From d6770dd47dcb871f021868dec2b333527ffb8ee8 Mon Sep 17 00:00:00 2001 From: tobigun Date: Sun, 26 Oct 2008 11:54:33 +0000 Subject: git-svn-id: svn://svn.code.sf.net/p/ultrastardx/svn/trunk@1479 b956fd51-792f-4845-bead-9b4dfca2ff2c --- src/lib/freetype/demo/nehe/UFreeType.pas | 326 +++++++++++++++++++++++++++++++ 1 file changed, 326 insertions(+) create mode 100644 src/lib/freetype/demo/nehe/UFreeType.pas (limited to 'src/lib/freetype/demo/nehe/UFreeType.pas') diff --git a/src/lib/freetype/demo/nehe/UFreeType.pas b/src/lib/freetype/demo/nehe/UFreeType.pas new file mode 100644 index 00000000..c1243aae --- /dev/null +++ b/src/lib/freetype/demo/nehe/UFreeType.pas @@ -0,0 +1,326 @@ +unit UFreeType; + +{$IFDEF FPC} + {$mode delphi}{$H+} +{$ENDIF} + +interface + +uses + FreeType, + gl, + glu, + classes, + sysutils; + +type + // This holds all of the information related to any + // freetype font that we want to create. + TFontData = class + h: single; ///< Holds the height of the font. + textures: array of GLuint; ///< Holds the texture id's + list_base: GLuint; ///< Holds the first display list id + + // The init function will create a font of + // of the height h from the file fname. + constructor Create(const fname: string; h: cardinal); + + // Free all the resources assosiated with the font. + destructor Destroy(); override; + end; + + TFreeType = class + public + // The flagship function of the library - this thing will print + // out text at window coordinates x,y, using the font ft_font. + // The current modelview matrix will also be applied to the text. + class procedure print(ft_font: TFontData; x, y: single; const str: string); + end; + + +implementation + + +// This function gets the first power of 2 >= the +// int that we pass it. +function next_p2 ( a: integer ): integer; inline; +begin + Result := 1; + while (Result < a) do + Result := Result shl 1; +end; + +type + PAGLuint = ^AGLuint; + AGLuint = array[0..High(Word)] of GLuint; + +// Create a display list coresponding to the given character. +procedure make_dlist ( face: FT_Face; ch: byte; list_base: GLuint; tex_base: PAGLuint ); +var + i, j: integer; + width, height: integer; + glyph: FT_Glyph; + bitmap_glyph: FT_BitmapGlyph; + bitmap: PFT_Bitmap; + expanded_data: array of GLubyte; + x, y: single; +begin + // The first thing we do is get FreeType to render our character + // into a bitmap. This actually requires a couple of FreeType commands: + + // Load the Glyph for our character. + if (FT_Load_Glyph( face, FT_Get_Char_Index( face, ch ), FT_LOAD_DEFAULT ) <> 0) then + raise Exception.create('FT_Load_Glyph failed'); + + // Move the face's glyph into a Glyph object. + if (FT_Get_Glyph( face^.glyph, glyph ) <> 0) then + raise Exception.create('FT_Get_Glyph failed'); + + // Convert the glyph to a bitmap. + FT_Glyph_To_Bitmap( glyph, ft_render_mode_normal, nil, 1 ); + bitmap_glyph := FT_BitmapGlyph(glyph); + + // This reference will make accessing the bitmap easier + bitmap := @bitmap_glyph^.bitmap; + + // Use our helper function to get the widths of + // the bitmap data that we will need in order to create + // our texture. + width := next_p2( bitmap.width ); + height := next_p2( bitmap.rows ); + + // Allocate memory for the texture data. + SetLength(expanded_data, 2 * width * height); + + // Here we fill in the data for the expanded bitmap. + // Notice that we are using two channel bitmap (one for + // luminocity and one for alpha), but we assign + // both luminocity and alpha to the value that we + // find in the FreeType bitmap. + // We use the ?: operator so that value which we use + // will be 0 if we are in the padding zone, and whatever + // is the the Freetype bitmap otherwise. + for j := 0 to height-1 do + begin + for i := 0 to width-1 do + begin + if ((i >= bitmap.width) or (j >= bitmap.rows)) then + expanded_data[2*(i+j*width)] := 0 + else + expanded_data[2*(i+j*width)] := byte(bitmap.buffer[i + bitmap.width*j]); + expanded_data[2*(i+j*width)+1] := expanded_data[2*(i+j*width)]; + end; + end; + + + // Now we just setup some texture paramaters. + glBindTexture( GL_TEXTURE_2D, tex_base[integer(ch)]); + glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); + glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); + + // Here we actually create the texture itself, notice + // that we are using GL_LUMINANCE_ALPHA to indicate that + // we are using 2 channel data. + glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, width, height, + 0, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, @expanded_data[0] ); + + //With the texture created, we don't need to expanded data anymore + SetLength(expanded_data, 0); + + //So now we can create the display list + glNewList(list_base+ch, GL_COMPILE); + + glBindTexture(GL_TEXTURE_2D, tex_base[ch]); + + glPushMatrix(); + + //first we need to move over a little so that + //the character has the right amount of space + //between it and the one before it. + glTranslatef(bitmap_glyph^.left, 0, 0); + + //Now we move down a little in the case that the + //bitmap extends past the bottom of the line + //(this is only true for characters like 'g' or 'y'. + glTranslatef(0, bitmap_glyph^.top - bitmap.rows, 0); + + //Now we need to account for the fact that many of + //our textures are filled with empty padding space. + //We figure what portion of the texture is used by + //the actual character and store that information in + //the x and y variables, then when we draw the + //quad, we will only reference the parts of the texture + //that we contain the character itself. + x := bitmap.width / width; + y := bitmap.rows / height; + + //Here we draw the texturemaped quads. + //The bitmap that we got from FreeType was not + //oriented quite like we would like it to be, + //so we need to link the texture to the quad + //so that the result will be properly aligned. + glBegin(GL_QUADS); + glTexCoord2d(0, 0); glVertex2f(0, bitmap.rows); + glTexCoord2d(0, y); glVertex2f(0, 0); + glTexCoord2d(x, y); glVertex2f(bitmap.width, 0); + glTexCoord2d(x, 0); glVertex2f(bitmap.width, bitmap.rows); + glEnd(); + + glPopMatrix(); + glTranslatef(face^.glyph^.advance.x shr 6, 0, 0); + + //increment the raster position as if we were a bitmap font. + //(only needed if you want to calculate text length) + //glBitmap(0,0,0,0,face->glyph->advance.x >> 6,0,NULL); + + //Finnish the display list + glEndList(); +end; + + +constructor TFontData.Create(const fname: string; h: cardinal); +var + library_: FT_Library; + //The object in which Freetype holds information on a given + //font is called a "face". + face: FT_Face; + i: byte; +begin + //Allocate some memory to store the texture ids. + SetLength(textures, 128); + + Self.h := h; + + //Create and initilize a freetype font library. + if (FT_Init_FreeType( library_ ) <> 0) then + raise Exception.create('FT_Init_FreeType failed'); + + //This is where we load in the font information from the file. + //Of all the places where the code might die, this is the most likely, + //as FT_New_Face will die if the font file does not exist or is somehow broken. + if (FT_New_Face( library_, PChar(fname), 0, face ) <> 0) then + raise Exception.create('FT_New_Face failed (there is probably a problem with your font file)'); + + //For some twisted reason, Freetype measures font size + //in terms of 1/64ths of pixels. Thus, to make a font + //h pixels high, we need to request a size of h*64. + //(h shl 6 is just a prettier way of writting h*64) + FT_Set_Char_Size( face, h shl 6, h shl 6, 96, 96); + + //Here we ask opengl to allocate resources for + //all the textures and displays lists which we + //are about to create. + list_base := glGenLists(128); + glGenTextures( 128, @textures[0] ); + + //This is where we actually create each of the fonts display lists. + for i := 0 to 127 do + make_dlist(face, i, list_base, @textures[0]); + + //We don't need the face information now that the display + //lists have been created, so we free the assosiated resources. + FT_Done_Face(face); + + //Ditto for the library. + FT_Done_FreeType(library_); +end; + +destructor TFontData.Destroy(); +begin + glDeleteLists(list_base, 128); + glDeleteTextures(128, @textures[0]); + SetLength(textures, 0); +end; + +/// A fairly straight forward function that pushes +/// a projection matrix that will make object world +/// coordinates identical to window coordinates. +procedure pushScreenCoordinateMatrix(); inline; +var + viewport: array [0..3] of GLint; +begin + glPushAttrib(GL_TRANSFORM_BIT); + glGetIntegerv(GL_VIEWPORT, @viewport); + glMatrixMode(GL_PROJECTION); + glPushMatrix(); + glLoadIdentity(); + gluOrtho2D(viewport[0], viewport[2], viewport[1], viewport[3]); + glPopAttrib(); +end; + +/// Pops the projection matrix without changing the current +/// MatrixMode. +procedure pop_projection_matrix(); inline; +begin + glPushAttrib(GL_TRANSFORM_BIT); + glMatrixMode(GL_PROJECTION); + glPopMatrix(); + glPopAttrib(); +end; + +///Much like Nehe's glPrint function, but modified to work +///with freetype fonts. +class procedure TFreeType.print(ft_font: TFontData; x, y: single; const str: string); +var + font: GLuint; + h: single; + i: cardinal; + lines: TStringList; + modelview_matrix: array[0..15] of single; +begin + // We want a coordinate system where things coresponding to window pixels. + pushScreenCoordinateMatrix(); + + font := ft_font.list_base; + h := ft_font.h / 0.63; //We make the height about 1.5* that of + + lines := TStringList.Create(); + ExtractStrings([#13], [], PChar(str), lines); + + glPushAttrib(GL_LIST_BIT or GL_CURRENT_BIT or GL_ENABLE_BIT or GL_TRANSFORM_BIT); + glMatrixMode(GL_MODELVIEW); + glDisable(GL_LIGHTING); + glEnable(GL_TEXTURE_2D); + glDisable(GL_DEPTH_TEST); + glEnable(GL_BLEND); + glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); + + glListBase(font); + + glGetFloatv(GL_MODELVIEW_MATRIX, @modelview_matrix); + + //This is where the text display actually happens. + //For each line of text we reset the modelview matrix + //so that the line's text will start in the correct position. + //Notice that we need to reset the matrix, rather than just translating + //down by h. This is because when each character is + //draw it modifies the current matrix so that the next character + //will be drawn immediatly after it. + for i := 0 to lines.Count-1 do + begin + glPushMatrix(); + glLoadIdentity(); + glTranslatef(x, y - h*i, 0); + glMultMatrixf(@modelview_matrix); + + // The commented out raster position stuff can be useful if you need to + // know the length of the text that you are creating. + // If you decide to use it make sure to also uncomment the glBitmap command + // in make_dlist(). + //glRasterPos2f(0,0); + glCallLists(Length(lines[i]), GL_UNSIGNED_BYTE, PChar(lines[i])); + //float rpos[4]; + //glGetFloatv(GL_CURRENT_RASTER_POSITION ,rpos); + //float len=x-rpos[0]; + + glPopMatrix(); + end; + + glPopAttrib(); + + pop_projection_matrix(); + + lines.Free(); +end; + +end. -- cgit v1.2.3