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-rw-r--r--Examples/GIFPlot/Lib/frame.c924
1 files changed, 0 insertions, 924 deletions
diff --git a/Examples/GIFPlot/Lib/frame.c b/Examples/GIFPlot/Lib/frame.c
deleted file mode 100644
index e006f0daf..000000000
--- a/Examples/GIFPlot/Lib/frame.c
+++ /dev/null
@@ -1,924 +0,0 @@
-/* -----------------------------------------------------------------------------
- * frame.c
- *
- * Frame buffer management
- *
- * Author(s) : David Beazley (beazley@cs.uchicago.edu)
- * Copyright (C) 1995-1996
- *
- * See the file LICENSE for information on usage and redistribution.
- * ----------------------------------------------------------------------------- */
-
-#define FRAME
-#include "gifplot.h"
-#include <float.h>
-
-/* ------------------------------------------------------------------------
- FrameBuffer *new_FrameBuffer(int width, int height)
-
- Creates a new framebuffer for storing data.
- ------------------------------------------------------------------------ */
-
-FrameBuffer *new_FrameBuffer(unsigned int width, unsigned int height) {
-
- FrameBuffer *f;
- int FrameBuffer_resize(FrameBuffer *f, int width, int height);
-
- /* Create a new frame buffer */
-
- f = (FrameBuffer *) malloc(sizeof(FrameBuffer));
- f->pixels = (Pixel **) 0;
- f->zbuffer = (Zvalue **) 0;
- /* Set its size */
-
- if (FrameBuffer_resize(f, width, height) == -1) {
- free((char *) f);
- return (FrameBuffer *) 0;
- }
-
- f->xmin = 0;
- f->ymin = 0;
- f->xmax = width;
- f->ymax = height;
- return f;
-}
-
-/* ------------------------------------------------------------------------
- void delete_FrameBuffer(FrameBuffer *f)
-
- Destroys the given framebuffer
- ------------------------------------------------------------------------ */
-
-void delete_FrameBuffer(FrameBuffer *f) {
-
- if (f) {
- if (f->pixels) {
- free((char *) f->pixels[0]);
- free((char *) f->pixels);
- }
- if (f->zbuffer) {
- free((char *) f->zbuffer[0]);
- free((char *) f->zbuffer);
- }
- free((char *)f);
- }
-}
-
-/* ------------------------------------------------------------------------
- int *FrameBuffer_resize(FrameBuffer *f, int width, int height)
-
- Resize the given framebuffer. Returns 0 on success, -1 on failure.
- ------------------------------------------------------------------------ */
-
-int FrameBuffer_resize(FrameBuffer *f, int width, int height) {
- int i;
- if ((f) && (width > 0) && (height > 0)) {
- if (f->pixels) {
- free((char *)f->pixels[0]);
- free((char *)f->pixels);
- }
- f->pixels = (Pixel **) malloc (height*sizeof(Pixel *));
- if (!f->pixels) return -1;
- f->pixels[0] = (Pixel *) malloc(height*width*sizeof(Pixel));
- if (!f->pixels[0]) {
- free((char *)f->pixels);
- return -1;
- }
- for (i = 0; i < height; i++)
- f->pixels[i] = f->pixels[0] + i*width;
- f->width = width;
- f->height = height;
- if (f->zbuffer) {
- FrameBuffer_zresize(f,width,height);
- }
- return 0;
- } else {
- return -1;
- }
-}
-
-/* ------------------------------------------------------------------------
- void FrameBuffer_clear(FrameBuffer *f, Pixel color)
-
- Clears the current FrameBuffer
- ------------------------------------------------------------------------ */
-
-void FrameBuffer_clear(FrameBuffer *f, Pixel color) {
- Pixel *p;
- unsigned int i;
- p = &f->pixels[0][0];
-
- for (i = 0; i < f->width*f->height; i++, p++)
- *p = color;
-}
-
-/* ------------------------------------------------------------------------
- void FrameBuffer_plot(FrameBuffer *f, int x1, int y1, Pixel color)
-
- Plots a point and does a bounds check.
- ------------------------------------------------------------------------ */
-
-void FrameBuffer_plot(FrameBuffer *f, int x1, int y1, Pixel color) {
-
- if ((x1 < f->xmin) || (x1 >= f->xmax) || (y1 < f->ymin) || (y1 >= f->ymax))
- return;
- f->pixels[y1][x1] = color;
-
-}
-
-/* ------------------------------------------------------------------------
- FrameBuffer_horizontal(Framebuffer *f, int xmin, int xmax, int y, Pixel color)
-
- Draw a horizontal line (clipped)
- ------------------------------------------------------------------------ */
-
-void FrameBuffer_horizontal(FrameBuffer *f, int xmin, int xmax, int y, Pixel color) {
-
- Pixel *p;
- int i;
-
- if ((y < f->ymin) || (y >= f->ymax)) return;
- if (xmin < f->xmin) xmin = f->xmin;
- if (xmax >= f->xmax) xmax = f->xmax - 1;
-
- p = &f->pixels[y][xmin];
- for (i = xmin; i <= xmax; i++, p++)
- *p = color;
-
-}
-
-/* ------------------------------------------------------------------------
- FrameBuffer_horizontalinterp(Framebuffer *f, int xmin, int xmax, int y,
- Pixel c1, Pixel c2)
-
- Draw a horizontal line (clipped) with color interpolation.
- ------------------------------------------------------------------------ */
-
-void FrameBuffer_horizontalinterp(FrameBuffer *f, int xmin, int xmax, int y,
- Pixel c1, Pixel c2) {
-
- Pixel *p;
- int i;
- double mc;
- int x1;
- if ((y < f->ymin) || (y >= f->ymax)) return;
-
- x1 = xmin;
- if (xmin < f->xmin) xmin = f->xmin;
- if (xmax >= f->xmax) xmax = f->xmax - 1;
- if (xmax < f->xmin) return;
- if (xmin >= f->xmax) return;
-
- if (xmin != xmax)
- mc = (double)(c2 - c1)/(double) (xmax - xmin);
- else
- mc = 0.0;
-
- p = &f->pixels[y][xmin];
- for (i = xmin; i <= xmax; i++, p++)
- *p = (Pixel) (mc*(i-x1) + c1);
-
-}
-
-
-/* ------------------------------------------------------------------------
- FrameBuffer_vertical(Framebuffer *f, int xmin, int xmax, int y, Pixel color)
-
- Draw a Vertical line (clipped)
- ------------------------------------------------------------------------ */
-
-void FrameBuffer_vertical(FrameBuffer *f, int ymin, int ymax, int x, Pixel color) {
-
- Pixel *p;
- int i;
-
- if ((x < f->xmin) || (x >= f->xmax)) return;
- if (ymax < f->ymin) return;
- if (ymin > f->ymax) return;
- if (ymin < f->ymin) ymin = f->ymin;
- if (ymax >= f->ymax) ymax = f->ymax - 1;
-
- p = &f->pixels[ymin][x];
- for (i = 0; i <= (ymax - ymin); i++, p+=f->width)
- *p = color;
-
-}
-
-/* ------------------------------------------------------------------------
- void FrameBuffer_box(FrameBuffer *f, int x1, int y1, int x2, int y2, Pixel color)
-
- Makes an outline box.
- ------------------------------------------------------------------------ */
-
-void FrameBuffer_box(FrameBuffer *f, int x1, int y1, int x2, int y2, Pixel color) {
-
- int xt, yt;
-
- /* Make sure points are in correct order */
-
- if (x2 < x1) {
- xt = x2;
- x2 = x1;
- x1 = xt;
- }
- if (y2 < y1) {
- yt = y2;
- y2 = y1;
- y1 = yt;
- }
-
- /* Draw lower edge */
-
- FrameBuffer_horizontal(f,x1,x2,y1,color);
-
- /* Draw upper edge */
-
- FrameBuffer_horizontal(f,x1,x2,y2,color);
-
- /* Draw left side */
-
- FrameBuffer_vertical(f,y1,y2,x1,color);
-
- /* Draw right side */
-
- FrameBuffer_vertical(f,y1,y2,x2,color);
-
-}
-
-/* ------------------------------------------------------------------------
- void FrameBuffer_solidbox(FrameBuffer *f, int x1, int y1, int x2, int y2, Pixel color)
-
- Makes an solid box.
- ------------------------------------------------------------------------ */
-
-void FrameBuffer_solidbox(FrameBuffer *f, int x1, int y1, int x2, int y2, Pixel color) {
-
- int xt, yt;
-
- /* Make sure points are in correct order */
-
- if (x2 < x1) {
- xt = x2;
- x2 = x1;
- x1 = xt;
- }
- if (y2 < y1) {
- yt = y2;
- y2 = y1;
- y1 = yt;
- }
-
- /* Now perform some clipping */
-
- if (y1 < f->ymin) y1 = f->ymin;
- if (y2 >= f->ymax) y2 = f->ymax - 1;
-
- /* Fill it in using horizontal lines */
-
- for (yt = y1; yt <= y2; yt++)
- FrameBuffer_horizontal(f,x1,x2,yt,color);
-
-}
-
-/* ------------------------------------------------------------------------
- void FrameBuffer_interpbox(FrameBuffer *f, int x1, int y1, int x2, int y2
- Pixel c1, Pixel c2, Pixel c3, Pixel c4)
-
- Makes a box with interpolated color. Colors are assigned as follows :
- (x1,y1) = c1
- (x1,y2) = c2
- (x2,y1) = c3
- (x2,y2) = c4
- ------------------------------------------------------------------------ */
-
-void FrameBuffer_interpbox(FrameBuffer *f, int x1, int y1, int x2, int y2,
- Pixel c1, Pixel c2, Pixel c3, Pixel c4) {
-
- int xt, yt;
- Pixel ct;
- double mc1,mc2;
- int ystart;
- /* Make sure points are in correct order */
-
- if (x2 < x1) {
- xt = x2;
- x2 = x1;
- x1 = xt;
- ct = c1;
- c1 = c3;
- c3 = ct;
- ct = c2;
- c2 = c4;
- c4 = ct;
- }
- if (y2 < y1) {
- yt = y2;
- y2 = y1;
- y1 = yt;
- ct = c1;
- c1 = c2;
- c2 = ct;
- ct = c3;
- c3 = c4;
- c4 = ct;
- }
-
- /* Now perform some clipping */
-
- ystart = y1;
- mc1 = (double) (c2 - c1)/(double) (y2 - y1);
- mc2 = (double) (c4 - c3)/(double) (y2 - y1);
- if (y1 < f->ymin) y1 = f->ymin;
- if (y2 >= f->ymax) y2 = f->ymax - 1;
-
- /* Fill it in using horizontal lines */
-
- for (yt = y1; yt <= y2; yt++)
- FrameBuffer_horizontalinterp(f,x1,x2,yt,(Pixel) ((mc1*(yt - ystart)) + c1),
- (Pixel) ((mc2*(yt-ystart))+c3));
-
-}
-
-/* ---------------------------------------------------------------------------
- FrameBuffer_line(FrameBuffer *f, int x1, int y1, int x2, int y2, color)
-
- Draws a line on the framebuffer using the Bresenham line algorithm. The
- line is clipped to fit within the current view window.
- ---------------------------------------------------------------------------- */
-
-void FrameBuffer_line(FrameBuffer *f, int x1, int y1, int x2, int y2, Pixel c) {
-
- int dx,dy,dxneg,dyneg, inc1,inc2,di;
- int x, y, xpixels, ypixels, xt, yt;
- Pixel *p;
- double m;
- int end1 = 0, end2 = 0;
-
- /* Need to figure out where in the heck this line is */
-
- dx = x2 - x1;
- dy = y2 - y1;
-
- if (dx == 0) {
- /* Draw a Vertical Line */
- if (y1 < y2)
- FrameBuffer_vertical(f,y1,y2,x1,c);
- else
- FrameBuffer_vertical(f,y2,y1,x1,c);
- return;
- }
- if (dy == 0) {
- /* Draw a Horizontal Line */
- if (x1 < x2)
- FrameBuffer_horizontal(f,x1,x2,y1,c);
- else
- FrameBuffer_horizontal(f,x2,x1,y1,c);
- return;
- }
-
- /* Figure out where in the heck these lines are using the
- Cohen-Sutherland Line Clipping Scheme. */
-
- end1 = ((x1 - f->xmin) < 0) |
- (((f->xmax- 1 - x1) < 0) << 1) |
- (((y1 - f->ymin) < 0) << 2) |
- (((f->ymax-1 - y1) < 0) << 3);
-
- end2 = ((x2 - f->xmin) < 0) |
- (((f->xmax-1 - x2) < 0) << 1) |
- (((y2 - f->ymin) < 0) << 2) |
- (((f->ymax-1 - y2) < 0) << 3);
-
- if (end1 & end2) return; /* Nope : Not visible */
-
- /* Make sure points have a favorable orientation */
-
- if (x1 > x2) {
- xt = x1;
- x1 = x2;
- x2 = xt;
- yt = y1;
- y1 = y2;
- y2 = yt;
- }
-
- /* Clip against the boundaries */
- m = (y2 - y1)/(double) (x2-x1);
- if (x1 < f->xmin) {
- y1 = (int) ((f->xmin - x1)*m + y1);
- x1 = (int) f->xmin;
- }
- if (x2 >= f->xmax) {
- y2 = (int) ((f->xmax -1 -x1)*m + y1);
- x2 = (int) (f->xmax - 1);
- }
-
- if (y1 > y2) {
- xt = x1;
- x1 = x2;
- x2 = xt;
- yt = y1;
- y1 = y2;
- y2 = yt;
- }
-
- m = 1/m;
- if (y1 < f->ymin) {
- x1 = (int) ((f->ymin - y1)*m + x1);
- y1 = (int) f->ymin;
- }
- if (y2 >= f->ymax) {
- x2 = (int) ((f->ymax-1-y1)*m + x1);
- y2 = (int) (f->ymax-1);
- }
-
- if ((x1 < f->xmin) || (x1 >= f->xmax) || (y1 < f->ymin) || (y1 >= f->ymax) ||
- (x2 < f->xmin) || (x2 >= f->xmax) || (y2 < f->ymin) || (y2 >= f->ymax)) return;
-
- dx = x2 - x1;
- dy = y2 - y1;
- xpixels = f->width;
- ypixels = f->height;
-
- dxneg = (dx < 0) ? 1 : 0;
- dyneg = (dy < 0) ? 1 : 0;
-
- dx = abs(dx);
- dy = abs(dy);
- if (dx >= dy) {
- /* Slope between -1 and 1. */
- if (dxneg) {
- x = x1;
- y = y1;
- x1 = x2;
- y1 = y2;
- x2 = x;
- y2 = y;
- dyneg = !dyneg;
- }
- inc1 = 2*dy;
- inc2 = 2*(dy-dx);
- di = 2*dy-dx;
-
- /* Draw a line using x as independent variable */
-
- p = &f->pixels[y1][x1];
- x = x1;
- while (x <= x2) {
- *(p++) = c;
- if (di < 0) {
- di = di + inc1;
- } else {
- if (dyneg) {
- p = p - xpixels;
- di = di + inc2;
- } else {
- p = p + xpixels;
- di = di + inc2;
- }
- }
- x++;
- }
- } else {
- /* Slope < -1 or > 1 */
- if (dyneg) {
- x = x1;
- y = y1;
- x1 = x2;
- y1 = y2;
- x2 = x;
- y2 = y;
- dxneg = !dxneg;
- }
- inc1 = 2*dx;
- inc2 = 2*(dx-dy);
- di = 2*dx-dy;
-
- /* Draw a line using y as independent variable */
-
- p = &f->pixels[y1][x1];
- y = y1;
- while (y <= y2) {
- *p = c;
- p = p + xpixels;
- if (di < 0) {
- di = di + inc1;
- } else {
- if (dxneg) {
- p = p - 1;
- di = di + inc2;
- } else {
- p = p + 1;
- di = di + inc2;
- }
- }
- y++;
- }
- }
-}
-
-
-/* -------------------------------------------------------------------------
- FrameBuffer_circle(FrameBuffer f, int xc, int yc, int radius, Pixel c)
-
- Create an outline circle
- ------------------------------------------------------------------------- */
-
-#define plot_circle(x,y,c) \
- if ((x >= xmin) && (x < xmax) && \
- (y >= ymin) && (y < ymax)) \
- pixels[y][x] = c;
-
-void FrameBuffer_circle(FrameBuffer *f, int xc, int yc, int radius, Pixel c) {
-
- int xpixels, ypixels, x, y, p;
- int xmin, ymin, xmax, ymax;
- Pixel **pixels;
-
- if (radius <= 0) return;
- xpixels = f->width;
- ypixels = f->height;
- pixels = f->pixels;
- xmin = f->xmin;
- ymin = f->ymin;
- xmax = f->xmax;
- ymax = f->ymax;
- x = 0;
- y = radius;
- p = 3-2*radius;
- while (x <= y) {
- plot_circle(xc+x,yc+y,c);
- plot_circle(xc-x,yc+y,c);
- plot_circle(xc+x,yc-y,c);
- plot_circle(xc-x,yc-y,c);
- plot_circle(xc+y,yc+x,c);
- plot_circle(xc-y,yc+x,c);
- plot_circle(xc+y,yc-x,c);
- plot_circle(xc-y,yc-x,c);
- if (p < 0) p = p + 4*x + 6;
- else {
- p = p + 4*(x-y) + 10;
- y = y -1;
- }
- x++;
- }
-}
-
-
-/* -------------------------------------------------------------------------
- FrameBuffer_solidcircle(FrameBuffer f, int xc, int yc, int radius, Pixel c)
-
- Create an filled circle
- ------------------------------------------------------------------------- */
-
-
-#define fill_circle(x,y,c) \
- x1 = xc - x; \
- x2 = xc + x; \
- FrameBuffer_horizontal(f,x1,x2,y,c);
-
-void FrameBuffer_solidcircle(FrameBuffer *f, int xc, int yc, int radius, Pixel c) {
-
- int xpixels, ypixels, x, y, p;
- int x1,x2;
- int xmin, ymin, xmax, ymax;
- Pixel **pixels;
-
- if (radius <= 0) return;
- xpixels = f->width;
- ypixels = f->height;
- pixels = f->pixels;
- xmin = f->xmin;
- ymin = f->ymin;
- xmax = f->xmax;
- ymax = f->ymax;
- x = 0;
- y = radius;
- p = 3-2*radius;
- while (x <= y) {
- fill_circle(x,yc+y,c);
- fill_circle(x,yc-y,c);
- fill_circle(y,yc+x,c);
- fill_circle(y,yc-x,c);
- if (p < 0) p = p + 4*x + 6;
- else {
- p = p + 4*(x-y) + 10;
- y = y -1;
- }
- x++;
- }
-}
-
-/* ------------------------------------------------------------------------
- void FrameBuffer_setclip(f,xmin,ymin,xmax,ymax)
-
- Set clipping region for plotting
- ------------------------------------------------------------------------ */
-
-void FrameBuffer_setclip(FrameBuffer *f, int xmin, int ymin, int xmax, int ymax) {
-
- if (xmin >= xmax) return;
- if (ymin >= ymax) return;
-
- if (xmin < 0) xmin = 0;
- if (ymin < 0) ymin = 0;
- if (xmax > (int) f->width) xmax = f->width;
- if (ymax > (int) f->height) ymax = f->height;
-
- f->xmin = xmin;
- f->ymin = ymin;
- f->xmax = xmax;
- f->ymax = ymax;
-}
-
-/* ------------------------------------------------------------------------
- void FrameBuffer_noclip(f)
-
- Disable clipping region
- ------------------------------------------------------------------------ */
-
-void FrameBuffer_noclip(FrameBuffer *f) {
- f->xmin = 0;
- f->ymin = 0;
- f->xmax = f->width;
- f->ymax = f->height;
-}
-
-
-/* ------------------------------------------------------------------------
- FrameBuffer_zresize(FrameBuffer *f, int width, int height)
-
- This function resizes the framebuffer's zbuffer. If none exist, it
- creates a new one.
- ------------------------------------------------------------------------ */
-
-void FrameBuffer_zresize(FrameBuffer *f, int width, int height) {
- int i;
-
- if (f->zbuffer) {
- free((char *)f->zbuffer[0]);
- free((char *)f->zbuffer);
- }
- f->zbuffer = (Zvalue **) malloc(height*sizeof(Zvalue *));
- f->zbuffer[0] = (Zvalue *) malloc(height*width*sizeof(Zvalue));
- for (i = 0; i < height; i++)
- f->zbuffer[i] = f->zbuffer[0]+i*width;
-}
-
-/* ------------------------------------------------------------------------
- FrameBuffer_zclear(FrameBuffer *f)
-
- Clears the z-buffer for a particular frame. Sets all of the z-values to
- ZMIN.
- ------------------------------------------------------------------------- */
-
-void FrameBuffer_zclear(FrameBuffer *f) {
- unsigned int i,j;
- if (f) {
- if (f->zbuffer) {
- for (i = 0; i < f->width; i++)
- for (j = 0; j < f->height; j++)
- f->zbuffer[j][i] = ZMIN;
- }
- }
-}
-
-
-
-/* -------------------------------------------------------------------------
- FrameBuffer_solidtriangle(FrameBuffer *f, int tx1, int ty2,
- int tx2, int ty2,
- int tx3, int ty3, Pixel color)
-
- This function draws a 2D filled triangle.
-
- General idea :
- 1. Transform the three points into screen coordinates
- 2. Order three points vertically on screen.
- 3. Check for degenerate cases (where 3 points are colinear).
- 4. Fill in the resulting triangle using horizontal lines.
- -------------------------------------------------------------------------- */
-
-void FrameBuffer_solidtriangle(FrameBuffer *f, int tx1, int ty1,
- int tx2, int ty2,
- int tx3, int ty3, Pixel color) {
- int tempx, tempy;
- double m1,m2,m3;
- int y;
- int ix1, ix2;
-
- /* Figure out which point has the greatest "y" value */
-
- if (ty2 > ty1) { /* Swap points 1 and 2 if 2 is higher */
- tempx = tx1;
- tempy = ty1;
- tx1 = tx2;
- ty1 = ty2;
- tx2 = tempx;
- ty2 = tempy;
- }
- if (ty3 > ty1) { /* Swap points 1 and 3 if 3 is higher */
- tempx = tx1;
- tempy = ty1;
- tx1 = tx3;
- ty1 = ty3;
- tx3 = tempx;
- ty3 = tempy;
- }
- if (ty3 > ty2) { /* Swap points 2 and 3 if 3 is higher */
- tempx = tx2;
- tempy = ty2;
- tx2 = tx3;
- ty2 = ty3;
- tx3 = tempx;
- ty3 = tempy;
- }
-
- /* Points are now order so that t_1 is the highest point, t_2 is the
- middle point, and t_3 is the lowest point */
-
- /* Check for degenerate cases here */
-
- if ((ty1 == ty2) && (ty2 == ty3)) {
-
- /* Points are aligned horizontally. Handle as a special case */
- /* Just draw three lines using the outline color */
-
- FrameBuffer_line(f,tx1,ty1,tx2,ty2,color);
- FrameBuffer_line(f,tx1,ty1,tx3,ty3,color);
- FrameBuffer_line(f,tx2,ty2,tx3,ty3,color);
-
- } else {
-
- if (ty2 < ty1) {
- /* First process line segments between (x1,y1)-(x2,y2)
- And between (x1,y1),(x3,y3) */
-
- m1 = (double) (tx2 - tx1)/(double) (ty2 - ty1);
- m2 = (double) (tx3 - tx1)/(double) (ty3 - ty1);
-
- y = ty1;
- while (y >= ty2) {
- /* Calculate x values from slope */
- ix1 = (int) (m1*(y-ty1)+0.5) + tx1;
- ix2 = (int) (m2*(y-ty1)+0.5) + tx1;
- if (ix1 > ix2)
- FrameBuffer_horizontal(f,ix2,ix1,y,color);
- else
- FrameBuffer_horizontal(f,ix1,ix2,y,color);
- y--;
- }
- }
- if (ty3 < ty2) {
- /* Draw lower half of the triangle */
- m2 = (double) (tx3 - tx1)/(double) (ty3 - ty1);
- m3 = (double) (tx3 - tx2)/(double)(ty3 - ty2);
- y = ty2;
- while (y >= ty3) {
- ix1 = (int) (m3*(y-ty2)+0.5)+tx2;
- ix2 = (int) (m2*(y-ty1)+0.5)+tx1;
- if (ix1 > ix2)
- FrameBuffer_horizontal(f,ix2,ix1,y,color);
- else
- FrameBuffer_horizontal(f,ix1,ix2,y,color);
- y--;
- }
- }
- }
-}
-
-/* -------------------------------------------------------------------------
- FrameBuffer_interptriangle(FrameBuffer *f,
- int tx1, int ty2, Pixel c1,
- int tx2, int ty2, Pixel c2,
- int tx3, int ty3, Pixel c3)
-
- This function draws a filled triangle with color
- interpolation.
-
- General idea :
- 1. Transform the three points into screen coordinates
- 2. Order three points vertically on screen.
- 3. Check for degenerate cases (where 3 points are colinear).
- 4. Fill in the resulting triangle using horizontal lines.
- 5. Colors are interpolated between end points
- -------------------------------------------------------------------------- */
-
-void FrameBuffer_interptriangle(FrameBuffer *f,
- int tx1, int ty1, Pixel c1,
- int tx2, int ty2, Pixel c2,
- int tx3, int ty3, Pixel c3) {
- int tempx, tempy;
- double m1,m2,m3;
- double mc1,mc2,mc3;
- Pixel ic1,ic2,tempc;
- int y;
- int ix1, ix2;
-
- /* Figure out which point has the greatest "y" value */
-
- if (ty2 > ty1) { /* Swap points 1 and 2 if 2 is higher */
- tempx = tx1;
- tempy = ty1;
- tempc = c1;
- tx1 = tx2;
- ty1 = ty2;
- c1 = c2;
- tx2 = tempx;
- ty2 = tempy;
- c2 = tempc;
- }
- if (ty3 > ty1) { /* Swap points 1 and 3 if 3 is higher */
- tempx = tx1;
- tempy = ty1;
- tempc = c1;
- tx1 = tx3;
- ty1 = ty3;
- c1 = c3;
- tx3 = tempx;
- ty3 = tempy;
- c3 = tempc;
- }
- if (ty3 > ty2) { /* Swap points 2 and 3 if 3 is higher */
- tempx = tx2;
- tempy = ty2;
- tempc = c2;
- tx2 = tx3;
- ty2 = ty3;
- c2 = c3;
- tx3 = tempx;
- ty3 = tempy;
- c3 = tempc;
- }
-
- /* Points are now order so that t_1 is the highest point, t_2 is the
- middle point, and t_3 is the lowest point */
-
- /* Check for degenerate cases here */
-
- if ((ty1 == ty2) && (ty2 == ty3)) {
-
- /* Points are aligned horizontally. Handle as a special case */
- /* Just draw three lines using the outline color */
-
- if (tx2 > tx1)
- FrameBuffer_horizontalinterp(f,tx1,tx2,ty1,c1,c2);
- else
- FrameBuffer_horizontalinterp(f,tx2,tx1,ty1,c2,c1);
- if (tx3 > tx1)
- FrameBuffer_horizontalinterp(f,tx1,tx3,ty1,c1,c3);
- else
- FrameBuffer_horizontalinterp(f,tx3,tx1,ty1,c3,c1);
- if (tx3 > tx2)
- FrameBuffer_horizontalinterp(f,tx2,tx3,ty2,c2,c3);
- else
- FrameBuffer_horizontalinterp(f,tx3,tx2,ty2,c3,c2);
-
- } else {
-
- /* First process line segments between (x1,y1)-(x2,y2)
- And between (x1,y1),(x3,y3) */
-
- if (ty2 < ty1) {
- m1 = (double) (tx2 - tx1)/(double) (ty2 - ty1);
- m2 = (double) (tx3 - tx1)/(double) (ty3 - ty1);
- mc1 = (c2 - c1)/(double) (ty2 - ty1);
- mc2 = (c3 - c1)/(double) (ty3 - ty1);
-
- y = ty1;
- while (y >= ty2) {
- /* Calculate x values from slope */
- ix1 = (int) (m1*(y-ty1)+0.5) + tx1;
- ix2 = (int) (m2*(y-ty1)+0.5) + tx1;
- ic1 = (int) (mc1*(y-ty1) + c1);
- ic2 = (int) (mc2*(y-ty1) + c1);
- if (ix1 > ix2)
- FrameBuffer_horizontalinterp(f,ix2,ix1,y,ic2,ic1);
- else
- FrameBuffer_horizontalinterp(f,ix1,ix2,y,ic1,ic2);
- y--;
- }
- }
- if (ty3 < ty2) {
- /* Draw lower half of the triangle */
- m2 = (double) (tx3 - tx1)/(double) (ty3 - ty1);
- mc2 = (c3 - c1)/(double) (ty3 - ty1);
- m3 = (double) (tx3 - tx2)/(double)(ty3 - ty2);
- mc3 = (c3 - c2)/(double) (ty3 - ty2);
- y = ty2;
- while (y >= ty3) {
- ix1 = (int) (m3*(y-ty2)+0.5)+tx2;
- ix2 = (int) (m2*(y-ty1)+0.5)+tx1;
- ic1 = (int) (mc3*(y-ty2)+c2);
- ic2 = (int) (mc2*(y-ty1)+c1);
- if (ix1 > ix2)
- FrameBuffer_horizontalinterp(f,ix2,ix1,y,ic2,ic1);
- else
- FrameBuffer_horizontalinterp(f,ix1,ix2,y,ic1,ic2);
- y--;
- }
- }
- }
-}
-
-
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