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digitalmars.D.learn - DerelictGL program draw nothing

reply "Zhenya" <zheny list.ru> writes:
Why this simple program don't show white square?

import std.stdio;

import derelict.opengl3.gl;
import derelict.glfw3.glfw3;

const uint width = 200;
const uint height = 200;

void init()
{
	glViewport(0,0,width,height);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(-width,width,-height,height,-1,1);
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
}

void display()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glBegin(GL_POLYGON);
		glVertex2d(0,0);
		glVertex2d(0,height);
		glVertex2d(width,height);
		glVertex2d(height,0);
	glEnd();
}

void main()
{
	DerelictGL.load();
	DerelictGLFW3.load();
	glfwInit();
	GLFWwindow window;
	window = glfwCreateWindow(width,height,GLFW_WINDOWED,"Hello 
DerelictGLFW3",null);
	init();
	bool opened = true;
	while(opened)
	{
		opened = !glfwGetWindowParam(window,GLFW_CLOSE_REQUESTED) && 
!glfwGetKey(window,GLFW_KEY_ESC);
		display();
		glfwSwapBuffers(window);
		glfwWaitEvents();
	}
	glfwTerminate();
}
Sep 03 2012
next sibling parent "cal" <callumenator gmail.com> writes:
On Monday, 3 September 2012 at 15:21:59 UTC, Zhenya wrote:

 Why this simple program don't show white square?
 void display()
 {
 	glClear(GL_COLOR_BUFFER_BIT);
 	glBegin(GL_POLYGON);
 		glVertex2d(0,0);
 		glVertex2d(0,height);
 		glVertex2d(width,height);
 		glVertex2d(height,0);        <<<<<<<< glVertex2d(width, 0)
 	glEnd();
 }



If that doesn't work, maybe you need to wind the vertices the 
other way to avoid backface culling, ie:

glVertex2d(0, 0)
glVertex2d(width, 0)
glVertex2d(width, height)
glVertex2d(0, height)
Sep 03 2012
prev sibling next sibling parent "Zhenya" <zheny list.ru> writes:
On Monday, 3 September 2012 at 16:57:08 UTC, cal wrote:

 On Monday, 3 September 2012 at 15:21:59 UTC, Zhenya wrote:

 Why this simple program don't show white square?
 void display()
 {
 	glClear(GL_COLOR_BUFFER_BIT);
 	glBegin(GL_POLYGON);
 		glVertex2d(0,0);
 		glVertex2d(0,height);
 		glVertex2d(width,height);
 		glVertex2d(height,0);        <<<<<<<< glVertex2d(width, 0)
 	glEnd();
 }



 If that doesn't work, maybe you need to wind the vertices the 
 other way to avoid backface culling, ie:

 glVertex2d(0, 0)
 glVertex2d(width, 0)
 glVertex2d(width, height)
 glVertex2d(0, height)



that dosn't work
Sep 03 2012
prev sibling next sibling parent "cal" <callumenator gmail.com> writes:
On Monday, 3 September 2012 at 17:02:46 UTC, Zhenya wrote:

 that dosn't work



How large is your window?

glViewport(0,0,width,height);

should really be setting to the window size - so if you make your 
window 800,800, this should be

glViewport(0,0,800,800);
Sep 03 2012
prev sibling next sibling parent "cal" <callumenator gmail.com> writes:
On Monday, 3 September 2012 at 17:08:55 UTC, cal wrote:

 On Monday, 3 September 2012 at 17:02:46 UTC, Zhenya wrote:

 that dosn't work



 How large is your window?

 glViewport(0,0,width,height);

 should really be setting to the window size - so if you make 
 your window 800,800, this should be

 glViewport(0,0,800,800);



Just saw it, never mind. Also, I think before you draw, you need 
to set the matrix mode to modelview, and load identity...

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
display();
Sep 03 2012
prev sibling next sibling parent "Zhenya" <zheny list.ru> writes:
On Monday, 3 September 2012 at 17:12:04 UTC, cal wrote:

 On Monday, 3 September 2012 at 17:08:55 UTC, cal wrote:

 On Monday, 3 September 2012 at 17:02:46 UTC, Zhenya wrote:

 that dosn't work



 How large is your window?

 glViewport(0,0,width,height);

 should really be setting to the window size - so if you make 
 your window 800,800, this should be

 glViewport(0,0,800,800);



 Just saw it, never mind. Also, I think before you draw, you 
 need to set the matrix mode to modelview, and load identity...

 glMatrixMode(GL_MODELVIEW);
 glLoadIdentity();
 display();



const uint width = 200;
const uint height = 200;


 glMatrixMode(GL_MODELVIEW);
 glLoadIdentity();
 display();



I added it to this code,but nothing changed(
Sep 03 2012
prev sibling next sibling parent "cal" <callumenator gmail.com> writes:
On Monday, 3 September 2012 at 17:16:54 UTC, Zhenya wrote:

 I added it to this code,but nothing changed(



Its a puzzler then, FWIW the following code works for me (I don't 
use GLFW, I have my own window routines, but the opengl-specific 
calls are the same).

Window("window1", WindowState(0,0,200,200), Flag!"Create".yes, 
Flag!"Show".yes);
Window.makeCurrent("window1");

glViewport(0,0,200,200);
glClearColor(0,0,0,1);

bool finish = false;
while (!finish)
{
         glMatrixMode(GL_PROJECTION);
         glLoadIdentity();
         glOrtho(-200, 200, -200, 200, -1, 1);
         glClear( GL_COLOR_BUFFER_BIT );
         glBegin(GL_POLYGON);
             glVertex2d(0, 0);
             glVertex2d(0, 200);
             glVertex2d(200, 200);
             glVertex2d(200, 0);
         glEnd();
         Window().swapBuffers();

         if (Window().keyState().keys[KEY.KC_ESCAPE])
             finish = true;
}

Perhaps something in the GLFW init is modyfying some OpenGL 
defaults or something, you might like to ask on their forum.
Sep 03 2012
prev sibling next sibling parent "Ivan Agafonov" <armadil yandex.ru> writes:
On Monday, 3 September 2012 at 15:21:59 UTC, Zhenya wrote:

 Why this simple program don't show white square?

 import std.stdio;

 import derelict.opengl3.gl;
 import derelict.glfw3.glfw3;

 const uint width = 200;
 const uint height = 200;

 void init()
 {
 	glViewport(0,0,width,height);
 	glMatrixMode(GL_PROJECTION);
 	glLoadIdentity();
 	glOrtho(-width,width,-height,height,-1,1);
 	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
 }

 void display()
 {
 	glClear(GL_COLOR_BUFFER_BIT);
 	glBegin(GL_POLYGON);
 		glVertex2d(0,0);
 		glVertex2d(0,height);
 		glVertex2d(width,height);
 		glVertex2d(height,0);
 	glEnd();
 }

 void main()
 {
 	DerelictGL.load();
 	DerelictGLFW3.load();
 	glfwInit();
 	GLFWwindow window;
 	window = glfwCreateWindow(width,height,GLFW_WINDOWED,"Hello 
 DerelictGLFW3",null);
 	init();
 	bool opened = true;
 	while(opened)
 	{
 		opened = !glfwGetWindowParam(window,GLFW_CLOSE_REQUESTED) && 
 !glfwGetKey(window,GLFW_KEY_ESC);
 		display();
 		glfwSwapBuffers(window);
 		glfwWaitEvents();
 	}
 	glfwTerminate();
 }



width and height must be int, not uint.
After window = glfwCreateWindow();
put glfwMakeContextCurrent(window);
And it will work!
Sep 03 2012
prev sibling next sibling parent "Zhenya" <zheny list.ru> writes:
On Monday, 3 September 2012 at 18:47:25 UTC, Ivan Agafonov wrote:

 On Monday, 3 September 2012 at 15:21:59 UTC, Zhenya wrote:

 Why this simple program don't show white square?

 import std.stdio;

 import derelict.opengl3.gl;
 import derelict.glfw3.glfw3;

 const uint width = 200;
 const uint height = 200;

 void init()
 {
 	glViewport(0,0,width,height);
 	glMatrixMode(GL_PROJECTION);
 	glLoadIdentity();
 	glOrtho(-width,width,-height,height,-1,1);
 	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
 }

 void display()
 {
 	glClear(GL_COLOR_BUFFER_BIT);
 	glBegin(GL_POLYGON);
 		glVertex2d(0,0);
 		glVertex2d(0,height);
 		glVertex2d(width,height);
 		glVertex2d(height,0);
 	glEnd();
 }

 void main()
 {
 	DerelictGL.load();
 	DerelictGLFW3.load();
 	glfwInit();
 	GLFWwindow window;
 	window = glfwCreateWindow(width,height,GLFW_WINDOWED,"Hello 
 DerelictGLFW3",null);
 	init();
 	bool opened = true;
 	while(opened)
 	{
 		opened = !glfwGetWindowParam(window,GLFW_CLOSE_REQUESTED) && 
 !glfwGetKey(window,GLFW_KEY_ESC);
 		display();
 		glfwSwapBuffers(window);
 		glfwWaitEvents();
 	}
 	glfwTerminate();
 }



 width and height must be int, not uint.
 After window = glfwCreateWindow();
 put glfwMakeContextCurrent(window);
 And it will work!
Sep 03 2012
prev sibling next sibling parent "Zhenya" <zheny list.ru> writes:
But why it doesn't convert uint to int correctly?
Sep 04 2012
prev sibling next sibling parent "Ivan Agafonov" <armadil yandex.ru> writes:
On Tuesday, 4 September 2012 at 07:32:47 UTC, Zhenya wrote:

 But why it doesn't convert uint to int correctly?



I dont know, small positive uint and int must have the same 
binary representation, and no need to conversion. Strangely...

O! May be problem is here:
glOrtho(-width,width,-height,height,-1,1);
-width and -height
Negative unsigned?
Sep 04 2012
prev sibling parent "Zhenya" <zheny list.ru> writes:
On Tuesday, 4 September 2012 at 16:17:30 UTC, Ivan Agafonov wrote:

 On Tuesday, 4 September 2012 at 07:32:47 UTC, Zhenya wrote:

 But why it doesn't convert uint to int correctly?



 I dont know, small positive uint and int must have the same 
 binary representation, and no need to conversion. Strangely...

 O! May be problem is here:
 glOrtho(-width,width,-height,height,-1,1);
 -width and -height
 Negative unsigned?



:)Understood
Sep 04 2012