Jump to content
  • Advertisement
Sign in to follow this  
ill

OpenGL How to copy the raw data used by OpenGL loaded by DevIL (Non pwr of 2 texture paddin)

This topic is 3234 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

OK, so i'm using DevIL to load textures into my OpenGL + SDL app. I'm using an image class to wrap all the image loading and drawing. It's going to be for a 2D engine so these will basically be sprites. Since it's for a 2D game where most of the sprite dimensions won't be powers of 2 I need to load them in padded with powers of 2 dimensions. I basically have everything working here right now except it doesn't appear to be copying the texture properly with my for loop. Basically each pixel is 4 bytes since the image is loaded in with RGBA format so for each pixel I copy over 4 bytes to the new array. The old array of image data is the nonpadded image. The new array is the padded image data. I don't really care what pixels there are outside of the boundary since those don't get drawn when I draw a textured quad with the sprite image since I also calculate the proper texture coordinates to clip the image to only show the valid pixel data. So from the way I see it, my for loop should be properly copying all of the image bytes but what I get instead is garbage when I display the padded image. I'm obviously doing something wrong and must be misunderstanding something about the way image data is stored in memory. Alternatively, I can use ILUT from DevIL to automatically load in the textures for me and pad them with power of 2 but I'm not sure if it'll allow me to extract data like image width and so on. Also I couldn't seem to get ILUT to properly load textures for me in the first place so I settled for the raw method. If someone has a good example of working ILUT texture loading directly into OpenGL that would be great. I'm also open to completely different ideas if mine totally sucks. Here is the entire loading function for the image.
/*
 * Loads image from file into an OpenGL texture
 *      fileNameArg:    file name of image to load
 *      xOriginArg:     x origin of image relative to top left corner
 *      yOriginArg:     y origin of image relative to top left corner
 */
Image::Image(const char* fileNameArg, GLfloat xOriginArg, GLfloat yOriginArg)
{
    //TODO: check if hardware supports nonpower of 2 texture dimensions to not do padding and save memory
    //TODO: check max texture width and height
    /*
     * int Max2DTextureWidth, Max2DTextureHeight;
     * glGetIntegerv(GL_MAX_TEXTURE_SIZE, &Max2DTextureWidth);
     * Max2DTextureWidth=Max2DTextureHeight;
     *
     */
    //TODO: place texture border pixels
    ILuint ilTexture;
    int paddedWidth;
    int paddedHeight;
    //GLvoid * imageData = NULL;
    ILubyte* imageDataOriginal = NULL;
    ILubyte* imageData = NULL;
    GLint imageBPP;

    ilGenImages(1, &ilTexture);
    ilBindImage(ilTexture);

    if(ilLoadImage(fileNameArg))
    {
        if(ilConvertImage(IL_RGBA, IL_UNSIGNED_BYTE))
        {
            width = ilGetInteger(IL_IMAGE_WIDTH);
            height = ilGetInteger(IL_IMAGE_HEIGHT);
            imageBPP = ilGetInteger(IL_IMAGE_BPP);

            //pad image if not power of 2
            paddedWidth = nextPow2(width);
            paddedHeight = nextPow2(height);

            //if resizing is necessary for padding
            if(paddedWidth != width || paddedHeight != height)
            {
                imageDataOriginal = ilGetData();

                ///////////////////////////////////////////////////
                //THIS IS WHERE I'M MANUALLY COPYING IMAGE DATA
                ///////////////////////////////////////////////////
                if((imageData = new (nothrow) ILubyte[width * imageBPP * height]) != NULL)
                {
                    for(int imageY; imageY <= height; imageY ++)
                    {
                        for(int imageX; imageX <= width * imageBPP; imageX ++)
                        {
                            imageData[imageX + imageY * paddedWidth * imageBPP] =
                                imageDataOriginal[imageX + imageY * width * imageBPP];
                        }
                    }
                }
                else
                {
                    exit(EXIT_FAILURE);
                }
            }
            else
            {
                imageData = ilGetData();
            }

            glGenTextures(1, &glTexture);
            glBindTexture(GL_TEXTURE_2D, glTexture);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

            glTexImage2D(GL_TEXTURE_2D, 0, imageBPP, paddedWidth, paddedHeight, 0,
                ilGetInteger(IL_IMAGE_FORMAT), GL_UNSIGNED_BYTE, imageData);
        }
        else
        {
            exit(EXIT_FAILURE);
        }
    }
    else
    {
        exit(EXIT_FAILURE);
    }

    ilDeleteImages(1, &ilTexture);

    if(paddedWidth != width || paddedHeight != height)
    {
        delete[] imageData;
    }

    if(glGetError() != GL_NO_ERROR)
    {
        exit(EXIT_FAILURE);
    }

    xOrigin = xOriginArg;
    yOrigin = yOriginArg;

    //set texture coordinates for clipping padded texture when texturing quad
    texClipCoordW = (float) width / paddedWidth;
    texClipCoordH = 1 - ((float) height / paddedHeight);
}

Share this post


Link to post
Share on other sites
Advertisement
You haven't initialized your loop variables. But assuming you want to initialize them to zero, and that texClipCoordW/H are the texture coordinates where the texture ends, the H-coordinate shall be texClipCoordH = (float)height / paddedHeight.

But, any reason you're not using the texture as it is, without padding to a power of two?

Share this post


Link to post
Share on other sites
HAHAHA thanks. Always helps to have someone else look at your code. I'm sure I would've never found this stupid mistake on my own.

Almost works now, except the entire image data in the sprite is offset down by 3 pixels.

I actually can't figure this out since it might be a way that GLtexImage2D is reading the pixel data.

This is the current for loop after a few fixes. cout outputs to stdout.txt so I can see that all the pixel data should be correct.

for(int imageY = 0; imageY < height; imageY ++)
{
for(int imageX = 0; imageX < width * imageBPP; imageX ++)
{
cout << (int) imageDataOriginal[imageX + imageY * width * imageBPP]
<< " " << (imageX + imageY * width * imageBPP) << endl;

imageData[imageX + imageY * paddedWidth * imageBPP] =
imageDataOriginal[imageX + imageY * width * imageBPP];
}
}


When it's loaded into OpenGL for a 24x29 image, it seems to be offset down by 3 pixels. 32-29 = 3. IDK if that's a coincidence or not. Anyway, the program always crashes for any other dimension so the fact that I have this 24x29 image just randomly not crashing on me while I'm testing is a miracle so I can actually see kinda what's happening. For example 32x24 crashes for some reason.

Basically, is there some kind of strange order that glTexImage2D reads the image data in, like in backwards y order or something? Maybe the raw data is actually upside down. I don't see how else this could be happening.






For now I fixed it by doing this:

if((imageData = new (nothrow) ILubyte[width * imageBPP * height]) != NULL)
{
for(int imageY = 0; imageY < height; imageY ++)
{
for(int imageX = 0; imageX < width * imageBPP; imageX ++)
{
//Here I'm offsetting the y coordinate of resulting image by paddedHeight-Height and it works great for all sizes
imageData[imageX + (imageY + (paddedHeight - height)) * paddedWidth * imageBPP] =
imageDataOriginal[imageX + imageY * width * imageBPP];
}
}
}

Is the image always loaded in upside down by OpenGL or is there some special case where this happens?

Also I figured out why I get a crash. After loading this in I free the data that was used.

//clean up image data
ilDeleteImages(1, &ilTexture);

if(paddedWidth != width || paddedHeight != height)
{
cout << "delA" << endl;

delete[] imageData;

cout << "delB" << endl;
}


I only get this crash when the image isn't 24x29 or isn't already with power of 2 dimensions (since that block shouldn't execute unless the image was padded). So should I not be freeing imageData or is there something seriously wrong or is my syntax completely off? I have a lot of experience with C and Java, but I'm basically just starting with C++ so I get a little confused sometimes. Like in C I would use malloc and free instead of new and delete. I could do that by including <cstdlib> or <stdlib.h> or something like that and use the C functions but what's the point of that? I might still get the error anyway and I would think it's better to use built in functions of the language.

[Edited by - ill on August 13, 2009 12:24:59 PM]

Share this post


Link to post
Share on other sites
You might want to look into the function when copying big chunks of data that you don't want to cut into peaces.

ILuint ilCopyPixels( ILuint XOff, ILuint YOff, ILuint ZOff, ILuint Width, ILuint Height, ILuint Depth, ILenum Format, ILenum Type, ILvoid *Data);

or

ILboolean ilOverlayImage(ILuint Src, ILint XCoord, ILint YCoord, ILint
ZCoord);
ILboolean ilBlit(ILuint Src, ILint DestX, ILint DestY, ILint DestZ, ILuint SrcX,
ILuint SrcY, ILuint SrcZ, ILuint Width, ILuint Height, ILuint
Depth);

which is probably more suitable in your case.

You can probably reduce your code immense using those functions instead of your custom method.

Also i think (not 100% sure tho) your array indexes should more look like

(x+y*width)*bpp

instead of

(x+y*width*bpp)

You could also use

ILboolean iluScale(ILuint Width, ILuint Height, ILuint Depth);

http://openil.sourceforge.net/docs/DevIL%20Manual.pdf

Share this post


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

  • Advertisement
  • Advertisement
  • Popular Tags

  • Similar Content

    • By McGrane
      Hey
      My laptop recently decided to die, so Ive been transferring my project to my work laptop just to get it up to date, and commit it. I was banging my head against the wall all day, as my textures where not displaying in my program- I was getting no errors and no indication of why it was occurring so I have been just trying to figure it out- I know the image loading was working ok, as im using image data elsewhere, I was pretty confident that the code was fine also, as ive never had an issue with displaying textures before, so I thought it might be the drivers on this laptop, (my old one was just using the built in IntelHD, while this laptop has a NVIDIA graphics card) but all seems to be up to date.
      Below are my basic shaders:
      Vertex Shader
      #version 330 core layout(location = 0) in vec3 position; layout(location = 1) in vec3 color; layout(location = 2) in vec3 normal; layout(location = 3) in vec2 texCoord; uniform mat4 Projection; uniform mat4 Model; out vec3 Color; out vec3 Normal; out vec2 TexCoord; void main() { gl_Position = Projection * Model * vec4( position, 1.0 ); Color = color; Normal = normal; TexCoord = vec2( texCoord.x, texCoord.y); } Fragment Shader
      #version 330 core in vec3 Color; in vec3 Normal; in vec2 TexCoord; uniform sampler2D textureData; void main() { vec4 textureColor = texture( textureData, TexCoord ); vec4 finalColor = textureColor * vec4( Color, 1.0f); gl_FragColor = finalColor; } Calling Code
      glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, textureID); glUniform1i(glGetUniformLocation(shaderID, "textureData"), textureID); Now this is the part i dont understand, I worked through my program, until I got to the above 'Calling Code'. This just displays a black texture.. my original issue. Out of desperation, I just tried changing the name in glGetUniformLocation from "textureData" to "textureData_invalid" to see if my error checks would through up something, but in actual fact, it is now displaying the texture as expected. Can anyone fathom a guess as too why this is occurring.. im assuming the random text is just picking up the correct location by c++ witchcraft, but why is the original one not getting picked up correctly and/or not working as expected
      I realize more code is probably needed to see how it all hangs together.. but it seems to come down to this as the issue
    • By QQemka
      Hello. So far i got decently looking 3d scene. I also managed to render a truetype font, on my way to implementing gui (windows, buttons and textboxes). There are several issues i am facing, would love to hear your feedback.
      1) I render text using atlas with VBO containing x/y/u/v of every digit in the atlas (calculated basing on x/y/z/width/height/xoffset/yoffset/xadvance data in binary .fnt format file, screenshot 1). I generated a Comic Sans MS with 32 size and times new roman with size 12 (screenshot 2 and 3). The first issue is the font looks horrible when rescaling. I guess it is because i am using fixed -1 to 1 screen space coords. This is where ortho matrix should be used, right?
      2) Rendering GUI. Situation is similar to above. I guess the widgets should NOT scale when scaling window, am i right? So what am i looking for is saying "this should be always in the middle, 200x200 size no matter the display window xy", and "this should stick to the bottom left corner". Is ortho matrix the cure for all such problems?
      3) The game is 3D but i have to go 2D to render static gui elements over the scene - and i want to do it properly! At the moment i am using matrix 3x3 for 2d transformations and vec3 for all kinds of coordinates. In shaders tho i technically still IS 3D. I have to set all 4 x y z w of the gl_Position while it would be much much more conventient to... just do the maths in 2d space. Can i achieve it somehow?
      4) Text again. I am kind of confused what is the reason of artifacts in Times New Roman font displaying (screenshot 1). I render from left to right, letter after letter. You can clearly see that letters on the right (so the ones rendered after ones on the left are covered by the previous one). I was toying around with blending options but no luck. I do not support kerning at the moment but that's definitely not the cause of error. The display of the small font looks dirty aliased too. I am knd of confused how to interpret the integer data and how should be scaled/adapted to the screen view. Is it just store the data as constant size and again - use ortho matrix?
      Thanks in advance for all your ideas and suggestions!
      https://i.imgur.com/4rd1VC3.png
      https://i.imgur.com/uHrSXfe.png
      https://i.imgur.com/xRTffPn.png
    • By plz717
      Hello, everyone! I hope my problem isn't too 'beginnerish'. I'm doing research on motion synthesis now, trying to implement the Deep Mimic paper (DeepMimic) by BINPENG XUE, in this paper, I need to first retarget character A's motion to another character B to make the reference motion clips for character B, since we don't have character B‘s reference motion. The most important thing is that in the paper, the author copied character A's joint's rotation with respective to joint's local coordinate system (not the parent) to character B. In my personal understanding, the joint's rotation with respective to joint's local coordinate system is something like that in the attached photo, where for the Elbow joint, i need to get the Elbow's rotation in the elbow's local coordinate system (i'm very grateful for you to share your ideas if i have misunderstanding about it 🙂)
      I have searched many materials on the internet about how to extract the local joint's information from FBX, the most relative one i found is the pivot rotation( and geometric transformation, object offset transformation). I'm a beginner in computer graphics, and i'm confused about whether the pivot rotation( or geometric transformation, object offset transformation) is exactly the joint's local rotation i'm seeking? I hope someone that have any ideas can help me, I'd be very grateful for any pointers in the right direction. Thanks in advance! 

    • By nOoNEE
      hello guys , i have some questions  what does glLinkProgram  and  glBindAttribLocation do?  i searched but there wasnt any good resource 
    • By owenjr
      Hi, I'm a Multimedia Engineering student. I am about to finish my dergree and I'm already thinking about what topic to cover in my final college project.
      I'm interested in the procedural animation with c++ and OpenGL of creatures, something like a spider for example. Can someone tell me what are the issues I should investigate to carry it out? I understand that it has some dependence on artificial intelligence but I do not know to what extent. Can someone help me to find information about it? Thank you very much.
       
      Examples: 
      - Procedural multi-legged walking animation
      - Procedural Locomotion of Multi-Legged Characters in Dynamic Environments
    • By Lewa
      So, i'm still on my quest to unterstanding the intricacies of HDR and implementing this into my engine. Currently i'm at the step to implementing tonemapping. I stumbled upon this blogposts:
      http://filmicworlds.com/blog/filmic-tonemapping-operators/
      http://frictionalgames.blogspot.com/2012/09/tech-feature-hdr-lightning.html
      and tried to implement some of those mentioned tonemapping methods into my postprocessing shader.
      The issue is that none of them creates the same results as shown in the blogpost which definitely has to do with the initial range in which the values are stored in the HDR buffer. For simplicity sake i store the values between 0 and 1 in the HDR buffer (ambient light is 0.3, directional light is 0.7)
      This is the tonemapping code:
      vec3 Uncharted2Tonemap(vec3 x) { float A = 0.15; float B = 0.50; float C = 0.10; float D = 0.20; float E = 0.02; float F = 0.30; return ((x*(A*x+C*B)+D*E)/(x*(A*x+B)+D*F))-E/F; } This is without the uncharted tonemapping:
      This is with the uncharted tonemapping:
      Which makes the image a lot darker.
      The shader code looks like this:
      void main() { vec3 color = texture2D(texture_diffuse, vTexcoord).rgb; color = Uncharted2Tonemap(color); //gamma correction (use only if not done in tonemapping code) color = gammaCorrection(color); outputF = vec4(color,1.0f); } Now, from my understanding is that tonemapping should bring the range down from HDR to 0-1.
      But the output of the tonemapping function heavily depends on the initial range of the values in the HDR buffer. (You can't expect to set the sun intensity the first time to 10 and the second time to 1000 and excpect the same result if you feed that into the tonemapper.) So i suppose that this also depends on the exposure which i have to implement?
      To check this i plotted the tonemapping curve:
      You can see that the curve goes only up to around to a value of 0.21 (while being fed a value of 1) and then basically flattens out. (which would explain why the image got darker.)
       
      My guestion is: In what range should the values in the HDR buffer be which then get tonemapped? Do i have to bring them down to a range of 0-1 by multiplying with the exposure?
      For example, if i increase the values of the light by 10 (directional light would be 7 and ambient light 3) then i would need to divide HDR values by 10 in order to get a value range of 0-1 which then could be fed into the tonemapping curve. Is that correct?
    • By nOoNEE
      i am reading this book : link
      in the OpenGL Rendering Pipeline section there is a picture like this: link
      but the question is this i dont really understand why it is necessary to turn pixel data in to fragment and then fragment into pixel could please give me a source or a clear Explanation that why it is necessary ? thank you so mu
       
       
    • By Inbar_xz
      I'm using the OPENGL with eclipse+JOGL.
      My goal is to create movement of the camera and the player.
      I create main class, which create some box in 3D and hold 
      an object of PlayerAxis.
      I create PlayerAxis class which hold the axis of the player.
      If we want to move the camera, then in the main class I call to 
      the func "cameraMove"(from PlayerAxis) and it update the player axis.
      That's work good.
      The problem start if I move the camera on 2 axis, 
      for example if I move with the camera right(that's on the y axis)
      and then down(on the x axis) -
      in some point the move front is not to the front anymore..
      In order to move to the front, I do
      player.playerMoving(0, 0, 1);
      And I learn that in order to keep the front move, 
      I need to convert (0, 0, 1) to the player axis, and then add this.
      I think I dont do the convert right.. 
      I will be glad for help!

      Here is part of my PlayerAxis class:
       
      //player coordinate float x[] = new float[3]; float y[] = new float[3]; float z[] = new float[3]; public PlayerAxis(float move_step, float angle_move) { x[0] = 1; y[1] = 1; z[2] = -1; step = move_step; angle = angle_move; setTransMatrix(); } public void cameraMoving(float angle_step, String axis) { float[] new_x = x; float[] new_y = y; float[] new_z = z; float alfa = angle_step * angle; switch(axis) { case "x": new_z = addVectors(multScalar(z, COS(alfa)), multScalar(y, SIN(alfa))); new_y = subVectors(multScalar(y, COS(alfa)), multScalar(z, SIN(alfa))); break; case "y": new_x = addVectors(multScalar(x, COS(alfa)), multScalar(z, SIN(alfa))); new_z = subVectors(multScalar(z, COS(alfa)), multScalar(x, SIN(alfa))); break; case "z": new_x = addVectors(multScalar(x, COS(alfa)), multScalar(y, SIN(alfa))); new_y = subVectors(multScalar(y, COS(alfa)), multScalar(x, SIN(alfa))); } x = new_x; y = new_y; z = new_z; normalization(); } public void playerMoving(float x_move, float y_move, float z_move) { float[] move = new float[3]; move[0] = x_move; move[1] = y_move; move[2] = z_move; setTransMatrix(); float[] trans_move = transVector(move); position[0] = position[0] + step*trans_move[0]; position[1] = position[1] + step*trans_move[1]; position[2] = position[2] + step*trans_move[2]; } public void setTransMatrix() { for (int i = 0; i < 3; i++) { coordiTrans[0][i] = x[i]; coordiTrans[1][i] = y[i]; coordiTrans[2][i] = z[i]; } } public float[] transVector(float[] v) { return multiplyMatrixInVector(coordiTrans, v); }  
      and in the main class i have this:
       
      public void keyPressed(KeyEvent e) { if (e.getKeyCode()== KeyEvent.VK_ESCAPE) { System.exit(0); //player move } else if (e.getKeyCode()== KeyEvent.VK_W) { //front //moveAmount[2] += -0.1f; player.playerMoving(0, 0, 1); } else if (e.getKeyCode()== KeyEvent.VK_S) { //back //moveAmount[2] += 0.1f; player.playerMoving(0, 0, -1); } else if (e.getKeyCode()== KeyEvent.VK_A) { //left //moveAmount[0] += -0.1f; player.playerMoving(-1, 0, 0); } else if (e.getKeyCode()== KeyEvent.VK_D) { //right //moveAmount[0] += 0.1f; player.playerMoving(1, 0, 0); } else if (e.getKeyCode()== KeyEvent.VK_E) { //moveAmount[0] += 0.1f; player.playerMoving(0, 1, 0); } else if (e.getKeyCode()== KeyEvent.VK_Q) { //moveAmount[0] += 0.1f; player.playerMoving(0, -1, 0); //camera move } else if (e.getKeyCode()== KeyEvent.VK_I) { //up player.cameraMoving(1, "x"); } else if (e.getKeyCode()== KeyEvent.VK_K) { //down player.cameraMoving(-1, "x"); } else if (e.getKeyCode()== KeyEvent.VK_L) { //right player.cameraMoving(-1, "y"); } else if (e.getKeyCode()== KeyEvent.VK_J) { //left player.cameraMoving(1, "y"); } else if (e.getKeyCode()== KeyEvent.VK_O) { //right round player.cameraMoving(-1, "z"); } else if (e.getKeyCode()== KeyEvent.VK_U) { //left round player.cameraMoving(1, "z"); } }  
      finallt found it.... i confused with the transformation matrix row and col. thanks anyway!
    • By Lewa
      So, i'm currently trying to implement an SSAO shader from THIS tutorial and i'm running into a few issues here.
      Now, this SSAO method requires view space positions and normals. I'm storing the normals in my deferred renderer in world-space so i had to do a conversion and reconstruct the position from the depth buffer.
      And something there goes horribly wrong (which has probably to do with worldspace to viewspace transformations).
      (here is the full shader source code if someone wants to take a look at it)
      Now, i suspect that the normals are the culprit.
      vec3 normal = ((uNormalViewMatrix*vec4(normalize(texture2D(sNormals, vTexcoord).rgb),1.0)).xyz); "sNormals" is a 2D texture which stores the normals in world space in a RGB FP16 buffer.
      Now i can't use the camera viewspace matrix to transform the normals into viewspace as the cameras position isn't set at (0,0,0), thus skewing the result.
      So what i did is to create a new viewmatrix specifically for this normal without the position at vec3(0,0,0);
      //"camera" is the camera which was used for rendering the normal buffer renderer.setUniform4m(ressources->shaderSSAO->getUniform("uNormalViewMatrix"), glmExt::createViewMatrix(glm::vec3(0,0,0),camera.getForward(),camera.getUp())//parameters are (position,forwardVector,upVector) ); Though i have the feeling this is the wrong approach. Is this right or is there a better/correct way of transforming a world space normal into viewspace?
    • By HawkDeath
      Hi,
      I'm trying mix two textures using own shader system, but I have a problem (I think) with uniforms.
      Code: https://github.com/HawkDeath/shader/tree/test
      To debug I use RenderDocs, but I did not receive good results. In the first attachment is my result, in the second attachment is what should be.
      PS. I base on this tutorial https://learnopengl.com/Getting-started/Textures.


  • Advertisement
  • Popular Now

  • Forum Statistics

    • Total Topics
      631397
    • Total Posts
      2999808
×

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!