/* * Test vertex arrays and multitexture. * Press 'a' to toggle vertex arrays on/off. * When you run this program you should see a square with four colors: * * +------+------+ * |yellow| pink | * +------+------+ * |green | blue | * +------+------+ */ #include <assert.h> #include <math.h> #include <stdlib.h> #include <stdio.h> #include <string.h> #include "GL/glew.h" #include "GL/glut.h" static GLuint Window = 0; static GLuint TexObj[2]; static GLfloat Angle = 0.0f; static GLboolean UseArrays = 1, Anim = 0; static GLfloat VertArray[4][2] = { {-1.2, -1.2}, {1.2, -1.2}, {1.2, 1.2}, {-1.2, 1.2} }; static GLfloat Tex0Array[4][2] = { {0, 0}, {1, 0}, {1, 1}, {0, 1} }; static GLfloat Tex1Array[4][2] = { {0, 0}, {1, 0}, {1, 1}, {0, 1} }; static void init_arrays(void) { glVertexPointer(2, GL_FLOAT, 0, VertArray); glEnableClientState(GL_VERTEX_ARRAY); glClientActiveTextureARB(GL_TEXTURE0_ARB); glTexCoordPointer(2, GL_FLOAT, 0, Tex0Array); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glClientActiveTextureARB(GL_TEXTURE1_ARB); glTexCoordPointer(2, GL_FLOAT, 0, Tex1Array); glEnableClientState(GL_TEXTURE_COORD_ARRAY); } static void draw( void ) { glClear( GL_COLOR_BUFFER_BIT ); glColor3f( 0.0, 0.0, 0.0 ); /* draw first polygon */ glPushMatrix(); glRotatef( Angle, 0.0, 0.0, 1.0 ); if (UseArrays) { glDrawArrays(GL_POLYGON, 0, 4); } else { glBegin( GL_POLYGON ); glTexCoord2f( 0.0, 0.0 ); glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0.0, 0.0); glVertex2f( -1.0, -1.0 ); glTexCoord2f( 1.0, 0.0 ); glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 1.0, 0.0); glVertex2f( 1.0, -1.0 ); glTexCoord2f( 1.0, 1.0 ); glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 1.0, 1.0); glVertex2f( 1.0, 1.0 ); glTexCoord2f( 0.0, 1.0 ); glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0.0, 1.0); glVertex2f( -1.0, 1.0 ); glEnd(); } glPopMatrix(); glutSwapBuffers(); } static void idle( void ) { Angle += 2.0; glutPostRedisplay(); } /* change view Angle, exit upon ESC */ static void key(unsigned char k, int x, int y) { (void) x; (void) y; switch (k) { case 'a': UseArrays = !UseArrays; printf("UseArrays: %d\n", UseArrays); break; case ' ': Anim = !Anim; if (Anim) glutIdleFunc(idle); else glutIdleFunc(NULL); break; case 27: glDeleteTextures( 2, TexObj ); glutDestroyWindow(Window); exit(0); } glutPostRedisplay(); } /* new window size or exposure */ static void reshape( int width, int height ) { glViewport(0, 0, (GLint)width, (GLint)height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); /* glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/ glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 ); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glTranslatef( 0.0, 0.0, -8.0 ); } static void init( void ) { static int width=8, height=8; GLubyte tex[64][3]; GLint i, j; /* generate texture object IDs */ glGenTextures( 2, TexObj ); /* * setup first texture object */ glActiveTextureARB(GL_TEXTURE0_ARB); glEnable( GL_TEXTURE_2D ); glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_ADD ); glBindTexture( GL_TEXTURE_2D, TexObj[0] ); assert(glIsTexture(TexObj[0])); /* red over black */ for (i=0;i<height;i++) { for (j=0;j<width;j++) { int p = i*width+j; if (i < height / 2) { tex[p][0] = 0; tex[p][1] = 0; tex[p][2] = 0; } else { tex[p][0] = 255; tex[p][1] = 0; tex[p][2] = 0; } } } glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, tex ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT ); /* * setup second texture object */ glActiveTextureARB(GL_TEXTURE1_ARB); glEnable( GL_TEXTURE_2D ); glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_ADD ); glBindTexture( GL_TEXTURE_2D, TexObj[1] ); assert(glIsTexture(TexObj[1])); /* left=green, right = blue */ for (i=0;i<height;i++) { for (j=0;j<width;j++) { int p = i*width+j; if (j < width / 2) { tex[p][0] = 0; tex[p][1] = 255; tex[p][2] = 0; } else { tex[p][0] = 0; tex[p][1] = 0; tex[p][2] = 255; } } } glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, tex ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT ); } int main( int argc, char *argv[] ) { glutInit(&argc, argv); glutInitWindowPosition(0, 0); glutInitWindowSize(300, 300); glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE ); Window = glutCreateWindow("Texture Objects"); glewInit(); if (!Window) { exit(1); } init(); init_arrays(); glutReshapeFunc( reshape ); glutKeyboardFunc( key ); if (Anim) glutIdleFunc( idle ); glutDisplayFunc( draw ); glutMainLoop(); return 0; }