Jump to content
  • Advertisement
Sign in to follow this  
MasterGohan

OpenGL Issue with Texture Borders

This topic is 4340 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

Hello everyone… Going to be detailed as possible here, so I apologize on the length. Implementing a Terrain Engine at the moment, however, hit somewhat of a snag with the texturing (or rather ugly seams between tiles). The Terrain Engine’s using VBO’s for the Texture Coordinates, Vertices, etc, so… Looking through the OpenGL documentation it seemed that the easiest way to tackle the problem was to use Texture Borders. Due to that each Texture tile is already sharing vertices with its adjacent tiles; they’re also sharing texture coordinates which I set to repeat back and forth from 0-1-0 … etc. Since everything was in-place other than altering the texture chopping to share a pixel on the border of each tile, I assumed that setting Texture Bordering would be cake…. Yet as things go, it didn’t quite work out that way.. -After expanding each texture to add a border, the entire terrain ended up looking corrupt. ::Where to start in explaining? A picture is worth a thousand words, or so people say:: -- As a side note, I apologize if the server goes down or doesn’t respond. Since I don’t have any immediate access to web hosting, I’m just going to host the images myself. http://71.194.70.104/Snaps/Image1.JPG -- This snapshot shows a tear through the center of the terrain. Interestingly, it only occurs dead center of the terrain and between vertical tiles.. It doesn’t occur at the intersection of any other flipped tiles (aside from the center intersecting that is). http://71.194.70.104/Snaps/Image2.JPG -- This snapshot is looking northward on the terrain from approx dead center. The seam between each neighboring tiles is extremely visible; however, the texture looks at least ‘remotely’ like the original. http://71.194.70.104/Snaps/Image3.JPG -- Now this one was taken just turning the camera around 180 degrees (facing the tiles that were vertically flipped – y coord starting from 1.0). http://71.194.70.104/Snaps/NoBorders.JPG -- And this one is exactly the same texture, but prepared without bordering.. --You’re probably wondering what the heck that texture is… Well, it’s something that I just thought up in hopes that it’d help hint me in the problem’s direction (if I could note a pattern in the texture distortion). int counter=0,counter2; BYTE* pTextureImage=new Uint8[textureWidth*textureHeight*3]; BYTE* pTextureImage_count=pTextureImage; memset(pTextureImage_count,0,textureWidth*textureHeight*3); for (y=0; y<textureHeight; y++) { counter2=0; for (x=0; x<textureWidth; x++) { pTextureImage_count[counter]=255; pTextureImage_count[counter2]=255; pTextureImage_count+=3; counter2++; if (counter2>=3) counter2=0; } counter++; if (counter>=3) counter=0; } The terrain rendered fine without the texture bordering and with Clamping, so I assumed that this was a fairly good indication that the coordinates/textures were fine (No visible seams without filtering).. But to be certain, I went ahead and wrote up a texture viewer to give a better view of the Terrain with Borders Enabled. Unfortunately, the texture viewer didn’t yield much insight into the problem either. http://71.194.70.104/Snaps/Texture.JPG -- Complete Terrain Texture – 515x515 (scanned across at 256+1 intervals) -Note that the viewed textures have flipping already applied to them. So, for instance, the rightmost column of pixels in Tile 1 and 2 should match (Given Tile 2 is flipped horizontally as per the texture coordinates). http://71.194.70.104/Snaps/Cell%200%20(Upper%20Left).JPG -- Tile 1 http://71.194.70.104/Snaps/Cell%201%20(Upper%20Right).JPG – Tile 2 http://71.194.70.104/Snaps/Cell%202%20(Lower%20Left).JPG – Tile 3 http://71.194.70.104/Snaps/Cell%203%20(Lower%20Right).JPG – Tile 4 http://71.194.70.104/Snaps/TexCoords.TIF -- Texture Coordinate layout for the 4 tiles. –The viewer directly reads the 1BYTE aligned texture packing (not using GDI/DIB’s or anything like that), and fetches immediately before an upload.. So, this looking correct at least convinces me that the texture data’s fine. Other observations whenever moving around the terrain: Textures “dim” the further that I walk along them vertically.. Colors become faded out, maximally at about half way, and then return to their prior color intensity on reaching the tile’s other end. ===================================================== Pertaining to the texture creation… 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_MIN_FILTER,GL_LINEAR_MIPMAP_LINEAR); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); glTexImage2D(GL_TEXTURE_2D,0,3,258,258,1,GL_RGB,GL_UNSIGNED_BYTE,TexData); gluBuild2DMipmaps(GL_TEXTURE_2D,3,258,258,GL_RGB,GL_UNSIGNED_BYTE,TexData); Texture Coordinate Generation:: // Note that VertPerHeight/width are infact exact integer values, there’s no precision being lost. Checked that imediately. Especially after I tried setting the texture to pure white right before upload. http://71.194.70.104/Snaps/FullWhite.JPG -- And here’s the center black rift again, with a pure white texture.. ... m_pTexture=new float[TotalVertices*2]; float u,v; int VertPerHeight=(cx+TilesCX-1)/TilesCX, verticesPerTileHeight=(cy+TilesCY-1)/TilesCY; int k=0,i,jEnd; int yCount=0,xCount; bool xDir,yDir=true; int j; for (i=0; i<TotalVertices; i+=cx) { xCount=0; //------------------------ if (yDir) v=MathInterpolate(0.0f,1.0f,double(yCount)/double(VertPerHeight-1)); else v=MathInterpolate(1.0f,0.0f,double(yCount)/double(VertPerHeight-1)); yCount++; if (yCount>=VertPerHeight) { yDir=!yDir; yCount=1; } //------------------------ xDir=true; // Starting from the left Texture Cell.. jEnd=i+cx; for (j=i; j<jEnd; j++) { //------------------------ if (xDir) u=MathInterpolate(0.0f,1.0f,double(xCount)/double(VertPerWidth-1)); else u=MathInterpolate(1.0f,0.0f,double(xCount)/double(VertPerWidth-1)); xCount++; if (xCount>=VertPerWidth) { xCount=1; xDir=!xDir; } //------------------------ m_pTexture[k++]=u; m_pTexture[k++]=v; } } ... And rendering.. ... glBindBufferARB(GL_ARRAY_BUFFER,VertexVBO); glVertexPointer(3,GL_FLOAT,0,0); glBindBufferARB(GL_ARRAY_BUFFER,NormalsVBO); glNormalPointer(GL_FLOAT,0,0); ... glActiveTextureARB(GL_TEXTURE1_ARB); glMatrixMode(GL_TEXTURE); glLoadIdentity(); glMatrixMode(GL_MODELVIEW); glActiveTextureARB(GL_TEXTURE0_ARB); glEnable(GL_TEXTURE_2D); glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE); glBindTexture(GL_TEXTURE_2D,cell.GetTexID()); cell.Render() ... if (nFanVertices>0) glDrawElements(GL_TRIANGLES,nFanVertices,GL_UNSIGNED_INT,pFanVertices); if (nTriangleVertices>0) glDrawElements(GL_TRIANGLES,nTriangleVertices,GL_UNSIGNED_INT,pTriangleVertices); } ... The source is a mess.. Hopefully it won’t come to it, but if the problem can’t be isolated the next step will be recreating it in a small closed test app. Any suggestions of where to look, or another means to avoid seams without using Texture Bordering, would be greatly appreciated. -Note that I’ve only been working with GL for a few weeks, so specifics in any advice will be of great help. Thanks in advance.

Share this post


Link to post
Share on other sites
Advertisement
1) why such an odd size: 258?? try 2^nx2^n
2) why do you first upload you texture with glTexImage2D and overwrite it with a glumipmap upload?
3) i think the problem is not solvable with borders. try GL_REPEAT instead of GL_CLAMP_TO_EDGE. (why do you want do clamp it??)

Share this post


Link to post
Share on other sites
1) why such an odd size: 258?? try 2^nx2^n

-One of the images shown uses standard power of two textures (the one without borders).

The 258's are 256+2,256+2's -- The 2 pixels being the borders on each side of the image. I was under the impression this was what the documentation claimed should be done for using a texture border.

As per why such small textures? Smaller textures are easier to see in that viewer, given I was too lazy to code scrollbars and instead stretched the texture to fit.

2) why do you first upload you texture with glTexImage2D and overwrite it with a glumipmap upload?

-The listed code is only the traced execution for loading the terrain textures.. May not be the optimal means for everything it does.. However, it's working fine when not using texture borders, and with the Glyphs for the text engine.

3) i think the problem is not solvable with borders. i think you only have to ajust the texcoords but maybe i don't understand you problem.

-I'll take another look at the generation of the Texture Coordinates.

Update - Using GL_REPEAT yields basically the same. Same black bounds through the center, etc.

Update 2 - Traced through the Generation of the Texture Coordinates. The points of overlap are definitely at 1.0 of their respective axis, followed by a flip in direction..

[Edited by - MasterGohan on July 5, 2006 2:01:41 PM]

Share this post


Link to post
Share on other sites
Another Update..

Interesting in that it's now working (kindof).. Yet I'm now even more confused.

Added an Alpha Channel to each Texture Tile and uploaded with GL_RGBA instead of GL_RGB. In doing that, the Texture Bordering is working flawlessly and there's zero seams (as long as Compression is disabled at least).

... Do I need to be working with Alpha whenever using Borders?

--Either way, the issue with "fading" still remains. The further I move vertically along a tile the more faded it becomes until reaching the opposite end's texture coordinates.

Though I'll be continuing searching, any ideas would be appreciated.

I'll be finding another videoboard to put in here as well and see if there's any differences in GL implimentations.

EDIT: -- I'll see if I can get images showing exactly what I mean by "faded".

EDIT2: Alright.. Here's the images. They're TIF this time instead of jpeg for purposes of accurate color.

http://71.194.70.104/Snaps/Upper%20Most%20Boundry.TIF -- A non faded section of the terrain taken from a tile boundry (top bounds of the map)

http://71.194.70.104/Snaps/Faded.TIF -- A faded section of the terrain, taken approx 1/2 way vertically between tiles.

NOTE: The color radiance appears to be consistent across the horizontal axis.



[Edited by - MasterGohan on July 6, 2006 5:34:23 AM]

Share this post


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

  • Advertisement
  • Advertisement
  • Popular Tags

  • Popular Now

  • Advertisement
  • Similar Content

    • By mmmax3d
      Hi everyone,
      I would need some assistance from anyone who has a similar experience
      or a nice idea!
      I have created a skybox (as cube) and now I need to add a floor/ground.
      The skybox is created from cubemap and initially it was infinite.
      Now it is finite with a specific size. The floor is a quad in the middle
      of the skybox, like a horizon.
      I have two problems:
      When moving the skybox upwards or downwards, I need to
      sample from points even above the horizon while sampling
      from the botton at the same time.  I am trying to create a seamless blending of the texture
      at the points of the horizon, when the quad is connected
      to the skybox. However, I get skew effects. Does anybody has done sth similar?
      Is there any good practice?
      Thanks everyone!
    • By mmmax3d
      Hi everyone,
      I would need some assistance from anyone who has a similar experience
      or a nice idea!
      I have created a skybox (as cube) and now I need to add a floor/ground.
      The skybox is created from cubemap and initially it was infinite.
      Now it is finite with a specific size. The floor is a quad in the middle
      of the skybox, like a horizon.
      I have two problems:
      When moving the skybox upwards or downwards, I need to
      sample from points even above the horizon while sampling
      from the botton at the same time.  I am trying to create a seamless blending of the texture
      at the points of the horizon, when the quad is connected
      to the skybox. However, I get skew effects. Does anybody has done sth similar?
      Is there any good practice?
      Thanks everyone!
    • By iArtist93
      I'm trying to implement PBR into my simple OpenGL renderer and trying to use multiple lighting passes, I'm using one pass per light for rendering as follow:
      1- First pass = depth
      2- Second pass = ambient
      3- [3 .. n] for all the lights in the scene.
      I'm using the blending function glBlendFunc(GL_ONE, GL_ONE) for passes [3..n], and i'm doing a Gamma Correction at the end of each fragment shader.
      But i still have a problem with the output image it just looks noisy specially when i'm using texture maps.
      Is there anything wrong with those steps or is there any improvement to this process?
    • By babaliaris
      Hello Everyone!
      I'm learning openGL, and currently i'm making a simple 2D game engine to test what I've learn so far.  In order to not say to much, i made a video in which i'm showing you the behavior of the rendering.
      Video: 
       
      What i was expecting to happen, was the player moving around. When i render only the player, he moves as i would expect. When i add a second Sprite object, instead of the Player, this new sprite object is moving and finally if i add a third Sprite object the third one is moving. And the weird think is that i'm transforming the Vertices of the Player so why the transformation is being applied somewhere else?
       
      Take a look at my code:
      Sprite Class
      (You mostly need to see the Constructor, the Render Method and the Move Method)
      #include "Brain.h" #include <glm/gtc/matrix_transform.hpp> #include <vector> struct Sprite::Implementation { //Position. struct pos pos; //Tag. std::string tag; //Texture. Texture *texture; //Model matrix. glm::mat4 model; //Vertex Array Object. VertexArray *vao; //Vertex Buffer Object. VertexBuffer *vbo; //Layout. VertexBufferLayout *layout; //Index Buffer Object. IndexBuffer *ibo; //Shader. Shader *program; //Brains. std::vector<Brain *> brains; //Deconstructor. ~Implementation(); }; Sprite::Sprite(std::string image_path, std::string tag, float x, float y) { //Create Pointer To Implementaion. m_Impl = new Implementation(); //Set the Position of the Sprite object. m_Impl->pos.x = x; m_Impl->pos.y = y; //Set the tag. m_Impl->tag = tag; //Create The Texture. m_Impl->texture = new Texture(image_path); //Initialize the model Matrix. m_Impl->model = glm::mat4(1.0f); //Get the Width and the Height of the Texture. int width = m_Impl->texture->GetWidth(); int height = m_Impl->texture->GetHeight(); //Create the Verticies. float verticies[] = { //Positions //Texture Coordinates. x, y, 0.0f, 0.0f, x + width, y, 1.0f, 0.0f, x + width, y + height, 1.0f, 1.0f, x, y + height, 0.0f, 1.0f }; //Create the Indicies. unsigned int indicies[] = { 0, 1, 2, 2, 3, 0 }; //Create Vertex Array. m_Impl->vao = new VertexArray(); //Create the Vertex Buffer. m_Impl->vbo = new VertexBuffer((void *)verticies, sizeof(verticies)); //Create The Layout. m_Impl->layout = new VertexBufferLayout(); m_Impl->layout->PushFloat(2); m_Impl->layout->PushFloat(2); m_Impl->vao->AddBuffer(m_Impl->vbo, m_Impl->layout); //Create the Index Buffer. m_Impl->ibo = new IndexBuffer(indicies, 6); //Create the new shader. m_Impl->program = new Shader("Shaders/SpriteShader.shader"); } //Render. void Sprite::Render(Window * window) { //Create the projection Matrix based on the current window width and height. glm::mat4 proj = glm::ortho(0.0f, (float)window->GetWidth(), 0.0f, (float)window->GetHeight(), -1.0f, 1.0f); //Set the MVP Uniform. m_Impl->program->setUniformMat4f("u_MVP", proj * m_Impl->model); //Run All The Brains (Scripts) of this game object (sprite). for (unsigned int i = 0; i < m_Impl->brains.size(); i++) { //Get Current Brain. Brain *brain = m_Impl->brains[i]; //Call the start function only once! if (brain->GetStart()) { brain->SetStart(false); brain->Start(); } //Call the update function every frame. brain->Update(); } //Render. window->GetRenderer()->Draw(m_Impl->vao, m_Impl->ibo, m_Impl->texture, m_Impl->program); } void Sprite::Move(float speed, bool left, bool right, bool up, bool down) { if (left) { m_Impl->pos.x -= speed; m_Impl->model = glm::translate(m_Impl->model, glm::vec3(-speed, 0, 0)); } if (right) { m_Impl->pos.x += speed; m_Impl->model = glm::translate(m_Impl->model, glm::vec3(speed, 0, 0)); } if (up) { m_Impl->pos.y += speed; m_Impl->model = glm::translate(m_Impl->model, glm::vec3(0, speed, 0)); } if (down) { m_Impl->pos.y -= speed; m_Impl->model = glm::translate(m_Impl->model, glm::vec3(0, -speed, 0)); } } void Sprite::AddBrain(Brain * brain) { //Push back the brain object. m_Impl->brains.push_back(brain); } pos *Sprite::GetPos() { return &m_Impl->pos; } std::string Sprite::GetTag() { return m_Impl->tag; } int Sprite::GetWidth() { return m_Impl->texture->GetWidth(); } int Sprite::GetHeight() { return m_Impl->texture->GetHeight(); } Sprite::~Sprite() { delete m_Impl; } //Implementation Deconstructor. Sprite::Implementation::~Implementation() { delete texture; delete vao; delete vbo; delete layout; delete ibo; delete program; }  
      Renderer Class
      #include "Renderer.h" #include "Error.h" Renderer::Renderer() { } Renderer::~Renderer() { } void Renderer::Draw(VertexArray * vao, IndexBuffer * ibo, Texture *texture, Shader * program) { vao->Bind(); ibo->Bind(); program->Bind(); if (texture != NULL) texture->Bind(); GLCall(glDrawElements(GL_TRIANGLES, ibo->GetCount(), GL_UNSIGNED_INT, NULL)); } void Renderer::Clear(float r, float g, float b) { GLCall(glClearColor(r, g, b, 1.0)); GLCall(glClear(GL_COLOR_BUFFER_BIT)); } void Renderer::Update(GLFWwindow *window) { /* Swap front and back buffers */ glfwSwapBuffers(window); /* Poll for and process events */ glfwPollEvents(); }  
      Shader Code
      #shader vertex #version 330 core layout(location = 0) in vec4 aPos; layout(location = 1) in vec2 aTexCoord; out vec2 t_TexCoord; uniform mat4 u_MVP; void main() { gl_Position = u_MVP * aPos; t_TexCoord = aTexCoord; } #shader fragment #version 330 core out vec4 aColor; in vec2 t_TexCoord; uniform sampler2D u_Texture; void main() { aColor = texture(u_Texture, t_TexCoord); } Also i'm pretty sure that every time i'm hitting the up, down, left and right arrows on the keyboard, i'm changing the model Matrix of the Player and not the others.
       
      Window Class:
      #include "Window.h" #include <GL/glew.h> #include <GLFW/glfw3.h> #include "Error.h" #include "Renderer.h" #include "Scene.h" #include "Input.h" //Global Variables. int screen_width, screen_height; //On Window Resize. void OnWindowResize(GLFWwindow *window, int width, int height); //Implementation Structure. struct Window::Implementation { //GLFW Window. GLFWwindow *GLFW_window; //Renderer. Renderer *renderer; //Delta Time. double delta_time; //Frames Per Second. int fps; //Scene. Scene *scnene; //Input. Input *input; //Deconstructor. ~Implementation(); }; //Window Constructor. Window::Window(std::string title, int width, int height) { //Initializing width and height. screen_width = width; screen_height = height; //Create Pointer To Implementation. m_Impl = new Implementation(); //Try initializing GLFW. if (!glfwInit()) { std::cout << "GLFW could not be initialized!" << std::endl; std::cout << "Press ENTER to exit..." << std::endl; std::cin.get(); exit(-1); } //Setting up OpenGL Version 3.3 Core Profile. glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); /* Create a windowed mode window and its OpenGL context */ m_Impl->GLFW_window = glfwCreateWindow(width, height, title.c_str(), NULL, NULL); if (!m_Impl->GLFW_window) { std::cout << "GLFW could not create a window!" << std::endl; std::cout << "Press ENTER to exit..." << std::endl; std::cin.get(); glfwTerminate(); exit(-1); } /* Make the window's context current */ glfwMakeContextCurrent(m_Impl->GLFW_window); //Initialize GLEW. if(glewInit() != GLEW_OK) { std::cout << "GLEW could not be initialized!" << std::endl; std::cout << "Press ENTER to exit..." << std::endl; std::cin.get(); glfwTerminate(); exit(-1); } //Enabling Blending. GLCall(glEnable(GL_BLEND)); GLCall(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)); //Setting the ViewPort. GLCall(glViewport(0, 0, width, height)); //**********Initializing Implementation**********// m_Impl->renderer = new Renderer(); m_Impl->delta_time = 0.0; m_Impl->fps = 0; m_Impl->input = new Input(this); //**********Initializing Implementation**********// //Set Frame Buffer Size Callback. glfwSetFramebufferSizeCallback(m_Impl->GLFW_window, OnWindowResize); } //Window Deconstructor. Window::~Window() { delete m_Impl; } //Window Main Loop. void Window::MainLoop() { //Time Variables. double start_time = 0, end_time = 0, old_time = 0, total_time = 0; //Frames Counter. int frames = 0; /* Loop until the user closes the window */ while (!glfwWindowShouldClose(m_Impl->GLFW_window)) { old_time = start_time; //Total time of previous frame. start_time = glfwGetTime(); //Current frame start time. //Calculate the Delta Time. m_Impl->delta_time = start_time - old_time; //Get Frames Per Second. if (total_time >= 1) { m_Impl->fps = frames; total_time = 0; frames = 0; } //Clearing The Screen. m_Impl->renderer->Clear(0, 0, 0); //Render The Scene. if (m_Impl->scnene != NULL) m_Impl->scnene->Render(this); //Updating the Screen. m_Impl->renderer->Update(m_Impl->GLFW_window); //Increasing frames counter. frames++; //End Time. end_time = glfwGetTime(); //Total time after the frame completed. total_time += end_time - start_time; } //Terminate GLFW. glfwTerminate(); } //Load Scene. void Window::LoadScene(Scene * scene) { //Set the scene. m_Impl->scnene = scene; } //Get Delta Time. double Window::GetDeltaTime() { return m_Impl->delta_time; } //Get FPS. int Window::GetFPS() { return m_Impl->fps; } //Get Width. int Window::GetWidth() { return screen_width; } //Get Height. int Window::GetHeight() { return screen_height; } //Get Input. Input * Window::GetInput() { return m_Impl->input; } Renderer * Window::GetRenderer() { return m_Impl->renderer; } GLFWwindow * Window::GetGLFWindow() { return m_Impl->GLFW_window; } //Implementation Deconstructor. Window::Implementation::~Implementation() { delete renderer; delete input; } //OnWindowResize void OnWindowResize(GLFWwindow *window, int width, int height) { screen_width = width; screen_height = height; //Updating the ViewPort. GLCall(glViewport(0, 0, width, height)); }  
      Brain Class
      #include "Brain.h" #include "Sprite.h" #include "Window.h" struct Brain::Implementation { //Just A Flag. bool started; //Window Pointer. Window *window; //Sprite Pointer. Sprite *sprite; }; Brain::Brain(Window *window, Sprite *sprite) { //Create Pointer To Implementation. m_Impl = new Implementation(); //Initialize Implementation. m_Impl->started = true; m_Impl->window = window; m_Impl->sprite = sprite; } Brain::~Brain() { //Delete Pointer To Implementation. delete m_Impl; } void Brain::Start() { } void Brain::Update() { } Window * Brain::GetWindow() { return m_Impl->window; } Sprite * Brain::GetSprite() { return m_Impl->sprite; } bool Brain::GetStart() { return m_Impl->started; } void Brain::SetStart(bool value) { m_Impl->started = value; } Script Class (Its a Brain Subclass!!!)
      #include "Script.h" Script::Script(Window *window, Sprite *sprite) : Brain(window, sprite) { } Script::~Script() { } void Script::Start() { std::cout << "Game Started!" << std::endl; } void Script::Update() { Input *input = this->GetWindow()->GetInput(); Sprite *sp = this->GetSprite(); //Move this sprite. this->GetSprite()->Move(200 * this->GetWindow()->GetDeltaTime(), input->GetKeyDown("left"), input->GetKeyDown("right"), input->GetKeyDown("up"), input->GetKeyDown("down")); std::cout << sp->GetTag().c_str() << ".x = " << sp->GetPos()->x << ", " << sp->GetTag().c_str() << ".y = " << sp->GetPos()->y << std::endl; }  
      Main:
      #include "SpaceShooterEngine.h" #include "Script.h" int main() { Window w("title", 600,600); Scene *scene = new Scene(); Sprite *player = new Sprite("Resources/Images/player.png", "Player", 100,100); Sprite *other = new Sprite("Resources/Images/cherno.png", "Other", 400, 100); Sprite *other2 = new Sprite("Resources/Images/cherno.png", "Other", 300, 400); Brain *brain = new Script(&w, player); player->AddBrain(brain); scene->AddSprite(player); scene->AddSprite(other); scene->AddSprite(other2); w.LoadScene(scene); w.MainLoop(); return 0; }  
       
      I literally can't find what is wrong. If you need more code, ask me to post it. I will also attach all the source files.
      Brain.cpp
      Error.cpp
      IndexBuffer.cpp
      Input.cpp
      Renderer.cpp
      Scene.cpp
      Shader.cpp
      Sprite.cpp
      Texture.cpp
      VertexArray.cpp
      VertexBuffer.cpp
      VertexBufferLayout.cpp
      Window.cpp
      Brain.h
      Error.h
      IndexBuffer.h
      Input.h
      Renderer.h
      Scene.h
      Shader.h
      SpaceShooterEngine.h
      Sprite.h
      Texture.h
      VertexArray.h
      VertexBuffer.h
      VertexBufferLayout.h
      Window.h
    • By Cristian Decu
      Hello fellow programmers,
      For a couple of days now i've decided to build my own planet renderer just to see how floating point precision issues
      can be tackled. As you probably imagine, i've quickly faced FPP issues when trying to render absurdly large planets.
       
      I have used the classical quadtree LOD approach;
      I've generated my grids with 33 vertices, (x: -1 to 1, y: -1 to 1, z = 0).
      Each grid is managed by a TerrainNode class that, depending on the side it represents (top, bottom, left right, front, back),
      creates a special rotation-translation matrix that moves and rotates the grid away from the origin so that when i finally
      normalize all the vertices on my vertex shader i can get a perfect sphere.
      T = glm::translate(glm::dmat4(1.0), glm::dvec3(0.0, 0.0, 1.0)); R = glm::rotate(glm::dmat4(1.0), glm::radians(180.0), glm::dvec3(1.0, 0.0, 0.0)); sides[0] = new TerrainNode(1.0, radius, T * R, glm::dvec2(0.0, 0.0), new TerrainTile(1.0, SIDE_FRONT)); T = glm::translate(glm::dmat4(1.0), glm::dvec3(0.0, 0.0, -1.0)); R = glm::rotate(glm::dmat4(1.0), glm::radians(0.0), glm::dvec3(1.0, 0.0, 0.0)); sides[1] = new TerrainNode(1.0, radius, R * T, glm::dvec2(0.0, 0.0), new TerrainTile(1.0, SIDE_BACK)); // So on and so forth for the rest of the sides As you can see, for the front side grid, i rotate it 180 degrees to make it face the camera and push it towards the eye;
      the back side is handled almost the same way only that i don't need to rotate it but simply push it away from the eye.
      The same technique is applied for the rest of the faces (obviously, with the proper rotations / translations).
      The matrix that result from the multiplication of R and T (in that particular order) is send to my vertex shader as `r_Grid'.
      // spherify vec3 V = normalize((r_Grid * vec4(r_Vertex, 1.0)).xyz); gl_Position = r_ModelViewProjection * vec4(V, 1.0); The `r_ModelViewProjection' matrix is generated on the CPU in this manner.
      // No the most efficient way, but it works. glm::dmat4 Camera::getMatrix() { // Create the view matrix // Roll, Yaw and Pitch are all quaternions. glm::dmat4 View = glm::toMat4(Roll) * glm::toMat4(Pitch) * glm::toMat4(Yaw); // The model matrix is generated by translating in the oposite direction of the camera. glm::dmat4 Model = glm::translate(glm::dmat4(1.0), -Position); // Projection = glm::perspective(fovY, aspect, zNear, zFar); // zNear = 0.1, zFar = 1.0995116e12 return Projection * View * Model; } I managed to get rid of z-fighting by using a technique called Logarithmic Depth Buffer described in this article; it works amazingly well, no z-fighting at all, at least not visible.
      Each frame i'm rendering each node by sending the generated matrices this way.
      // set the r_ModelViewProjection uniform // Sneak in the mRadiusMatrix which is a matrix that contains the radius of my planet. Shader::setUniform(0, Camera::getInstance()->getMatrix() * mRadiusMatrix); // set the r_Grid matrix uniform i created earlier. Shader::setUniform(1, r_Grid); grid->render(); My planet's radius is around 6400000.0 units, absurdly large, but that's what i really want to achieve;
      Everything works well, the node's split and merge as you'd expect, however whenever i get close to the surface
      of the planet the rounding errors start to kick in giving me that lovely stairs effect.
      I've read that if i could render each grid relative to the camera i could get better precision on the surface, effectively
      getting rid of those rounding errors.
       
      My question is how can i achieve this relative to camera rendering in my scenario here?
      I know that i have to do most of the work on the CPU with double, and that's exactly what i'm doing.
      I only use double on the CPU side where i also do most of the matrix multiplications.
      As you can see from my vertex shader i only do the usual r_ModelViewProjection * (some vertex coords).
       
      Thank you for your suggestions!
       
  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

Participate in the game development conversation and more when you create an account on GameDev.net!

Sign me up!