summaryrefslogtreecommitdiffstats
path: root/progs/trivial/tex-quads.c
blob: 626e178b873114682c15062145327781a493806d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/**
 * Draw a series of quads, each with a different texture.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <GL/glew.h>
#include <GL/glut.h>

#define NUM_TEX 10

static GLint Win = 0;
static GLuint Tex[NUM_TEX];


static void Init(void)
{
   int i;

   fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
   fflush(stderr);

   glGenTextures(NUM_TEX, Tex);

   for (i = 0; i < NUM_TEX; i++) {
      glBindTexture(GL_TEXTURE_2D, Tex[i]);

      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);
   }
}


static void Reshape(int width, int height)
{
   float ar = (float) width / height;
   glViewport(0, 0, width, height);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glOrtho(-ar, ar, -1.0, 1.0, -1.0, 1.0);
   glMatrixMode(GL_MODELVIEW);
}


static void Key(unsigned char key, int x, int y)
{
   if (key == 27) {
      glDeleteTextures(NUM_TEX, Tex);
      glutDestroyWindow(Win);
      exit(1);
   }
   glutPostRedisplay();
}


static void Draw(void)
{
   GLubyte tex[16][16][4];
   int t, i, j;

   for (t = 0; t < NUM_TEX; t++) {

      for (i = 0; i < 16; i++) {
         for (j = 0; j < 16; j++) {
            if (i < t) {
               /* red row */
               tex[i][j][0] = 255;
               tex[i][j][1] = 0;
               tex[i][j][2] = 0;
               tex[i][j][3] = 255;
            }
            else if ((i + j) & 1) {
               tex[i][j][0] = 128;
               tex[i][j][1] = 128;
               tex[i][j][2] = 128;
               tex[i][j][3] = 255;
            }
            else {
               tex[i][j][0] = 255;
               tex[i][j][1] = 255;
               tex[i][j][2] = 255;
               tex[i][j][3] = 255;
            }
         }
      }

      glBindTexture(GL_TEXTURE_2D, Tex[t]);
      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 16, 16, 0,
                   GL_RGBA, GL_UNSIGNED_BYTE, tex);
   }

   glEnable(GL_TEXTURE_2D);

   glClear(GL_COLOR_BUFFER_BIT);

   for (i = 0; i < NUM_TEX; i++) {

      glBindTexture(GL_TEXTURE_2D, Tex[i]);

      glPushMatrix();
      glTranslatef(-4.0 + i, 0, 0);
      glScalef(0.5, 0.5, 1.0);

      glBegin(GL_QUADS);
      glTexCoord2f(1,0);
      glVertex3f( 0.9, -0.9, 0.0);
      glTexCoord2f(1,1);
      glVertex3f( 0.9,  0.9, 0.0);
      glTexCoord2f(0,1);
      glVertex3f(-0.9,  0.9, 0.0);
      glTexCoord2f(0,0);
      glVertex3f(-0.9,  -0.9, 0.0);
      glEnd();

      glPopMatrix();
   }


   glutSwapBuffers();
}


int main(int argc, char **argv)
{
   glutInit(&argc, argv);
   glutInitWindowSize(900, 200);
   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
   Win = glutCreateWindow(*argv);
   if (!Win) {
      exit(1);
   }
   glewInit();
   Init();
   glutReshapeFunc(Reshape);
   glutKeyboardFunc(Key);
   glutDisplayFunc(Draw);
   glutMainLoop();
   return 0;
}