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* Test vertex arrays with GL_NV_vertex_program
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* Based on a stripped-down version of the isosurf demo.
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* The vertex program is trivial: compute the resulting
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* RGB color as a linear function of vertex XYZ.
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#define GL_GLEXT_PROTOTYPES
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#define MAXVERTS 10000
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static float data[MAXVERTS][6];
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static GLint numverts;
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static GLboolean useArrays = GL_TRUE;
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static GLboolean useProgram = GL_TRUE;
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static GLboolean useList = GL_FALSE;
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static void read_surface( char *filename )
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f = fopen(filename,"r");
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printf("couldn't read %s\n", filename);
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while (!feof(f) && numverts < MAXVERTS) {
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fscanf( f, "%f %f %f %f %f %f",
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&data[numverts][0], &data[numverts][1], &data[numverts][2],
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&data[numverts][3], &data[numverts][4], &data[numverts][5] );
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printf("%d vertices, %d triangles\n", numverts, numverts-2);
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printf("data = %p\n", (void *) data);
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static void Display(void)
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glEnable(GL_VERTEX_PROGRAM_NV);
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glDisable(GL_VERTEX_PROGRAM_NV);
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glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
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glRotatef(xrot, 1, 0, 0);
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glRotatef(yrot, 0, 1, 0);
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glVertexAttribPointerNV( 0, 3, GL_FLOAT, 6 * sizeof(GLfloat), data );
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glEnableClientState( GL_VERTEX_ATTRIB_ARRAY0_NV );
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glVertexAttribPointerNV( 2, 3, GL_FLOAT, 6 * sizeof(GLfloat), ((GLfloat *) data) + 3);
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glEnableClientState( GL_VERTEX_ATTRIB_ARRAY2_NV);
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glVertexPointer( 3, GL_FLOAT, 6 * sizeof(GLfloat), data );
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glEnableClientState( GL_VERTEX_ARRAY );
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glNormalPointer( GL_FLOAT, 6 * sizeof(GLfloat), ((GLfloat *) data) + 3);
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glEnableClientState( GL_NORMAL_ARRAY );
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/* dumb, but a good test */
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glNewList(1,GL_COMPILE);
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glDrawArrays(GL_TRIANGLE_STRIP, 0, numverts);
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glDrawArrays(GL_TRIANGLE_STRIP, 0, numverts);
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glDisableClientState( GL_VERTEX_ATTRIB_ARRAY0_NV );
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glDisableClientState( GL_VERTEX_ATTRIB_ARRAY2_NV);
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glDisableClientState( GL_VERTEX_ARRAY );
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glDisableClientState( GL_NORMAL_ARRAY );
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glBegin(GL_TRIANGLE_STRIP);
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for (i = 0; i < numverts; i++) {
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glNormal3fv( data[i] + 3 );
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glVertex3fv( data[i] + 0 );
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static void InitMaterials(void)
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static float ambient[] = {0.1, 0.1, 0.1, 1.0};
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static float diffuse[] = {0.5, 1.0, 1.0, 1.0};
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static float position0[] = {0.0, 0.0, 20.0, 0.0};
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static float position1[] = {0.0, 0.0, -20.0, 0.0};
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static float front_mat_shininess[] = {60.0};
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static float front_mat_specular[] = {0.2, 0.2, 0.2, 1.0};
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static float front_mat_diffuse[] = {0.5, 0.28, 0.38, 1.0};
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static float back_mat_shininess[] = {60.0};
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static float back_mat_specular[] = {0.5, 0.5, 0.2, 1.0};
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static float back_mat_diffuse[] = {1.0, 1.0, 0.2, 1.0};
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static float lmodel_ambient[] = {1.0, 1.0, 1.0, 1.0};
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static float lmodel_twoside[] = {GL_FALSE};
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glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
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glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
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glLightfv(GL_LIGHT0, GL_POSITION, position0);
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glLightfv(GL_LIGHT1, GL_AMBIENT, ambient);
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glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse);
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glLightfv(GL_LIGHT1, GL_POSITION, position1);
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glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
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glLightModelfv(GL_LIGHT_MODEL_TWO_SIDE, lmodel_twoside);
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glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, front_mat_shininess);
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glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, front_mat_specular);
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glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, front_mat_diffuse);
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glEnable(GL_LIGHTING);
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static void init_program(void)
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* c[0..3] = modelview matrix
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* c[4..7] = inverse modelview matrix
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* c[30] = color scale
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static const char prog[] =
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"# RGB is proportional to XYZ \n"
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"MUL R0, v[OPOS], c[30]; \n"
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"ADD o[COL0], R0, c[31]; \n"
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"# Continue with typical modelview/projection\n"
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"MOV R3, v[OPOS]; \n"
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"DP4 o[HPOS].x, c[0], R3 ; # object x MVP -> clip\n"
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"DP4 o[HPOS].y, c[1], R3 ;\n"
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"DP4 o[HPOS].z, c[2], R3 ;\n"
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"DP4 o[HPOS].w, c[3], R3 ;\n"
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static const GLfloat scale[4] = {2.0, 2.0, 2.0, 0.0};
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static const GLfloat bias[4] = {1.0, 1.0, 1.0, 0.0};
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if (!glutExtensionSupported("GL_NV_vertex_program")) {
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printf("Sorry, this program requires GL_NV_vertex_program");
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glLoadProgramNV(GL_VERTEX_PROGRAM_NV, 1,
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strlen(prog), (const GLubyte *) prog);
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assert(glIsProgramNV(1));
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glBindProgramNV(GL_VERTEX_PROGRAM_NV, 1);
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/* Load the program registers */
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glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 0, GL_MODELVIEW_PROJECTION_NV, GL_IDENTITY_NV);
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glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 4, GL_MODELVIEW, GL_INVERSE_TRANSPOSE_NV);
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glProgramParameter4fvNV(GL_VERTEX_PROGRAM_NV, 30, scale);
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glProgramParameter4fvNV(GL_VERTEX_PROGRAM_NV, 31, bias);
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static void init(void)
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glClearColor(0.0, 0.0, 1.0, 0.0);
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glEnable( GL_DEPTH_TEST );
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glEnable(GL_NORMALIZE);
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read_surface( "../demos/isosurf.dat" );
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static void Reshape(int width, int height)
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glViewport(0, 0, (GLint)width, (GLint)height);
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glMatrixMode(GL_PROJECTION);
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glFrustum( -1.0, 1.0, -1.0, 1.0, 5, 25 );
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glMatrixMode(GL_MODELVIEW);
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glTranslatef(0, 0, -15);
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static void Key( unsigned char key, int x, int y )
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useArrays = !useArrays;
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printf("use arrays: %s\n", useArrays ? "yes" : "no");
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printf("use list: %s\n", useList ? "yes" : "no");
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useProgram = !useProgram;
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printf("use program: %s\n", useProgram ? "yes" : "no");
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static void SpecialKey( int key, int x, int y )
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int main(int argc, char **argv)
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glutInit(&argc, argv);
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glutInitDisplayMode( GLUT_DEPTH | GLUT_RGB | GLUT_DOUBLE );
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glutInitWindowPosition(0, 0);
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glutInitWindowSize(400, 400);
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if (glutCreateWindow("Isosurface") <= 0) {
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glutReshapeFunc(Reshape);
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glutKeyboardFunc(Key);
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glutSpecialFunc(SpecialKey);
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glutDisplayFunc(Display);