graph_draw.c

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/*
 * $Id: graph_draw.c 36786 2011-05-20 01:02:00Z campbellbarton $
 *
 * ***** BEGIN GPL 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.
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) Blender Foundation
 *
 * Contributor(s): Joshua Leung (2009 Recode)
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <stdio.h>
#include <math.h>
#include <string.h>
#include <float.h>

#ifndef _WIN32
#include <unistd.h>
#else
#include <io.h>
#endif


#include "BLI_blenlib.h"
#include "BLI_math.h"
#include "BLI_utildefines.h"

#include "DNA_anim_types.h"
#include "DNA_object_types.h"
#include "DNA_screen_types.h"
#include "DNA_space_types.h"
#include "DNA_windowmanager_types.h"

#include "BKE_context.h"
#include "BKE_curve.h"
#include "BKE_fcurve.h"


#include "BIF_gl.h"
#include "BIF_glutil.h"

#include "ED_anim_api.h"

#include "graph_intern.h"

#include "UI_interface.h"
#include "UI_resources.h"
#include "UI_view2d.h"

/* *************************** */
/* Utility Drawing Defines */

/* determine the alpha value that should be used when 
 * drawing components for some F-Curve (fcu)
 *      - selected F-Curves should be more visible than partially visible ones
 */
#define drawFCurveFade(fcu) ( ((fcu)->flag & FCURVE_SELECTED)? 1.0f : 0.25f )

/* set the color for some point from some value given packed into an int 
 *      - intV: integer value containing color info packed into an int
 *      - alpha: float value describing the 
 */
#define cpackA(intVC, alpha) \
        { \
                float _cpackCol[3]; \
                cpack_to_rgb(intVC, &_cpackCol[0], &_cpackCol[1], &_cpackCol[2]); \
                glColor4f(_cpackCol[0], _cpackCol[1], _cpackCol[2], alpha); \
        }

/* *************************** */
/* F-Curve Modifier Drawing */

/* Envelope -------------- */

// TODO: draw a shaded poly showing the region of influence too!!!
static void draw_fcurve_modifier_controls_envelope (FModifier *fcm, View2D *v2d)
{
        FMod_Envelope *env= (FMod_Envelope *)fcm->data;
        FCM_EnvelopeData *fed;
        const float fac= 0.05f * (v2d->cur.xmax - v2d->cur.xmin);
        int i;
        
        /* draw two black lines showing the standard reference levels */
        glColor3f(0.0f, 0.0f, 0.0f);
        setlinestyle(5);
        
        glBegin(GL_LINES);
                glVertex2f(v2d->cur.xmin, env->midval+env->min);
                glVertex2f(v2d->cur.xmax, env->midval+env->min);
                
                glVertex2f(v2d->cur.xmin, env->midval+env->max);
                glVertex2f(v2d->cur.xmax, env->midval+env->max);
        glEnd(); // GL_LINES
        setlinestyle(0);
        
        /* set size of vertices (non-adjustable for now) */
        glPointSize(2.0f);
        
        // for now, point color is fixed, and is white
        glColor3f(1.0f, 1.0f, 1.0f);
        
        /* we use bgl points not standard gl points, to workaround vertex 
         * drawing bugs that some drivers have (probably legacy ones only though)
         */
        bglBegin(GL_POINTS);
        for (i=0, fed=env->data; i < env->totvert; i++, fed++) {
                /* only draw if visible
                 *      - min/max here are fixed, not relative
                 */
                if IN_RANGE(fed->time, (v2d->cur.xmin - fac), (v2d->cur.xmax + fac)) {
                        glVertex2f(fed->time, fed->min);
                        glVertex2f(fed->time, fed->max);
                }
        }
        bglEnd(); // GL_POINTS
        
        glPointSize(1.0f);
}

/* *************************** */
/* F-Curve Drawing */

/* Points ---------------- */

/* helper func - draw keyframe vertices only for an F-Curve */
static void draw_fcurve_vertices_keyframes (FCurve *fcu, SpaceIpo *UNUSED(sipo), View2D *v2d, short edit, short sel)
{
        BezTriple *bezt= fcu->bezt;
        const float fac= 0.05f * (v2d->cur.xmax - v2d->cur.xmin);
        int i;
        
        /* we use bgl points not standard gl points, to workaround vertex 
         * drawing bugs that some drivers have (probably legacy ones only though)
         */
        bglBegin(GL_POINTS);
        
        for (i = 0; i < fcu->totvert; i++, bezt++) {
                /* as an optimisation step, only draw those in view 
                 *      - we apply a correction factor to ensure that points don't pop in/out due to slight twitches of view size
                 */
                if IN_RANGE(bezt->vec[1][0], (v2d->cur.xmin - fac), (v2d->cur.xmax + fac)) {
                        if (edit) {
                                /* 'Keyframe' vertex only, as handle lines and handles have already been drawn
                                 *      - only draw those with correct selection state for the current drawing color
                                 *      - 
                                 */
                                if ((bezt->f2 & SELECT) == sel)
                                        bglVertex3fv(bezt->vec[1]);
                        }
                        else {
                                /* no check for selection here, as curve is not editable... */
                                // XXX perhaps we don't want to even draw points?   maybe add an option for that later
                                bglVertex3fv(bezt->vec[1]);
                        }
                }
        }
        
        bglEnd(); // GL_POINTS
}


/* helper func - draw handle vertex for an F-Curve as a round unfilled circle 
 * NOTE: the caller MUST HAVE GL_LINE_SMOOTH & GL_BLEND ENABLED, otherwise, the controls don't 
 * have a consistent appearance (due to off-pixel alignments)...
 */
static void draw_fcurve_handle_control (float x, float y, float xscale, float yscale, float hsize)
{
        static GLuint displist=0;
        
        /* initialise round circle shape */
        if (displist == 0) {
                GLUquadricObj *qobj;
                
                displist= glGenLists(1);
                glNewList(displist, GL_COMPILE);
                
                qobj    = gluNewQuadric(); 
                gluQuadricDrawStyle(qobj, GLU_SILHOUETTE); 
                gluDisk(qobj, 0,  0.7, 8, 1);
                gluDeleteQuadric(qobj);  
                
                glEndList();
        }
        
        /* adjust view transform before starting */
        glTranslatef(x, y, 0.0f);
        glScalef(1.0f/xscale*hsize, 1.0f/yscale*hsize, 1.0f);
        
        /* draw! */
        glCallList(displist);
        
        /* restore view transform */
        glScalef(xscale/hsize, yscale/hsize, 1.0);
        glTranslatef(-x, -y, 0.0f);
}

/* helper func - draw handle vertices only for an F-Curve (if it is not protected) */
static void draw_fcurve_vertices_handles (FCurve *fcu, SpaceIpo *sipo, View2D *v2d, short sel, short sel_handle_only)
{
        BezTriple *bezt= fcu->bezt;
        BezTriple *prevbezt = NULL;
        float hsize, xscale, yscale;
        int i;
        
        /* get view settings */
        hsize= UI_GetThemeValuef(TH_HANDLE_VERTEX_SIZE);
        UI_view2d_getscale(v2d, &xscale, &yscale);
        
        /* set handle color */
        if (sel) UI_ThemeColor(TH_HANDLE_VERTEX_SELECT);
        else UI_ThemeColor(TH_HANDLE_VERTEX);
        
        /* anti-aliased lines for more consistent appearance */
        if ((sipo->flag & SIPO_BEAUTYDRAW_OFF)==0) glEnable(GL_LINE_SMOOTH);
        glEnable(GL_BLEND);
        
        for (i=0; i < fcu->totvert; i++, prevbezt=bezt, bezt++) {
                /* Draw the editmode handles for a bezier curve (others don't have handles) 
                 * if their selection status matches the selection status we're drawing for
                 *      - first handle only if previous beztriple was bezier-mode
                 *      - second handle only if current beztriple is bezier-mode
                 *
                 * Also, need to take into account whether the keyframe was selected
                 * if a Graph Editor option to only show handles of selected keys is on.
                 */
                if ( !sel_handle_only || BEZSELECTED(bezt) ) {
                        if ( (!prevbezt && (bezt->ipo==BEZT_IPO_BEZ)) || (prevbezt && (prevbezt->ipo==BEZT_IPO_BEZ)) ) {
                                if ((bezt->f1 & SELECT) == sel)/* && v2d->cur.xmin < bezt->vec[0][0] < v2d->cur.xmax)*/
                                        draw_fcurve_handle_control(bezt->vec[0][0], bezt->vec[0][1], xscale, yscale, hsize);
                        }
                        
                        if (bezt->ipo==BEZT_IPO_BEZ) {
                                if ((bezt->f3 & SELECT) == sel)/* && v2d->cur.xmin < bezt->vec[2][0] < v2d->cur.xmax)*/
                                        draw_fcurve_handle_control(bezt->vec[2][0], bezt->vec[2][1], xscale, yscale, hsize);
                        }
                }
        }
        
        if ((sipo->flag & SIPO_BEAUTYDRAW_OFF)==0) glDisable(GL_LINE_SMOOTH);
        glDisable(GL_BLEND);
}

/* helper func - set color to draw F-Curve data with */
static void set_fcurve_vertex_color (FCurve *fcu, short sel)
{
        /* Fade the 'intensity' of the vertices based on the selection of the curves too */
        int alphaOffset= (int)((drawFCurveFade(fcu) - 1.0f) * 255);
        
        /* Set color of curve vertex based on state of curve (i.e. 'Edit' Mode) */
        if ((fcu->flag & FCURVE_PROTECTED)==0) {
                /* Curve's points ARE BEING edited */
                if (sel) UI_ThemeColorShadeAlpha(TH_VERTEX_SELECT, 0, alphaOffset); 
                else UI_ThemeColorShadeAlpha(TH_VERTEX, 0, alphaOffset);
        } 
        else {
                /* Curve's points CANNOT BE edited */
                if (sel) UI_ThemeColorShadeAlpha(TH_TEXT_HI, 0, alphaOffset);
                else UI_ThemeColorShadeAlpha(TH_TEXT, 0, alphaOffset);
        }
}


static void draw_fcurve_vertices (SpaceIpo *sipo, ARegion *ar, FCurve *fcu, short do_handles, short sel_handle_only)
{
        View2D *v2d= &ar->v2d;
        
        /* only draw points if curve is visible 
         *      - draw unselected points before selected points as separate passes to minimise color-changing overhead
         *         (XXX dunno if this is faster than drawing all in one pass though) 
         *         and also to make sure in the case of overlapping points that the selected is always visible
         *      - draw handles before keyframes, so that keyframes will overlap handles (keyframes are more important for users)
         */
        
        glPointSize(UI_GetThemeValuef(TH_VERTEX_SIZE));
        
        /* draw the two handles first (if they're shown, the curve doesn't have just a single keyframe, and the curve is being edited) */
        if (do_handles)
        {
                set_fcurve_vertex_color(fcu, 0);
                draw_fcurve_vertices_handles(fcu, sipo, v2d, 0, sel_handle_only);
                
                set_fcurve_vertex_color(fcu, 1);
                draw_fcurve_vertices_handles(fcu, sipo, v2d, 1, sel_handle_only);
        }
                
        /* draw keyframes over the handles */
        set_fcurve_vertex_color(fcu, 0);
        draw_fcurve_vertices_keyframes(fcu, sipo, v2d, !(fcu->flag & FCURVE_PROTECTED), 0);
        
        set_fcurve_vertex_color(fcu, 1);
        draw_fcurve_vertices_keyframes(fcu, sipo, v2d, !(fcu->flag & FCURVE_PROTECTED), 1);
        
        glPointSize(1.0f);
}

/* Handles ---------------- */

static int draw_fcurve_handles_check(SpaceIpo *sipo, FCurve *fcu)
{
        /* don't draw handle lines if handles are not to be shown */
        if (    (sipo->flag & SIPO_NOHANDLES) || /* handles shouldn't be shown anywhere */
                        (fcu->flag & FCURVE_PROTECTED) || /* keyframes aren't editable */
#if 0           /* handles can still be selected and handle types set, better draw - campbell */
                        (fcu->flag & FCURVE_INT_VALUES) || /* editing the handles here will cause weird/incorrect interpolation issues */
#endif
                        ((fcu->grp) && (fcu->grp->flag & AGRP_PROTECTED)) || /* group that curve belongs to is not editable */
                        (fcu->totvert <= 1) /* do not show handles if there is only 1 keyframe, otherwise they all clump together in an ugly ball */
                ) 
        {
                return 0;
        } 
        else 
        {
                return 1;
        }
}

/* draw lines for F-Curve handles only (this is only done in EditMode)
 * note: draw_fcurve_handles_check must be checked before running this. */
static void draw_fcurve_handles (SpaceIpo *sipo, FCurve *fcu)
{
        int sel, b;
        
        /* a single call to GL_LINES here around these calls should be sufficient to still
         * get separate line segments, but which aren't wrapped with GL_LINE_STRIP everytime we
         * want a single line
         */
        glBegin(GL_LINES);
        
        /* slightly hacky, but we want to draw unselected points before selected ones 
         * so that selected points are clearly visible
         */
        for (sel= 0; sel < 2; sel++) {
                BezTriple *bezt=fcu->bezt, *prevbezt=NULL;
                int basecol= (sel)? TH_HANDLE_SEL_FREE : TH_HANDLE_FREE;
                float *fp;
                unsigned char col[4];
                
                /* if only selected keyframes have handles shown, skip the first round */
                if ((sel == 0) && (sipo->flag & SIPO_SELVHANDLESONLY))
                        continue;
                
                for (b= 0; b < fcu->totvert; b++, prevbezt=bezt, bezt++) {
                        /* if only selected keyframes can get their handles shown, 
                         * check that keyframe is selected
                         */
                        if (sipo->flag & SIPO_SELVHANDLESONLY) {
                                if (BEZSELECTED(bezt) == 0)
                                        continue;
                        }
                        
                        /* draw handle with appropriate set of colors if selection is ok */
                        if ((bezt->f2 & SELECT)==sel) {
                                fp= bezt->vec[0];

                                /* only draw first handle if previous segment had handles */
                                if ( (!prevbezt && (bezt->ipo==BEZT_IPO_BEZ)) || (prevbezt && (prevbezt->ipo==BEZT_IPO_BEZ)) ) 
                                {
                                        UI_GetThemeColor3ubv(basecol + bezt->h1, col);
                                        col[3]= drawFCurveFade(fcu) * 255;
                                        glColor4ubv((GLubyte *)col);
                                        
                                        glVertex2fv(fp); glVertex2fv(fp+3); 
                                }

                                /* only draw second handle if this segment is bezier */
                                if (bezt->ipo == BEZT_IPO_BEZ) 
                                {
                                        UI_GetThemeColor3ubv(basecol + bezt->h2, col);
                                        col[3]= drawFCurveFade(fcu) * 255;
                                        glColor4ubv((GLubyte *)col);

                                        glVertex2fv(fp+3); glVertex2fv(fp+6); 
                                }
                        }
                        else {
                                /* only draw first handle if previous segment was had handles, and selection is ok */
                                if ( ((bezt->f1 & SELECT)==sel) && 
                                         ( (!prevbezt && (bezt->ipo==BEZT_IPO_BEZ)) || (prevbezt && (prevbezt->ipo==BEZT_IPO_BEZ)) ) ) 
                                {
                                        fp= bezt->vec[0];
                                        UI_GetThemeColor3ubv(basecol + bezt->h1, col);
                                        col[3]= drawFCurveFade(fcu) * 255;
                                        glColor4ubv((GLubyte *)col);

                                        glVertex2fv(fp); glVertex2fv(fp+3); 
                                }
                                
                                /* only draw second handle if this segment is bezier, and selection is ok */
                                if ( ((bezt->f3 & SELECT)==sel) &&
                                         (bezt->ipo == BEZT_IPO_BEZ) )
                                {
                                        fp= bezt->vec[1];
                                        UI_GetThemeColor3ubv(basecol + bezt->h2, col);
                                        col[3]= drawFCurveFade(fcu) * 255;
                                        glColor4ubv((GLubyte *)col);
                                        
                                        glVertex2fv(fp); glVertex2fv(fp+3); 
                                }
                        }
                }
        }
        
        glEnd(); // GL_LINES 
}

/* Samples ---------------- */

/* helper func - draw sample-range marker for an F-Curve as a cross 
 * NOTE: the caller MUST HAVE GL_LINE_SMOOTH & GL_BLEND ENABLED, otherwise, the controls don't 
 * have a consistent appearance (due to off-pixel alignments)...
 */
static void draw_fcurve_sample_control (float x, float y, float xscale, float yscale, float hsize)
{
        static GLuint displist=0;
        
        /* initialise X shape */
        if (displist == 0) {
                displist= glGenLists(1);
                glNewList(displist, GL_COMPILE);
                
                glBegin(GL_LINES);
                        glVertex2f(-0.7f, -0.7f);
                        glVertex2f(+0.7f, +0.7f);
                        
                        glVertex2f(-0.7f, +0.7f);
                        glVertex2f(+0.7f, -0.7f);
                glEnd(); // GL_LINES
                
                glEndList();
        }
        
        /* adjust view transform before starting */
        glTranslatef(x, y, 0.0f);
        glScalef(1.0f/xscale*hsize, 1.0f/yscale*hsize, 1.0f);
        
        /* draw! */
        glCallList(displist);
        
        /* restore view transform */
        glScalef(xscale/hsize, yscale/hsize, 1.0);
        glTranslatef(-x, -y, 0.0f);
}

/* helper func - draw keyframe vertices only for an F-Curve */
static void draw_fcurve_samples (SpaceIpo *sipo, ARegion *ar, FCurve *fcu)
{
        FPoint *first, *last;
        float hsize, xscale, yscale;
        
        /* get view settings */
        hsize= UI_GetThemeValuef(TH_VERTEX_SIZE);
        UI_view2d_getscale(&ar->v2d, &xscale, &yscale);
        
        /* set vertex color */
        if (fcu->flag & (FCURVE_ACTIVE|FCURVE_SELECTED)) UI_ThemeColor(TH_TEXT_HI);
        else UI_ThemeColor(TH_TEXT);
        
        /* get verts */
        first= fcu->fpt;
        last= (first) ? (first + (fcu->totvert-1)) : (NULL);
        
        /* draw */
        if (first && last) {
                /* anti-aliased lines for more consistent appearance */
                if ((sipo->flag & SIPO_BEAUTYDRAW_OFF)==0) glEnable(GL_LINE_SMOOTH);
                glEnable(GL_BLEND);
                
                draw_fcurve_sample_control(first->vec[0], first->vec[1], xscale, yscale, hsize);
                draw_fcurve_sample_control(last->vec[0], last->vec[1], xscale, yscale, hsize);
                
                glDisable(GL_BLEND);
                if ((sipo->flag & SIPO_BEAUTYDRAW_OFF)==0) glDisable(GL_LINE_SMOOTH);
        }
}

/* Curve ---------------- */

/* helper func - just draw the F-Curve by sampling the visible region (for drawing curves with modifiers) */
static void draw_fcurve_curve (bAnimContext *ac, ID *id, FCurve *fcu, View2D *v2d, View2DGrid *grid)
{
        ChannelDriver *driver;
        float samplefreq, ctime;
        float stime, etime;
        float unitFac;
        float dx, dy;

        /* when opening a blend file on a different sized screen or while dragging the toolbar this can happen
         * best just bail out in this case */
        UI_view2d_grid_size(grid, &dx, &dy);
        if(dx <= 0.0f)
                return;


        /* disable any drivers temporarily */
        driver= fcu->driver;
        fcu->driver= NULL;
        
        /* compute unit correction factor */
        unitFac= ANIM_unit_mapping_get_factor(ac->scene, id, fcu, 0);
        
        /* Note about sampling frequency:
         *      Ideally, this is chosen such that we have 1-2 pixels = 1 segment
         *      which means that our curves can be as smooth as possible. However,
         *      this does mean that curves may not be fully accurate (i.e. if they have
         *      sudden spikes which happen at the sampling point, we may have problems).
         *      Also, this may introduce lower performance on less densely detailed curves,'
         *      though it is impossible to predict this from the modifiers!
         *
         *      If the automatically determined sampling frequency is likely to cause an infinite
         *      loop (i.e. too close to 0), then clamp it to a determined "safe" value. The value
         *      chosen here is just the coarsest value which still looks reasonable...
         */
                /* grid->dx represents the number of 'frames' between gridlines, but we divide by U.v2d_min_gridsize to get pixels-steps */
                // TODO: perhaps we should have 1.0 frames as upper limit so that curves don't get too distorted?
        samplefreq= dx / U.v2d_min_gridsize;
        if (samplefreq < 0.00001f) samplefreq= 0.00001f;
        
        
        /* the start/end times are simply the horizontal extents of the 'cur' rect */
        stime= v2d->cur.xmin;
        etime= v2d->cur.xmax + samplefreq; /* + samplefreq here so that last item gets included... */
        
        
        /* at each sampling interval, add a new vertex 
         *      - apply the unit correction factor to the calculated values so that 
         *        the displayed values appear correctly in the viewport
         */
        glBegin(GL_LINE_STRIP);
        
        for (ctime= stime; ctime <= etime; ctime += samplefreq)
                glVertex2f( ctime, evaluate_fcurve(fcu, ctime)*unitFac );
        
        glEnd();
        
        /* restore driver */
        fcu->driver= driver;
}

/* helper func - draw a samples-based F-Curve */
static void draw_fcurve_curve_samples (bAnimContext *ac, ID *id, FCurve *fcu, View2D *v2d)
{
        FPoint *prevfpt= fcu->fpt;
        FPoint *fpt= prevfpt + 1;
        float fac, v[2];
        int b= fcu->totvert-1;
        
        glBegin(GL_LINE_STRIP);
        
        /* apply unit mapping */
        ANIM_unit_mapping_apply_fcurve(ac->scene, id, fcu, 0);
        
        /* extrapolate to left? - left-side of view comes before first keyframe? */
        if (prevfpt->vec[0] > v2d->cur.xmin) {
                v[0]= v2d->cur.xmin;
                
                /* y-value depends on the interpolation */
                if ((fcu->extend==FCURVE_EXTRAPOLATE_CONSTANT) || (fcu->flag & FCURVE_INT_VALUES) || (fcu->totvert==1)) {
                        /* just extend across the first keyframe's value */
                        v[1]= prevfpt->vec[1];
                } 
                else {
                        /* extrapolate linear dosnt use the handle, use the next points center instead */
                        fac= (prevfpt->vec[0]-fpt->vec[0])/(prevfpt->vec[0]-v[0]);
                        if (fac) fac= 1.0f/fac;
                        v[1]= prevfpt->vec[1]-fac*(prevfpt->vec[1]-fpt->vec[1]);
                }
                
                glVertex2fv(v);
        }
        
        /* if only one sample, add it now */
        if (fcu->totvert == 1)
                glVertex2fv(prevfpt->vec);
        
        /* loop over samples, drawing segments */
        /* draw curve between first and last keyframe (if there are enough to do so) */
        while (b--) {
                /* Linear interpolation: just add one point (which should add a new line segment) */
                glVertex2fv(prevfpt->vec);
                
                /* get next pointers */
                prevfpt= fpt; 
                fpt++;
                
                /* last point? */
                if (b == 0)
                        glVertex2fv(prevfpt->vec);
        }
        
        /* extrapolate to right? (see code for left-extrapolation above too) */
        if (prevfpt->vec[0] < v2d->cur.xmax) {
                v[0]= v2d->cur.xmax;
                
                /* y-value depends on the interpolation */
                if ((fcu->extend==FCURVE_EXTRAPOLATE_CONSTANT) || (fcu->flag & FCURVE_INT_VALUES) || (fcu->totvert==1)) {
                        /* based on last keyframe's value */
                        v[1]= prevfpt->vec[1];
                } 
                else {
                        /* extrapolate linear dosnt use the handle, use the previous points center instead */
                        fpt = prevfpt-1;
                        fac= (prevfpt->vec[0]-fpt->vec[0])/(prevfpt->vec[0]-v[0]);
                        if (fac) fac= 1.0f/fac;
                        v[1]= prevfpt->vec[1]-fac*(prevfpt->vec[1]-fpt->vec[1]);
                }
                
                glVertex2fv(v);
        }
        
        /* unapply unit mapping */
        ANIM_unit_mapping_apply_fcurve(ac->scene, id, fcu, ANIM_UNITCONV_RESTORE);
        
        glEnd();
}

/* helper func - draw one repeat of an F-Curve */
static void draw_fcurve_curve_bezts (bAnimContext *ac, ID *id, FCurve *fcu, View2D *v2d)
{
        BezTriple *prevbezt= fcu->bezt;
        BezTriple *bezt= prevbezt+1;
        float v1[2], v2[2], v3[2], v4[2];
        float *fp, data[120];
        float fac= 0.0f;
        int b= fcu->totvert-1;
        int resol;
        
        glBegin(GL_LINE_STRIP);
        
        /* apply unit mapping */
        ANIM_unit_mapping_apply_fcurve(ac->scene, id, fcu, 0);
        
        /* extrapolate to left? */
        if (prevbezt->vec[1][0] > v2d->cur.xmin) {
                /* left-side of view comes before first keyframe, so need to extend as not cyclic */
                v1[0]= v2d->cur.xmin;
                
                /* y-value depends on the interpolation */
                if ((fcu->extend==FCURVE_EXTRAPOLATE_CONSTANT) || (prevbezt->ipo==BEZT_IPO_CONST) || (fcu->totvert==1)) {
                        /* just extend across the first keyframe's value */
                        v1[1]= prevbezt->vec[1][1];
                } 
                else if (prevbezt->ipo==BEZT_IPO_LIN) {
                        /* extrapolate linear dosnt use the handle, use the next points center instead */
                        fac= (prevbezt->vec[1][0]-bezt->vec[1][0])/(prevbezt->vec[1][0]-v1[0]);
                        if (fac) fac= 1.0f/fac;
                        v1[1]= prevbezt->vec[1][1]-fac*(prevbezt->vec[1][1]-bezt->vec[1][1]);
                } 
                else {
                        /* based on angle of handle 1 (relative to keyframe) */
                        fac= (prevbezt->vec[0][0]-prevbezt->vec[1][0])/(prevbezt->vec[1][0]-v1[0]);
                        if (fac) fac= 1.0f/fac;
                        v1[1]= prevbezt->vec[1][1]-fac*(prevbezt->vec[0][1]-prevbezt->vec[1][1]);
                }
                
                glVertex2fv(v1);
        }
        
        /* if only one keyframe, add it now */
        if (fcu->totvert == 1) {
                v1[0]= prevbezt->vec[1][0];
                v1[1]= prevbezt->vec[1][1];
                glVertex2fv(v1);
        }
        
        /* draw curve between first and last keyframe (if there are enough to do so) */
        while (b--) {
                if (prevbezt->ipo==BEZT_IPO_CONST) {
                        /* Constant-Interpolation: draw segment between previous keyframe and next, but holding same value */
                        v1[0]= prevbezt->vec[1][0];
                        v1[1]= prevbezt->vec[1][1];
                        glVertex2fv(v1);
                        
                        v1[0]= bezt->vec[1][0];
                        v1[1]= prevbezt->vec[1][1];
                        glVertex2fv(v1);
                }
                else if (prevbezt->ipo==BEZT_IPO_LIN) {
                        /* Linear interpolation: just add one point (which should add a new line segment) */
                        v1[0]= prevbezt->vec[1][0];
                        v1[1]= prevbezt->vec[1][1];
                        glVertex2fv(v1);
                }
                else {
                        /* Bezier-Interpolation: draw curve as series of segments between keyframes 
                         *      - resol determines number of points to sample in between keyframes
                         */
                        
                        /* resol not depending on horizontal resolution anymore, drivers for example... */
                        // TODO: would be nice to make this depend on the scale of the graph too...
                        if (fcu->driver) 
                                resol= 32;
                        else 
                                resol= (int)(3.0*sqrt(bezt->vec[1][0] - prevbezt->vec[1][0]));
                        
                        if (resol < 2) {
                                /* only draw one */
                                v1[0]= prevbezt->vec[1][0];
                                v1[1]= prevbezt->vec[1][1];
                                glVertex2fv(v1);
                        }
                        else {
                                /* clamp resolution to max of 32 */
                                if (resol > 32) resol= 32;
                                
                                v1[0]= prevbezt->vec[1][0];
                                v1[1]= prevbezt->vec[1][1];
                                v2[0]= prevbezt->vec[2][0];
                                v2[1]= prevbezt->vec[2][1];
                                
                                v3[0]= bezt->vec[0][0];
                                v3[1]= bezt->vec[0][1];
                                v4[0]= bezt->vec[1][0];
                                v4[1]= bezt->vec[1][1];
                                
                                correct_bezpart(v1, v2, v3, v4);
                                
                                forward_diff_bezier(v1[0], v2[0], v3[0], v4[0], data, resol, sizeof(float)*3);
                                forward_diff_bezier(v1[1], v2[1], v3[1], v4[1], data+1, resol, sizeof(float)*3);
                                
                                for (fp= data; resol; resol--, fp+= 3)
                                        glVertex2fv(fp);
                        }
                }
                
                /* get next pointers */
                prevbezt= bezt; 
                bezt++;
                
                /* last point? */
                if (b == 0) {
                        v1[0]= prevbezt->vec[1][0];
                        v1[1]= prevbezt->vec[1][1];
                        glVertex2fv(v1);
                }
        }
        
        /* extrapolate to right? (see code for left-extrapolation above too) */
        if (prevbezt->vec[1][0] < v2d->cur.xmax) {
                v1[0]= v2d->cur.xmax;
                
                /* y-value depends on the interpolation */
                if ((fcu->extend==FCURVE_EXTRAPOLATE_CONSTANT) || (fcu->flag & FCURVE_INT_VALUES) || (prevbezt->ipo==BEZT_IPO_CONST) || (fcu->totvert==1)) {
                        /* based on last keyframe's value */
                        v1[1]= prevbezt->vec[1][1];
                } 
                else if (prevbezt->ipo==BEZT_IPO_LIN) {
                        /* extrapolate linear dosnt use the handle, use the previous points center instead */
                        bezt = prevbezt-1;
                        fac= (prevbezt->vec[1][0]-bezt->vec[1][0])/(prevbezt->vec[1][0]-v1[0]);
                        if (fac) fac= 1.0f/fac;
                        v1[1]= prevbezt->vec[1][1]-fac*(prevbezt->vec[1][1]-bezt->vec[1][1]);
                } 
                else {
                        /* based on angle of handle 1 (relative to keyframe) */
                        fac= (prevbezt->vec[2][0]-prevbezt->vec[1][0])/(prevbezt->vec[1][0]-v1[0]);
                        if (fac) fac= 1.0f/fac;
                        v1[1]= prevbezt->vec[1][1]-fac*(prevbezt->vec[2][1]-prevbezt->vec[1][1]);
                }
                
                glVertex2fv(v1);
        }
        
        /* unapply unit mapping */
        ANIM_unit_mapping_apply_fcurve(ac->scene, id, fcu, ANIM_UNITCONV_RESTORE);
        
        glEnd();
} 

/* Public Curve-Drawing API  ---------------- */

/* Draw the 'ghost' F-Curves (i.e. snapshots of the curve) 
 * NOTE: unit mapping has already been applied to the values, so do not try and apply again
 */
void graph_draw_ghost_curves (bAnimContext *ac, SpaceIpo *sipo, ARegion *ar)
{
        FCurve *fcu;
        
        /* draw with thick dotted lines */
        setlinestyle(10);
        glLineWidth(3.0f);
        
        /* anti-aliased lines for less jagged appearance */
        if ((sipo->flag & SIPO_BEAUTYDRAW_OFF)==0) glEnable(GL_LINE_SMOOTH);
        glEnable(GL_BLEND);
        
        /* the ghost curves are simply sampled F-Curves stored in sipo->ghostCurves */
        for (fcu= sipo->ghostCurves.first; fcu; fcu= fcu->next) {
                /* set whatever color the curve has set 
                 *      - this is set by the function which creates these
                 *      - draw with a fixed opacity of 2
                 */
                glColor4f(fcu->color[0], fcu->color[1], fcu->color[2], 0.5f);
                
                /* simply draw the stored samples */
                draw_fcurve_curve_samples(ac, NULL, fcu, &ar->v2d);
        }
        
        /* restore settings */
        setlinestyle(0);
        glLineWidth(1.0f);
        
        if ((sipo->flag & SIPO_BEAUTYDRAW_OFF)==0) glDisable(GL_LINE_SMOOTH);
        glDisable(GL_BLEND);
}

/* This is called twice from space_graph.c -> graph_main_area_draw()
 * Unselected then selected F-Curves are drawn so that they do not occlude each other.
 */
void graph_draw_curves (bAnimContext *ac, SpaceIpo *sipo, ARegion *ar, View2DGrid *grid, short sel)
{
        ListBase anim_data = {NULL, NULL};
        bAnimListElem *ale;
        int filter;
        
        /* build list of curves to draw */
        filter= (ANIMFILTER_VISIBLE|ANIMFILTER_CURVESONLY|ANIMFILTER_CURVEVISIBLE);
        filter |= ((sel) ? (ANIMFILTER_SEL) : (ANIMFILTER_UNSEL));
        ANIM_animdata_filter(ac, &anim_data, filter, ac->data, ac->datatype);
                
        /* for each curve:
         *      draw curve, then handle-lines, and finally vertices in this order so that 
         *      the data will be layered correctly
         */
        for (ale=anim_data.first; ale; ale=ale->next) {
                FCurve *fcu= (FCurve *)ale->key_data;
                FModifier *fcm= find_active_fmodifier(&fcu->modifiers);
                AnimData *adt= ANIM_nla_mapping_get(ac, ale);
                
                /* map keyframes for drawing if scaled F-Curve */
                if (adt)
                        ANIM_nla_mapping_apply_fcurve(adt, ale->key_data, 0, 0); 
                
                /* draw curve:
                 *      - curve line may be result of one or more destructive modifiers or just the raw data,
                 *        so we need to check which method should be used
                 *      - controls from active modifier take precidence over keyframes
                 *        (XXX! editing tools need to take this into account!)
                 */
                 
                /* 1) draw curve line */
                {
                        /* set color/drawing style for curve itself */
                        if ( ((fcu->grp) && (fcu->grp->flag & AGRP_PROTECTED)) || (fcu->flag & FCURVE_PROTECTED) ) {
                                /* protected curves (non editable) are drawn with dotted lines */
                                setlinestyle(2);
                        }
                        if ( ((fcu->grp) && (fcu->grp->flag & AGRP_MUTED)) || (fcu->flag & FCURVE_MUTED) ) {
                                /* muted curves are drawn in a greyish hue */
                                // XXX should we have some variations?
                                UI_ThemeColorShade(TH_HEADER, 50);
                        }
                        else {
                                /* set whatever color the curve has set 
                                 *      - unselected curves draw less opaque to help distinguish the selected ones
                                 */
                                glColor4f(fcu->color[0], fcu->color[1], fcu->color[2], drawFCurveFade(fcu));
                        }
                        
                        /* anti-aliased lines for less jagged appearance */
                        if ((sipo->flag & SIPO_BEAUTYDRAW_OFF)==0) glEnable(GL_LINE_SMOOTH);
                        glEnable(GL_BLEND);
                        
                        /* draw F-Curve */
                        if ((fcu->modifiers.first) || (fcu->flag & FCURVE_INT_VALUES)) {
                                /* draw a curve affected by modifiers or only allowed to have integer values 
                                 * by sampling it at various small-intervals over the visible region 
                                 */
                                draw_fcurve_curve(ac, ale->id, fcu, &ar->v2d, grid);
                        }
                        else if ( ((fcu->bezt) || (fcu->fpt)) && (fcu->totvert) ) { 
                                /* just draw curve based on defined data (i.e. no modifiers) */
                                if (fcu->bezt)
                                        draw_fcurve_curve_bezts(ac, ale->id, fcu, &ar->v2d);
                                else if (fcu->fpt)
                                        draw_fcurve_curve_samples(ac, ale->id, fcu, &ar->v2d);
                        }
                        
                        /* restore settings */
                        setlinestyle(0);
                        
                        if ((sipo->flag & SIPO_BEAUTYDRAW_OFF)==0) glDisable(GL_LINE_SMOOTH);
                        glDisable(GL_BLEND);
                }
                
                /* 2) draw handles and vertices as appropriate based on active 
                 *      - if the option to only show controls if the F-Curve is selected is enabled, we must obey this
                 */
                if (!(sipo->flag & SIPO_SELCUVERTSONLY) || (fcu->flag & FCURVE_SELECTED)) {
                        if (fcurve_are_keyframes_usable(fcu) == 0) {
                                /* only draw controls if this is the active modifier */
                                if ((fcu->flag & FCURVE_ACTIVE) && (fcm)) {
                                        switch (fcm->type) {
                                                case FMODIFIER_TYPE_ENVELOPE: /* envelope */
                                                        draw_fcurve_modifier_controls_envelope(fcm, &ar->v2d);
                                                        break;
                                        }
                                }
                        }
                        else if ( ((fcu->bezt) || (fcu->fpt)) && (fcu->totvert) ) { 
                                /* apply unit mapping */
                                ANIM_unit_mapping_apply_fcurve(ac->scene, ale->id, fcu, 0);
                                
                                if (fcu->bezt) {
                                        int do_handles = draw_fcurve_handles_check(sipo, fcu);
                                        
                                        if (do_handles) {
                                                /* only draw handles/vertices on keyframes */
                                                glEnable(GL_BLEND);
                                                draw_fcurve_handles(sipo, fcu);
                                                glDisable(GL_BLEND);
                                        }
                                        
                                        draw_fcurve_vertices(sipo, ar, fcu, do_handles, (sipo->flag & SIPO_SELVHANDLESONLY));
                                }
                                else {
                                        /* samples: only draw two indicators at either end as indicators */
                                        draw_fcurve_samples(sipo, ar, fcu);
                                }
                                
                                /* unapply unit mapping */
                                ANIM_unit_mapping_apply_fcurve(ac->scene, ale->id, fcu, ANIM_UNITCONV_RESTORE);
                        }
                }
                
                /* undo mapping of keyframes for drawing if scaled F-Curve */
                if (adt)
                        ANIM_nla_mapping_apply_fcurve(adt, ale->key_data, 1, 0); 
        }
        
        /* free list of curves */
        BLI_freelistN(&anim_data);
}

/* ************************************************************************* */
/* Channel List */

/* left hand part */
void graph_draw_channel_names(bContext *C, bAnimContext *ac, ARegion *ar) 
{
        ListBase anim_data = {NULL, NULL};
        bAnimListElem *ale;
        int filter;
        
        View2D *v2d= &ar->v2d;
        float y= 0.0f, height;
        int items, i=0;
        
        /* build list of channels to draw */
        filter= (ANIMFILTER_VISIBLE|ANIMFILTER_CHANNELS);
        items= ANIM_animdata_filter(ac, &anim_data, filter, ac->data, ac->datatype);
        
        /* Update max-extent of channels here (taking into account scrollers):
         *      - this is done to allow the channel list to be scrollable, but must be done here
         *        to avoid regenerating the list again and/or also because channels list is drawn first
         *      - offset of ACHANNEL_HEIGHT*2 is added to the height of the channels, as first is for 
         *        start of list offset, and the second is as a correction for the scrollers.
         */
        height= (float)((items*ACHANNEL_STEP) + (ACHANNEL_HEIGHT*2));
        UI_view2d_totRect_set(v2d, ar->winx, height);
        
        /* loop through channels, and set up drawing depending on their type  */        
        {       /* first pass: just the standard GL-drawing for backdrop + text */
                y= (float)ACHANNEL_FIRST;
                
                for (ale= anim_data.first, i=0; ale; ale= ale->next, i++) {
                        const float yminc= (float)(y - ACHANNEL_HEIGHT_HALF);
                        const float ymaxc= (float)(y + ACHANNEL_HEIGHT_HALF);
                        
                        /* check if visible */
                        if ( IN_RANGE(yminc, v2d->cur.ymin, v2d->cur.ymax) ||
                                 IN_RANGE(ymaxc, v2d->cur.ymin, v2d->cur.ymax) ) 
                        {
                                /* draw all channels using standard channel-drawing API */
                                ANIM_channel_draw(ac, ale, yminc, ymaxc);
                        }
                        
                        /* adjust y-position for next one */
                        y -= ACHANNEL_STEP;
                }
        }
        {       /* second pass: widgets */
                uiBlock *block= uiBeginBlock(C, ar, "graph channel buttons", UI_EMBOSS);
                
                y= (float)ACHANNEL_FIRST;
                
                /* set blending again, as may not be set in previous step */
                glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
                glEnable(GL_BLEND);
                
                for (ale= anim_data.first, i=0; ale; ale= ale->next, i++) {
                        const float yminc= (float)(y - ACHANNEL_HEIGHT_HALF);
                        const float ymaxc= (float)(y + ACHANNEL_HEIGHT_HALF);
                        
                        /* check if visible */
                        if ( IN_RANGE(yminc, v2d->cur.ymin, v2d->cur.ymax) ||
                                 IN_RANGE(ymaxc, v2d->cur.ymin, v2d->cur.ymax) ) 
                        {
                                /* draw all channels using standard channel-drawing API */
                                ANIM_channel_draw_widgets(ac, ale, block, yminc, ymaxc);
                        }
                        
                        /* adjust y-position for next one */
                        y -= ACHANNEL_STEP;
                }
                
                uiEndBlock(C, block);
                uiDrawBlock(C, block);
                
                glDisable(GL_BLEND);
        }
        
        /* free tempolary channels */
        BLI_freelistN(&anim_data);
}