| /* |
| * Use glCopyTexSubImage2D to draw animated gears on the sides of a box. |
| * |
| * Brian Paul |
| * 27 January 2006 |
| */ |
| |
| #include <math.h> |
| #include <stdlib.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <GL/glut.h> |
| |
| #ifndef M_PI |
| #define M_PI 3.14159265 |
| #endif |
| |
| static GLint WinWidth = 800, WinHeight = 500; |
| static GLint TexWidth, TexHeight; |
| static GLuint TexObj = 1; |
| static GLenum IntFormat = GL_RGB; |
| |
| static GLboolean WireFrame = GL_FALSE; |
| |
| static GLint T0 = 0; |
| static GLint Frames = 0; |
| static GLint Win = 0; |
| |
| static GLfloat ViewRotX = 20.0, ViewRotY = 30.0, ViewRotZ = 0.0; |
| static GLint Gear1, Gear2, Gear3; |
| static GLfloat GearRot = 0.0; |
| static GLfloat CubeRot = 0.0; |
| |
| |
| /** |
| Draw a gear wheel. You'll probably want to call this function when |
| building a display list since we do a lot of trig here. |
| |
| Input: inner_radius - radius of hole at center |
| outer_radius - radius at center of teeth |
| width - width of gear |
| teeth - number of teeth |
| tooth_depth - depth of tooth |
| **/ |
| static void |
| gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width, |
| GLint teeth, GLfloat tooth_depth) |
| { |
| GLint i; |
| GLfloat r0, r1, r2; |
| GLfloat angle, da; |
| GLfloat u, v, len; |
| |
| r0 = inner_radius; |
| r1 = outer_radius - tooth_depth / 2.0; |
| r2 = outer_radius + tooth_depth / 2.0; |
| |
| da = 2.0 * M_PI / teeth / 4.0; |
| |
| glShadeModel(GL_FLAT); |
| |
| glNormal3f(0.0, 0.0, 1.0); |
| |
| /* draw front face */ |
| glBegin(GL_QUAD_STRIP); |
| for (i = 0; i <= teeth; i++) { |
| angle = i * 2.0 * M_PI / teeth; |
| glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5); |
| glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5); |
| if (i < teeth) { |
| glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5); |
| glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5); |
| } |
| } |
| glEnd(); |
| |
| /* draw front sides of teeth */ |
| glBegin(GL_QUADS); |
| da = 2.0 * M_PI / teeth / 4.0; |
| for (i = 0; i < teeth; i++) { |
| angle = i * 2.0 * M_PI / teeth; |
| |
| glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5); |
| glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5); |
| glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5); |
| glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5); |
| } |
| glEnd(); |
| |
| glNormal3f(0.0, 0.0, -1.0); |
| |
| /* draw back face */ |
| glBegin(GL_QUAD_STRIP); |
| for (i = 0; i <= teeth; i++) { |
| angle = i * 2.0 * M_PI / teeth; |
| glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5); |
| glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5); |
| if (i < teeth) { |
| glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5); |
| glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5); |
| } |
| } |
| glEnd(); |
| |
| /* draw back sides of teeth */ |
| glBegin(GL_QUADS); |
| da = 2.0 * M_PI / teeth / 4.0; |
| for (i = 0; i < teeth; i++) { |
| angle = i * 2.0 * M_PI / teeth; |
| |
| glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5); |
| glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5); |
| glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5); |
| glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5); |
| } |
| glEnd(); |
| |
| /* draw outward faces of teeth */ |
| glBegin(GL_QUAD_STRIP); |
| for (i = 0; i < teeth; i++) { |
| angle = i * 2.0 * M_PI / teeth; |
| |
| glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5); |
| glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5); |
| u = r2 * cos(angle + da) - r1 * cos(angle); |
| v = r2 * sin(angle + da) - r1 * sin(angle); |
| len = sqrt(u * u + v * v); |
| u /= len; |
| v /= len; |
| glNormal3f(v, -u, 0.0); |
| glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5); |
| glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5); |
| glNormal3f(cos(angle), sin(angle), 0.0); |
| glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5); |
| glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5); |
| u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da); |
| v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da); |
| glNormal3f(v, -u, 0.0); |
| glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5); |
| glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5); |
| glNormal3f(cos(angle), sin(angle), 0.0); |
| } |
| |
| glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5); |
| glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5); |
| |
| glEnd(); |
| |
| glShadeModel(GL_SMOOTH); |
| |
| /* draw inside radius cylinder */ |
| glBegin(GL_QUAD_STRIP); |
| for (i = 0; i <= teeth; i++) { |
| angle = i * 2.0 * M_PI / teeth; |
| glNormal3f(-cos(angle), -sin(angle), 0.0); |
| glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5); |
| glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5); |
| } |
| glEnd(); |
| |
| } |
| |
| static void |
| cleanup(void) |
| { |
| glDeleteTextures(1, &TexObj); |
| glDeleteLists(Gear1, 1); |
| glDeleteLists(Gear2, 1); |
| glDeleteLists(Gear3, 1); |
| glutDestroyWindow(Win); |
| } |
| |
| |
| static void |
| DrawGears(void) |
| { |
| if (WireFrame) { |
| glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); |
| } |
| |
| glPushMatrix(); |
| glRotatef(20/*ViewRotX*/, 1.0, 0.0, 0.0); |
| glRotatef(ViewRotY, 0.0, 1.0, 0.0); |
| glRotatef(ViewRotZ, 0.0, 0.0, 1.0); |
| |
| glPushMatrix(); |
| glTranslatef(-3.0, -2.0, 0.0); |
| glRotatef(GearRot, 0.0, 0.0, 1.0); |
| glCallList(Gear1); |
| glPopMatrix(); |
| |
| glPushMatrix(); |
| glTranslatef(3.1, -2.0, 0.0); |
| glRotatef(-2.0 * GearRot - 9.0, 0.0, 0.0, 1.0); |
| glCallList(Gear2); |
| glPopMatrix(); |
| |
| glPushMatrix(); |
| glTranslatef(-3.1, 4.2, 0.0); |
| glRotatef(-2.0 * GearRot - 25.0, 0.0, 0.0, 1.0); |
| glCallList(Gear3); |
| glPopMatrix(); |
| |
| glPopMatrix(); |
| |
| glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); |
| } |
| |
| |
| static void |
| DrawCube(void) |
| { |
| static const GLfloat texcoords[4][2] = { |
| { 0, 0 }, { 1, 0 }, { 1, 1 }, { 0, 1 } |
| }; |
| static const GLfloat vertices[4][2] = { |
| { -1, -1 }, { 1, -1 }, { 1, 1 }, { -1, 1 } |
| }; |
| static const GLfloat xforms[6][4] = { |
| { 0, 0, 1, 0 }, |
| { 90, 0, 1, 0 }, |
| { 180, 0, 1, 0 }, |
| { 270, 0, 1, 0 }, |
| { 90, 1, 0, 0 }, |
| { -90, 1, 0, 0 } |
| }; |
| static const GLfloat mat[4] = { 1.0, 1.0, 0.5, 1.0 }; |
| GLint i, j; |
| |
| glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat); |
| glEnable(GL_TEXTURE_2D); |
| |
| glPushMatrix(); |
| glRotatef(ViewRotX, 1.0, 0.0, 0.0); |
| glRotatef(15, 1, 0, 0); |
| glRotatef(CubeRot, 0, 1, 0); |
| glScalef(4, 4, 4); |
| |
| for (i = 0; i < 6; i++) { |
| glPushMatrix(); |
| glRotatef(xforms[i][0], xforms[i][1], xforms[i][2], xforms[i][3]); |
| glTranslatef(0, 0, 1.1); |
| glBegin(GL_POLYGON); |
| glNormal3f(0, 0, 1); |
| for (j = 0; j < 4; j++) { |
| glTexCoord2fv(texcoords[j]); |
| glVertex2fv(vertices[j]); |
| } |
| glEnd(); |
| glPopMatrix(); |
| } |
| glPopMatrix(); |
| |
| glDisable(GL_TEXTURE_2D); |
| } |
| |
| |
| static void |
| draw(void) |
| { |
| float ar; |
| |
| glMatrixMode(GL_MODELVIEW); |
| glLoadIdentity(); |
| glTranslatef(0.0, 0.0, -40.0); |
| |
| /* clear whole depth buffer */ |
| glDisable(GL_SCISSOR_TEST); |
| glClear(GL_DEPTH_BUFFER_BIT); |
| glEnable(GL_SCISSOR_TEST); |
| |
| /* clear upper-left corner of color buffer (unused space) */ |
| glScissor(0, TexHeight, TexWidth, WinHeight - TexHeight); |
| glClearColor(0.0, 0.0, 0.0, 0.0); |
| glClear(GL_COLOR_BUFFER_BIT); |
| |
| /* clear lower-left corner of color buffer */ |
| glViewport(0, 0, TexWidth, TexHeight); |
| glScissor(0, 0, TexWidth, TexHeight); |
| glClearColor(1, 1, 1, 0); |
| glClear(GL_COLOR_BUFFER_BIT); |
| |
| /* draw gears in lower-left corner */ |
| glMatrixMode(GL_PROJECTION); |
| glLoadIdentity(); |
| glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 60.0); |
| glMatrixMode(GL_MODELVIEW); |
| DrawGears(); |
| |
| /* copy color buffer to texture */ |
| glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, TexWidth, TexHeight); |
| |
| /* clear right half of color buffer */ |
| glViewport(TexWidth, 0, WinWidth - TexWidth, WinHeight); |
| glScissor(TexWidth, 0, WinWidth - TexWidth, WinHeight); |
| glClearColor(0.5, 0.5, 0.8, 0.0); |
| glClear(GL_COLOR_BUFFER_BIT); |
| |
| /* draw textured cube in right half of window */ |
| ar = (float) (WinWidth - TexWidth) / WinHeight; |
| glMatrixMode(GL_PROJECTION); |
| glLoadIdentity(); |
| glFrustum(-ar, ar, -1.0, 1.0, 5.0, 60.0); |
| glMatrixMode(GL_MODELVIEW); |
| DrawCube(); |
| |
| /* finish up */ |
| glutSwapBuffers(); |
| |
| Frames++; |
| { |
| GLint t = glutGet(GLUT_ELAPSED_TIME); |
| if (t - T0 >= 5000) { |
| GLfloat seconds = (t - T0) / 1000.0; |
| GLfloat fps = Frames / seconds; |
| printf("%d frames in %6.3f seconds = %6.3f FPS\n", Frames, seconds, fps); |
| fflush(stdout); |
| T0 = t; |
| Frames = 0; |
| } |
| } |
| } |
| |
| |
| static void |
| idle(void) |
| { |
| static double t0 = -1.; |
| double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0; |
| if (t0 < 0.0) |
| t0 = t; |
| dt = t - t0; |
| t0 = t; |
| |
| /* fmod to prevent overflow */ |
| GearRot = fmod(GearRot + 70.0 * dt, 360.0); /* 70 deg/sec */ |
| CubeRot = fmod(CubeRot + 15.0 * dt, 360.0); /* 15 deg/sec */ |
| |
| glutPostRedisplay(); |
| } |
| |
| |
| /* change view angle, exit upon ESC */ |
| static void |
| key(unsigned char k, int x, int y) |
| { |
| (void) x; |
| (void) y; |
| switch (k) { |
| case 'w': |
| WireFrame = !WireFrame; |
| break; |
| case 'z': |
| ViewRotZ += 5.0; |
| break; |
| case 'Z': |
| ViewRotZ -= 5.0; |
| break; |
| case 27: /* Escape */ |
| cleanup(); |
| exit(0); |
| break; |
| default: |
| return; |
| } |
| glutPostRedisplay(); |
| } |
| |
| /* change view angle */ |
| static void |
| special(int k, int x, int y) |
| { |
| (void) x; |
| (void) y; |
| switch (k) { |
| case GLUT_KEY_UP: |
| ViewRotX += 5.0; |
| break; |
| case GLUT_KEY_DOWN: |
| ViewRotX -= 5.0; |
| break; |
| case GLUT_KEY_LEFT: |
| ViewRotY += 5.0; |
| break; |
| case GLUT_KEY_RIGHT: |
| ViewRotY -= 5.0; |
| break; |
| default: |
| return; |
| } |
| glutPostRedisplay(); |
| } |
| |
| |
| /* new window size or exposure */ |
| static void |
| reshape(int width, int height) |
| { |
| WinWidth = width; |
| WinHeight = height; |
| } |
| |
| |
| static void |
| init(int argc, char *argv[]) |
| { |
| static GLfloat pos[4] = {5.0, 5.0, 10.0, 0.0}; |
| static GLfloat red[4] = {0.8, 0.1, 0.0, 1.0}; |
| static GLfloat green[4] = {0.0, 0.8, 0.2, 1.0}; |
| static GLfloat blue[4] = {0.2, 0.2, 1.0, 1.0}; |
| GLint i; |
| |
| glLightfv(GL_LIGHT0, GL_POSITION, pos); |
| #if 0 |
| glEnable(GL_CULL_FACE); |
| #endif |
| glEnable(GL_LIGHTING); |
| glEnable(GL_LIGHT0); |
| glEnable(GL_DEPTH_TEST); |
| |
| /* make the gears */ |
| Gear1 = glGenLists(1); |
| glNewList(Gear1, GL_COMPILE); |
| glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red); |
| gear(1.0, 4.0, 1.0, 20, 0.7); |
| glEndList(); |
| |
| Gear2 = glGenLists(1); |
| glNewList(Gear2, GL_COMPILE); |
| glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green); |
| gear(0.5, 2.0, 2.0, 10, 0.7); |
| glEndList(); |
| |
| Gear3 = glGenLists(1); |
| glNewList(Gear3, GL_COMPILE); |
| glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue); |
| gear(1.3, 2.0, 0.5, 10, 0.7); |
| glEndList(); |
| |
| glEnable(GL_NORMALIZE); |
| |
| /* xxx make size dynamic */ |
| TexWidth = 256; |
| TexHeight = 256; |
| |
| glBindTexture(GL_TEXTURE_2D, TexObj); |
| glTexImage2D(GL_TEXTURE_2D, 0, IntFormat, TexWidth, TexHeight, 0, |
| GL_RGBA, GL_UNSIGNED_BYTE, NULL); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); |
| glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); |
| |
| for ( i=1; i<argc; i++ ) { |
| if (strcmp(argv[i], "-info")==0) { |
| printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER)); |
| printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION)); |
| printf("GL_VENDOR = %s\n", (char *) glGetString(GL_VENDOR)); |
| printf("GL_EXTENSIONS = %s\n", (char *) glGetString(GL_EXTENSIONS)); |
| } |
| } |
| } |
| |
| |
| static void |
| visible(int vis) |
| { |
| if (vis == GLUT_VISIBLE) |
| glutIdleFunc(idle); |
| else |
| glutIdleFunc(NULL); |
| } |
| |
| |
| int |
| main(int argc, char *argv[]) |
| { |
| glutInitWindowSize(WinWidth, WinHeight); |
| glutInit(&argc, argv); |
| glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE); |
| |
| Win = glutCreateWindow("gearbox"); |
| init(argc, argv); |
| |
| glutDisplayFunc(draw); |
| glutReshapeFunc(reshape); |
| glutKeyboardFunc(key); |
| glutSpecialFunc(special); |
| glutVisibilityFunc(visible); |
| |
| glutMainLoop(); |
| return 0; /* ANSI C requires main to return int. */ |
| } |