• Advertisement
Sign in to follow this  

OpenGL Build UI in OpenGL for my 3D game world?

This topic is 1480 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

i'm trying to create my own User Interface such as: Button, panel, window, radiobutton, checkbox, etc..

the word "create" here means:

-designing UI  with own style

-programming they all.

 

well, my problem is: what functions/codes that i must call to draw it all?

 

in this terms, maybe the points are:

-Drawing 2d texture on screen NOT in 3d world game.

so if we're doing translation camera in 3d world game, the UI texture won't  be move.

 

-determine xy coordinates based on screen NOT based in 3d world game.

of course before we set UI texture  first thing that we have to do is determine some textures.

 

to more cleary, take look at the picture

this is a sample User Interface that i've found in google. but this is XNA c#. 

Capture2_zps917ccb91.png

i've learned the source codes how they work. after i understood the concept (include how they draw many textures with structured coordinates)

 

ok so, the problem is: could you show me the point/codes that i should use in openGL graphic programming? include:

-Drawing 2d texture on screen NOT in 3d world game.

-determine xy coordinates in screen.

Edited by Rizkay

Share this post


Link to post
Share on other sites
Advertisement
What you're looking for is called an orthographic projection. This is a 3D projection that does not include any perspective "shrinking" as objects get further away. Older versions of GL included the now-deprecated glOrtho function to accomplish this, but you should be able to duplicate the effects easily enough using a matrix math library such as GLM.

Essentially, an orthographic projection maps the screen to some range of coordinates, X and Y, so that you can draw objects on the X/Y grid and have them appear in the correct location on-screen.

The typical drawing order is to draw the game view using the game camera and projection, then switch the projection to an orthographic matrix and draw the UI elements as a series of quads. These quads will technically be 3D, in that they are drawn using the same exact types of function calls as drawing the game objects (binding vertex buffers, shaders and textures, rendering triangles) but the geometry is configured so that the shapes are flat quads on the X/Y plane. The Z coordinate is typically set to 0; or, if desired, you can use the Z coordinate to determine the visible ordering of the objects as necessary.

Share this post


Link to post
Share on other sites

*with mouse driver: you can draw your interface using photo shop,

*add animated buttons, similair to a web page design (hover, click ; textures),

then interact with your GUI using Test POS XY relative to screen pos (if not full screen) and by checking if your mouse button is

down or up. Then you have to support those handles for your buttons;

what will they do when clicked, or hovered over?.

 

example is coded using c/C++ (oop/structured)

//FILE MouseClass.h //
//windows mouse driver
//using windows library
//handles are usually updated via win main Loop, and passed data to windows handle
 
#include <windows.h>
#include <winuser.h>
#include <windef.h>
//simple example for winmouse class
//for using the windows mouse
//POINT  members { long x,y }
class WinMouse
{
private:
POINT CP;  //cursor position
public:
HWND windH;
RECT RectA;
long x, y;
long cx,cy;
int button1, button2;
WinMouse();
~WinMouse();
long CalcWindowX();
long CalcWindowY();
void ResetPos(long, long);
void GetRectPos(RECT );
void GetPos();
void SetPos(long x,long y);
void SetCenter();
void GetCenter();
void UpdateWindowCenter();
long GetX();
long GetY();
PosTest(int x, int y, int tx, int ty);
//note needed for relative mouse pos
//rect->left - GetX() , rect->top - GetY()
//GetWindowRect(HWND,RECT IN PTR)
//then Call
//this->GetRectPos(RECT );
};

////////////////////function definitions/////////////////////

WinMouse::WinMouse()
{
button1 = 0;
button2 = 0;
x=0;
y=0;
cx = 0;
cy = 0;
}
WinMouse::~WinMouse()
{
}
void WinMouse::UpdateWindowCenter()
{
this->GetPos();
 this->x = GetX() - this->cx;
 this->y = GetY() - this->cy;
}
WinMouse::PosTest(int x, int y, int tx, int ty)
{
 if(x < (GetX() -RectA.left ) && x + tx > (GetX() -RectA.left ))
 {
  if( y < (GetY() - RectA.top) && y + ty > (GetY() - RectA.top) )
  return 1;
  else
  return 0;
 }
 else
 return 0;
}
void WinMouse::GetCenter()
{
 x = (RectA.right + RectA.left)/2;
 y = (RectA.top + RectA.bottom)/2;
 
 cx = x;
 cy = y;
}
void WinMouse::SetCenter()
{
 x = RectA.left + RectA.right;
 y = RectA.top + RectA.bottom;  
 
 cx = x/2;
 cy = y/2;
 SetCursorPos(x/2,y/2);
}
 
void WinMouse::GetRectPos(RECT RectW)
{
 
 RectA.left = RectW.left;
 RectA.right = RectW.right;
 RectA.top = RectW.top;
 RectA.bottom = RectW.bottom;
}
long WinMouse::CalcWindowX()
{
 return this->RectA.right + this->RectA.left;
}
long WinMouse::CalcWindowY()
{
 return this->RectA.top + this->RectA.bottom;
}
 
void WinMouse::ResetPos(long Width, long Height)
{
 this->x = (long)(Width * (float).5);
 this->y = (long)(Height * (float).5);
SetCursorPos( this->x , this->y );
}
void WinMouse::SetPos(long x, long y)
{
SetCursorPos(x, y);
}
void WinMouse::GetPos()
{
GetCursorPos(&this->CP);
}
long WinMouse::GetX()
{
 return this->CP.x;
 
}
long WinMouse::GetY()
{
 return this->CP.y;
 
}
 
//EOF

Share this post


Link to post
Share on other sites

ok i got it.

here i got the things that must be understood before. there are some points to build User Interface in openGL.

  • firstly,  glOrtho help us to command "Orthographic Projection". although we're drawing 3d vertex no matter how far they are (in z coordinate). it will looks like 2D Image. but if we'd like to set our vertex Stay in front we should set z coordinate to 0.

          ok, lets try my code that i've made.

 void DrawImage(void) 
{
	int width = window.width;  //your window width
	int height = window.height;//your window height
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glOrtho(0, width, height, 0, -1.0, 1.0);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
// here you will set xy coordinate of vertex on our screen
glBegin(GL_QUADS);
//there are reason why z must be set to 0
glVertex3f(0, 0, 0.0);
glVertex3f(0, 0.5f, 0.0);
glVertex3f(-1.0f, 0.5f, 0.0);
glVertex3f(-1.0f, 0, 0.0);
glEnd();
glPopMatrix();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glMatrixMode(GL_MODELVIEW);
}
  • second, set up our input/output for Keyboard and Mouse. that's why  it be called Graphic User Interface
Edited by Rizkay

Share this post


Link to post
Share on other sites

Note that if you are using an orthographic projection that is windowwidth by windowheight in size, then drawing a quad as small as you are drawing will pretty much just draw a single pixel or two, since the viewport is now windowwidth units wide and windowheight units tall, and you are drawing a quad 1 unit wide and 1/2 unit tall. You need to draw your objects larger in order to see anything useful.

Edited by JTippetts

Share this post


Link to post
Share on other sites

Note that if you are using an orthographic projection that is windowwidth by windowheight in size, then drawing a quad as small as you are drawing will pretty much just draw a single pixel or two, since the viewport is now windowwidth units wide and windowheight units tall, and you are drawing a quad 1 unit wide and 1/2 unit tall. You need to draw your objects larger in order to see anything useful.

of course,, you've remind me.

when we build User Interface i think the best way to set the parameters of glOrtho like:

  • left : 0.0f
  • right: in accordance with our window width
  • top: 0.0f
  • bottom: in accordance with our window height
  • Znear Zfar: 0,1  -> i don't know why is this so match with UI graphic (these values make the plane always on foreground of the vieweport)

there is a reason why do i set the right and the bottom in accordance with our window size. whenever we resize the window Coordinate of glOrtho won't be screwed.

do you remember in desktop application programming we're like drawing on Quadrant 4 (270 - 360 degree) but y coordinate it's just positive value NOT negative. therefore i set it up in accordance with desktop programming, it wold be easy!

 

well, for drawing vertex actually we have to adjust the coordinate also where  the max x/y coordinate is in accordance with our window size. so if we would follow this way you must set your vertex like we're doing graphic programming on deskop programming. lets look at my vertex code:

::glTranslatef(0,0,0); //the position of the element
glBegin(GL_QUADS
//look actully we've created left sidebar
glVertex3f(200, 0, 0); 
glVertex3f(200, height, 0);
glVertex3f(0.0f, height, 0);
glVertex3f(0, 0, 0);
glEnd();

yeahh we've created a sidebar at viewport.

 

you see? x/y coordinate is set to large value (Something unusual). but in this term i've set before, with this command: glOrtho(0, window.width, window.height, 0, 0, 1);

the viewport will be fit to our window. even you resize your window size i think we're just build simple algorithm (something like anchor?) cz the viewport and the window are same!

Edited by Rizkay

Share this post


Link to post
Share on other sites

Just so you understand that

Mouse coord' system only uses 2 deminsions X,Y

the coord starts from the Top zero and the left zero (going top to  (<, greater) down, and left to  (<, greater) right)

You dont need to use Ortho graphic projection to use a 2d (or 3D) GUI.

 

the default OpenGL matrix is 4 x 4 units,

if you do that math and a little guessing or debugging, it is simple enough to

match your mouse Position checks with your Cursor and buttons.

 

when the screen position or size is changed

 

code:

//inside MainWindowProc  (these are your handles for your window and GUI)

//(windows messege SIZE)

//(windows messege MOVE)

 

// dispatch messages
 switch (uMsg)

{

//...

 

case WM_SIZE:
  height = HIWORD(lParam);  // retrieve width and height
  width = LOWORD(lParam);
// ~(update mouse coords' center "relative")~ //

 

case WM_MOVE:

//~(update new mouse postions relative to new RECT screen position)~//
// Mouse_.GetRectPos(windowRect); //

 

Example thumb PIC (JPEG)

[attachment=19265:ex1.JPG]

Edited by Mathimetric

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
  • Advertisement
  • Popular Now

  • Advertisement
  • Similar Content

    • By Balma Alparisi
      i got error 1282 in my code.
      sf::ContextSettings settings; settings.majorVersion = 4; settings.minorVersion = 5; settings.attributeFlags = settings.Core; sf::Window window; window.create(sf::VideoMode(1600, 900), "Texture Unit Rectangle", sf::Style::Close, settings); window.setActive(true); window.setVerticalSyncEnabled(true); glewInit(); GLuint shaderProgram = createShaderProgram("FX/Rectangle.vss", "FX/Rectangle.fss"); float vertex[] = { -0.5f,0.5f,0.0f, 0.0f,0.0f, -0.5f,-0.5f,0.0f, 0.0f,1.0f, 0.5f,0.5f,0.0f, 1.0f,0.0f, 0.5,-0.5f,0.0f, 1.0f,1.0f, }; GLuint indices[] = { 0,1,2, 1,2,3, }; GLuint vao; glGenVertexArrays(1, &vao); glBindVertexArray(vao); GLuint vbo; glGenBuffers(1, &vbo); glBindBuffer(GL_ARRAY_BUFFER, vbo); glBufferData(GL_ARRAY_BUFFER, sizeof(vertex), vertex, GL_STATIC_DRAW); GLuint ebo; glGenBuffers(1, &ebo); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices,GL_STATIC_DRAW); glVertexAttribPointer(0, 3, GL_FLOAT, false, sizeof(float) * 5, (void*)0); glEnableVertexAttribArray(0); glVertexAttribPointer(1, 2, GL_FLOAT, false, sizeof(float) * 5, (void*)(sizeof(float) * 3)); glEnableVertexAttribArray(1); GLuint texture[2]; glGenTextures(2, texture); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture[0]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); sf::Image* imageOne = new sf::Image; bool isImageOneLoaded = imageOne->loadFromFile("Texture/container.jpg"); if (isImageOneLoaded) { glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageOne->getSize().x, imageOne->getSize().y, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageOne->getPixelsPtr()); glGenerateMipmap(GL_TEXTURE_2D); } delete imageOne; glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, texture[1]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); sf::Image* imageTwo = new sf::Image; bool isImageTwoLoaded = imageTwo->loadFromFile("Texture/awesomeface.png"); if (isImageTwoLoaded) { glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageTwo->getSize().x, imageTwo->getSize().y, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageTwo->getPixelsPtr()); glGenerateMipmap(GL_TEXTURE_2D); } delete imageTwo; glUniform1i(glGetUniformLocation(shaderProgram, "inTextureOne"), 0); glUniform1i(glGetUniformLocation(shaderProgram, "inTextureTwo"), 1); GLenum error = glGetError(); std::cout << error << std::endl; sf::Event event; bool isRunning = true; while (isRunning) { while (window.pollEvent(event)) { if (event.type == event.Closed) { isRunning = false; } } glClear(GL_COLOR_BUFFER_BIT); if (isImageOneLoaded && isImageTwoLoaded) { glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture[0]); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, texture[1]); glUseProgram(shaderProgram); } glBindVertexArray(vao); glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr); glBindVertexArray(0); window.display(); } glDeleteVertexArrays(1, &vao); glDeleteBuffers(1, &vbo); glDeleteBuffers(1, &ebo); glDeleteProgram(shaderProgram); glDeleteTextures(2,texture); return 0; } and this is the vertex shader
      #version 450 core layout(location=0) in vec3 inPos; layout(location=1) in vec2 inTexCoord; out vec2 TexCoord; void main() { gl_Position=vec4(inPos,1.0); TexCoord=inTexCoord; } and the fragment shader
      #version 450 core in vec2 TexCoord; uniform sampler2D inTextureOne; uniform sampler2D inTextureTwo; out vec4 FragmentColor; void main() { FragmentColor=mix(texture(inTextureOne,TexCoord),texture(inTextureTwo,TexCoord),0.2); } I was expecting awesomeface.png on top of container.jpg

    • By khawk
      We've just released all of the source code for the NeHe OpenGL lessons on our Github page at https://github.com/gamedev-net/nehe-opengl. code - 43 total platforms, configurations, and languages are included.
      Now operated by GameDev.net, NeHe is located at http://nehe.gamedev.net where it has been a valuable resource for developers wanting to learn OpenGL and graphics programming.

      View full story
    • By TheChubu
      The Khronos™ Group, an open consortium of leading hardware and software companies, announces from the SIGGRAPH 2017 Conference the immediate public availability of the OpenGL® 4.6 specification. OpenGL 4.6 integrates the functionality of numerous ARB and EXT extensions created by Khronos members AMD, Intel, and NVIDIA into core, including the capability to ingest SPIR-V™ shaders.
      SPIR-V is a Khronos-defined standard intermediate language for parallel compute and graphics, which enables content creators to simplify their shader authoring and management pipelines while providing significant source shading language flexibility. OpenGL 4.6 adds support for ingesting SPIR-V shaders to the core specification, guaranteeing that SPIR-V shaders will be widely supported by OpenGL implementations.
      OpenGL 4.6 adds the functionality of these ARB extensions to OpenGL’s core specification:
      GL_ARB_gl_spirv and GL_ARB_spirv_extensions to standardize SPIR-V support for OpenGL GL_ARB_indirect_parameters and GL_ARB_shader_draw_parameters for reducing the CPU overhead associated with rendering batches of geometry GL_ARB_pipeline_statistics_query and GL_ARB_transform_feedback_overflow_querystandardize OpenGL support for features available in Direct3D GL_ARB_texture_filter_anisotropic (based on GL_EXT_texture_filter_anisotropic) brings previously IP encumbered functionality into OpenGL to improve the visual quality of textured scenes GL_ARB_polygon_offset_clamp (based on GL_EXT_polygon_offset_clamp) suppresses a common visual artifact known as a “light leak” associated with rendering shadows GL_ARB_shader_atomic_counter_ops and GL_ARB_shader_group_vote add shader intrinsics supported by all desktop vendors to improve functionality and performance GL_KHR_no_error reduces driver overhead by allowing the application to indicate that it expects error-free operation so errors need not be generated In addition to the above features being added to OpenGL 4.6, the following are being released as extensions:
      GL_KHR_parallel_shader_compile allows applications to launch multiple shader compile threads to improve shader compile throughput WGL_ARB_create_context_no_error and GXL_ARB_create_context_no_error allow no error contexts to be created with WGL or GLX that support the GL_KHR_no_error extension “I’m proud to announce OpenGL 4.6 as the most feature-rich version of OpenGL yet. We've brought together the most popular, widely-supported extensions into a new core specification to give OpenGL developers and end users an improved baseline feature set. This includes resolving previous intellectual property roadblocks to bringing anisotropic texture filtering and polygon offset clamping into the core specification to enable widespread implementation and usage,” said Piers Daniell, chair of the OpenGL Working Group at Khronos. “The OpenGL working group will continue to respond to market needs and work with GPU vendors to ensure OpenGL remains a viable and evolving graphics API for all its customers and users across many vital industries.“
      The OpenGL 4.6 specification can be found at https://khronos.org/registry/OpenGL/index_gl.php. The GLSL to SPIR-V compiler glslang has been updated with GLSL 4.60 support, and can be found at https://github.com/KhronosGroup/glslang.
      Sophisticated graphics applications will also benefit from a set of newly released extensions for both OpenGL and OpenGL ES to enable interoperability with Vulkan and Direct3D. These extensions are named:
      GL_EXT_memory_object GL_EXT_memory_object_fd GL_EXT_memory_object_win32 GL_EXT_semaphore GL_EXT_semaphore_fd GL_EXT_semaphore_win32 GL_EXT_win32_keyed_mutex They can be found at: https://khronos.org/registry/OpenGL/index_gl.php
      Industry Support for OpenGL 4.6
      “With OpenGL 4.6 our customers have an improved set of core features available on our full range of OpenGL 4.x capable GPUs. These features provide improved rendering quality, performance and functionality. As the graphics industry’s most popular API, we fully support OpenGL and will continue to work closely with the Khronos Group on the development of new OpenGL specifications and extensions for our customers. NVIDIA has released beta OpenGL 4.6 drivers today at https://developer.nvidia.com/opengl-driver so developers can use these new features right away,” said Bob Pette, vice president, Professional Graphics at NVIDIA.
      "OpenGL 4.6 will be the first OpenGL release where conformant open source implementations based on the Mesa project will be deliverable in a reasonable timeframe after release. The open sourcing of the OpenGL conformance test suite and ongoing work between Khronos and X.org will also allow for non-vendor led open source implementations to achieve conformance in the near future," said David Airlie, senior principal engineer at Red Hat, and developer on Mesa/X.org projects.

      View full story
    • By _OskaR
      Hi,
      I have an OpenGL application but without possibility to wite own shaders.
      I need to perform small VS modification - is possible to do it in an alternative way? Do we have apps or driver modifictions which will catch the shader sent to GPU and override it?
    • By xhcao
      Does sync be needed to read texture content after access texture image in compute shader?
      My simple code is as below,
      glUseProgram(program.get());
      glBindImageTexture(0, texture[0], 0, GL_FALSE, 3, GL_READ_ONLY, GL_R32UI);
      glBindImageTexture(1, texture[1], 0, GL_FALSE, 4, GL_WRITE_ONLY, GL_R32UI);
      glDispatchCompute(1, 1, 1);
      // Does sync be needed here?
      glUseProgram(0);
      glBindFramebuffer(GL_READ_FRAMEBUFFER, framebuffer);
      glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                     GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture[1], 0);
      glReadPixels(0, 0, kWidth, kHeight, GL_RED_INTEGER, GL_UNSIGNED_INT, outputValues);
       
      Compute shader is very simple, imageLoad content from texture[0], and imageStore content to texture[1]. Does need to sync after dispatchCompute?
  • Advertisement