Transcription

1 OpenGL for dummies

2

3

4

5 hello.c #include <GL/glut.h> int main(int argc, char** argv) { glutinit(&argc, argv); glutinitdisplaymode (GLUT_SINGLE GLUT_RGB); glutinitwindowsize (250, 250); glutinitwindowposition (100, 100); glutcreatewindow ("hello"); glclearcolor (0.0, 0.0, 0.0, 0.0); glmatrixmode(gl_projection); glloadidentity(); glortho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0); glutdisplayfunc(display); glutmainloop(); return 0; void display(void) { glclear (GL_COLOR_BUFFER_BIT); glcolor3f (1.0, 1.0, 1.0); glbegin(gl_polygon); glvertex3f (0.25, 0.25, 0.0); glvertex3f (0.75, 0.25, 0.0); glvertex3f (0.75, 0.75, 0.0); glvertex3f (0.25, 0.75, 0.0); glend(); glflush ();

6 Comment obtenir l exécutable? >> g++ -framework GLUT -framework OpenGL -lgl -lglu -lm -lobjc -lstdc++ -L"/System/Library/Frameworks/ OpenGL.framework/Libraries" -o hello hello.o

7

8

9

10

11

12

13 OpenGL s rendering pipeline Vertex Data Evaluators Operations with vertices Assembling primitives Fragments operations Display lists Rasterization Assembling textures Frame Buffer Pixel Data Operations with pixels

14 cube.c

15 cube.c #include <GL/glut.h> #include <stdlib.h> int main(int argc, char** argv) { glutinit(&argc, argv); glutinitdisplaymode (GLUT_SINGLE GLUT_RGB); glutinitwindowsize (500, 500); glutinitwindowposition (100, 100); glutcreatewindow (argv[0]); glclearcolor (0.0, 0.0, 0.0, 0.0); glshademodel (GL_FLAT); glutdisplayfunc(display); glutreshapefunc(reshape); glutkeyboardfunc(keyboard); glutmainloop(); return 0; void display(void){ glclear (GL_COLOR_BUFFER_BIT); glcolor3f (1.0, 1.0, 1.0); Places the camera at (0,0,5) Aims the camera lens towards (0,0,0) Up-vector is (0,1,0) This defines a unique position and orientation of the camera Modeling transformation Viewing transformation glloadidentity (); glulookat (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0); glscalef (1.0, 2.0, 1.0); glutwirecube (1.0); glflush ();

16 cube.c #include <GL/glut.h> #include <stdlib.h> int main(int argc, char** argv) { glutinit(&argc, argv); glutinitdisplaymode (GLUT_SINGLE GLUT_RGB); glutinitwindowsize (500, 500); glutinitwindowposition (100, 100); glutcreatewindow (argv[0]); glclearcolor (0.0, 0.0, 0.0, 0.0); glshademodel (GL_FLAT); glutdisplayfunc(display); glutreshapefunc(reshape); glutkeyboardfunc(keyboard); glutmainloop(); return 0; Projection transformation Defines left and right clipping planes, Defines bottom and top clipping planes, Defines znear and zfar This defines a perpective matrix void reshape (int w, int h){ glviewport (0, 0, (GLsizei) w, (GLsizei) h); glmatrixmode (GL_PROJECTION); glloadidentity (); glfrustum (-1.0, 1.0, -1.0, 1.0, 1.5, 20.0); glmatrixmode (GL_MODELVIEW);

17

18

19 glfrustrum How to obtain an accurate specification of the parameters?

20 cube.c #include <GL/glut.h> #include <stdlib.h> int main(int argc, char** argv) { glutinit(&argc, argv); glutinitdisplaymode (GLUT_SINGLE GLUT_RGB); glutinitwindowsize (500, 500); glutinitwindowposition (100, 100); glutcreatewindow (argv[0]); glclearcolor (0.0, 0.0, 0.0, 0.0); glshademodel (GL_FLAT); glutdisplayfunc(display); glutreshapefunc(reshape); glutkeyboardfunc(keyboard); glutmainloop(); return 0; ESC allows the user to exit! void keyboard(unsigned char key, int x, int y) { switch (key) { case 27: exit(0); break;

21 double.c

22 #include <GL/glut.h> #include <stdlib.h> static GLfloat spin = 0.0; int main(int argc, char** argv) { glutinit(&argc, argv); glutinitdisplaymode (GLUT_DOUBLE GLUT_RGB); glutinitwindowsize (250, 250); glutinitwindowposition (100, 100); glutcreatewindow (argv[0]); glclearcolor (0.0, 0.0, 0.0, 0.0); glshademodel (GL_FLAT); glutdisplayfunc(display); void display(void) glutreshapefunc(reshape); glutmousefunc(mouse); { glclear(gl_color_buffer_bit); glutmainloop(); glpushmatrix(); return 0; glrotatef(spin, 0.0, 0.0, 1.0); glcolor3f(1.0, 1.0, 1.0); glrectf(-25.0, -25.0, 25.0, 25.0); glpopmatrix(); glutswapbuffers(); double.c void reshape (int w, int h) { glviewport (0, 0, (GLsizei) w, (GLsizei) h); glmatrixmode(gl_projection); glloadidentity(); glortho(-50.0, 50.0, -50.0, 50.0, -1.0, 1.0); glmatrixmode(gl_modelview); glloadidentity();

23 #include <GL/glut.h> #include <stdlib.h> static GLfloat spin = 0.0; int main(int argc, char** argv) { glutinit(&argc, argv); glutinitdisplaymode (GLUT_DOUBLE GLUT_RGB); glutinitwindowsize (250, 250); glutinitwindowposition (100, 100); glutcreatewindow (argv[0]); glclearcolor (0.0, 0.0, 0.0, 0.0); glshademodel (GL_FLAT); glutdisplayfunc(display); glutreshapefunc(reshape); glutmousefunc(mouse); glutmainloop(); return 0; void spindisplay(void) { spin = spin + 2.0; if (spin > 360.0) spin = spin ; glutpostredisplay(); void mouse(int button, int state, int x, int y) { switch (button) { case GLUT_LEFT_BUTTON: if (state == GLUT_DOWN) glutidlefunc(spindisplay); break; case GLUT_MIDDLE_BUTTON: case GLUT_RIGHT_BUTTON: if (state == GLUT_DOWN) glutidlefunc(null); break; default: break; double.c

24 bezcurve.c

25 #include <GL/glut.h> #include <stdlib.h> GLfloat ctrlpoints[4][3] = { { -4.0, -4.0, 0.0, { -2.0, 4.0, 0.0, {2.0, -4.0, 0.0, {4.0, 4.0, 0.0; int main(int argc, char** argv) { glutinit(&argc, argv); glutinitdisplaymode (GLUT_SINGLE GLUT_RGB); glutinitwindowsize (500, 500); glutinitwindowposition (100, 100); glutcreatewindow (argv[0]); glclearcolor(0.0, 0.0, 0.0, 0.0); glshademodel(gl_flat); glmap1f(gl_map1_vertex_3, 0.0, 1.0, 3, 4, &ctrlpoints[0][0]); glenable(gl_map1_vertex_3); glutdisplayfunc(display); glutreshapefunc(reshape); glutkeyboardfunc(keyboard); glutmainloop(); return 0; void display(void) { int i; glclear(gl_color_buffer_bit); glcolor3f(1.0, 1.0, 1.0); bezcurve.c glbegin(gl_line_strip); for (i = 0; i <= 30; i++) glevalcoord1f((glfloat) i/30.0); glend(); glpointsize(5.0); glcolor3f(1.0, 1.0, 0.0); glbegin(gl_points); for (i = 0; i < 4; i++) glvertex3fv(&ctrlpoints[i][0]); glend(); glflush();

26 #include <GL/glut.h> #include <stdlib.h> GLfloat ctrlpoints[4][3] = { {-4.0,-4.0, 0.0, {-2.0, 4.0, 0.0, { 2.0,-4.0, 0.0, { 4.0, 4.0, 0.0; int main(int argc, char** argv) { glutinit(&argc, argv); glutinitdisplaymode (GLUT_SINGLE GLUT_RGB); glutinitwindowsize (500, 500); glutinitwindowposition (100, 100); glutcreatewindow (argv[0]); glclearcolor(0.0, 0.0, 0.0, 0.0); glshademodel(gl_flat); glmap1f(gl_map1_vertex_3, 0.0, 1.0, 3, 4, &ctrlpoints[0][0]); glenable(gl_map1_vertex_3); glutdisplayfunc(display); glutreshapefunc(reshape); glutkeyboardfunc(keyboard); glutmainloop(); return 0; void reshape(int w, int h) bezcurve.c { glviewport(0, 0, (GLsizei) w, (GLsizei) h); glmatrixmode(gl_projection); glloadidentity(); if (w <= h) glortho(-5.0, 5.0, 5.0*(GLfloat)h/(GLfloat)w, 5.0*(GLfloat)h/(GLfloat)w, -5.0, 5.0); else glortho(5.0*(glfloat)w/(glfloat)h, 5.0*(GLfloat)w/(GLfloat)h, -5.0, 5.0,-5.0, 5.0); glmatrixmode(gl_modelview); glloadidentity();

27 #include <GL/glut.h> #include <stdlib.h> GLUnurbsObj *nurb; GLfloat knots[9] = {-3.0,-2.0,-1.0,0.0,1.0,2.0,3.0,4.0,5.0; GLfloat ctrlpoints[12][3] = { {-3.0,-3.0, 0.0,{-1.0, 3.0, 0.0,{ 1.0,-3.0, 0.0, { 3.0, 3.0, 0.0,{-3.0,-4.0, 0.0,{-2.0,-4.0, 0.0, {-1.0,-4.0, 0.0,{ 0.0,-4.0, 0.0,{ 1.0,-4.0, 0.0, { 2.0,-4.0, 0.0,{ 3.0,-4.0, 0.0,{ 4.0,-4.0, 0.0; int main(int argc, char** argv) { glutinit(&argc, argv); glutinitdisplaymode (GLUT_SINGLE GLUT_RGB); glutinitwindowsize (500, 500); glutinitwindowposition (100, 100); glutcreatewindow (argv[0]); glclearcolor(0.0, 0.0, 0.0, 0.0); glshademodel(gl_flat); glmap1f(gl_map1_vertex_3, 0.0, 1.0, 3, 4, &ctrlpoints[0][0]); glenable(gl_map1_vertex_3); glutdisplayfunc(display); glutreshapefunc(reshape); glutkeyboardfunc(keyboard); glutmotionfunc(drag); glutmainloop(); return 0; Et les B-splines.

28 Nurbs = B-splines = Beziers! Knots, pts de contrôle void display(void) { glclear(gl_color_buffer_bit); glcolor3f(1.0, 1.0, 1.0); glbegin(gl_line_strip); for (i = 0; i <= 30; i++) glevalcoord1f((glfloat) i/30.0); glend(); glpointsize(8.0); glbegin(gl_points); for (i = 0; i < 4; i++) { glcolor3f( *(double)i, *(double)i,2.0*(double)i); glvertex3fv(&ctrlpoints[i][0]); glend(); nurb = glunewnurbsrenderer(); glubegincurve(nurb); glunurbsproperty(nurb, GLU_SAMPLING_TOLERANCE, 1.0); glunurbsproperty(nurb, GLU_DISPLAY_MODE, GLU_FILL); glmaterialfv(gl_front, GL_DIFFUSE, mat_red_diffuse); glunurbscurve(nurb,8,knots,3,&ctrlpoints[0][0],4,gl_map1_vertex_3); gluendcurve(nurb); glflush();

29 Joindre deux Nurbs nurb = glunewnurbsrenderer(); glubegincurve(nurb); glunurbsproperty(nurb, GLU_SAMPLING_TOLERANCE, 1.0); glunurbsproperty(nurb, GLU_DISPLAY_MODE, GLU_FILL); glmaterialfv(gl_front, GL_DIFFUSE, mat_red_diffuse); glunurbscurve(nurb,8,&knots[0],3,&ctrlpoints[0][0],4,gl_map1_vertex_3); gluendcurve(nurb); glcolor3f(1.0,0.0,0.0); nurb = glunewnurbsrenderer(); glunurbsproperty(nurb, GLU_SAMPLING_TOLERANCE, 1.0); glunurbsproperty(nurb, GLU_DISPLAY_MODE, GLU_FILL); glmaterialfv(gl_front, GL_DIFFUSE, mat_red_diffuse); glubegincurve(nurb); glunurbscurve(nurb,8,&knots[1],3,&ctrlpoints[1][0],4,gl_map1_vertex_3); gluendcurve(nurb);

30 OpenGL for dummies