Created
April 3, 2013 23:35
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Improved version of https://gist.github.com/tai2/5008183 using glDrowPixels().
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#include <stdio.h> | |
#include <stdlib.h> | |
#include <GLUT/glut.h> | |
#define KEY_ESC 27 | |
#define WINDOW_POS_X 100 | |
#define WINDOW_POS_Y 100 | |
#define DEF_SCREEN_WIDTH 640 | |
#define DEF_SCREEN_HEIGHT 360 | |
static int curr_width = 0; | |
static int curr_height = 0; | |
static GLubyte *screen_buf = NULL; | |
static int fullscreen = 0; | |
static void | |
keyboard(unsigned char c, int x, int y) | |
{ | |
switch (c) { | |
case KEY_ESC: | |
exit(0); | |
break; | |
case 'f': | |
if (fullscreen) { | |
glutReshapeWindow(DEF_SCREEN_WIDTH, DEF_SCREEN_HEIGHT); | |
glutPositionWindow(WINDOW_POS_X, WINDOW_POS_Y); | |
fullscreen = 0; | |
} else { | |
glutFullScreen(); | |
fullscreen = 1; | |
} | |
break; | |
} | |
} | |
void | |
idle() | |
{ | |
glutPostRedisplay(); | |
} | |
static void | |
reshape(int w, int h) | |
{ | |
curr_width = w; | |
curr_height = h; | |
if (screen_buf) { | |
free(screen_buf); | |
} | |
screen_buf = (GLubyte *)malloc(curr_width * curr_height * 4); | |
if (!screen_buf) { | |
abort(); | |
} | |
} | |
static void | |
draw_pixel(int x, int y, GLubyte r, GLubyte g, GLubyte b) | |
{ | |
int base = 4 * ((curr_height - 1 - y) * curr_width + x); | |
screen_buf[base + 0] = r; | |
screen_buf[base + 1] = g; | |
screen_buf[base + 2] = b; | |
screen_buf[base + 3] = 255; | |
} | |
static void | |
display() | |
{ | |
int x, y; | |
glClear(GL_COLOR_BUFFER_BIT); | |
for (y = 0; y < curr_height; y++) { | |
for (x = 0; x < curr_width; x++) { | |
GLubyte v = rand() % 256; | |
draw_pixel(x, y, v, v, v); | |
} | |
} | |
glWindowPos2i(0, 0); | |
glDrawPixels(curr_width, curr_height, GL_RGBA, GL_UNSIGNED_BYTE, screen_buf); | |
glutSwapBuffers(); | |
} | |
int | |
main(int argc, char** argv) | |
{ | |
srand(0); | |
glutInit(&argc, argv); | |
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH ); | |
glutInitWindowSize(DEF_SCREEN_WIDTH, DEF_SCREEN_HEIGHT); | |
glutInitWindowPosition(WINDOW_POS_X, WINDOW_POS_Y); | |
glutCreateWindow(argv[0]); | |
glutKeyboardFunc(keyboard); | |
glutIdleFunc(idle); | |
glutReshapeFunc(reshape); | |
glutDisplayFunc(display); | |
glClearColor(0.0, 0.0, 0.0, 0.0); | |
glShadeModel(GL_FLAT); | |
glutMainLoop(); | |
return 0; | |
} |
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