gimp/app/asupsample.c

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1997-11-25 06:05:25 +08:00
/* The GIMP -- an image manipulation program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* General, non-jittered adaptive supersampling library
* Copyright (C) 1997 Federico Mena Quintero
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
*/
/* This code is *largely* based on the sources for POV-Ray 3.0. I am
* grateful to the POV-Team for such a great program and for making
* their sources available. All comments / bug reports /
* etc. regarding this library should be addressed to me, not to the
* POV-Ray team. Any bugs are my responsibility, not theirs.
*/
#include <math.h>
#include "appenv.h"
#include "asupsample.h"
/***** Types *****/
typedef struct {
char ready;
color_t color;
} sample_t;
/***** Local functions *****/
static unsigned long render_sub_pixel(int max_depth, int depth, sample_t **block,
int x, int y, int x1, int y1, int x3, int y3,
double threshold, int sub_pixel_size, render_func_t render_func,
color_t *color, void *render_data);
static double color_dist(color_t c1, color_t c2);
/***** Functions *****/
/*****/
unsigned long
adaptive_supersample_area(int x1, int y1, int x2, int y2, int max_depth, double threshold,
render_func_t render_func, void *render_data,
put_pixel_func_t put_pixel_func, void *put_pixel_data,
progress_func_t progress_func, void *progress_data)
{
int x, y, width; /* Counters, width of region */
int xt, xtt, yt; /* Temporary counters */
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int sub_pixel_size; /* Numbe of samples per pixel (1D) */
size_t row_size; /* Memory needed for one row */
color_t color; /* Rendered pixel's color */
sample_t tmp_sample; /* For swapping samples */
sample_t *top_row, *bot_row, *tmp_row; /* Sample rows */
sample_t **block; /* Sample block matrix */
unsigned long num_samples;
/* Initialize color */
color.r = 0.0;
color.g = 0.0;
color.b = 0.0;
color.a = 0.0;
/* Calculate sub-pixel size */
sub_pixel_size = 1 << max_depth; /* 2**max_depth */
/* Create row arrays */
width = x2 - x1 + 1;
row_size = (sub_pixel_size * width + 1) * sizeof(sample_t);
top_row = g_malloc(row_size);
bot_row = g_malloc(row_size);
for (x = 0; x < (sub_pixel_size * width + 1); x++) {
top_row[x].ready = 0;
top_row[x].color.r = 0.0;
top_row[x].color.g = 0.0;
top_row[x].color.b = 0.0;
top_row[x].color.a = 0.0;
bot_row[x].ready = 0;
bot_row[x].color.r = 0.0;
bot_row[x].color.g = 0.0;
bot_row[x].color.b = 0.0;
bot_row[x].color.a = 0.0;
} /* for */
/* Allocate block matrix */
block = g_malloc((sub_pixel_size + 1) * sizeof(sample_t *)); /* Rows */
for (y = 0; y < (sub_pixel_size + 1); y++) {
block[y] = g_malloc((sub_pixel_size + 1) * sizeof(sample_t)); /* Columns */
for (x = 0; x < (sub_pixel_size + 1); x++) {
block[y][x].ready = 0;
block[y][x].color.r = 0;
block[y][x].color.g = 0;
block[y][x].color.b = 0;
block[y][x].color.a = 0;
}
}
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/* Render region */
num_samples = 0;
for (y = y1; y <= y2; y++) {
/* Clear the bottom row */
for (xt = 0; xt < (sub_pixel_size * width + 1); xt++)
bot_row[xt].ready = 0;
/* Clear first column */
for (yt = 0; yt < (sub_pixel_size + 1); yt++)
block[yt][0].ready = 0;
/* Render row */
for (x = x1; x <= x2; x++) {
/* Initialize block by clearing all but first row/column */
for (yt = 1; yt < (sub_pixel_size + 1); yt++)
for (xt = 1; xt < (sub_pixel_size + 1); xt++)
block[yt][xt].ready = 0;
/* Copy samples from top row to block */
for (xtt = 0, xt = (x - x1) * sub_pixel_size;
xtt < (sub_pixel_size + 1);
xtt++, xt++)
block[0][xtt] = top_row[xt];
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/* Render pixel on (x, y) */
num_samples += render_sub_pixel(max_depth, 1, block, x, y, 0, 0,
sub_pixel_size, sub_pixel_size,
threshold, sub_pixel_size, render_func, &color,
render_data);
if (put_pixel_func)
(*put_pixel_func)(x, y, color, put_pixel_data);
/* Copy block information to rows */
top_row[((x - x1) + 1) * sub_pixel_size] = block[0][sub_pixel_size];
for (xtt = 0, xt = (x - x1) * sub_pixel_size;
xtt < (sub_pixel_size + 1);
xtt++, xt++)
bot_row[xt] = block[sub_pixel_size][xtt];
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/* Swap first and last columns */
for (yt = 0; yt < (sub_pixel_size + 1); yt++) {
tmp_sample = block[yt][0];
block[yt][0] = block[yt][sub_pixel_size];
block[yt][sub_pixel_size] = tmp_sample;
} /* for */
} /* for */
/* Swap rows */
tmp_row = top_row;
top_row = bot_row;
bot_row = tmp_row;
/* Call progress display function */
if (progress_func)
(*progress_func)(y1, y2, y, progress_data);
} /* for */
/* Free memory */
for (y = 0; y < (sub_pixel_size + 1); y++)
g_free(block[y]);
g_free(block);
g_free(top_row);
g_free(bot_row);
return num_samples;
} /* adaptive_supersample_area */
/*****/
static unsigned long
render_sub_pixel(int max_depth, int depth, sample_t **block,
int x, int y, int x1, int y1, int x3, int y3,
double threshold, int sub_pixel_size, render_func_t render_func,
color_t *color, void *render_data)
{
int x2, y2; /* Coords of center sample */
double dx1, dy1; /* Delta to upper left sample */
double dx3, dy3; /* Delta to lower right sample */
color_t c1, c2, c3, c4; /* Sample colors */
unsigned long num_samples;
/* Get offsets for corners */
dx1 = (double) (x1 - sub_pixel_size / 2) / sub_pixel_size;
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dx3 = (double) (x3 - sub_pixel_size / 2) / sub_pixel_size;
dy1 = (double) (y1 - sub_pixel_size / 2) / sub_pixel_size;
dy3 = (double) (y3 - sub_pixel_size / 2) / sub_pixel_size;
num_samples = 0;
/* Render upper left sample */
if (!block[y1][x1].ready) {
num_samples++;
(*render_func)(x + dx1, y + dy1, &c1, render_data);
block[y1][x1].ready = 1;
block[y1][x1].color = c1;
} else
c1 = block[y1][x1].color;
/* Render upper right sample */
if (!block[y1][x3].ready) {
num_samples++;
(*render_func)(x + dx3, y + dy1, &c2, render_data);
block[y1][x3].ready = 1;
block[y1][x3].color = c2;
} else
c2 = block[y1][x3].color;
/* Render lower left sample */
if (!block[y3][x1].ready) {
num_samples++;
(*render_func)(x + dx1, y + dy3, &c3, render_data);
block[y3][x1].ready = 1;
block[y3][x1].color = c3;
} else
c3 = block[y3][x1].color;
/* Render lower right sample */
if (!block[y3][x3].ready) {
num_samples++;
(*render_func)(x + dx3, y + dy3, &c4, render_data);
block[y3][x3].ready = 1;
block[y3][x3].color = c4;
} else
c4 = block[y3][x3].color;
/* Check for supersampling */
if (depth <= max_depth) {
/* Check whether we have tu supersample */
if ((color_dist(c1, c2) >= threshold) ||
(color_dist(c1, c3) >= threshold) ||
(color_dist(c1, c4) >= threshold) ||
(color_dist(c2, c3) >= threshold) ||
(color_dist(c2, c4) >= threshold) ||
(color_dist(c3, c4) >= threshold)) {
/* Calc coordinates of center subsample */
x2 = (x1 + x3) / 2;
y2 = (y1 + y3) / 2;
/* Render sub-blocks */
num_samples += render_sub_pixel(max_depth, depth + 1, block, x, y, x1, y1, x2, y2,
threshold, sub_pixel_size, render_func, &c1,
render_data);
num_samples += render_sub_pixel(max_depth, depth + 1, block, x, y, x2, y1, x3, y2,
threshold, sub_pixel_size, render_func, &c2,
render_data);
num_samples += render_sub_pixel(max_depth, depth + 1, block, x, y, x1, y2, x2, y3,
threshold, sub_pixel_size, render_func, &c3,
render_data);
num_samples += render_sub_pixel(max_depth, depth + 1, block, x, y, x2, y2, x3, y3,
threshold, sub_pixel_size, render_func, &c4,
render_data);
} /* if */
} /* if */
color->r = 0.25 * (c1.r + c2.r + c3.r + c4.r);
color->g = 0.25 * (c1.g + c2.g + c3.g + c4.g);
color->b = 0.25 * (c1.b + c2.b + c3.b + c4.b);
color->a = 0.25 * (c1.a + c2.a + c3.a + c4.a);
return num_samples;
} /* render_sub_pixel */
/*****/
static double
color_dist(color_t c1, color_t c2)
{
return fabs(c1.r - c2.r) +
fabs(c1.g - c2.g) +
fabs(c1.b - c2.b) +
fabs(c1.a - c2.a);
} /* color_dist */