFont::GlyphData g = { u, -v, u+w, -v+h, (i16)OffsetX, (i16)-OffsetY, (i16)(OffsetX+Width), (i16)(-OffsetY+Height), (i16)Advance };
font->m_Glyphs.set((u16)Codepoint, g);
font->m_BoundsX0 = std::min(font->m_BoundsX0, (float)g.x0);
font->m_BoundsY0 = std::min(font->m_BoundsY0, (float)g.y0);
font->m_BoundsX1 = std::max(font->m_BoundsX1, (float)g.x1);
font->m_BoundsY1 = std::max(font->m_BoundsY1, (float)g.y1);
}
ENSURE(font->m_Height); // Ensure the height has been found (which should always happen if the font includes an 'I')

15
source/graphics/TextRenderer.cpp
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@ -66,6 +66,11 @@ void CTextRenderer::Translate(float x, float y, float z)
m_Dirty = true;
}
void CTextRenderer::SetClippingRect(const CRect& rect)
{
m_Clipping = rect;
}
void CTextRenderer::Color(const CColor& color)
{
if (m_Color != color)
@ -151,6 +156,16 @@ void CTextRenderer::PutString(float x, float y, const std::wstring* buf, bool ow
if (!m_Font)
return; // invalid font; can't render
if (m_Clipping != CRect())
{
float x0, y0, x1, y1;
m_Font->GetGlyphBounds(x0, y0, x1, y1);
if (y + y1 < m_Clipping.top)
return;
if (y + y0 > m_Clipping.bottom)
return;
}
// If any state has changed since the last batch, start a new batch
if (m_Dirty)
{

9
source/graphics/TextRenderer.h
View File

@ -41,6 +41,14 @@ public:
void Translate(float x, float y, float z);
/**
* Set clipping rectangle, in pre-transform coordinates (i.e. text is clipped against
* this rect based purely on the x,y values passed into Put()). Text fully outside the
* clipping rectangle may not be rendered. Should be used in conjunction with glScissor
* for precise clipping - this is just an optimisation.
*/
void SetClippingRect(const CRect& rect);
/**
* Set the color for subsequent print calls.
*/
@ -149,6 +157,7 @@ private:
CShaderProgramPtr m_Shader;
CMatrix3D m_Transform;
CRect m_Clipping;
CColor m_Color;
CStrW m_FontName;

6
source/gui/CGUI.cpp
View File

@ -945,13 +945,15 @@ void CGUI::DrawText(SGUIText &Text, const CColor &DefaultColor,
tech->BeginPass();
if (clipping != CRect())
bool isClipped = (clipping != CRect());
if (isClipped)
{
glEnable(GL_SCISSOR_TEST);
glScissor(clipping.left, g_yres - clipping.bottom, clipping.GetWidth(), clipping.GetHeight());
}
CTextRenderer textRenderer(tech->GetShader());
textRenderer.SetClippingRect(clipping);
textRenderer.Translate(0.0f, 0.0f, z);
for (std::vector<SGUIText::STextCall>::const_iterator it = Text.m_TextCalls.begin();
@ -978,7 +980,7 @@ void CGUI::DrawText(SGUIText &Text, const CColor &DefaultColor,
DrawSprite(it->m_Sprite, it->m_CellID, z, it->m_Area + pos);
}
if (clipping != CRect())
if (isClipped)
glDisable(GL_SCISSOR_TEST);
tech->EndPass();