Campbell Barton
9e365069af
- Added space below non doc-string comments to make it clear these aren't comments for the symbols directly below them. - Use doxy sections for some headers. - Minor improvements to doc-strings. Ref T92709
494 lines
13 KiB
C
494 lines
13 KiB
C
/*
|
|
* 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) 2001-2002 by NaN Holding BV.
|
|
* All rights reserved.
|
|
*
|
|
* The Original Code is: some of this file.
|
|
*/
|
|
|
|
/** \file
|
|
* \ingroup bli
|
|
*
|
|
* Utility functions for primitive drawing operations.
|
|
*/
|
|
|
|
#include <limits.h>
|
|
|
|
#include "MEM_guardedalloc.h"
|
|
|
|
#include "BLI_bitmap_draw_2d.h"
|
|
|
|
#include "BLI_math_base.h"
|
|
#include "BLI_sort.h"
|
|
#include "BLI_utildefines.h"
|
|
|
|
#include "BLI_strict_flags.h"
|
|
|
|
/* -------------------------------------------------------------------- */
|
|
/** \name Draw Line
|
|
* \{ */
|
|
|
|
void BLI_bitmap_draw_2d_line_v2v2i(const int p1[2],
|
|
const int p2[2],
|
|
bool (*callback)(int, int, void *),
|
|
void *user_data)
|
|
{
|
|
/* Bresenham's line algorithm. */
|
|
int x1 = p1[0];
|
|
int y1 = p1[1];
|
|
int x2 = p2[0];
|
|
int y2 = p2[1];
|
|
|
|
if (callback(x1, y1, user_data) == 0) {
|
|
return;
|
|
}
|
|
|
|
/* if x1 == x2 or y1 == y2, then it does not matter what we set here */
|
|
const int sign_x = (x2 > x1) ? 1 : -1;
|
|
const int sign_y = (y2 > y1) ? 1 : -1;
|
|
|
|
const int delta_x = (sign_x == 1) ? (x2 - x1) : (x1 - x2);
|
|
const int delta_y = (sign_y == 1) ? (y2 - y1) : (y1 - y2);
|
|
|
|
const int delta_x_step = delta_x * 2;
|
|
const int delta_y_step = delta_y * 2;
|
|
|
|
if (delta_x >= delta_y) {
|
|
/* error may go below zero */
|
|
int error = delta_y_step - delta_x;
|
|
|
|
while (x1 != x2) {
|
|
if (error >= 0) {
|
|
if (error || (sign_x == 1)) {
|
|
y1 += sign_y;
|
|
error -= delta_x_step;
|
|
}
|
|
/* else do nothing */
|
|
}
|
|
/* else do nothing */
|
|
|
|
x1 += sign_x;
|
|
error += delta_y_step;
|
|
|
|
if (callback(x1, y1, user_data) == 0) {
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
else {
|
|
/* error may go below zero */
|
|
int error = delta_x_step - delta_y;
|
|
|
|
while (y1 != y2) {
|
|
if (error >= 0) {
|
|
if (error || (sign_y == 1)) {
|
|
x1 += sign_x;
|
|
error -= delta_y_step;
|
|
}
|
|
/* else do nothing */
|
|
}
|
|
/* else do nothing */
|
|
|
|
y1 += sign_y;
|
|
error += delta_x_step;
|
|
|
|
if (callback(x1, y1, user_data) == 0) {
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/** \} */
|
|
|
|
/* -------------------------------------------------------------------- */
|
|
/** \name Draw Filled Triangle
|
|
* \{ */
|
|
|
|
/**
|
|
* Fill a triangle
|
|
*
|
|
* Standard algorithm,
|
|
* See: http://www.sunshine2k.de/coding/java/TriangleRasterization/TriangleRasterization.html
|
|
*
|
|
* Changes to the basic implementation:
|
|
*
|
|
* - Reuse slope calculation when drawing the second triangle.
|
|
* - Don't calculate the 4th point at all for the triangle split.
|
|
* - Order line drawing from left to right (minor detail).
|
|
* - 1-pixel offsets are applied so adjacent triangles don't overlap.
|
|
*
|
|
* This is not clipped, a clipped version can be added if needed.
|
|
*/
|
|
|
|
/* Macros could be moved to a shared location. */
|
|
#define ORDERED_SWAP(ty, a, b) \
|
|
if (a > b) { \
|
|
SWAP(ty, a, b); \
|
|
} \
|
|
((void)0)
|
|
|
|
#define ORDERED_SWAP_BY(ty, a, b, by) \
|
|
if ((a by) > (b by)) { \
|
|
SWAP(ty, a, b); \
|
|
} \
|
|
((void)0)
|
|
|
|
#define ORDER_VARS2(ty, a, b) \
|
|
{ \
|
|
ORDERED_SWAP(ty, a, b); \
|
|
} \
|
|
((void)0)
|
|
|
|
#define ORDER_VARS3_BY(ty, a, b, c, by) \
|
|
{ \
|
|
ORDERED_SWAP_BY(ty, b, c, by); \
|
|
ORDERED_SWAP_BY(ty, a, c, by); \
|
|
ORDERED_SWAP_BY(ty, a, b, by); \
|
|
} \
|
|
((void)0)
|
|
|
|
static float inv_slope(const int a[2], const int b[2])
|
|
{
|
|
return ((float)(a[0] - b[0]) / (float)(a[1] - b[1]));
|
|
}
|
|
|
|
/**
|
|
* <pre>
|
|
* *---*
|
|
* \ /
|
|
* *
|
|
* </pre>
|
|
*/
|
|
static void draw_tri_flat_max(const int p[2],
|
|
const int max_y,
|
|
const float inv_slope1,
|
|
const float inv_slope2,
|
|
void (*callback)(int x, int x_end, int y, void *),
|
|
void *user_data)
|
|
{
|
|
float cur_x1 = (float)p[0];
|
|
float cur_x2 = cur_x1;
|
|
/* start-end inclusive */
|
|
const int min_y = p[1];
|
|
const int max_y_end = max_y + 1;
|
|
for (int scanline_y = min_y; scanline_y != max_y_end; scanline_y += 1) {
|
|
callback((int)cur_x1, 1 + (int)cur_x2, scanline_y, user_data);
|
|
cur_x1 += inv_slope1;
|
|
cur_x2 += inv_slope2;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* <pre>
|
|
* *
|
|
* / \
|
|
* *---*
|
|
* </pre>
|
|
*/
|
|
static void draw_tri_flat_min(const int p[2],
|
|
const int min_y,
|
|
const float inv_slope1,
|
|
const float inv_slope2,
|
|
void (*callback)(int x, int x_end, int y, void *),
|
|
void *user_data)
|
|
{
|
|
float cur_x1 = (float)p[0];
|
|
float cur_x2 = cur_x1;
|
|
/* start-end inclusive */
|
|
const int max_y = p[1];
|
|
const int min_y_end = min_y - 1;
|
|
for (int scanline_y = max_y; scanline_y != min_y_end; scanline_y -= 1) {
|
|
callback((int)cur_x1, 1 + (int)cur_x2, scanline_y, user_data);
|
|
cur_x1 -= inv_slope1;
|
|
cur_x2 -= inv_slope2;
|
|
}
|
|
}
|
|
|
|
void BLI_bitmap_draw_2d_tri_v2i(
|
|
/* all 2d */
|
|
const int p1[2],
|
|
const int p2[2],
|
|
const int p3[2],
|
|
void (*callback)(int x, int x_end, int y, void *),
|
|
void *user_data)
|
|
{
|
|
/* At first sort the three vertices by y-coordinate ascending so p1 is the top-most vertice */
|
|
ORDER_VARS3_BY(const int *, p1, p2, p3, [1]);
|
|
|
|
BLI_assert(p1[1] <= p2[1] && p2[1] <= p3[1]);
|
|
|
|
/* Check for trivial case of bottom-flat triangle. */
|
|
if (p2[1] == p3[1]) {
|
|
float inv_slope1 = inv_slope(p2, p1);
|
|
float inv_slope2 = inv_slope(p3, p1);
|
|
ORDER_VARS2(float, inv_slope1, inv_slope2);
|
|
BLI_assert(!(inv_slope1 > inv_slope2));
|
|
draw_tri_flat_max(p1, p2[1], inv_slope1, inv_slope2, callback, user_data);
|
|
}
|
|
else if (p1[1] == p2[1]) {
|
|
/* Check for trivial case of top-flat triangle. */
|
|
float inv_slope1 = inv_slope(p3, p1);
|
|
float inv_slope2 = inv_slope(p3, p2);
|
|
ORDER_VARS2(float, inv_slope2, inv_slope1);
|
|
BLI_assert(!(inv_slope1 < inv_slope2));
|
|
draw_tri_flat_min(p3,
|
|
p2[1] + 1, /* avoid overlap */
|
|
inv_slope1,
|
|
inv_slope2,
|
|
callback,
|
|
user_data);
|
|
}
|
|
else {
|
|
/* General case - split the triangle in a top-flat and bottom-flat one. */
|
|
const float inv_slope_p21 = inv_slope(p2, p1);
|
|
const float inv_slope_p31 = inv_slope(p3, p1);
|
|
const float inv_slope_p32 = inv_slope(p3, p2);
|
|
|
|
float inv_slope1_max, inv_slope2_max;
|
|
float inv_slope2_min, inv_slope1_min;
|
|
|
|
if (inv_slope_p21 < inv_slope_p31) {
|
|
inv_slope1_max = inv_slope_p21;
|
|
inv_slope2_max = inv_slope_p31;
|
|
inv_slope2_min = inv_slope_p31;
|
|
inv_slope1_min = inv_slope_p32;
|
|
}
|
|
else {
|
|
inv_slope1_max = inv_slope_p31;
|
|
inv_slope2_max = inv_slope_p21;
|
|
inv_slope2_min = inv_slope_p32;
|
|
inv_slope1_min = inv_slope_p31;
|
|
}
|
|
|
|
draw_tri_flat_max(p1, p2[1], inv_slope1_max, inv_slope2_max, callback, user_data);
|
|
draw_tri_flat_min(p3,
|
|
p2[1] + 1, /* avoid overlap */
|
|
inv_slope1_min,
|
|
inv_slope2_min,
|
|
callback,
|
|
user_data);
|
|
}
|
|
}
|
|
|
|
#undef ORDERED_SWAP
|
|
#undef ORDERED_SWAP_BY
|
|
#undef ORDER_VARS2
|
|
#undef ORDER_VARS3_BY
|
|
|
|
/** \} */
|
|
|
|
/* -------------------------------------------------------------------- */
|
|
/** \name Draw Filled Polygon
|
|
* \{ */
|
|
|
|
/* sort edge-segments on y, then x axis */
|
|
static int draw_poly_v2i_n__span_y_sort(const void *a_p, const void *b_p, void *verts_p)
|
|
{
|
|
const int(*verts)[2] = verts_p;
|
|
const int *a = a_p;
|
|
const int *b = b_p;
|
|
const int *co_a = verts[a[0]];
|
|
const int *co_b = verts[b[0]];
|
|
|
|
if (co_a[1] < co_b[1]) {
|
|
return -1;
|
|
}
|
|
if (co_a[1] > co_b[1]) {
|
|
return 1;
|
|
}
|
|
if (co_a[0] < co_b[0]) {
|
|
return -1;
|
|
}
|
|
if (co_a[0] > co_b[0]) {
|
|
return 1;
|
|
}
|
|
/* co_a & co_b are identical, use the line closest to the x-min */
|
|
const int *co = co_a;
|
|
co_a = verts[a[1]];
|
|
co_b = verts[b[1]];
|
|
int ord = (((co_b[0] - co[0]) * (co_a[1] - co[1])) - ((co_a[0] - co[0]) * (co_b[1] - co[1])));
|
|
if (ord > 0) {
|
|
return -1;
|
|
}
|
|
if (ord < 0) {
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
void BLI_bitmap_draw_2d_poly_v2i_n(const int xmin,
|
|
const int ymin,
|
|
const int xmax,
|
|
const int ymax,
|
|
const int verts[][2],
|
|
const int verts_len,
|
|
void (*callback)(int x, int x_end, int y, void *),
|
|
void *user_data)
|
|
{
|
|
/* Originally by Darel Rex Finley, 2007.
|
|
* Optimized by Campbell Barton, 2016 to track sorted intersections. */
|
|
|
|
int(*span_y)[2] = MEM_mallocN(sizeof(*span_y) * (size_t)verts_len, __func__);
|
|
int span_y_len = 0;
|
|
|
|
for (int i_curr = 0, i_prev = verts_len - 1; i_curr < verts_len; i_prev = i_curr++) {
|
|
const int *co_prev = verts[i_prev];
|
|
const int *co_curr = verts[i_curr];
|
|
|
|
if (co_prev[1] != co_curr[1]) {
|
|
/* Any segments entirely above or below the area of interest can be skipped. */
|
|
if ((min_ii(co_prev[1], co_curr[1]) >= ymax) || (max_ii(co_prev[1], co_curr[1]) < ymin)) {
|
|
continue;
|
|
}
|
|
|
|
int *s = span_y[span_y_len++];
|
|
if (co_prev[1] < co_curr[1]) {
|
|
s[0] = i_prev;
|
|
s[1] = i_curr;
|
|
}
|
|
else {
|
|
s[0] = i_curr;
|
|
s[1] = i_prev;
|
|
}
|
|
}
|
|
}
|
|
|
|
BLI_qsort_r(
|
|
span_y, (size_t)span_y_len, sizeof(*span_y), draw_poly_v2i_n__span_y_sort, (void *)verts);
|
|
|
|
struct NodeX {
|
|
int span_y_index;
|
|
int x;
|
|
} *node_x = MEM_mallocN(sizeof(*node_x) * (size_t)(verts_len + 1), __func__);
|
|
int node_x_len = 0;
|
|
|
|
int span_y_index = 0;
|
|
if (span_y_len != 0 && verts[span_y[0][0]][1] < ymin) {
|
|
while ((span_y_index < span_y_len) && (verts[span_y[span_y_index][0]][1] < ymin)) {
|
|
BLI_assert(verts[span_y[span_y_index][0]][1] < verts[span_y[span_y_index][1]][1]);
|
|
if (verts[span_y[span_y_index][1]][1] >= ymin) {
|
|
struct NodeX *n = &node_x[node_x_len++];
|
|
n->span_y_index = span_y_index;
|
|
}
|
|
span_y_index += 1;
|
|
}
|
|
}
|
|
|
|
/* Loop through the rows of the image. */
|
|
for (int pixel_y = ymin; pixel_y < ymax; pixel_y++) {
|
|
bool is_sorted = true;
|
|
bool do_remove = false;
|
|
|
|
for (int i = 0, x_ix_prev = INT_MIN; i < node_x_len; i++) {
|
|
struct NodeX *n = &node_x[i];
|
|
const int *s = span_y[n->span_y_index];
|
|
const int *co_prev = verts[s[0]];
|
|
const int *co_curr = verts[s[1]];
|
|
|
|
BLI_assert(co_prev[1] < pixel_y && co_curr[1] >= pixel_y);
|
|
|
|
const double x = (co_prev[0] - co_curr[0]);
|
|
const double y = (co_prev[1] - co_curr[1]);
|
|
const double y_px = (pixel_y - co_curr[1]);
|
|
const int x_ix = (int)((double)co_curr[0] + ((y_px / y) * x));
|
|
n->x = x_ix;
|
|
|
|
if (is_sorted && (x_ix_prev > x_ix)) {
|
|
is_sorted = false;
|
|
}
|
|
if (do_remove == false && co_curr[1] == pixel_y) {
|
|
do_remove = true;
|
|
}
|
|
x_ix_prev = x_ix;
|
|
}
|
|
|
|
/* Sort the nodes, via a simple "Bubble" sort. */
|
|
if (is_sorted == false) {
|
|
int i = 0;
|
|
const int node_x_end = node_x_len - 1;
|
|
while (i < node_x_end) {
|
|
if (node_x[i].x > node_x[i + 1].x) {
|
|
SWAP(struct NodeX, node_x[i], node_x[i + 1]);
|
|
if (i != 0) {
|
|
i -= 1;
|
|
}
|
|
}
|
|
else {
|
|
i += 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Fill the pixels between node pairs. */
|
|
for (int i = 0; i < node_x_len; i += 2) {
|
|
int x_src = node_x[i].x;
|
|
int x_dst = node_x[i + 1].x;
|
|
|
|
if (x_src >= xmax) {
|
|
break;
|
|
}
|
|
|
|
if (x_dst > xmin) {
|
|
if (x_src < xmin) {
|
|
x_src = xmin;
|
|
}
|
|
if (x_dst > xmax) {
|
|
x_dst = xmax;
|
|
}
|
|
/* for single call per x-span */
|
|
if (x_src < x_dst) {
|
|
callback(x_src - xmin, x_dst - xmin, pixel_y - ymin, user_data);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Clear finalized nodes in one pass, only when needed
|
|
* (avoids excessive array-resizing). */
|
|
if (do_remove == true) {
|
|
int i_dst = 0;
|
|
for (int i_src = 0; i_src < node_x_len; i_src += 1) {
|
|
const int *s = span_y[node_x[i_src].span_y_index];
|
|
const int *co = verts[s[1]];
|
|
if (co[1] != pixel_y) {
|
|
if (i_dst != i_src) {
|
|
/* x is initialized for the next pixel_y (no need to adjust here) */
|
|
node_x[i_dst].span_y_index = node_x[i_src].span_y_index;
|
|
}
|
|
i_dst += 1;
|
|
}
|
|
}
|
|
node_x_len = i_dst;
|
|
}
|
|
|
|
/* Scan for new x-nodes */
|
|
while ((span_y_index < span_y_len) && (verts[span_y[span_y_index][0]][1] == pixel_y)) {
|
|
/* NOTE: node_x these are just added at the end,
|
|
* not ideal but sorting once will resolve. */
|
|
|
|
/* x is initialized for the next pixel_y */
|
|
struct NodeX *n = &node_x[node_x_len++];
|
|
n->span_y_index = span_y_index;
|
|
span_y_index += 1;
|
|
}
|
|
}
|
|
|
|
MEM_freeN(span_y);
|
|
MEM_freeN(node_x);
|
|
}
|
|
|
|
/** \} */
|