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/*
* Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc.
*
* Permission to use, copy, modify, distribute, and sell this software and
* its documentation for any purpose is hereby granted without fee, provided
* that (i) the above copyright notices and this permission notice appear in
* all copies of the software and related documentation, and (ii) the name of
* Silicon Graphics may not be used in any advertising or
* publicity relating to the software without the specific, prior written
* permission of Silicon Graphics.
*
* THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF
* ANY KIND,
* EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
* WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
*
* IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR
* ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
* OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
* WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
* LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
* OF THIS SOFTWARE.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <GL/glew.h>
#include <GL/glut.h>
#define CI_OFFSET_1 16
#define CI_OFFSET_2 32
#define SIZE 16
GLenum doubleBuffer;
GLint line = 0;
static void MakeImage()
{
GLubyte tex2d[SIZE][SIZE][3];
GLint s, t;
for (s = 0; s < SIZE; s++) {
for (t = 0; t < SIZE; t++) {
tex2d[s][t][0] = s*255/(SIZE-1);
tex2d[s][t][1] = t*255/(SIZE-1);
tex2d[s][t][2] = 0*255/(SIZE-1);
}
}
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB,
SIZE, SIZE,
0,
GL_RGB, GL_UNSIGNED_BYTE, tex2d);
glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
glEnable(GL_TEXTURE_2D);
}
static void UpdateLine()
{
GLubyte tex[SIZE][3];
GLint s, t;
t = line % SIZE;
for (s = 0; s < SIZE; s++) {
tex[s][0] = s*255/(SIZE-1);
tex[s][1] = t*255/(SIZE-1);
tex[s][2] = 255;
}
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexSubImage2D(GL_TEXTURE_2D, 0,
0, t,
SIZE, 1,
GL_RGB, GL_UNSIGNED_BYTE, tex);
glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
}
static void Init(void)
{
fprintf(stderr, "GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
fprintf(stderr, "GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
fprintf(stderr, "GL_VENDOR = %s\n", (char *) glGetString(GL_VENDOR));
glClearColor(0.0, 0.0, 1.0, 0.0);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
MakeImage();
UpdateLine();
line++;
}
static void Reshape(int width, int height)
{
glViewport(0, 0, (GLint)width, (GLint)height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
glMatrixMode(GL_MODELVIEW);
}
static void Key(unsigned char key, int x, int y)
{
switch (key) {
case 27:
exit(1);
default:
UpdateLine();
line++;
break;
}
glutPostRedisplay();
}
static void Draw(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glBegin(GL_QUADS);
glTexCoord2f(1,0);
glVertex3f( 0.9, -0.9, -30.0);
glTexCoord2f(1,1);
glVertex3f( 0.9, 0.9, -30.0);
glTexCoord2f(0,1);
glVertex3f(-0.9, 0.9, -30.0);
glTexCoord2f(0,0);
glVertex3f(-0.9, -0.9, -30.0);
glEnd();
glFlush();
if (doubleBuffer) {
glutSwapBuffers();
}
}
static GLenum Args(int argc, char **argv)
{
GLint i;
doubleBuffer = GL_FALSE;
for (i = 1; i < argc; i++) {
if (strcmp(argv[i], "-sb") == 0) {
doubleBuffer = GL_FALSE;
} else if (strcmp(argv[i], "-db") == 0) {
doubleBuffer = GL_TRUE;
} else {
fprintf(stderr, "%s (Bad option).\n", argv[i]);
return GL_FALSE;
}
}
return GL_TRUE;
}
int main(int argc, char **argv)
{
GLenum type;
glutInit(&argc, argv);
if (Args(argc, argv) == GL_FALSE) {
exit(1);
}
glutInitWindowPosition(0, 0);
glutInitWindowSize(250, 250);
type = GLUT_RGB | GLUT_ALPHA;
type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
glutInitDisplayMode(type);
if (glutCreateWindow(*argv) == GL_FALSE) {
exit(1);
}
glewInit();
Init();
glutReshapeFunc(Reshape);
glutKeyboardFunc(Key);
glutDisplayFunc(Draw);
glutMainLoop();
return 0;
}
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