Fix issue #406: Empty glyphs cause some ATI cards to crash in Font::addGlyph().

src/modules/graphics/opengl/Font.cpp

@@ -95,17 +95,10 @@ namespace opengl
 
 	Font::Glyph * Font::addGlyph(int glyph)
 	{
-		Glyph * g = new Glyph;
-		g->list = glGenLists(1);
-		if (g->list == 0)
-		{ // opengl failed to generate the list
-			delete g;
-			return NULL;
-		}
 		love::font::GlyphData *gd = rasterizer->getGlyphData(glyph);
-		g->spacing = gd->getAdvance();
 		int w = gd->getWidth();
 		int h = gd->getHeight();
+
 		if (texture_x + w + TEXTURE_PADDING > TEXTURE_WIDTH)
 		{ // out of space - new row!
 			texture_x = TEXTURE_PADDING;
@@ -116,6 +109,21 @@ namespace opengl
 		{ // totally out of space - new texture!
 			createTexture();
 		}
+
+		Glyph * g = new Glyph;
+		g->list = g->texture = 0;
+		g->spacing = gd->getAdvance();
+
+		// don't waste space for empty glyphs. also fixes a division by zero bug with ati drivers
+		if (w > 0 && h > 0)
+		{
+			g->list = glGenLists(1);
+			if (0 == g->list)
+			{
+				delete g;
+				return NULL;
+			}
+
 			GLuint t = textures.back();
 			bindTexture(t);
 			glTexSubImage2D(GL_TEXTURE_2D, 0, texture_x, texture_y, w, h, (type == FONT_TRUETYPE ? GL_LUMINANCE_ALPHA : GL_RGBA), GL_UNSIGNED_BYTE, gd->getData());
@@ -146,11 +154,14 @@ namespace opengl
 			glDisableClientState(GL_VERTEX_ARRAY);
 
 			delete q;
-		delete gd;
+		}
 
+		if (w > 0)
 			texture_x += (w + TEXTURE_PADDING);
+		if (h > 0)
 			rowHeight = std::max(rowHeight, h + TEXTURE_PADDING);
 
+		delete gd;
 		glyphs[glyph] = g;
 		return g;
 	}
@@ -205,12 +216,16 @@ namespace opengl
 	{
 		Glyph * glyph = glyphs[character];
 		if (!glyph) glyph = addGlyph(character);
+
+		if (0 != glyph->texture)
+		{
 			glPushMatrix();
 			glTranslatef(x, floor(y+getHeight() + 0.5f), 0.0f);
 			bindTexture(glyph->texture);
 			glCallList(glyph->list);
 			glPopMatrix();
 		}
+	}
 
 	int Font::getWidth(const std::string & line)
 	{