dinodraw.c
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上传日期:2007-05-28
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文件大小:12k
- /*
- * Dinodraw.c
- *
- * Copyright (c) James Bowman 1998,
- * parts (c) Mark J. Kilgard, 1994.
- */
- /* This program is freely distributable without licensing fees
- and is provided without guarantee or warrantee expressed or
- implied. This program is -not- in the public domain. */
- /* Modified version of Mark J. Kilgard's dinospin that demontrates use of
- * stencil buffer to interactively view overdraw.
- */
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <math.h> /* for cos(), sin(), and sqrt() */
- #include <GL/glut.h>
- #include "trackball.h"
- typedef enum {
- RESERVED, BODY_SIDE, BODY_EDGE, BODY_WHOLE, ARM_SIDE, ARM_EDGE, ARM_WHOLE,
- LEG_SIDE, LEG_EDGE, LEG_WHOLE, EYE_SIDE, EYE_EDGE, EYE_WHOLE, DINOSAUR
- } displayLists;
- GLfloat angle = -150; /* in degrees */
- GLboolean doubleBuffer = GL_TRUE, iconic = GL_FALSE, keepAspect = GL_FALSE;
- int spinning = 0, moving = 0;
- int beginx, beginy;
- int W = 300, H = 300;
- float curquat[4];
- float lastquat[4];
- GLdouble bodyWidth = 2.0;
- int newModel = 1;
- int scaling;
- float scalefactor = 1.0;
- /* *INDENT-OFF* */
- GLfloat body[][2] = { {0, 3}, {1, 1}, {5, 1}, {8, 4}, {10, 4}, {11, 5},
- {11, 11.5}, {13, 12}, {13, 13}, {10, 13.5}, {13, 14}, {13, 15}, {11, 16},
- {8, 16}, {7, 15}, {7, 13}, {8, 12}, {7, 11}, {6, 6}, {4, 3}, {3, 2},
- {1, 2} };
- GLfloat arm[][2] = { {8, 10}, {9, 9}, {10, 9}, {13, 8}, {14, 9}, {16, 9},
- {15, 9.5}, {16, 10}, {15, 10}, {15.5, 11}, {14.5, 10}, {14, 11}, {14, 10},
- {13, 9}, {11, 11}, {9, 11} };
- GLfloat leg[][2] = { {8, 6}, {8, 4}, {9, 3}, {9, 2}, {8, 1}, {8, 0.5}, {9, 0},
- {12, 0}, {10, 1}, {10, 2}, {12, 4}, {11, 6}, {10, 7}, {9, 7} };
- GLfloat eye[][2] = { {8.75, 15}, {9, 14.7}, {9.6, 14.7}, {10.1, 15},
- {9.6, 15.25}, {9, 15.25} };
- GLfloat lightZeroPosition[] = {10.0, 4.0, 10.0, 1.0};
- GLfloat lightZeroColor[] = {0.8, 1.0, 0.8, 1.0}; /* green-tinted */
- GLfloat lightOnePosition[] = {-1.0, -2.0, 1.0, 0.0};
- GLfloat lightOneColor[] = {0.6, 0.3, 0.2, 1.0}; /* red-tinted */
- GLfloat skinColor[] = {0.1, 1.0, 0.1, 1.0}, eyeColor[] = {1.0, 0.2, 0.2, 1.0};
- /* *INDENT-ON* */
- void
- extrudeSolidFromPolygon(GLfloat data[][2], unsigned int dataSize,
- GLdouble thickness, GLuint side, GLuint edge, GLuint whole)
- {
- static GLUtriangulatorObj *tobj = NULL;
- GLdouble vertex[3], dx, dy, len;
- int i;
- int count = dataSize / (2 * sizeof(GLfloat));
- if (tobj == NULL) {
- tobj = gluNewTess(); /* create and initialize a GLU
- polygon * * tesselation object */
- gluTessCallback(tobj, GLU_BEGIN, glBegin);
- gluTessCallback(tobj, GLU_VERTEX, glVertex2fv); /* semi-tricky
- */
- gluTessCallback(tobj, GLU_END, glEnd);
- }
- glNewList(side, GL_COMPILE);
- glShadeModel(GL_SMOOTH); /* smooth minimizes seeing
- tessellation */
- gluBeginPolygon(tobj);
- for (i = 0; i < count; i++) {
- vertex[0] = data[i][0];
- vertex[1] = data[i][1];
- vertex[2] = 0;
- gluTessVertex(tobj, vertex, data[i]);
- }
- gluEndPolygon(tobj);
- glEndList();
- glNewList(edge, GL_COMPILE);
- glShadeModel(GL_FLAT); /* flat shade keeps angular hands
- from being * * "smoothed" */
- glBegin(GL_QUAD_STRIP);
- for (i = 0; i <= count; i++) {
- /* mod function handles closing the edge */
- glVertex3f(data[i % count][0], data[i % count][1], 0.0);
- glVertex3f(data[i % count][0], data[i % count][1], thickness);
- /* Calculate a unit normal by dividing by Euclidean
- distance. We * could be lazy and use
- glEnable(GL_NORMALIZE) so we could pass in * arbitrary
- normals for a very slight performance hit. */
- dx = data[(i + 1) % count][1] - data[i % count][1];
- dy = data[i % count][0] - data[(i + 1) % count][0];
- len = sqrt(dx * dx + dy * dy);
- glNormal3f(dx / len, dy / len, 0.0);
- }
- glEnd();
- glEndList();
- glNewList(whole, GL_COMPILE);
- glFrontFace(GL_CW);
- glCallList(edge);
- glNormal3f(0.0, 0.0, -1.0); /* constant normal for side */
- glCallList(side);
- glPushMatrix();
- glTranslatef(0.0, 0.0, thickness);
- glFrontFace(GL_CCW);
- glNormal3f(0.0, 0.0, 1.0); /* opposite normal for other side
- */
- glCallList(side);
- glPopMatrix();
- glEndList();
- }
- void
- makeDinosaur(void)
- {
- GLfloat bodyWidth = 3.0;
- extrudeSolidFromPolygon(body, sizeof(body), bodyWidth,
- BODY_SIDE, BODY_EDGE, BODY_WHOLE);
- extrudeSolidFromPolygon(arm, sizeof(arm), bodyWidth / 4,
- ARM_SIDE, ARM_EDGE, ARM_WHOLE);
- extrudeSolidFromPolygon(leg, sizeof(leg), bodyWidth / 2,
- LEG_SIDE, LEG_EDGE, LEG_WHOLE);
- extrudeSolidFromPolygon(eye, sizeof(eye), bodyWidth + 0.2,
- EYE_SIDE, EYE_EDGE, EYE_WHOLE);
- glNewList(DINOSAUR, GL_COMPILE);
- glMaterialfv(GL_FRONT, GL_DIFFUSE, skinColor);
- glCallList(BODY_WHOLE);
- glPushMatrix();
- glTranslatef(0.0, 0.0, bodyWidth);
- glCallList(ARM_WHOLE);
- glCallList(LEG_WHOLE);
- glTranslatef(0.0, 0.0, -bodyWidth - bodyWidth / 4);
- glCallList(ARM_WHOLE);
- glTranslatef(0.0, 0.0, -bodyWidth / 4);
- glCallList(LEG_WHOLE);
- glTranslatef(0.0, 0.0, bodyWidth / 2 - 0.1);
- glMaterialfv(GL_FRONT, GL_DIFFUSE, eyeColor);
- glCallList(EYE_WHOLE);
- glPopMatrix();
- glEndList();
- }
- void
- recalcModelView(void)
- {
- GLfloat m[4][4];
- glPopMatrix();
- glPushMatrix();
- build_rotmatrix(m, curquat);
- glMultMatrixf(&m[0][0]);
- glScalef(scalefactor, scalefactor, scalefactor);
- glTranslatef(-8, -8, -bodyWidth / 2);
- newModel = 0;
- }
- void
- showMessage(GLfloat x, GLfloat y, GLfloat z, char *message)
- {
- glPushMatrix();
- glDisable(GL_LIGHTING);
- glTranslatef(x, y, z);
- glScalef(.02, .02, .02);
- while (*message) {
- glutStrokeCharacter(GLUT_STROKE_ROMAN, *message);
- message++;
- }
- glEnable(GL_LIGHTING);
- glPopMatrix();
- }
- void
- redraw(void)
- {
- if (newModel)
- recalcModelView();
- glClear(GL_COLOR_BUFFER_BIT |
- GL_DEPTH_BUFFER_BIT |
- GL_STENCIL_BUFFER_BIT);
- /* Draw the real scene in the left viewport... */
- glViewport(0, 0, W / 2, H);
- glDisable(GL_STENCIL_TEST);
- glCallList(DINOSAUR);
- showMessage(2, 7.1, 4.1, "Spin me.");
- /* ...and the overdraw indicator in the right viewport */
- glViewport(W / 2, 0, W / 2, H);
- /* First draw the scene again, this time without color updates,
- * just counting pixels drawn in the stencil buffer.
- */
- glEnable(GL_STENCIL_TEST);
- glStencilFunc(GL_ALWAYS, 0, 0);
- glStencilOp(GL_KEEP, GL_INCR, GL_INCR);
- glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
- glCallList(DINOSAUR);
- showMessage(2, 7.1, 4.1, "Spin me.");
- glMatrixMode(GL_MODELVIEW);
- glPushMatrix();
- glLoadIdentity();
- glMatrixMode(GL_PROJECTION);
- glPushMatrix();
- glLoadIdentity();
- glDisable(GL_LIGHTING);
- glDisable(GL_DEPTH_TEST);
- glColor3f(1.0f, 1.0f, 1.0f);
- glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
- /* Copy bit 0 into the blue plane */
- glColorMask(GL_FALSE, GL_FALSE, GL_TRUE, GL_FALSE);
- glStencilFunc(GL_NOTEQUAL, 0, 0xf8 | 0x01);
- glRectf(-1.0f, -1.0f, 1.0f, 1.0f);
- /* Copy bit 1 into the red plane */
- glColorMask(GL_TRUE, GL_FALSE, GL_FALSE, GL_FALSE);
- glStencilFunc(GL_NOTEQUAL, 0, 0xf8 | 0x02);
- glRectf(-1.0f, -1.0f, 1.0f, 1.0f);
- /* Copy bit 2 into the green plane */
- glColorMask(GL_FALSE, GL_TRUE, GL_FALSE, GL_FALSE);
- glStencilFunc(GL_NOTEQUAL, 0, 0xf8 | 0x04);
- glRectf(-1.0f, -1.0f, 1.0f, 1.0f);
- /* Note that anything greater than 7 will have one of bits 3-7 set,
- * hence will be drawn on all three planes by the mask with 0xf8 above.
- * So anything overdrawn 7 or more times will be drawn in white.
- */
- glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
- glEnable(GL_DEPTH_TEST);
- glEnable(GL_LIGHTING);
- glMatrixMode(GL_PROJECTION);
- glPopMatrix();
- glMatrixMode(GL_MODELVIEW);
- glPopMatrix();
- glutSwapBuffers();
- }
- void
- myReshape(int w, int h)
- {
- glViewport(0, 0, w / 2, h);
- W = w;
- H = h;
- }
- void
- mouse(int button, int state, int x, int y)
- {
- if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
- spinning = 0;
- glutIdleFunc(NULL);
- moving = 1;
- beginx = x;
- beginy = y;
- if (glutGetModifiers() & GLUT_ACTIVE_SHIFT) {
- scaling = 1;
- } else {
- scaling = 0;
- }
- }
- if (button == GLUT_LEFT_BUTTON && state == GLUT_UP) {
- moving = 0;
- }
- }
- void
- animate(void)
- {
- add_quats(lastquat, curquat, curquat);
- newModel = 1;
- glutPostRedisplay();
- }
- void
- motion(int x, int y)
- {
- if (scaling) {
- scalefactor = scalefactor * (1.0 + (((float) (beginy - y)) / H));
- beginx = x;
- beginy = y;
- newModel = 1;
- glutPostRedisplay();
- return;
- }
- if (moving) {
- trackball(lastquat,
- (2.0 * beginx - W) / W,
- (H - 2.0 * beginy) / H,
- (2.0 * x - W) / W,
- (H - 2.0 * y) / H
- );
- beginx = x;
- beginy = y;
- spinning = 1;
- glutIdleFunc(animate);
- }
- }
- GLboolean lightZeroSwitch = GL_TRUE, lightOneSwitch = GL_TRUE;
- void
- controlLights(int value)
- {
- switch (value) {
- case 1:
- lightZeroSwitch = !lightZeroSwitch;
- if (lightZeroSwitch) {
- glEnable(GL_LIGHT0);
- } else {
- glDisable(GL_LIGHT0);
- }
- break;
- case 2:
- lightOneSwitch = !lightOneSwitch;
- if (lightOneSwitch) {
- glEnable(GL_LIGHT1);
- } else {
- glDisable(GL_LIGHT1);
- }
- break;
- #ifdef GL_MULTISAMPLE_SGIS
- case 3:
- if (glIsEnabled(GL_MULTISAMPLE_SGIS)) {
- glDisable(GL_MULTISAMPLE_SGIS);
- } else {
- glEnable(GL_MULTISAMPLE_SGIS);
- }
- break;
- #endif
- case 4:
- glutFullScreen();
- break;
- case 5:
- exit(0);
- break;
- }
- glutPostRedisplay();
- }
- void
- vis(int visible)
- {
- if (visible == GLUT_VISIBLE) {
- if (spinning)
- glutIdleFunc(animate);
- } else {
- if (spinning)
- glutIdleFunc(NULL);
- }
- }
- int
- main(int argc, char **argv)
- {
- glutInit(&argc, argv);
- glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH | GLUT_STENCIL);
- trackball(curquat, 0.0, 0.0, 0.0, 0.0);
- glutInitWindowSize(600, 300);
- glutCreateWindow("dinodraw");
- glutDisplayFunc(redraw);
- glutReshapeFunc(myReshape);
- glutVisibilityFunc(vis);
- glutMouseFunc(mouse);
- glutMotionFunc(motion);
- glutCreateMenu(controlLights);
- glutAddMenuEntry("Toggle right light", 1);
- glutAddMenuEntry("Toggle left light", 2);
- if (glutGet(GLUT_WINDOW_NUM_SAMPLES) > 0) {
- glutAddMenuEntry("Toggle multisampling", 3);
- glutSetWindowTitle("dinospin (multisample capable)");
- }
- glutAddMenuEntry("Full screen", 4);
- glutAddMenuEntry("Quit", 5);
- glutAttachMenu(GLUT_RIGHT_BUTTON);
- makeDinosaur();
- glEnable(GL_CULL_FACE);
- glEnable(GL_DEPTH_TEST);
- glEnable(GL_LIGHTING);
- glMatrixMode(GL_PROJECTION);
- gluPerspective( /* field of view in degree */ 40.0,
- /* aspect ratio */ 1.0,
- /* Z near */ 1.0, /* Z far */ 40.0);
- glMatrixMode(GL_MODELVIEW);
- gluLookAt(0.0, 0.0, 30.0, /* eye is at (0,0,30) */
- 0.0, 0.0, 0.0, /* center is at (0,0,0) */
- 0.0, 1.0, 0.); /* up is in positive Y direction */
- glPushMatrix(); /* dummy push so we can pop on model
- recalc */
- glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, 1);
- glLightfv(GL_LIGHT0, GL_POSITION, lightZeroPosition);
- glLightfv(GL_LIGHT0, GL_DIFFUSE, lightZeroColor);
- glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 0.1);
- glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.05);
- glLightfv(GL_LIGHT1, GL_POSITION, lightOnePosition);
- glLightfv(GL_LIGHT1, GL_DIFFUSE, lightOneColor);
- glEnable(GL_LIGHT0);
- glEnable(GL_LIGHT1);
- glLineWidth(2.0);
- glutMainLoop();
- return 0; /* ANSI C requires main to return int. */
- }