Jump to content
  • Advertisement
cebugdev

OpenGL OpenGL 2D GUI system question

Recommended Posts

hi all,

i am trying to build an OpenGL 2D GUI system, (yeah yeah, i know i should not be re inventing the wheel, but this is for educational and some other purpose only),
i have built GUI system before using 2D systems such as that of HTML/JS canvas, but in 2D system, i can directly match a mouse coordinates to the actual graphic coordinates with additional computation for screen size/ratio/scale ofcourse.

now i want to port it to OpenGL, i know that to render a 2D object in OpenGL we specify coordiantes in Clip space or use the orthographic projection, now heres what i need help about.

1. what is the right way of rendering the GUI? is it thru drawing in clip space or switching to ortho projection?

2. from screen coordinates (top left is 0,0 nd bottom right is width height), how can i map the mouse coordinates to OpenGL 2D so that mouse events such as button click works? In consideration ofcourse to the current screen/size dimension.

3. when let say if the screen size/dimension is different, how to handle this? in my previous javascript 2D engine using canvas, i just have my working coordinates and then just perform the bitblk or copying my working canvas to screen canvas and scale the mouse coordinates from there, in OpenGL how to work on a multiple screen sizes (more like an OpenGL ES question).

lastly, if you guys know any books, resources, links or tutorials that handle or discuss this, i found one with marekknows opengl game engine website but its not free,

Just let me know. Did not have any luck finding resource in google for writing our own OpenGL GUI framework.

IF there are no any available online, just let me know, what things do i need to look into for OpenGL and i will study them one by one to make it work.

thank you, and looking forward to positive replies.

Share this post


Link to post
Share on other sites
Advertisement

No no no, you can pass pixel coords to vertex shader and there recalculate actual vertex clip position on screen not to mention y axis is flipped so you start from y=0 at bottom left corner

 

So how to do that in shader well first of all you pass vertex pixel coords then you pass screen size in pixels then you make something like nv.x = v.x / screen_width to get percentage of screen coords this should give you a number from 0..1 then you need to multiple it by 0.5 and subtract it by -1??? I really forgot how to do this anyway you need to end with a number between -1 and 1 or was it 0.5 as I said I'm on the phone now and can't actually check that for code let others think

Share this post


Link to post
Share on other sites

Store the coordinates in screen coordinates. Use this to check against mouse position.

Set up a VAO, and VBO with a rectangle only 1.0f by 1.0f, and 0.0f as the depth. You can also disable depth before rendering, and enabling it again after.

Translate the model matrix (intialized to identity matrix) by (xPos, yPos, 0.0f).

Scale the model matrix by (width, height, 1.0f).

Multiply the projection matrix (use ortho for 2D that doesn't ever need to simulate depth) by the model matrix. Then send that one resulting matrix to the shader.

These are the steps I use, the first one ensures that the mouse checks pass. The others ensure that the sprite renders at the same position.

Edited by Yxjmir

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Advertisement
  • Advertisement
  • Popular Tags

  • Popular Now

  • Advertisement
  • Similar Content

    • By LukasBanana
      Hi all,
       
      I'm trying to generate MIP-maps of a 2D-array texture, but only a limited amount of array layers and MIP-levels.
      For instance, to generate only the first 3 MIP-maps of a single array layer of a large 2D-array.
       
      After experimenting with glBlitFramebuffer to generate the MIP-maps manually but still with some sort of hardware acceleration,
      I ended up with glTextureView which already works with the limited amount of array layers (I can also verify the result in RenderDoc).
      However, glGenerateMipmap (or glGenerateTextureMipmap) always generates the entire MIP-chain for the specified array layer.
       
      Thus, the <numlevels> parameter of glTextureView seems to be ignored in the MIP-map generation process.
      I also tried to use glTexParameteri(..., GL_TEXTURE_MAX_LEVEL, 3), but this has the same result.
      Can anyone explain me how to solve this?
       
      Here is an example code, how I do it:
      void GenerateSubMips( GLuint texID, GLenum texTarget, GLenum internalFormat, GLuint baseMipLevel, GLuint numMipLevels, GLuint baseArrayLayer, GLuint numArrayLayers) { GLuint texViewID = 0; glGenTextures(1, &texViewID); glTextureView( texViewID, texTarget, texID, internalFormat, baseMipLevel, numMipLevels, baseArrayLayer, numArrayLayers ); glGenerateTextureMipmap(texViewID); glDeleteTextures(1, &texViewID); } GenerateSubMips( myTex, GL_TEXTURE_2D_ARRAY, GL_RGBA8, 0, 3, // only the first 3 MIP-maps 4, 1 // only one array layer with index 4 );  
      Thanks and kind regards,
      Lukas
    • By KKTHXBYE
      I have a fullscreen sized quad, now i draw it on screen then in fragment shader i choose whenever linenis visible or not and draw it on screen (2d grid rendering)
      However when i zoom out lines dissapear not to mention i cant achieve one thickeness regardless of the zoom
      Left zoomed in right and below zoomed out

       
      And heres the shader
      precision highp float; uniform vec3 translation; uniform float grid_size; uniform vec3 bg_color; uniform vec3 grid_color; uniform float lthick; uniform float sw; uniform float sh; uniform float scale; varying vec3 vc; int modulo(float x, float y) { return int (x - y * float ( int (x/y))); } float modulof(float x, float y) { return x - y * float ( int (x/y) ); } void main() { bool found = false; vec2 fragcoord = vc.xy * 0.5 + 0.5; //find how much units do we have in worldspace for a halfspace vec2 sc = ( vec2(sw, sh) / 2.0 ) / scale; sc = sc * vc.xy + translation.xy; //world position int px = modulo(float (sc.x), grid_size); int py = modulo(float (sc.y), grid_size); if ( (px == 0) || (py == 0) ) found = true; if (found) gl_FragColor = vec4(grid_color, 1.0); else gl_FragColor = vec4(bg_color, 1.0); } I know that when zooming out, a fragment can not represent actual grid line.
    • By KKTHXBYE
      I wonder how one could achieve that, personally i could pass another vertex data first would be actual geometric position, second would be next vertex in array. But its way too overcomplicated, ill have to build two sets of arrays so i just don't.
      Can't actually think of something. Something that would not force me to pass another attribute to shaders, something that wont force me to change my internal model atructure at all,
       
      By the way im drawing lines with usage of GL_LINE_LOOP
      Any thoughts ?
    • By Psychopathetica
      Hello. For the last two weeks, I've been struggling with one thing... 3D object picking. And I'm near getting it right! Works great when facing front! With a first person style camera, I can go up, down, forward, backward, strafe left, straft right, and it works. Problem is, when I rotate the camera, the other end of the ray that is not the mouse end goes off in another place other than the camera, completely throwing it off! So I'm going to go step by step, and see if you guys can spot what went wrong.
      The first step was to normalize the mouse device coordinates, or in my case, touch coordinates:
      public static float[] getNormalizedDeviceCoords(float touchX, float touchY){ float[] result = new float[2]; result[0] = (2f * touchX) / Render.camera.screenWidth - 1f; result[1] = 1f - (2f * touchY) / Render.camera.screenHeight; return result; } which in turn is converted into Homogeneous Clip Coordinates:
      float[] homogeneousClipCoords = new float[]{normalizedDeviceCoords[0], normalizedDeviceCoords[1], -1f, 1f}; The next step was to convert this Homogeneous Clip Coordinates into Eye Coordinates:
      public static float[] getEyeCoords(float[] clipCoords){ float[] invertedProjection = new float[16]; Matrix.invertM(invertedProjection, 0, Render.camera.projMatrix, 0); float[] eyeCoords = new float[4]; Matrix.multiplyMV(eyeCoords, 0, invertedProjection, 0 ,clipCoords, 0); float[] result = new float[]{eyeCoords[0], eyeCoords[1], -1f, 0f}; return result; } Next was to convert the Eye Coordinates into World Coordinates and normalize it:
      public static float[] getWorldCoords(float[] eyeCoords){ float[] invertedViewMatrix = new float[16]; Matrix.invertM(invertedViewMatrix, 0, Render.camera.viewM, 0); float[] rayWorld = new float[4]; Matrix.multiplyMV(rayWorld, 0, invertedViewMatrix, 0 ,eyeCoords, 0); float length = (float)Math.sqrt(rayWorld[0] * rayWorld[0] + rayWorld[1] * rayWorld[1] + rayWorld[2] * rayWorld[2]); if(length != 0){ rayWorld[0] /= length; rayWorld[1] /= length; rayWorld[2] /= length; } return rayWorld; } Putting this all together gives me a method to get the ray direction I need:
      public static float[] calculateMouseRay(){ float touchX = MainActivity.touch.x; float touchY = MainActivity.touch.y; float[] normalizedDeviceCoords = getNormalizedDeviceCoords(touchX, touchY); float[] homogeneousClipCoords = new float[]{normalizedDeviceCoords[0], normalizedDeviceCoords[1], -1f, 1f}; float[] eyeCoords = getEyeCoords(homogeneousClipCoords); float[] worldCoords = getWorldCoords(eyeCoords); return worldCoords; } I then test for the Ray / Sphere intersection using this with double precision:
      public static boolean getRaySphereIntersection(float[] rayOrigin, float[] spherePosition, float[] rayDirection, float radius){ double[] v = new double[4]; double[] dir = new double[4]; // Calculate the a, b, c and d coefficients. // a = (XB-XA)^2 + (YB-YA)^2 + (ZB-ZA)^2 // b = 2 * ((XB-XA)(XA-XC) + (YB-YA)(YA-YC) + (ZB-ZA)(ZA-ZC)) // c = (XA-XC)^2 + (YA-YC)^2 + (ZA-ZC)^2 - r^2 // d = b^2 - 4*a*c v[0] = (double)rayOrigin[0] - (double)spherePosition[0]; v[1] = (double)rayOrigin[1] - (double)spherePosition[1]; v[2] = (double)rayOrigin[2] - (double)spherePosition[2]; dir[0] = (double)rayDirection[0]; dir[1] = (double)rayDirection[1]; dir[2] = (double)rayDirection[2]; double a = (dir[0] * dir[0]) + (dir[1] * dir[1]) + (dir[2] * dir[2]); double b = (dir[0] * v[0] + dir[1] * v[1] + dir[2] * v[2]) * 2.0; double c = (v[0] * v[0] + v[1] * v[1] + v[2] * v[2]) - ((double)radius * (double)radius); // Find the discriminant. //double d = (b * b) - c; double d = (b * b) - (4.0 * a * c); Log.d("d", String.valueOf(d)); if (d == 0f) { //one root } else if (d > 0f) { //two roots double x1 = -b - Math.sqrt(d) / (2.0 * a); double x2 = -b + Math.sqrt(d) / (2.0 * a); Log.d("X1 X2", String.valueOf(x1) + ", " + String.valueOf(x2)); if ((x1 >= 0.0) || (x2 >= 0.0)){ return true; } if ((x1 < 0.0) || (x2 >= 0.0)){ return true; } } return false; } After a week and a half of playing around with this chunk of code, and researching everything I could on google, I found out by sheer accident that the sphere position to use in this method must be the transformed sphere position extracted from the model matrix, not the position itself. Which not one damn tutorial or forum article mentioned! And works great using this. Haven't tested the objects modelView yet though. To visually see the ray, I made a class to draw the 3D line, and noticed that it has no trouble at all with one end being my mouse cursor. The other end, which is the origin, is sort of working. And it only messes up when I rotate left or right as I move around in a FPS style camera. Which brings me to my next point. I have no idea what the ray origin should be for the camera. And I have 4 choices. 3 of them worked but gave me the same results.
      Ray Origin Choices:
      1. Using just the camera.position.x, camera.position.y, and camera.position.z for my ray origin worked flawlessly straight due to the fact that the ray origin remained in the center of the screen, but messed up when I rotated the camera, and moved off screen as I was rotating. Now theoretically, even if you were facing at an angle, you still are fixated at that point, and the ray origin shouldn't be flying off away from the center of the screen at all. A point is a point after all.
      2.Using the cameras model matrix (used for translating and rotating the camera, and later multiplied to the cameras view matrix), specifically -modelMatrix[12], -modelMatrix[13], and -modelMatrix[14] (note I am using negative), basically gave me nearly the same results. Only difference is that camera rotations play a role in the cameras positions. Great facing straight, but the ray origin is no longer centered at different angles.
      3.Using the camera's view matrix didn't work at all, positive or negative, using 12, 13, and 14 in the matrix.
      4.Using the camera's inverted view matrix (positive invertedViewMatrix[12], invertedViewMatrix[13], and invertedViewMatrix[14]) did work, but gave me what probably seemed like the same results as #2.
      So basically, I'm having difficulty getting the other end of the ray, which is the ray origin. Shooting the ray to the mouse pointer was no problem, like I said. With the camera end of the ray being off, it throws off the accuracy a lot at different camera angles other than straight. If anyone has any idea's, please let me know. I'm sure my math is correct. If you need any more information, such as the camera, or how I render the ray, which I don't think is needed, I can show that too. Thanks in advance!
       
       
    • By DevAndroid
      Hello everyone,
      I'm trying to display a 2D texture to screen but the rendering isn't working correctly.
      First of all I did follow this tutorial to be able to render a Text to screen (I adapted it to render with OpenGL ES 2.0) : https://learnopengl.com/code_viewer.php?code=in-practice/text_rendering
      So here is the shader I'm using :
      const char gVertexShader[] = "#version 320 es\n" "layout (location = 0) in vec4 vertex;\n" "out vec2 TexCoords;\n" "uniform mat4 projection;\n" "void main() {\n" " gl_Position = projection * vec4(vertex.xy, 0.0, 1.0);\n" " TexCoords = vertex.zw;\n" "}\n"; const char gFragmentShader[] = "#version 320 es\n" "precision mediump float;\n" "in vec2 TexCoords;\n" "out vec4 color;\n" "uniform sampler2D text;\n" "uniform vec3 textColor;\n" "void main() {\n" " vec4 sampled = vec4(1.0, 1.0, 1.0, texture(text, TexCoords).r);\n" " color = vec4(textColor, 1.0) * sampled;\n" "}\n"; The render text works very well so I would like to keep those Shaders program to render a texture loaded from PNG.
      For that I'm using libPNG to load the PNG to a texture, here is my code :
      GLuint Cluster::loadPngFromPath(const char *file_name, int *width, int *height) { png_byte header[8]; FILE *fp = fopen(file_name, "rb"); if (fp == 0) { return 0; } fread(header, 1, 8, fp); if (png_sig_cmp(header, 0, 8)) { fclose(fp); return 0; } png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); if (!png_ptr) { fclose(fp); return 0; } png_infop info_ptr = png_create_info_struct(png_ptr); if (!info_ptr) { png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL); fclose(fp); return 0; } png_infop end_info = png_create_info_struct(png_ptr); if (!end_info) { png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp) NULL); fclose(fp); return 0; } if (setjmp(png_jmpbuf(png_ptr))) { png_destroy_read_struct(&png_ptr, &info_ptr, &end_info); fclose(fp); return 0; } png_init_io(png_ptr, fp); png_set_sig_bytes(png_ptr, 8); png_read_info(png_ptr, info_ptr); int bit_depth, color_type; png_uint_32 temp_width, temp_height; png_get_IHDR(png_ptr, info_ptr, &temp_width, &temp_height, &bit_depth, &color_type, NULL, NULL, NULL); if (width) { *width = temp_width; } if (height) { *height = temp_height; } png_read_update_info(png_ptr, info_ptr); int rowbytes = png_get_rowbytes(png_ptr, info_ptr); rowbytes += 3 - ((rowbytes-1) % 4); png_byte * image_data; image_data = (png_byte *) malloc(rowbytes * temp_height * sizeof(png_byte)+15); if (image_data == NULL) { png_destroy_read_struct(&png_ptr, &info_ptr, &end_info); fclose(fp); return 0; } png_bytep * row_pointers = (png_bytep *) malloc(temp_height * sizeof(png_bytep)); if (row_pointers == NULL) { png_destroy_read_struct(&png_ptr, &info_ptr, &end_info); free(image_data); fclose(fp); return 0; } int i; for (i = 0; i < temp_height; i++) { row_pointers[temp_height - 1 - i] = image_data + i * rowbytes; } png_read_image(png_ptr, row_pointers); GLuint texture; glGenTextures(1, &texture); glBindTexture(GL_TEXTURE_2D, texture); glPixelStorei(GL_UNPACK_ALIGNMENT, 1); glTexImage2D(GL_TEXTURE_2D, GL_ZERO, GL_RGB, temp_width, temp_height, GL_ZERO, GL_RGB, GL_UNSIGNED_BYTE, image_data); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); 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_WRAP_R, GL_CLAMP_TO_EDGE); png_destroy_read_struct(&png_ptr, &info_ptr, &end_info); free(image_data); free(row_pointers); fclose(fp); return texture; } This code just generates the texture and I store the id on memory
      And then I want to display my texture on any position (X, Y) of my screen so I did the following (That's works, at least the positioning).
      //MY TEXTURE IS 32x32 pixels ! void Cluster::printTexture(GLuint idTexture, GLfloat x, GLfloat y) { glActiveTexture(GL_TEXTURE0); glBindVertexArray(VAO); GLfloat vertices[6][4] = { { x, y + 32, 0.0, 0.0 }, { x, y, 0.0, 1.0 }, { x + 32, y, 1.0, 1.0 }, { x, y + 32, 0.0, 0.0 }, { x + 32, y, 1.0, 1.0 }, { x + 32, y + 32, 1.0, 0.0 } }; glBindTexture(GL_TEXTURE_2D, idTexture); glBindBuffer(GL_ARRAY_BUFFER, VBO); glBufferSubData(GL_ARRAY_BUFFER, GL_ZERO, sizeof(vertices), vertices); glBindBuffer(GL_ARRAY_BUFFER, GL_ZERO); glUniform1i(this->mTextShaderHandle, GL_ZERO); glDrawArrays(GL_TRIANGLE_STRIP, GL_ZERO, 6); } My .png is a blue square.
      The result is that my texture is not loaded correctly. It is not complete and there are many small black spots. I don't know what's going on ? It could be the vertices or the load ? Or maybe I need to add something on the shader. I don't know, I really need help.
      Thanks !
    • 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!
       
  • Forum Statistics

    • Total Topics
      631068
    • Total Posts
      2997741
×

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!