2-point perspective via angles
Rather than using straight horizontal & vertical, it now snaps to lines with the same slope as the two vanishing points (the horizon chosen by the user), and lines perpendicular to that. Note - Still need guides during drag. Also, there's a bug when calculating slope that causes the line to go way off in the opposite direction, which needs addressing.
This commit is contained in:
Bill Kendrick
parent
e9db3d2393
commit
05b76c8b5f
1 changed files with 82 additions and 43 deletions
|
|
@ -17,6 +17,8 @@
|
|||
#include "SDL_image.h"
|
||||
#include "SDL_mixer.h"
|
||||
|
||||
#define SNAP 10
|
||||
|
||||
|
||||
enum
|
||||
{
|
||||
|
|
@ -79,7 +81,7 @@ int a1_pt_x, a1_pt_y;
|
|||
int a2_pt_x[2], a2_pt_y[2], a2_pt_cur;
|
||||
int a3_pt_x[3], a3_pt_y[3], a3_pt_cur;
|
||||
int line_start_x, line_start_y;
|
||||
|
||||
float a2_valid_angle[8];
|
||||
|
||||
/* Function prototypes: */
|
||||
Uint32 n_pt_persp_api_version(void);
|
||||
|
|
@ -276,6 +278,17 @@ void n_pt_persp_click(magic_api * api, int which, int mode ATTRIBUTE_UNUSED,
|
|||
/* Set next position of 2-point perspective */
|
||||
a2_pt_x[a2_pt_cur] = x;
|
||||
a2_pt_y[a2_pt_cur] = y;
|
||||
|
||||
if (abs(a2_pt_x[0] - a2_pt_x[1]) < SNAP) {
|
||||
if (a2_pt_x[0] <= a2_pt_x[1]) {
|
||||
a2_pt_x[0] -= (SNAP / 2);
|
||||
a2_pt_x[1] += (SNAP / 2);
|
||||
} else {
|
||||
a2_pt_x[0] += (SNAP / 2);
|
||||
a2_pt_x[1] -= (SNAP / 2);
|
||||
}
|
||||
}
|
||||
|
||||
a2_pt_cur = (a2_pt_cur + 1) % 2;
|
||||
} else if (which == TOOL_3PT_SELECT) {
|
||||
/* Set next position of 3-point perspective */
|
||||
|
|
@ -286,6 +299,34 @@ void n_pt_persp_click(magic_api * api, int which, int mode ATTRIBUTE_UNUSED,
|
|||
/* Start drawing a line */
|
||||
SDL_BlitSurface(canvas, NULL, n_pt_persp_snapshot, NULL);
|
||||
|
||||
if (which == TOOL_2PT_DRAW) {
|
||||
int i;
|
||||
|
||||
/* Horizon between vanishing points, and perpendicular (rise above/below) */
|
||||
a2_valid_angle[0] = atan2(a2_pt_y[1] - a2_pt_y[0], a2_pt_x[1] - a2_pt_x[0]);
|
||||
a2_valid_angle[1] = a2_valid_angle[0] + M_PI;
|
||||
a2_valid_angle[2] = a2_valid_angle[0] + (M_PI / 2.0);
|
||||
a2_valid_angle[3] = a2_valid_angle[0] + (M_PI / 2.0) + M_PI;
|
||||
|
||||
/* Angles that point toward the two vanishing points */
|
||||
if (x == a2_pt_x[0]) {
|
||||
x++;
|
||||
}
|
||||
if (x == a2_pt_x[1]) {
|
||||
x++;
|
||||
}
|
||||
a2_valid_angle[4] = atan2(a2_pt_y[0] - y, a2_pt_x[0] - x);
|
||||
a2_valid_angle[5] = a2_valid_angle[4] + M_PI;
|
||||
a2_valid_angle[6] = atan2(a2_pt_y[1] - y, a2_pt_x[1] - x);
|
||||
a2_valid_angle[7] = a2_valid_angle[6] + M_PI;
|
||||
|
||||
for (i = 0; i < 8; i++) {
|
||||
if (a2_valid_angle[i] > M_PI) {
|
||||
a2_valid_angle[i] -= (M_PI * 2);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
line_start_x = x;
|
||||
line_start_y = y;
|
||||
n_pt_persp_drag(api, which, canvas, snapshot, x, y, x, y, update_rect);
|
||||
|
|
@ -342,8 +383,6 @@ void n_pt_persp_drag(magic_api * api, int which,
|
|||
}
|
||||
}
|
||||
|
||||
#define SNAP 10
|
||||
|
||||
void n_pt_persp_work(magic_api * api, int which,
|
||||
SDL_Surface * canvas, int x, int y,
|
||||
SDL_Rect * update_rect, int xor)
|
||||
|
|
@ -400,54 +439,54 @@ void n_pt_persp_work(magic_api * api, int which,
|
|||
}
|
||||
} else if (which == TOOL_2PT_DRAW) {
|
||||
/* 2-point perspective */
|
||||
int i, best_angle_idx;
|
||||
float cursor_angle, diff, best_diff;
|
||||
|
||||
/* Find the valid angle that the drawn angle fits best to */
|
||||
cursor_angle = atan2f(y - line_start_y, x - line_start_x);
|
||||
|
||||
best_angle_idx = -1;
|
||||
best_diff = M_PI * 2;
|
||||
|
||||
for (i = 0; i < 8; i++) {
|
||||
diff = fabs(cursor_angle - a2_valid_angle[i]);
|
||||
|
||||
if (diff < best_diff) {
|
||||
best_angle_idx = i;
|
||||
best_diff = diff;
|
||||
}
|
||||
}
|
||||
|
||||
if (best_angle_idx == -1) {
|
||||
printf("???\n");
|
||||
return;
|
||||
}
|
||||
|
||||
/* Calculate a line segment, so we can determine the slope */
|
||||
x1 = line_start_x;
|
||||
y1 = line_start_y;
|
||||
x2 = line_start_x + cos(a2_valid_angle[best_angle_idx]) * 1000;
|
||||
y2 = line_start_y + sin(a2_valid_angle[best_angle_idx]) * 1000;
|
||||
|
||||
if (abs(line_start_x - x) <= SNAP) {
|
||||
/* Vertical */
|
||||
x2 = x1;
|
||||
y2 = y;
|
||||
} else if (abs(line_start_y - y) <= SNAP) {
|
||||
/* Horizontal */
|
||||
// printf("angle #%d (%d)\n", best_angle_idx, (int) (a2_valid_angle[best_angle_idx] * 180.0 / M_PI));
|
||||
|
||||
if (x2 != x1) {
|
||||
slope = ((float) y2 - (float) y1) / ((float) x2 - (float) x1);
|
||||
x2 = x;
|
||||
y2 = y1;
|
||||
} else {
|
||||
int ok, i;
|
||||
y2 = line_start_y + (slope * (x - line_start_x));
|
||||
|
||||
/* Diagonal */
|
||||
|
||||
ok = 0;
|
||||
|
||||
for (i = 0; i < 2 && ok == 0; i++) {
|
||||
slope = ((float) y1 - (float) a2_pt_y[i]) / ((float) x1 - (float) a2_pt_x[i]);
|
||||
x2 = x;
|
||||
y2 = line_start_y + (slope * (x - line_start_x));
|
||||
|
||||
/* Don't go past our cursor's Y */
|
||||
if ((y < line_start_y && y2 < y) ||
|
||||
(y > line_start_y && y2 > y)) {
|
||||
if (slope != 0.0) {
|
||||
y2 = y;
|
||||
x2 = ((y - line_start_y) / slope) + line_start_x;
|
||||
}
|
||||
}
|
||||
|
||||
/* Wrong side? Use the point 2 */
|
||||
slope2 = ((float) line_start_y - (float) y) / ((float) line_start_x - (float) x);
|
||||
if ((slope2 > 0.00 && slope < 0.00) ||
|
||||
(slope2 < 0.00 && slope > 0.00)) {
|
||||
ok = 0;
|
||||
|
||||
if (i == 1) {
|
||||
/* Worst case, snap to horizontal */
|
||||
x2 = x;
|
||||
y2 = y1;
|
||||
}
|
||||
} else {
|
||||
ok = 1;
|
||||
/* Don't go past our cursor's Y */
|
||||
if ((y < line_start_y && y2 < y) ||
|
||||
(y > line_start_y && y2 > y)) {
|
||||
if (slope != 0.0) {
|
||||
y2 = y;
|
||||
x2 = ((y - line_start_y) / slope) + line_start_x;
|
||||
}
|
||||
}
|
||||
/* FIXME: Sometimes the line goes off in the wrong direction! */
|
||||
} else {
|
||||
x2 = x;
|
||||
y2 = y;
|
||||
}
|
||||
} else if (which == TOOL_3PT_DRAW) {
|
||||
/* 3-point perspective */
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue