2
* Warp a triangle mesh with a vertex program.
10
#define GL_GLEXT_PROTOTYPES
13
static float Xrot = -60.0, Yrot = 0.0, Zrot = 0.0;
14
static GLboolean Anim = GL_TRUE;
15
static GLfloat Phi = 0.0;
18
static void Idle( void )
25
static void DrawMesh( int rows, int cols )
27
static const GLfloat colorA[3] = { 0, 1, 0 };
28
static const GLfloat colorB[3] = { 0, 0, 1 };
29
const float dx = 2.0 / (cols - 1);
30
const float dy = 2.0 / (rows - 1);
35
#define COLOR3FV(c) glVertexAttrib3fvARB(3, c)
36
#define VERTEX2F(x, y) glVertexAttrib2fARB(0, x, y)
38
#define COLOR3FV(c) glColor3fv(c)
39
#define VERTEX2F(x, y) glVertex2f(x, y)
43
for (i = 0; i < rows - 1; i++) {
44
glBegin(GL_QUAD_STRIP);
46
for (j = 0; j < cols; j++) {
61
static void Display( void )
63
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
66
glRotatef(Xrot, 1, 0, 0);
67
glRotatef(Yrot, 0, 1, 0);
68
glRotatef(Zrot, 0, 0, 1);
70
/* Position the gravity source */
72
GLfloat x, y, z, r = 0.5;
76
glProgramLocalParameter4fARB(GL_VERTEX_PROGRAM_ARB, 30, x, y, z, 1);
77
glDisable(GL_VERTEX_PROGRAM_ARB);
84
glEnable(GL_VERTEX_PROGRAM_ARB);
92
static void Reshape( int width, int height )
94
float ar = (float) width / (float) height;
95
glViewport( 0, 0, width, height );
96
glMatrixMode( GL_PROJECTION );
98
glFrustum( -1.0 * ar, 1.0 * ar, -1.0, 1.0, 5.0, 25.0 );
99
glMatrixMode( GL_MODELVIEW );
101
glTranslatef( 0.0, 0.0, -12.0 );
106
static void Key( unsigned char key, int x, int y )
135
static void SpecialKey( int key, int x, int y )
137
const GLfloat step = 3.0;
158
static void Init( void )
164
* c[0..3] = modelview matrix
165
* c[4..7] = inverse modelview matrix
166
* c[30] = gravity source location
167
* c[31] = gravity source strength
169
* c[35] = diffuse color
171
static const char prog[] =
175
"# Compute distance from vertex to gravity source\n"
176
"ADD R1, program.local[30], -vertex.position; # vector from vertex to gravity\n"
177
"DP3 R2, R1, R1; # dot product\n"
178
"RSQ R2, R2.x; # square root = distance\n"
179
"MUL R2, R2, program.local[31].xxxx; # scale by the gravity factor\n"
181
"# Displace vertex by gravity factor along R1 vector\n"
182
"MAD R3, R1, R2, vertex.position;\n"
184
"# Continue with typical modelview/projection\n"
185
"DP4 result.position.x, state.matrix.mvp.row[0], R3 ; # object x MVP -> clip\n"
186
"DP4 result.position.y, state.matrix.mvp.row[1], R3 ;\n"
187
"DP4 result.position.z, state.matrix.mvp.row[2], R3 ;\n"
188
"DP4 result.position.w, state.matrix.mvp.row[3], R3 ;\n"
190
"MOV result.color, vertex.attrib[3];\n # copy input color to output color\n"
194
if (!glutExtensionSupported("GL_ARB_vertex_program")) {
195
printf("Sorry, this program requires GL_ARB_vertex_program\n");
199
glGenProgramsARB(1, &prognum);
200
glBindProgramARB(GL_VERTEX_PROGRAM_ARB, prognum);
201
glProgramStringARB(GL_VERTEX_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
202
strlen(prog), (const GLubyte *)prog);
203
errno = glGetError();
204
printf("glGetError = %d\n", errno);
206
if (errno != GL_NO_ERROR)
210
glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &errorpos);
211
printf("errorpos: %d\n", errorpos);
212
printf("%s\n", glGetString(GL_PROGRAM_ERROR_STRING_ARB));
216
glProgramLocalParameter4fARB(GL_VERTEX_PROGRAM_ARB, 32, 2, 2, 4, 1);
217
/* Diffuse material color */
218
glProgramLocalParameter4fARB(GL_VERTEX_PROGRAM_ARB, 35, 0.25, 0, 0.25, 1);
220
/* Gravity strength */
221
glProgramLocalParameter4fARB(GL_VERTEX_PROGRAM_ARB, 31, .5, 0, 0, 0);
223
glEnable(GL_DEPTH_TEST);
224
glClearColor(0.3, 0.3, 0.3, 1);
225
glShadeModel(GL_FLAT);
230
int main( int argc, char *argv[] )
232
glutInit( &argc, argv );
233
glutInitWindowPosition( 0, 0 );
234
glutInitWindowSize( 250, 250 );
235
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
236
glutCreateWindow(argv[0]);
237
glutReshapeFunc( Reshape );
238
glutKeyboardFunc( Key );
239
glutSpecialFunc( SpecialKey );
240
glutDisplayFunc( Display );