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/**
* Test flat shading and clipping.
*
* Brian Paul
* 30 August 2007
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>
static int Win;
static GLfloat Scale = 2.0, Zrot = 50;
static GLenum Mode = GL_LINE_LOOP;
static GLboolean Smooth = 0;
static GLenum PolygonMode = GL_FILL;
static void
Draw(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
if (Smooth)
glShadeModel(GL_SMOOTH);
else
glShadeModel(GL_FLAT);
glPushMatrix();
glScalef(Scale, Scale, 1);
glRotatef(Zrot, 0, 0, 1);
glPolygonMode(GL_FRONT_AND_BACK, PolygonMode);
glBegin(Mode);
glColor3f(1, 0, 0);
glVertex2f(-1, -1);
glColor3f(0, 1, 0);
glVertex2f( 2, -1);
glColor3f(0, 0, 1);
glVertex2f( 0, 1);
glEnd();
glPushMatrix();
glScalef(0.9, 0.9, 1);
glBegin(Mode);
glColor3f(1, 0, 0);
glVertex2f( 0, 1);
glColor3f(0, 0, 1);
glVertex2f( 2, -1);
glColor3f(0, 1, 0);
glVertex2f(-1, -1);
glEnd();
glPopMatrix();
glPopMatrix();
glutSwapBuffers();
}
static void
Reshape(int width, int height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0, 0.0, -15.0);
}
static void
Key(unsigned char key, int x, int y)
{
(void) x;
(void) y;
switch (key) {
case 'p':
if (Mode == GL_TRIANGLES)
Mode = GL_LINE_LOOP;
else
Mode = GL_TRIANGLES;
break;
case 'f':
if (PolygonMode == GL_POINT)
PolygonMode = GL_LINE;
else if (PolygonMode == GL_LINE)
PolygonMode = GL_FILL;
else
PolygonMode = GL_POINT;
printf("PolygonMode = 0x%x\n", PolygonMode);
break;
case 'r':
Zrot -= 5.0;
break;
case 'R':
Zrot += 5.0;
break;
case 'z':
Scale *= 1.1;
break;
case 'Z':
Scale /= 1.1;
break;
case 's':
Smooth = !Smooth;
break;
case 27:
glutDestroyWindow(Win);
exit(0);
break;
}
glutPostRedisplay();
}
static void
Init(void)
{
printf("Usage:\n");
printf(" z/Z: change triangle size\n");
printf(" r/R: rotate\n");
printf(" p: toggle line/fill mode\n");
}
int
main(int argc, char *argv[])
{
glutInit(&argc, argv);
glutInitWindowPosition(0, 0);
glutInitWindowSize(400, 400);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
Win = glutCreateWindow(argv[0]);
glutReshapeFunc(Reshape);
glutKeyboardFunc(Key);
glutDisplayFunc(Draw);
Init();
glutMainLoop();
return 0;
}
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