davie

04-16-2010, 06:12 AM

Hi there,

I want to draw a rect occupied all the client area. so i do the following, but it cannt work.

GLdouble projection[16], modelview[16];

GLint viewport[4];

GLdouble x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, z4;

glGetDoublev(GL_PROJECTION_MATRIX, projection);

glGetDoublev(GL_MODELVIEW_MATRIX, modelview);

glGetIntegerv(GL_VIEWPORT, viewport);

GLfloat wndX,wndY, wndZ;

wndX = g_iWindowWidth;

wndY= viewport[3] - 0;

glReadBuffer(GL_BACK);

glReadPixels(wndX,wndY,1,1,GL_DEPTH_COMPONENT ,GL_INT, &wndZ);

gluUnProject(wndX, wndY, wndZ, modelview, projection, viewport, &x1, &y1, &z1);

wndX = 0;

wndY = viewport[3] - g_iWindowHeight;

glReadBuffer(GL_BACK);

glReadPixels(wndX,wndY,1,1,GL_DEPTH_COMPONENT ,GL_INT, &wndZ);

gluUnProject(wndX, wndY, wndZ, modelview, projection, viewport, &x2, &y2, &z2);

wndX = 0;

wndY = viewport[3] - g_iWindowHeight;

glReadBuffer(GL_BACK);

glReadPixels(wndX,wndY,1,1,GL_DEPTH_COMPONENT ,GL_INT, &wndZ);

gluUnProject(wndX, wndY, wndZ, modelview, projection, viewport, &x3, &y3, &z3);

wndX = g_iWindowWidth;

wndY = viewport[3] - 0;

glReadBuffer(GL_BACK);

glReadPixels(wndX,wndY,1,1,GL_DEPTH_COMPONENT ,GL_INT, &wndZ);

gluUnProject(wndX, wndY, wndZ, modelview, projection, viewport, &x4, &y4, &z4);

glBindTexture(GL_TEXTURE_2D, g_texture[0]);

glBegin(GL_QUADS);

glTexCoord2f(1.0f, 1.0f); glVertex3f(x1, y1, z1);

glTexCoord2f(0.0f, 1.0f); glVertex3f(x2, y2, z2);

glTexCoord2f(0.0f, 0.0f); glVertex3f(x3, y3, z3);

glTexCoord2f(1.0f, 0.0f); glVertex3f(x4, y4, z4);

glEnd();

i use glUnProject to convert the four corner pixel to the object coordinate, but i

dont know if this is right, can anybody help me? Thanks a lot!

I want to draw a rect occupied all the client area. so i do the following, but it cannt work.

GLdouble projection[16], modelview[16];

GLint viewport[4];

GLdouble x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, z4;

glGetDoublev(GL_PROJECTION_MATRIX, projection);

glGetDoublev(GL_MODELVIEW_MATRIX, modelview);

glGetIntegerv(GL_VIEWPORT, viewport);

GLfloat wndX,wndY, wndZ;

wndX = g_iWindowWidth;

wndY= viewport[3] - 0;

glReadBuffer(GL_BACK);

glReadPixels(wndX,wndY,1,1,GL_DEPTH_COMPONENT ,GL_INT, &wndZ);

gluUnProject(wndX, wndY, wndZ, modelview, projection, viewport, &x1, &y1, &z1);

wndX = 0;

wndY = viewport[3] - g_iWindowHeight;

glReadBuffer(GL_BACK);

glReadPixels(wndX,wndY,1,1,GL_DEPTH_COMPONENT ,GL_INT, &wndZ);

gluUnProject(wndX, wndY, wndZ, modelview, projection, viewport, &x2, &y2, &z2);

wndX = 0;

wndY = viewport[3] - g_iWindowHeight;

glReadBuffer(GL_BACK);

glReadPixels(wndX,wndY,1,1,GL_DEPTH_COMPONENT ,GL_INT, &wndZ);

gluUnProject(wndX, wndY, wndZ, modelview, projection, viewport, &x3, &y3, &z3);

wndX = g_iWindowWidth;

wndY = viewport[3] - 0;

glReadBuffer(GL_BACK);

glReadPixels(wndX,wndY,1,1,GL_DEPTH_COMPONENT ,GL_INT, &wndZ);

gluUnProject(wndX, wndY, wndZ, modelview, projection, viewport, &x4, &y4, &z4);

glBindTexture(GL_TEXTURE_2D, g_texture[0]);

glBegin(GL_QUADS);

glTexCoord2f(1.0f, 1.0f); glVertex3f(x1, y1, z1);

glTexCoord2f(0.0f, 1.0f); glVertex3f(x2, y2, z2);

glTexCoord2f(0.0f, 0.0f); glVertex3f(x3, y3, z3);

glTexCoord2f(1.0f, 0.0f); glVertex3f(x4, y4, z4);

glEnd();

i use glUnProject to convert the four corner pixel to the object coordinate, but i

dont know if this is right, can anybody help me? Thanks a lot!