+ cp->posc[0] = tan(Pi/12); /* 0.268 */
+ cp->posc[1] = 1.0/cos(Pi/12); /* 1.035 */
+ cp->posc[2] = cos(Pi/6)/cos(Pi/12); /* 0.897 */
+ cp->posc[3] = sin(Pi/6)/cos(Pi/12); /* 0.518 */
+ cp->posc[4] = sqrt(2)*cos(Pi/6); /* 1.225 */
+ cp->posc[5] = sqrt(2)*sin(Pi/6); /* 0.707 = 1/sqrt(2) */
+}
+
+static void draw_horz_line(cube21_conf *cp, int x1, int x2, int y)
+{
+ int x, y0 = y, w;
+ if(y<BORDER) y = -y;
+ else y = -BORDER;
+ for(; y<BORDER; y++) {
+ if(y0+y>=TEX_HEIGHT) break;
+ w = y*y*255/BORDER2;
+ for(x=x1; x<=x2; x++)
+ if(cp->texture[y0+y][x]>w) cp->texture[y0+y][x] = w;
+ }
+}
+
+static void draw_vert_line(cube21_conf *cp, int x, int y1, int y2)
+{
+ int x0 = x, y, w;
+ if(x<BORDER) x = -x;
+ else x = -BORDER;
+ for(; x<BORDER; x++) {
+ if(x0+x>=TEX_WIDTH) break;
+ w = x*x*255/BORDER2;
+ for(y=y1; y<=y2; y++)
+ if(cp->texture[y][x0+x]>w) cp->texture[y][x0+x] = w;
+ }
+}
+
+static void draw_slanted_horz(cube21_conf *cp, int x1, int y1, int x2, int y2)
+{
+ int x, y, dx = x2-x1, dy = y2-y1, y0, w;
+ for(x=x1; x<=x2; x++) {
+ y0 = y1+(y2-y1)*(x-x1)/(x2-x1);
+ for(y=-1-BORDER; y<2+BORDER; y++) {
+ w = dx*(y0+y-y1)-dy*(x-x1);
+ w = w*w/(dx*dx+dy*dy);
+ w = w*255/BORDER2;
+ if(cp->texture[y0+y][x]>w) cp->texture[y0+y][x] = w;
+ }
+ }
+}
+
+static void draw_slanted_vert(cube21_conf *cp, int x1, int y1, int x2, int y2)
+{
+ int x, y, dx = x2-x1, dy = y2-y1, x0, w;
+ for(y=y1; y<=y2; y++) {
+ x0 = x1+(x2-x1)*(y-y1)/(y2-y1);
+ for(x=-1-BORDER; x<2+BORDER; x++) {
+ w = dy*(x0+x-x1)-dx*(y-y1);
+ w = w*w/(dy*dy+dx*dx);
+ w = w*255/BORDER2;
+ if(cp->texture[y][x0+x]>w) cp->texture[y][x0+x] = w;
+ }
+ }
+}
+
+static void make_texture(cube21_conf *cp)
+{
+ int x, y, x0, y0;
+ float grayp[2] = {TEX_GRAY};
+ for(y=0; y<TEX_HEIGHT; y++)
+ for(x=0; x<TEX_WIDTH; x++)
+ cp->texture[y][x] = 255;
+ draw_horz_line(cp, 0, TEX_WIDTH-1, 0);
+ draw_horz_line(cp, cp->texq*TEX_WIDTH, TEX_WIDTH-1, cp->texp*TEX_HEIGHT);
+ draw_horz_line(cp, cp->texq*TEX_WIDTH, TEX_WIDTH-1, cp->texq*TEX_HEIGHT);
+ draw_horz_line(cp, 0, cp->texq*TEX_WIDTH, TEX_HEIGHT/2);
+ draw_horz_line(cp, 0, TEX_WIDTH-1, TEX_HEIGHT*3/4);
+ draw_horz_line(cp, 0, TEX_WIDTH-1, TEX_HEIGHT-1);
+ draw_vert_line(cp, 0, 0, TEX_HEIGHT-1);
+ draw_vert_line(cp, cp->texq*TEX_WIDTH, 0, TEX_HEIGHT*3/4);
+ draw_vert_line(cp, TEX_WIDTH-1, 0, TEX_HEIGHT-1);
+ draw_slanted_horz(cp, 0, cp->texp*TEX_HEIGHT, TEX_WIDTH/2, TEX_HEIGHT/2);
+ draw_slanted_vert(cp, cp->texp*TEX_WIDTH, 0, TEX_WIDTH/2, TEX_HEIGHT/2);
+ draw_slanted_vert(cp, cp->texq*TEX_WIDTH, 0, TEX_WIDTH/2, TEX_HEIGHT/2);
+ x0 = grayp[0]*TEX_WIDTH;
+ y0 = grayp[1]*TEX_HEIGHT;
+ for(y=-1; y<=1; y++)
+ for(x=-1; x<=1; x++)
+ cp->texture[y0+y][x0+x] = 100;