OpenGL Programming Guide version Seventh source code bug Page35 lines.c Red Book

Question 1: According to the source code, when I found the time to knock. The effect is not implemented correctly. Where is not correct? There is no source code glpushattrib (gl_line_stipple) Glpopattrib (). So there's going to be a final draw. The information that is provided in the drawing is redrawn each time the updated dash time is overwritten before the line has been developed. The negotiation stack is processed so that the brush frame redraw will not affect the drawing results of other frames. (The reason is I'm not sure at the moment, it is expected to be a state machine management issue.) To understand the internal drawing mechanism.

But every time I manually add the stack and the stack is too much trouble, so I deal with the C_style macro definition form to achieve

Problem 2:reshape The operation of the screen and found that only display in the correct setting of the form parameters, or can be drawn normally.

The question comes, reshape shouldn't I stretch the form to trigger it? However, the situation can still be displayed if the changes are correct. Best of all, please enlighten me.

Change 1 source code such as the following:

#include "stdafx.h" #include <GL/freeglut.h> #define Drawoneline (x1,y1,x2,y2) glbegin (gl_lines); glvertex2f (x1 ), (y1)); glvertex2f ((x2), (y2)); Glend (); void init (void) {Glclearcolor (0.0,0.0,0.0,0.0); Glshademodel (Gl_flat);} void display (void) {//initial initialization definition form, I'm good to move this out. Test reshape function call, problem 2:int w = 400,h =150;glviewport (0,0,static_cast<glsizei > (w),static_cast<glsizei> (h)); Glmatrixmode (gl_projection); glloadidentity (); Gluortho2d (0.0,static_cast <GLfloat> (W),0.0,static_cast<glfloat> (h)); Glmatrixmode (Gl_modelview); glloadidentity ();//int i; Glclear (gl_color_buffer_bit); Glpushmatrix (); glcolor3f (1.0,1.0,1.0); glenable (gl_line_stipple);//1st Rowglpushattrib (gl_line_stipple);//read in binary, draw from low, the first parameter is the stretch parameter gllinestipple (1,0x0101);d Rawoneline ( 50.0,125.0,150,125.0); Glpopattrib (); Glpushattrib (gl_line_stipple); Gllinestipple (1,0X00FF);d Rawoneline ( 150.0,125.0,250.0,125.0); Glpopattrib (); Glpushattrib (gl_line_stipple); Gllinestipple (1,0x1c47);d Rawoneline ( 250.0,125.0,350.0,125.0); Glpopattrib ();//2nd ROwgllinewidth (5.0); Glpushattrib (gl_line_stipple);//read in binary, draw from the low, the first parameter is the tensile parameters Gllinestipple (1,0x0101); Drawoneline (50.0,100.0,150.0,100.0); Glpopattrib (); Glpushattrib (gl_line_stipple); Gllinestipple (1,0X00FF); Drawoneline (150.0,100.0,250.0,100.0); Glpopattrib (); Glpushattrib (gl_line_stipple); Gllinestipple (1,0X1C47); Drawoneline (250.0,100.0,350.0,100.0); Glpopattrib (); Gllinewidth (1.0);//3rd Rowglpushattrib (GL_LINE_STIPPLE); Gllinestipple (1,0X1C47); Glbegin (Gl_line_strip); for (int i = 0; i < 7; i++) {glvertex2f (50.0+static_cast<glfloat > (i*50.0), 75.0);} Glend (); Glpopattrib (); gldisable (gl_line_stipple); Glpopmatrix (); Glflush ();} void reshape (int w,int h) {}int _tmain (int argc, char * argv[]) {glutinit (&AMP;ARGC,ARGV); Glutinitdisplaymode (glut_ single| GLUT_RGB); glutinitwindowsize (400,150); glutinitwindowposition (0,0); Glutcreatewindow (argv[0]); init (); Glutdisplayfunc (display); Glutreshapefunc (NULL); Glutmainloop (); return 0;}

Correct source code demonstration:

Lines_p35.cpp: Defines the entry point of the console application. #include "stdafx.h" #include <GL/freeglut.h> #define Drawoneline (scale,stipple,x1,y1,x2,y2) Glpushattrib (gl_ Line_stipple); gllinestipple (scale), (stipple)); Glbegin (gl_lines); glvertex2f ((x1), (y1)); glvertex2f ((x2), (y2)); Glend (); Glpopattrib (); void init (void) {Glclearcolor (0.0,0.0,0.0,0.0); Glshademodel (Gl_flat);} void display (void) {glclear (gl_color_buffer_bit); Glpushmatrix (); glcolor3f (1.0,1.0,1.0); Glenable (Gl_line_stipple) The//1st row//is read in binary, drawn from the low start. The first parameter is the stretch parameter Drawoneline (1,0x0101,50.0,125.0,150,125.0);d rawoneline (1,0x00ff,150.0,125.0,250.0,125.0);d Rawoneline (1,0x1c47,250.0,125.0,350.0,125.0);//2nd rowgllinewidth (5.0);//read in binary. Draw from the low start. The first parameter is the stretch parameter Drawoneline (1,0x0101,50.0,100.0,150.0,100.0);d rawoneline (1,0x00ff,150.0,100.0,250.0,100.0); Drawoneline (1,0x1c47,250.0,100.0,350.0,100.0); Gllinewidth (1.0);//3rd Rowglpushattrib (Gl_line_stipple); Gllinestipple (1,0X1C47); Glbegin (Gl_line_strip); for (int i = 0; i < 7; i++) {glvertex2f (50.0+static_cast<glfloat > (i*50.0), 75.0);} Glend (); Glpopattrib ();//4thfor (int i = 0; i < 6; i++) {Drawoneline (1,0x1c47,50.0+static_cast<glfloat> (i*50.0)) ,50.0,50.0+static_cast<glfloat> (i+1) *50.0,50.0);} 5thdrawOneLine (5,0x1c47,50.0,25.0,350.0,25.0); gldisable (gl_line_stipple); Glpopmatrix (); Glflush ();} void reshape (int w,int h) {Glviewport (0,0,static_cast<glsizei> (w),static_cast<glsizei> (h)); Glmatrixmode (gl_projection); glloadidentity (); gluortho2d (0.0,static_cast<glfloat> (w),0.0,static_cast< Glfloat> (h)); Glmatrixmode (Gl_modelview); glloadidentity (); int _tmain (int argc, char * argv[]) {glutinit (&AMP;ARGC,ARGV); Glutinitdisplaymode (glut_single| GLUT_RGB); glutinitwindowsize (400,150); glutinitwindowposition (0,0); Glutcreatewindow (argv[0]); init (); Glutdisplayfunc (display); Glutreshapefunc (reshape); Glutmainloop (); return 0;}

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OpenGL Programming Guide version Seventh source code bug Page35 lines.c Red Book