Draw white square in lower-left corner to test orientation

2007-08-13 13:57:31 -06:00
parent 21b9b8b74e
commit b7693ee559
1 changed files with 8 additions and 0 deletions
--- a/progs/trivial/readpixels.c
+++ b/progs/trivial/readpixels.c
@@ -57,6 +57,14 @@ static void Draw(void)
   glVertex3f( 0.0,  0.9, -30.0);
   glEnd();

+   glBegin(GL_QUADS);
+   glColor3f(1, 1, 1);
+   glVertex2f(-1.0, -1.0);
+   glVertex2f(-0.9, -1.0);
+   glVertex2f(-0.9, -0.9);
+   glVertex2f(-1.0, -0.9);
+   glEnd();
+
   glReadPixels(0, 0, Width, Height, GL_RGBA, GL_FLOAT, image);
   printf("Pixel(0,0) = %f, %f, %f, %f\n",
          image[0], image[1], image[2], image[3]);