/* transformation.c Nate Robins, 1997 Tool for teaching about OpenGL transformations. */ #include <math.h> #include <stdio.h> #include <stdlib.h> #include <stdarg.h> #include <string.h> #include <GL/glut.h> #include "glm.h" #pragma comment( linker, "/entry:\"mainCRTStartup\"" ) // set the entry point to be main() typedef struct _cell { int id; int x, y; float min, max; float value; float step; char* info; char* format; } cell; cell translation[3] = { { 1, 120, 40, -5.0, 5.0, 0.0, 0.01, "Specifies X coordinate of translation vector.", "%.2f" }, { 2, 180, 40, -5.0, 5.0, 0.0, 0.01, "Specifies Y coordinate of translation vector.", "%.2f" }, { 3, 240, 40, -5.0, 5.0, 0.0, 0.01, "Specifies Z coordinate of translation vector.", "%.2f" }, }; cell rotation[4] = { { 4, 120, 80, -360.0, 360.0, 0.0, 1.0, "Specifies angle of rotation, in degrees.", "%.1f" }, { 5, 180, 80, -1.0, 1.0, 0.0, 0.01, "Specifies X coordinate of vector to rotate about.", "%.2f" }, { 6, 240, 80, -1.0, 1.0, 1.0, 0.01, "Specifies Y coordinate of vector to rotate about.", "%.2f" }, { 7, 300, 80, -1.0, 1.0, 0.0, 0.01, "Specifies Z coordinate of vector to rotate about.", "%.2f" }, }; cell scale[3] = { { 8, 120, 120, -5.0, 5.0, 1.0, 0.01, "Specifies scale factor along X axis.", "%.2f" }, { 9, 180, 120, -5.0, 5.0, 1.0, 0.01, "Specifies scale factor along Y axis.", "%.2f" }, { 10, 240, 120, -5.0, 5.0, 1.0, 0.01, "Specifies scale factor along Z axis.", "%.2f" }, }; GLfloat eye[3] = { 0.0, 0.0, 2.0 }; GLfloat at[3] = { 0.0, 0.0, 0.0 }; GLfloat up[3] = { 0.0, 1.0, 0.0 }; GLboolean swapped = GL_FALSE; GLboolean world_draw = GL_TRUE; GLMmodel* pmodel = NULL; GLint selection = 0; void redisplay_all(void); GLdouble projection[16], modelview[16], inverse[16]; GLuint window, world, screen, command; GLuint sub_width = 256, sub_height = 256; GLvoid *font_style = GLUT_BITMAP_TIMES_ROMAN_10; void setfont(char* name, int size) { font_style = GLUT_BITMAP_HELVETICA_10; if (strcmp(name, "helvetica") == 0) { if (size == 12) font_style = GLUT_BITMAP_HELVETICA_12; else if (size == 18) font_style = GLUT_BITMAP_HELVETICA_18; } else if (strcmp(name, "times roman") == 0) { font_style = GLUT_BITMAP_TIMES_ROMAN_10; if (size == 24) font_style = GLUT_BITMAP_TIMES_ROMAN_24; } else if (strcmp(name, "8x13") == 0) { font_style = GLUT_BITMAP_8_BY_13; } else if (strcmp(name, "9x15") == 0) { font_style = GLUT_BITMAP_9_BY_15; } } void drawstr(GLuint x, GLuint y, char* format, ...) { va_list args; char buffer[255], *s; va_start(args, format); vsprintf(buffer, format, args); va_end(args); glRasterPos2i(x, y); for (s = buffer; *s; s++) glutBitmapCharacter(font_style, *s); } void cell_draw(cell* cell) { glColor3ub(0, 255, 128); if (selection == cell->id) { glColor3ub(255, 255, 0); drawstr(10, 240, cell->info); glColor3ub(255, 0, 0); } drawstr(cell->x, cell->y, cell->format, cell->value); } int cell_hit(cell* cell, int x, int y) { if (x > cell->x && x < cell->x + 60 && y > cell->y-30 && y < cell->y+10) return cell->id; return 0; } void cell_update(cell* cell, int update) { if (selection != cell->id) return; cell->value += update * cell->step; if (cell->value < cell->min) cell->value = cell->min; else if (cell->value > cell->max) cell->value = cell->max; } void cell_vector(float* dst, cell* cell, int num) { while (--num >= 0) dst[num] = cell[num].value; } void drawmodel(void) { if (!pmodel) { pmodel = glmReadOBJ("data/porsche.obj"); if (!pmodel) exit(0); glmUnitize(pmodel); glmFacetNormals(pmodel); glmVertexNormals(pmodel, 90.0); } glmDraw(pmodel, GLM_SMOOTH | GLM_MATERIAL); } void drawaxes(void) { glColor3ub(255, 0, 0); glBegin(GL_LINE_STRIP); glVertex3f(0.0, 0.0, 0.0); glVertex3f(1.0, 0.0, 0.0); glVertex3f(0.75, 0.25, 0.0); glVertex3f(0.75, -0.25, 0.0); glVertex3f(1.0, 0.0, 0.0); glVertex3f(0.75, 0.0, 0.25); glVertex3f(0.75, 0.0, -0.25); glVertex3f(1.0, 0.0, 0.0); glEnd(); glBegin(GL_LINE_STRIP); glVertex3f(0.0, 0.0, 0.0); glVertex3f(0.0, 1.0, 0.0); glVertex3f(0.0, 0.75, 0.25); glVertex3f(0.0, 0.75, -0.25); glVertex3f(0.0, 1.0, 0.0); glVertex3f(0.25, 0.75, 0.0); glVertex3f(-0.25, 0.75, 0.0); glVertex3f(0.0, 1.0, 0.0); glEnd(); glBegin(GL_LINE_STRIP); glVertex3f(0.0, 0.0, 0.0); glVertex3f(0.0, 0.0, 1.0); glVertex3f(0.25, 0.0, 0.75); glVertex3f(-0.25, 0.0, 0.75); glVertex3f(0.0, 0.0, 1.0); glVertex3f(0.0, 0.25, 0.75); glVertex3f(0.0, -0.25, 0.75); glVertex3f(0.0, 0.0, 1.0); glEnd(); glColor3ub(255, 255, 0); glRasterPos3f(1.1, 0.0, 0.0); glutBitmapCharacter(GLUT_BITMAP_HELVETICA_12, 'x'); glRasterPos3f(0.0, 1.1, 0.0); glutBitmapCharacter(GLUT_BITMAP_HELVETICA_12, 'y'); glRasterPos3f(0.0, 0.0, 1.1); glutBitmapCharacter(GLUT_BITMAP_HELVETICA_12, 'z'); } void identity(GLdouble m[16]) { m[0+4*0] = 1; m[0+4*1] = 0; m[0+4*2] = 0; m[0+4*3] = 0; m[1+4*0] = 0; m[1+4*1] = 1; m[1+4*2] = 0; m[1+4*3] = 0; m[2+4*0] = 0; m[2+4*1] = 0; m[2+4*2] = 1; m[2+4*3] = 0; m[3+4*0] = 0; m[3+4*1] = 0; m[3+4*2] = 0; m[3+4*3] = 1; } GLboolean invert(GLdouble src[16], GLdouble inverse[16]) { double t; int i, j, k, swap; GLdouble tmp[4][4]; identity(inverse); for (i = 0; i < 4; i++) { for (j = 0; j < 4; j++) { tmp[i][j] = src[i*4+j]; } } for (i = 0; i < 4; i++) { /* look for largest element in column. */ swap = i; for (j = i + 1; j < 4; j++) { if (fabs(tmp[j][i]) > fabs(tmp[i][i])) { swap = j; } } if (swap != i) { /* swap rows. */ for (k = 0; k < 4; k++) { t = tmp[i][k]; tmp[i][k] = tmp[swap][k]; tmp[swap][k] = t; t = inverse[i*4+k]; inverse[i*4+k] = inverse[swap*4+k]; inverse[swap*4+k] = t; } } if (tmp[i][i] == 0) { /* no non-zero pivot. the matrix is singular, which shouldn't happen. This means the user gave us a bad matrix. */ return GL_FALSE; } t = tmp[i][i]; for (k = 0; k < 4; k++) { tmp[i][k] /= t; inverse[i*4+k] /= t; } for (j = 0; j < 4; j++) { if (j != i) { t = tmp[j][i]; for (k = 0; k < 4; k++) { tmp[j][k] -= tmp[i][k]*t; inverse[j*4+k] -= inverse[i*4+k]*t; } } } } return GL_TRUE; } float normalize(float* v) { float length; length = sqrt(v[0]*v[0] + v[1]*v[1] + v[2]*v[2]); v[0] /= length; v[1] /= length; v[2] /= length; return length; } void main_reshape(int width, int height) { glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(0, width, height, 0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); #define GAP 25 /* gap between subwindows */ sub_width = (width-GAP*3)/2.0; sub_height = (height-GAP*3)/2.0; glutSetWindow(world); glutPositionWindow(GAP, GAP); glutReshapeWindow(sub_width, sub_height); glutSetWindow(screen); glutPositionWindow(GAP+sub_width+GAP, GAP); glutReshapeWindow(sub_width, sub_height); glutSetWindow(command); glutPositionWindow(GAP, GAP+sub_height+GAP); glutReshapeWindow(sub_width+GAP+sub_width, sub_height); } void main_display(void) { glClearColor(0.8, 0.8, 0.8, 0.0); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glColor3ub(0, 0, 0); setfont("helvetica", 12); drawstr(GAP, GAP-5, "World-space view"); drawstr(GAP+sub_width+GAP, GAP-5, "Screen-space view"); drawstr(GAP, GAP+sub_height+GAP-5, "Command manipulation window"); glutSwapBuffers(); } void main_keyboard(unsigned char key, int x, int y) { switch (key) { case 's': swapped = !swapped; break; case 'r': translation[0].value = 0.0; translation[1].value = 0.0; translation[2].value = 0.0; rotation[0].value = 0.0; rotation[1].value = 0.0; rotation[2].value = 1.0; rotation[3].value = 0.0; scale[0].value = 1.0; scale[1].value = 1.0; scale[2].value = 1.0; break; case 27: exit(0); } redisplay_all(); } void world_reshape(int width, int height) { glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(60.0, (GLfloat)width/height, 0.01, 256.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glTranslatef(0.0, 0.0, -5.0); glRotatef(-45.0, 0.0, 1.0, 0.0); glClearColor(0.0, 0.0, 0.0, 0.0); glEnable(GL_DEPTH_TEST); glEnable(GL_LIGHT0); } void world_display(void) { GLfloat pos[] = { 0.0, 0.0, 1.0, 0.0 }; double length; float l[3]; l[0] = at[0] - eye[0]; l[1] = at[0] - eye[1]; l[2] = at[0] - eye[2]; length = normalize(l); invert(modelview, inverse); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); if (world_draw) { glEnable(GL_LIGHTING); glPushMatrix(); glMultMatrixd(inverse); glLightfv(GL_LIGHT0, GL_POSITION, pos); glPopMatrix(); drawmodel(); glDisable(GL_LIGHTING); } glPushMatrix(); glMultMatrixd(inverse); glLightfv(GL_LIGHT0, GL_POSITION, pos); /* draw the axis and eye vector */ glPushMatrix(); glColor3ub(0, 0, 255); glBegin(GL_LINE_STRIP); glVertex3f(0.0, 0.0, 0.0); glVertex3f(0.0, 0.0, -1.0*length); glVertex3f(0.1, 0.0, -0.9*length); glVertex3f(-0.1, 0.0, -0.9*length); glVertex3f(0.0, 0.0, -1.0*length); glVertex3f(0.0, 0.1, -0.9*length); glVertex3f(0.0, -0.1, -0.9*length); glVertex3f(0.0, 0.0, -1.0*length); glEnd(); glColor3ub(255, 255, 0); glRasterPos3f(0.0, 0.0, -1.1*length); glutBitmapCharacter(GLUT_BITMAP_HELVETICA_12, 'e'); glColor3ub(255, 0, 0); glScalef(0.4, 0.4, 0.4); drawaxes(); glPopMatrix(); invert(projection, inverse); glMultMatrixd(inverse); /* draw the viewing frustum */ glColor3f(0.2, 0.2, 0.2); glBegin(GL_QUADS); glVertex3i(1, 1, 1); glVertex3i(-1, 1, 1); glVertex3i(-1, -1, 1); glVertex3i(1, -1, 1); glEnd(); glColor3ub(128, 196, 128); glBegin(GL_LINES); glVertex3i(1, 1, -1); glVertex3i(1, 1, 1); glVertex3i(-1, 1, -1); glVertex3i(-1, 1, 1); glVertex3i(-1, -1, -1); glVertex3i(-1, -1, 1); glVertex3i(1, -1, -1); glVertex3i(1, -1, 1); glEnd(); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glColor4f(0.2, 0.2, 0.4, 0.5); glBegin(GL_QUADS); glVertex3i(1, 1, -1); glVertex3i(-1, 1, -1); glVertex3i(-1, -1, -1); glVertex3i(1, -1, -1); glEnd(); glDisable(GL_BLEND); glPopMatrix(); glutSwapBuffers(); } void world_menu(int value) { switch (value) { case 'm': world_draw = !world_draw; break; } redisplay_all(); } void screen_reshape(int width, int height) { glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(60.0, (float)width/height, 0.5, 8.0); glGetDoublev(GL_PROJECTION_MATRIX, projection); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); gluLookAt(eye[0], eye[1], eye[2], at[0], at[1], at[2], up[0], up[1],up[2]); if (swapped) { glRotatef(rotation[0].value, rotation[1].value, rotation[2].value, rotation[3].value); glTranslatef(translation[0].value, translation[1].value, translation[2].value); } else { glTranslatef(translation[0].value, translation[1].value, translation[2].value); glRotatef(rotation[0].value, rotation[1].value, rotation[2].value, rotation[3].value); } glScalef(scale[0].value, scale[1].value, scale[2].value); glGetDoublev(GL_MODELVIEW_MATRIX, modelview); glClearColor(0.2, 0.2, 0.2, 0.0); glEnable(GL_DEPTH_TEST); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); } void screen_display(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); drawmodel(); glutSwapBuffers(); } void screen_menu(int value) { char* name = 0; switch (value) { case 'a': name = "data/al.obj"; break; case 's': name = "data/soccerball.obj"; break; case 'd': name = "data/dolphins.obj"; break; case 'f': name = "data/flowers.obj"; break; case 'j': name = "data/f-16.obj"; break; case 'p': name = "data/porsche.obj"; break; case 'r': name = "data/rose+vase.obj"; break; } if (name) { pmodel = glmReadOBJ(name); if (!pmodel) exit(0); glmUnitize(pmodel); glmFacetNormals(pmodel); glmVertexNormals(pmodel, 90.0); } redisplay_all(); } void command_reshape(int width, int height) { glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(0, width, height, 0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glClearColor(0.0, 0.0, 0.0, 0.0); } void command_display(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); if (swapped) { translation[0].y = 80; translation[1].y = 80; translation[2].y = 80; rotation[0].y = 40; rotation[1].y = 40; rotation[2].y = 40; rotation[3].y = 40; } else { translation[0].y = 40; translation[1].y = 40; translation[2].y = 40; rotation[0].y = 80; rotation[1].y = 80; rotation[2].y = 80; rotation[3].y = 80; } glColor3ub(255, 255, 255); setfont("helvetica", 18); drawstr(30, rotation[0].y, "glRotatef("); drawstr(170, rotation[0].y, ","); drawstr(230, rotation[0].y, ","); drawstr(290, rotation[0].y, ","); drawstr(350, rotation[0].y, ");"); drawstr(10, translation[0].y, "glTranslatef("); drawstr(170, translation[0].y, ","); drawstr(230, translation[0].y, ","); drawstr(290, translation[0].y, ");"); drawstr(38, 120, "glScalef("); drawstr(170, 120, ","); drawstr(230, 120, ","); drawstr(290, 120, ");"); drawstr(41, 160, "glBegin( . . . );"); drawstr(41, 200, " . . ."); cell_draw(&translation[0]); cell_draw(&translation[1]); cell_draw(&translation[2]); cell_draw(&rotation[0]); cell_draw(&rotation[1]); cell_draw(&rotation[2]); cell_draw(&rotation[3]); cell_draw(&scale[0]); cell_draw(&scale[1]); cell_draw(&scale[2]); if (!selection) { glColor3ub(255, 255, 0); drawstr(10, 240, "Click on the arguments and move the mouse to modify values."); } glutSwapBuffers(); } int old_y; void command_mouse(int button, int state, int x, int y) { selection = 0; if (state == GLUT_DOWN) { /* mouse should only hit _one_ of the cells, so adding up all the hits just propagates a single hit. */ selection += cell_hit(&translation[0], x, y); selection += cell_hit(&translation[1], x, y); selection += cell_hit(&translation[2], x, y); selection += cell_hit(&rotation[0], x, y); selection += cell_hit(&rotation[1], x, y); selection += cell_hit(&rotation[2], x, y); selection += cell_hit(&rotation[3], x, y); selection += cell_hit(&scale[0], x, y); selection += cell_hit(&scale[1], x, y); selection += cell_hit(&scale[2], x, y); } old_y = y; redisplay_all(); } void command_motion(int x, int y) { cell_update(&translation[0], old_y-y); cell_update(&translation[1], old_y-y); cell_update(&translation[2], old_y-y); cell_update(&rotation[0], old_y-y); cell_update(&rotation[1], old_y-y); cell_update(&rotation[2], old_y-y); cell_update(&rotation[3], old_y-y); cell_update(&scale[0], old_y-y); cell_update(&scale[1], old_y-y); cell_update(&scale[2], old_y-y); old_y = y; redisplay_all(); } void command_menu(int value) { main_keyboard((unsigned char)value, 0, 0); } void redisplay_all(void) { glutSetWindow(command); glutPostRedisplay(); glutSetWindow(world); world_reshape(sub_width, sub_height); glutPostRedisplay(); glutSetWindow(screen); screen_reshape(sub_width, sub_height); glutPostRedisplay(); } int main(int argc, char** argv) { glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE); glutInitWindowSize(512+GAP*3, 512+GAP*3); glutInitWindowPosition(50, 50); glutInit(&argc, argv); window = glutCreateWindow("Transformation"); glutReshapeFunc(main_reshape); glutDisplayFunc(main_display); glutKeyboardFunc(main_keyboard); world = glutCreateSubWindow(window, GAP, GAP, 256, 256); glutReshapeFunc(world_reshape); glutDisplayFunc(world_display); glutKeyboardFunc(main_keyboard); glutCreateMenu(world_menu); glutAddMenuEntry("Toggle model", 'm'); glutAttachMenu(GLUT_RIGHT_BUTTON); screen = glutCreateSubWindow(window, GAP+256+GAP, GAP, 256, 256); glutReshapeFunc(screen_reshape); glutDisplayFunc(screen_display); glutKeyboardFunc(main_keyboard); glutCreateMenu(screen_menu); glutAddMenuEntry("Models", 0); glutAddMenuEntry("", 0); glutAddMenuEntry("Soccerball", 's'); glutAddMenuEntry("Al Capone", 'a'); glutAddMenuEntry("F-16 Jet", 'j'); glutAddMenuEntry("Dolphins", 'd'); glutAddMenuEntry("Flowers", 'f'); glutAddMenuEntry("Porsche", 'p'); glutAddMenuEntry("Rose", 'r'); glutAttachMenu(GLUT_RIGHT_BUTTON); command = glutCreateSubWindow(window, GAP+256+GAP, GAP+256+GAP, 256, 256); glutReshapeFunc(command_reshape); glutDisplayFunc(command_display); glutMotionFunc(command_motion); glutMouseFunc(command_mouse); glutKeyboardFunc(main_keyboard); glutCreateMenu(command_menu); glutAddMenuEntry("Projection", 0); glutAddMenuEntry("", 0); glutAddMenuEntry("[s] Swap translate/rotate", 's'); glutAddMenuEntry("[r] Reset parameters", 'r'); glutAddMenuEntry("", 0); glutAddMenuEntry("Quit", 27); glutAttachMenu(GLUT_RIGHT_BUTTON); redisplay_all(); glutMainLoop(); return 0; }