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/*************************************************************************
* Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of The Dimension Library. *
* *
* The Dimension Library is free software; you can redistribute it and/ *
* or modify it under the terms of the GNU Lesser General Public License *
* as published by the Free Software Foundation; either version 3 of the *
* License, or (at your option) any later version. *
* *
* The Dimension Library 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 *
* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
#include "dimension.h"
#include <GL/gl.h>
/* Write canvas to GL framebuffer. Returns 0 on success, nonzero on failure */
int
dmnsn_gl_write_canvas(const dmnsn_canvas *canvas)
{
GLuint *pixels; /* Array of 32-bit ints in RGBA order */
GLuint *pixel;
dmnsn_sRGB sRGB;
dmnsn_color color;
unsigned int x, y, width, height;
width = canvas->x;
height = canvas->y;
pixels = malloc(4*width*height*sizeof(GLuint));
if (!pixels) {
return 1;
}
for (y = 0; y < height; ++y) {
for (x = 0; x < width; ++x) {
pixel = pixels + 4*(y*width + x);
color = dmnsn_get_pixel(canvas, x, y);
sRGB = dmnsn_sRGB_from_color(color);
/* Saturate R, G, and B to [0, UINT32_MAX] */
if (sRGB.R <= 0.0) {
pixel[0] = 0;
} else if (sRGB.R >= 1.0) {
pixel[0] = UINT32_MAX;
} else {
pixel[0] = sRGB.R*UINT32_MAX;
}
if (sRGB.G <= 0.0) {
pixel[1] = 0;
} else if (sRGB.G >= 1.0) {
pixel[1] = UINT32_MAX;
} else {
pixel[1] = sRGB.G*UINT32_MAX;
}
if (sRGB.B <= 0.0) {
pixel[2] = 0;
} else if (sRGB.B >= 1.0) {
pixel[2] = UINT32_MAX;
} else {
pixel[2] = sRGB.B*UINT32_MAX;
}
/* color.filter + color.trans is in [0.0, 1.0] by definition */
pixel[3] = (color.filter + color.trans)*UINT32_MAX;
}
}
glDrawPixels(width, height, GL_RGBA, GL_UNSIGNED_INT, pixels);
free(pixels);
return 0;
}
/* Read a canvas from a GL framebuffer. Returns NULL on failure. */
dmnsn_canvas *
dmnsn_gl_read_canvas(unsigned int x0, unsigned int y0,
unsigned int width, unsigned int height)
{
dmnsn_canvas *canvas;
GLuint *pixels; /* Array of 32-bit ints in RGBA order */
GLuint *pixel;
dmnsn_sRGB sRGB;
dmnsn_color *color;
unsigned int x, y;
canvas = dmnsn_new_canvas(width, height);
if (!canvas) {
return NULL;
}
pixels = malloc(4*width*height*sizeof(GLuint));
if (!pixels) {
dmnsn_delete_canvas(canvas);
return NULL;
}
glReadPixels(x0, y0, width, height, GL_RGBA, GL_UNSIGNED_INT, pixels);
for (y = 0; y < height; ++y) {
for (x = 0; x < width; ++x) {
color = dmnsn_pixel_at(canvas, x, y);
pixel = pixels + 4*(y*width + x);
sRGB.R = ((double)pixel[0])/UINT32_MAX;
sRGB.G = ((double)pixel[1])/UINT32_MAX;
sRGB.B = ((double)pixel[2])/UINT32_MAX;
*color = dmnsn_color_from_sRGB(sRGB);
color->filter = ((double)pixel[3])/UINT32_MAX;
}
}
free(pixels);
return canvas;
}
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