// glut_example.c
// Stanford University, CS248, Fall 2000
//
// Demonstrates basic use of GLUT toolkit for CS248 video game assignment.
// More GLUT details at http://reality.sgi.com/mjk_asd/spec3/spec3.html
// Here you'll find examples of initialization, basic viewing transformations,
// mouse and keyboard callbacks, menus, some rendering primitives, lighting,
// double buffering, Z buffering, and texturing.
//
// Matt Ginzton -- [email protected]
#include <glut.h>
#include <stdio.h>
#include <stdlib.h>
#ifdef _WIN32
# include <windows.h>
#else
# include <sys/time.h>
#endif
#include "texture.h"
#define VIEWING_DISTANCE_MIN 3.0
#define TEXTURE_ID_CUBE 1
enum {
MENU_LIGHTING = 1,
MENU_POLYMODE,
MENU_TEXTURING,
MENU_EXIT
};
typedef int BOOL;
#define TRUE 1
#define FALSE 0
static BOOL g_bLightingEnabled = TRUE;
static BOOL g_bFillPolygons = TRUE;
static BOOL g_bTexture = FALSE;
static BOOL g_bButton1Down = FALSE;
static GLfloat g_fTeapotAngle = 0.0;
static GLfloat g_fTeapotAngle2 = 0.0;
static GLfloat g_fViewDistance = 3 * VIEWING_DISTANCE_MIN;
static GLfloat g_nearPlane = 1;
static GLfloat g_farPlane = 1000;
static int g_Width = 600; // Initial window width
static int g_Height = 600; // Initial window height
static int g_yClick = 0;
static float g_lightPos[4] = { 10, 10, -100, 1 }; // Position of light
#ifdef _WIN32
static DWORD last_idle_time;
#else
static struct timeval last_idle_time;
#endif
void DrawCubeFace(float fSize)
{
fSize /= 2.0;
glBegin(GL_QUADS);
glVertex3f(-fSize, -fSize, fSize); glTexCoord2f (0, 0);
glVertex3f(fSize, -fSize, fSize); glTexCoord2f (1, 0);
glVertex3f(fSize, fSize, fSize); glTexCoord2f (1, 1);
glVertex3f(-fSize, fSize, fSize); glTexCoord2f (0, 1);
glEnd();
}
void DrawCubeWithTextureCoords (float fSize)
{
glPushMatrix();
DrawCubeFace (fSize);
glRotatef (90, 1, 0, 0);
DrawCubeFace (fSize);
glRotatef (90, 1, 0, 0);
DrawCubeFace (fSize);
glRotatef (90, 1, 0, 0);
DrawCubeFace (fSize);
glRotatef (90, 0, 1, 0);
DrawCubeFace (fSize);
glRotatef (180, 0, 1, 0);
DrawCubeFace (fSize);
glPopMatrix();
}
void RenderObjects(void)
{
float colorBronzeDiff[4] = { 0.8, 0.6, 0.0, 1.0 };
float colorBronzeSpec[4] = { 1.0, 1.0, 0.4, 1.0 };
float colorBlue[4] = { 0.0, 0.2, 1.0, 1.0 };
float colorNone[4] = { 0.0, 0.0, 0.0, 0.0 };
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
// Main object (cube) ... transform to its coordinates, and render
glRotatef(15, 1, 0, 0);
glRotatef(45, 0, 1, 0);
glRotatef(g_fTeapotAngle, 0, 0, 1);
glMaterialfv(GL_FRONT, GL_DIFFUSE, colorBlue);
glMaterialfv(GL_FRONT, GL_SPECULAR, colorNone);
glColor4fv(colorBlue);
glBindTexture(GL_TEXTURE_2D, TEXTURE_ID_CUBE);
DrawCubeWithTextureCoords(1.0);
// Child object (teapot) ... relative transform, and render
glPushMatrix();
glTranslatef(2, 0, 0);
glRotatef(g_fTeapotAngle2, 1, 1, 0);
glMaterialfv(GL_FRONT, GL_DIFFUSE, colorBronzeDiff);
glMaterialfv(GL_FRONT, GL_SPECULAR, colorBronzeSpec);
glMaterialf(GL_FRONT, GL_SHININESS, 50.0);
glColor4fv(colorBronzeDiff);
glBindTexture(GL_TEXTURE_2D, 0);
glutSolidTeapot(0.3);
glPopMatrix();
glPopMatrix();
}
void display(void)
{
// Clear frame buffer and depth buffer
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Set up viewing transformation, looking down -Z axis
glLoadIdentity();
gluLookAt(0, 0, -g_fViewDistance, 0, 0, -1, 0, 1, 0);
// Set up the stationary light
glLightfv(GL_LIGHT0, GL_POSITION, g_lightPos);
// Render the scene
RenderObjects();
// Make sure changes appear onscreen
glutSwapBuffers();
}
void reshape(GLint width, GLint height)
{
g_Width = width;
g_Height = height;
glViewport(0, 0, g_Width, g_Height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(65.0, (float)g_Width / g_Height, g_nearPlane, g_farPlane);
glMatrixMode(GL_MODELVIEW);
}
void InitGraphics(void)
{
int width, height;
int nComponents;
void* pTextureImage;
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
glShadeModel(GL_SMOOTH);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
// Create texture for cube; load marble texture from file and bind it
pTextureImage = read_texture("marble.rgb", &width, &height, &nComponents);
glBindTexture(GL_TEXTURE_2D, TEXTURE_ID_CUBE);
gluBuild2DMipmaps(GL_TEXTURE_2D, // texture to specify
GL_RGBA, // internal texture storage format
width, // texture width
height, // texture height
GL_RGBA, // pixel format
GL_UNSIGNED_BYTE, // color component format
pTextureImage); // pointer to texture image
glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
GL_LINEAR_MIPMAP_LINEAR);
glTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
}
void MouseButton(int button, int state, int x, int y)
{
// Respond to mouse button presses.
// If button1 pressed, mark this state so we know in motion function.
if (button == GLUT_LEFT_BUTTON)
{
g_bButton1Down = (state == GLUT_DOWN) ? TRUE : FALSE;
g_yClick = y - 3 * g_fViewDistance;
}
}
void MouseMotion(int x, int y)
{
// If button1 pressed, zoom in/out if mouse is moved up/down.
if (g_bButton1Down)
{
g_fViewDistance = (y - g_yClick) / 3.0;
if (g_fViewDistance < VIEWING_DISTANCE_MIN)
g_fViewDistance = VIEWING_DISTANCE_MIN;
glutPostRedisplay();
}
}
void AnimateScene(void)
{
float dt;
#ifdef _WIN32
DWORD time_now;
time_now = GetTickCount();
dt = (float) (time_now - last_idle_time) / 1000.0;
#else
// Figure out time elapsed since last call to idle function
struct timeval time_now;
gettimeofday(&time_now, NULL);
dt = (float)(time_now.tv_sec - last_idle_time.tv_sec) +
1.0e-6*(time_now.tv_usec - last_idle_time.tv_usec);
#endif
// Animate the teapot by updating its angles
g_fTeapotAngle += dt * 30.0;
g_fTeapotAngle2 += dt * 100.0;
// Save time_now for next time
last_idle_time = time_now;
// Force redraw
glutPostRedisplay();
}
void SelectFromMenu(int idCommand)
{
switch (idCommand)
{
case MENU_LIGHTING:
g_bLightingEnabled = !g_bLightingEnabled;
if (g_bLightingEnabled)
glEnable(GL_LIGHTING);
else
glDisable(GL_LIGHTING);
break;
case MENU_POLYMODE:
g_bFillPolygons = !g_bFillPolygons;
glPolygonMode (GL_FRONT_AND_BACK, g_bFillPolygons ? GL_FILL : GL_LINE);
break;
case MENU_TEXTURING:
g_bTexture = !g_bTexture;
if (g_bTexture)
glEnable(GL_TEXTURE_2D);
else
glDisable(GL_TEXTURE_2D);
break;
case MENU_EXIT:
exit (0);
break;
}
// Almost any menu selection requires a redraw
glutPostRedisplay();
}
void Keyboard(unsigned char key, int x, int y)
{
switch (key)
{
case 27: // ESCAPE key
exit (0);
break;
case 'l':
SelectFromMenu(MENU_LIGHTING);
break;
case 'p':
SelectFromMenu(MENU_POLYMODE);
break;
case 't':
SelectFromMenu(MENU_TEXTURING);
break;
}
}
int BuildPopupMenu (void)
{
int menu;
menu = glutCreateMenu (SelectFromMenu);
glutAddMenuEntry ("Toggle lighting\tl", MENU_LIGHTING);
glutAddMenuEntry ("Toggle polygon fill\tp", MENU_POLYMODE);
glutAddMenuEntry ("Toggle texturing\tt", MENU_TEXTURING);
glutAddMenuEntry ("Exit demo\tEsc", MENU_EXIT);
return menu;
}
int main(int argc, char** argv)
{
// GLUT Window Initialization:
glutInit (&argc, argv);
glutInitWindowSize (g_Width, g_Height);
glutInitDisplayMode ( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
glutCreateWindow ("CS248 GLUT example");
// Initialize OpenGL graphics state
InitGraphics();
// Register callbacks:
glutDisplayFunc (display);
glutReshapeFunc (reshape);
glutKeyboardFunc (Keyboard);
glutMouseFunc (MouseButton);
glutMotionFunc (MouseMotion);
glutIdleFunc (AnimateScene);
// Create our popup menu
BuildPopupMenu ();
glutAttachMenu (GLUT_RIGHT_BUTTON);
// Get the initial time, for use by animation
#ifdef _WIN32
last_idle_time = GetTickCount();
#else
gettimeofday (&last_idle_time, NULL);
#endif
// Turn the flow of control over to GLUT
glutMainLoop ();
return 0;
}