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
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
/*
* Warp a triangle mesh with a vertex program.
*/
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define GL_GLEXT_PROTOTYPES
#include <GL/glut.h>
static float Xrot = -60.0, Yrot = 0.0, Zrot = 0.0;
static GLboolean Anim = GL_TRUE;
static GLfloat Phi = 0.0;
static void Idle( void )
{
Phi += 0.01;
glutPostRedisplay();
}
static void DrawMesh( int rows, int cols )
{
static const GLfloat colorA[3] = { 0, 1, 0 };
static const GLfloat colorB[3] = { 0, 0, 1 };
const float dx = 2.0 / (cols - 1);
const float dy = 2.0 / (rows - 1);
float x, y;
int i, j;
#if 1
#define COLOR3FV(c) glVertexAttrib3fvNV(3, c)
#define VERTEX2F(x, y) glVertexAttrib2fNV(0, x, y)
#else
#define COLOR3FV(c) glColor3fv(c)
#define VERTEX2F(x, y) glVertex2f(x, y)
#endif
y = -1.0;
for (i = 0; i < rows - 1; i++) {
glBegin(GL_QUAD_STRIP);
x = -1.0;
for (j = 0; j < cols; j++) {
if ((i + j) & 1)
COLOR3FV(colorA);
else
COLOR3FV(colorB);
VERTEX2F(x, y);
VERTEX2F(x, y + dy);
x += dx;
}
glEnd();
y += dy;
}
}
static void Display( void )
{
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glPushMatrix();
glRotatef(Xrot, 1, 0, 0);
glRotatef(Yrot, 0, 1, 0);
glRotatef(Zrot, 0, 0, 1);
/* Position the gravity source */
{
GLfloat x, y, z, r = 0.5;
x = r * cos(Phi);
y = r * sin(Phi);
z = 1.0;
glProgramParameter4fNV(GL_VERTEX_PROGRAM_NV, 30, x, y, z, 1);
glDisable(GL_VERTEX_PROGRAM_NV);
glBegin(GL_POINTS);
glColor3f(1,1,1);
glVertex3f(x, y, z);
glEnd();
}
glEnable(GL_VERTEX_PROGRAM_NV);
DrawMesh(8, 8);
glPopMatrix();
glutSwapBuffers();
}
static void Reshape( int width, int height )
{
float ar = (float) width / (float) height;
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum( -1.0 * ar, 1.0 * ar, -1.0, 1.0, 5.0, 25.0 );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef( 0.0, 0.0, -12.0 );
glScalef(2, 2, 2);
}
static void Key( unsigned char key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case 'a':
Anim = !Anim;
if (Anim)
glutIdleFunc(Idle);
else
glutIdleFunc(NULL);
break;
case 'p':
Phi += 0.2;
break;
case 'z':
Zrot -= 5.0;
break;
case 'Z':
Zrot += 5.0;
break;
case 27:
exit(0);
break;
}
glutPostRedisplay();
}
static void SpecialKey( int key, int x, int y )
{
const GLfloat step = 3.0;
(void) x;
(void) y;
switch (key) {
case GLUT_KEY_UP:
Xrot -= step;
break;
case GLUT_KEY_DOWN:
Xrot += step;
break;
case GLUT_KEY_LEFT:
Yrot -= step;
break;
case GLUT_KEY_RIGHT:
Yrot += step;
break;
}
glutPostRedisplay();
}
static void Init( void )
{
/*
* c[0..3] = modelview matrix
* c[4..7] = inverse modelview matrix
* c[30] = gravity source location
* c[31] = gravity source strength
* c[32] = light pos
* c[35] = diffuse color
*/
static const char prog[] =
"!!VP1.0\n"
"# Compute distance from vertex to gravity source\n"
"ADD R1, c[30], -v[OPOS]; # vector from vertex to gravity\n"
"DP3 R2, R1, R1; # dot product\n"
"RSQ R2, R2.x; # square root = distance\n"
"MUL R2, R2, c[31].xxxx; # scale by the gravity factor\n"
"# Displace vertex by gravity factor along R1 vector\n"
"MAD R3, R1, R2, v[OPOS];\n"
"# Continue with typical modelview/projection\n"
"DP4 o[HPOS].x, c[0], R3 ; # object x MVP -> clip\n"
"DP4 o[HPOS].y, c[1], R3 ;\n"
"DP4 o[HPOS].z, c[2], R3 ;\n"
"DP4 o[HPOS].w, c[3], R3 ;\n"
"MOV o[COL0], v[COL0];\n # copy input color to output color\n"
"END";
if (!glutExtensionSupported("GL_NV_vertex_program")) {
printf("Sorry, this program requires GL_NV_vertex_program");
exit(1);
}
glLoadProgramNV(GL_VERTEX_PROGRAM_NV, 1,
strlen(prog), (const GLubyte *) prog);
assert(glIsProgramNV(1));
glBindProgramNV(GL_VERTEX_PROGRAM_NV, 1);
/* Load the program registers */
glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 0, GL_MODELVIEW_PROJECTION_NV, GL_IDENTITY_NV);
glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 4, GL_MODELVIEW, GL_INVERSE_TRANSPOSE_NV);
/* Light position */
glProgramParameter4fNV(GL_VERTEX_PROGRAM_NV, 32, 2, 2, 4, 1);
/* Diffuse material color */
glProgramParameter4fNV(GL_VERTEX_PROGRAM_NV, 35, 0.25, 0, 0.25, 1);
/* Gravity strength */
glProgramParameter4fNV(GL_VERTEX_PROGRAM_NV, 31, .5, 0, 0, 0);
glEnable(GL_DEPTH_TEST);
glClearColor(0.3, 0.3, 0.3, 1);
glShadeModel(GL_FLAT);
glPointSize(3);
printf("glGetError = %d\n", (int) glGetError());
}
int main( int argc, char *argv[] )
{
glutInit( &argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( 250, 250 );
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
glutCreateWindow(argv[0]);
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutSpecialFunc( SpecialKey );
glutDisplayFunc( Display );
if (Anim)
glutIdleFunc(Idle);
Init();
glutMainLoop();
return 0;
}
|
