Opengl Samples - Accum

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <GL/glut.h> GLenum doubleBuffer; GLint thing1, thing2; static void Init(void) { glClearColor(0.0, 0.0, 0.0, 0.0); glClearAccum(0.0, 0.0, 0.0, 0.0); thing1 = glGenLists(1); glNewList(thing1, GL_COMPILE); glColor3f(1.0, 0.0, 0.0); glRectf(-1.0, -1.0, 1.0, 0.0); glEndList(); thing2 = glGenLists(1); glNewList(thing2, GL_COMPILE); glColor3f(0.0, 1.0, 0.0); glRectf(0.0, -1.0, 1.0, 1.0); glEndList(); } static void Reshape(int width, int height) { glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } static void Key(unsigned char key, int x, int y) { switch (key) { case '1': glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); glutPostRedisplay(); break; case '2': glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); glutPostRedisplay(); break; case 27: exit(0); } } static void Draw(void) { glPushMatrix(); glScalef(0.8, 0.8, 1.0); glClear(GL_COLOR_BUFFER_BIT); glCallList(thing1); glAccum(GL_LOAD, 0.5); glClear(GL_COLOR_BUFFER_BIT); glCallList(thing2); glAccum(GL_ACCUM, 0.5); glAccum(GL_RETURN, 1.0); glPopMatrix(); if (doubleBuffer) { glutSwapBuffers(); } else { glFlush(); } } static void Args(int argc, char **argv) { GLint i; doubleBuffer = GL_FALSE; for (i = 1; i < argc; i++) { if (strcmp(argv[i], "-sb") == 0) { doubleBuffer = GL_FALSE; } else if (strcmp(argv[i], "-db") == 0) { doubleBuffer = GL_TRUE; } } } int main(int argc, char **argv) { GLenum type; glutInit(&argc, argv); Args(argc, argv); type = GLUT_RGB | GLUT_ACCUM; type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE; glutInitDisplayMode(type); glutInitWindowSize(300, 300); glutCreateWindow("Accum Test"); Init(); glutReshapeFunc(Reshape); glutKeyboardFunc(Key); glutDisplayFunc(Draw); glutMainLoop(); }