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BIF_glutil.h

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/**
 * @file BIF_glutil.h
 * 
 * OpenGL drawing utility functions.
 * 
 * $Id: BIF_glutil.h,v 1.8 2004/09/25 13:42:31 ton Exp $
 *
 * ***** BEGIN GPL/BL DUAL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version. The Blender
 * Foundation also sells licenses for use in proprietary software under
 * the Blender License.  See http://www.blender.org/BL/ for information
 * about this.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL/BL DUAL LICENSE BLOCK *****
 */

#ifndef BIF_GLUTIL_H
#define BIF_GLUTIL_H

struct rcti;
struct rctf;

void sdrawXORline(int x0, int y0, int x1, int y1);
void sdrawXORline4(int nr, int x0, int y0, int x1, int y1);

void fdrawXORcirc(float xofs, float yofs, float rad);

      /**
       * Draw an XOR'd line in the front buffer between
       * the given points. 
       *
       * @attention This function also handles flushing the GL
       * pipeline, which means it is inappropriate for drawing
       * a large number of lines at once.
       */
void glutil_draw_front_xor_line(int x0, int y0, int x1, int y1);

      /**
       * Draw a lined (non-looping) arc with the given
       * @a radius, starting at angle @a start and arcing 
       * through @a angle. The arc is centered at the origin 
       * and drawn in the XY plane.
       * 
       * @param start The initial angle (in radians).
       * @param angle The length of the arc (in radians).
       * @param radius The arc radius.
       * @param nsegments The number of segments to use in drawing the arc.
       */
void glutil_draw_lined_arc    (float start, float angle, float radius, int nsegments);

      /**
       * Draw a filled arc with the given @a radius, 
       * starting at angle @a start and arcing through 
       * @a angle. The arc is centered at the origin 
       * and drawn in the XY plane.
       * 
       * @param start The initial angle (in radians).
       * @param angle The length of the arc (in radians).
       * @param radius The arc radius.
       * @param nsegments The number of segments to use in drawing the arc.
       */
void glutil_draw_filled_arc   (float start, float angle, float radius, int nsegments);

      /**
       * Routines an integer value as obtained by glGetIntegerv.
       * The param must cause only one value to be gotten from GL.
       */
int glaGetOneInteger          (int param);

      /**
       * Routines a float value as obtained by glGetIntegerv.
       * The param must cause only one value to be gotten from GL.
       */
float glaGetOneFloat          (int param);

      /**
       * Functions like glRasterPos2i, except ensures that the resulting
       * raster position is valid. @a known_good_x and @a known_good_y
       * should be coordinates of a point known to be within the current
       * view frustum.
       * @attention This routine should be used when the distance of @a x 
       * and @y away from the known good point is small (ie. for small icons
       * and for bitmap characters), when drawing large+zoomed images it is
       * possible for overflow to occur, the glaDrawPixelsSafe routine should
       * be used instead.
       */
void glaRasterPosSafe2f       (float x, float y, float known_good_x, float known_good_y);

      /**
       * Functions like a limited glDrawPixels, except ensures that 
       * the image is displayed onscreen even if the @a x and @a y 
       * coordinates for would be clipped. The routine respects the
       * glPixelZoom values, pixel unpacking parameters are _not_ 
       * respected.

       * @attention This routine makes many assumptions: the rect data
       * is expected to be in RGBA unsigned byte format, the coordinate
       * (0.375, 0.375) is assumed to be within the view frustum, and the 
       * modelview and projection matrices are assumed to define a 
       * 1-to-1 mapping to screen space.
       * @attention Furthmore, in the case of zoomed or unpixel aligned
       * images extending outside the view frustum, but still within the 
       * window, some portion of the image may be visible left and/or
       * below of the given @a x and @a y coordinates. It is recommended
       * to use the glScissor functionality if images are to be drawn
       * with an inset view matrix.
       */
void glaDrawPixelsSafe        (float x, float y, int img_w, int img_h, void *rect);

      /**
       * Functions like a limited glDrawPixels, but actually draws the
       * image using textures, which can be tremendously faster on low-end
       * cards, and also avoids problems with the raster position being
       * clipped when offscreen. The routine respects the glPixelZoom values, 
       * pixel unpacking parameters are _not_ respected.

       * @attention This routine makes many assumptions: the rect data
       * is expected to be in RGBA unsigned byte format, and the 
       * modelview and projection matrices are assumed to define a 
       * 1-to-1 mapping to screen space.
       */
void glaDrawPixelsTex         (float x, float y, int img_w, int img_h, void *rect);

      /* 2D Drawing Assistance */

      /** Define a 2D area (viewport, scissor, matrices) for OpenGL rendering.
       * This routine sets up an OpenGL state appropriate for drawing using
       * both vertice (glVertex, etc) and raster (glRasterPos, glRect) commands.
       * All coordinates should be at integer positions. There is little to
       * no reason to use glVertex2f etc. functions during 2D rendering, and
       * thus no reason to +-0.5 the coordinates or perform other silly
       * tricks.
       *
       * @param screen_rect The screen rectangle to be defined for 2D drawing.
       */
void glaDefine2DArea          (struct rcti *screen_rect);

typedef struct gla2DDrawInfo gla2DDrawInfo;

      /** Save the current OpenGL state and initialize OpenGL for 2D
       * rendering. glaEnd2DDraw should be called on the returned structure
       * to free it and to return OpenGL to its previous state. The
       * scissor rectangle is set to match the viewport.
       *
       * This routine sets up an OpenGL state appropriate for drawing using
       * both vertice (glVertex, etc) and raster (glRasterPos, glRect) commands.
       * All coordinates should be at integer positions. There is little to
       * no reason to use glVertex2f etc. functions during 2D rendering, and
       * thus no reason to +-0.5 the coordinates or perform other silly
       * tricks.
       *
       * @param screen_rect The screen rectangle to be used for 2D drawing.
       * @param world_rect The world rectangle that the 2D area represented
       * by @a screen_rect is supposed to represent. If NULL it is assumed the
       * world has a 1 to 1 mapping to the screen.
       */
gla2DDrawInfo*    glaBegin2DDraw                (struct rcti *screen_rect, struct rctf *world_rect);

      /** Translate the (@a wo_x, @a wo_y) point from world coordinates into screen space. */
void              gla2DDrawTranslatePt    (gla2DDrawInfo *di, float wo_x, float wo_y, int *sc_x_r, int *sc_y_r);

      /** Translate the @a world point from world coordiantes into screen space. */
void              gla2DDrawTranslatePtv   (gla2DDrawInfo *di, float world[2], int screen_r[2]);

      /* Restores the previous OpenGL state and free's the auxilary
       * gla data.
       */
void              glaEnd2DDraw                  (gla2DDrawInfo *di);

/* use this for platform hacks. for now glPointSize is solved here */
void bglBegin(int mode);
void bglEnd(void);
void bglVertex3fv(float *vec);
void bglVertex2fv(float *vec);

/* own working polygon offset */
void bglPolygonOffset(float dist);

#endif /* BIF_GLUTIL_H */


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