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
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
#include <assert.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <GL/glew.h>
#include <GL/glu.h>
#include "readtex.h"
#include "skybox.h"
static int
load(GLenum target, const char *filename,
GLboolean flipTB, GLboolean flipLR)
{
GLint w, h;
GLenum format;
GLubyte *img = LoadRGBImage( filename, &w, &h, &format );
if (!img) {
printf("Error: couldn't load texture image %s\n", filename);
return 0;
}
assert(format == GL_RGB);
printf("Load cube face 0x%x: %s %d x %d\n", target, filename, w, h);
/* <sigh> the way the texture cube mapping works, we have to flip
* images to make things look right.
*/
if (flipTB) {
const int stride = 3 * w;
GLubyte temp[3*1024];
int i;
for (i = 0; i < h / 2; i++) {
memcpy(temp, img + i * stride, stride);
memcpy(img + i * stride, img + (h - i - 1) * stride, stride);
memcpy(img + (h - i - 1) * stride, temp, stride);
}
}
if (flipLR) {
const int stride = 3 * w;
GLubyte temp[3];
GLubyte *row;
int i, j;
for (i = 0; i < h; i++) {
row = img + i * stride;
for (j = 0; j < w / 2; j++) {
int k = w - j - 1;
temp[0] = row[j*3+0];
temp[1] = row[j*3+1];
temp[2] = row[j*3+2];
row[j*3+0] = row[k*3+0];
row[j*3+1] = row[k*3+1];
row[j*3+2] = row[k*3+2];
row[k*3+0] = temp[0];
row[k*3+1] = temp[1];
row[k*3+2] = temp[2];
}
}
}
gluBuild2DMipmaps(target, GL_RGB, w, h, format, GL_UNSIGNED_BYTE, img);
free(img);
return 1;
}
GLuint
LoadSkyBoxCubeTexture(const char *filePosX,
const char *fileNegX,
const char *filePosY,
const char *fileNegY,
const char *filePosZ,
const char *fileNegZ)
{
GLuint tex;
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_CUBE_MAP, tex);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER,
GL_LINEAR_MIPMAP_NEAREST);
if (!load(GL_TEXTURE_CUBE_MAP_POSITIVE_X, filePosX, GL_TRUE, GL_TRUE))
return 0;
if (!load(GL_TEXTURE_CUBE_MAP_NEGATIVE_X, fileNegX, GL_TRUE, GL_TRUE))
return 0;
if (!load(GL_TEXTURE_CUBE_MAP_POSITIVE_Y, filePosY, 1+GL_FALSE, GL_TRUE))
return 0;
if (!load(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, fileNegY, 1+GL_FALSE, GL_TRUE))
return 0;
if (!load(GL_TEXTURE_CUBE_MAP_POSITIVE_Z, filePosZ, GL_TRUE, GL_TRUE))
return 0;
if (!load(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, fileNegZ, GL_TRUE, GL_TRUE))
return 0;
return tex;
}
#define eps1 0.99
#define br 20.0 /* box radius */
void
DrawSkyBoxCubeTexture(GLuint tex)
{
struct vertex {
float x, y, z, s, t, r;
};
static const struct vertex verts[24] = {
/* +X side */
{ br, -br, -br, 1.0, -eps1, -eps1 },
{ br, -br, br, 1.0, -eps1, eps1 },
{ br, br, br, 1.0, eps1, eps1 },
{ br, br, -br, 1.0, eps1, -eps1 },
/* -X side */
{ -br, br, -br, -1.0, eps1, -eps1 },
{ -br, br, br, -1.0, eps1, eps1 },
{ -br, -br, br, -1.0, -eps1, eps1 },
{ -br, -br, -br, -1.0, -eps1, -eps1 },
/* +Y side */
{ br, br, -br, eps1, 1.0, -eps1 },
{ br, br, br, eps1, 1.0, eps1 },
{ -br, br, br, -eps1, 1.0, eps1 },
{ -br, br, -br, -eps1, 1.0, -eps1 },
/* -Y side */
{ -br, -br, -br, -eps1, -1.0, -eps1 },
{ -br, -br, br, -eps1, -1.0, eps1 },
{ br, -br, br, eps1, -1.0, eps1 },
{ br, -br, -br, eps1, -1.0, -eps1 },
/* +Z side */
{ br, -br, br, eps1, -eps1, 1.0 },
{ -br, -br, br, -eps1, -eps1, 1.0 },
{ -br, br, br, -eps1, eps1, 1.0 },
{ br, br, br, eps1, eps1, 1.0 },
/* -Z side */
{ br, br, -br, eps1, eps1, -1.0 },
{ -br, br, -br, -eps1, eps1, -1.0 },
{ -br, -br, -br, -eps1, -eps1, -1.0 },
{ br, -br, -br, eps1, -eps1, -1.0 },
};
static GLuint vbo = 0;
if (!vbo ) {
glGenBuffersARB(1, &vbo);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, vbo);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, sizeof(verts), verts,
GL_STATIC_DRAW_ARB);
}
else {
glBindBufferARB(GL_ARRAY_BUFFER_ARB, vbo);
}
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glVertexPointer(3, GL_FLOAT, sizeof(struct vertex),
(void *) offsetof(struct vertex, x));
glTexCoordPointer(3, GL_FLOAT, sizeof(struct vertex),
(void *) offsetof(struct vertex, s));
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glBindTexture(GL_TEXTURE_CUBE_MAP, tex);
glEnable(GL_TEXTURE_CUBE_MAP);
//glDisable(GL_LIGHTING);
glDisable(GL_BLEND);
glDrawArrays(GL_QUADS, 0, 24);
//glEnable(GL_LIGHTING);
glDisable(GL_TEXTURE_CUBE_MAP);
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
}
|
