How can i add a texture to an object in Java Open GL (especially for AndAR)... What's wrong with my code ? I read a few examples but always the same, only a "Black Rectangle" or the texture is bound on the background... How can i bind it to my rectangle ?
Here is my Code:
int[] textureIDs = new int[1];
gl.glEnable(GL10.GL_TEXTURE_2D);
gl.glGenTextures(1, textureIDs, 0);
//load the textures into the graphics memory
Bitmap bm = BitmapFactory.decodeResource(CustomActivity.context.getResources(), R.drawable.icon);
gl.glBindTexture(GL10.GL_TEXTURE_2D, textureIDs[0]);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bm,0);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_LINEAR);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);
GLUT.glutSolidBox(gl,200.0f,100.0f,10.0f);
For texturinh to have a useful effect, you will need texture coordianates which tell the GL which part of the texture is to be mapped to which parts of the primitives. Since you are using the fixed function pipeline, there are two options:
Supply geometric primitives with texture coordinates per vertex, or
use the automatic texture coordinate generation.
The GLUT objects never provide any texture coordinates. Which means that OpenGL will use the currently set texture coordinate for every vertex. That will result that just uni specific texture location is sampled over and over again - it doesn't have to be black, but your object will be evenly colored.
You might be tempted to go for option 2 then, automatic texture coordinate generation, which is controlled with the `glTexGen() family of functions. However, the available texture coordinate generation modes are all not suitable for texturing a cube.
SO the only real solution is to specify the cube vertex manually, and specifying useful texture coordinates. You never specified the mapping you wanted. The texture is a rectangular image, you could map it to each of the face, our you could want to have a different sub-rectangle of your image mapped to each side - and you have to tell the GL how to map it, it cannot guess that just because you draw 6 faces and have texturing enabled.
or the texture is bound on the background.
You need to disable texturing again when you want to draw untextured.
Related
I have a simple 16 x 16 grid to which I apply a single texture. The texture file is divided into four parts - each a different color. By default each square is colored green (upper left part of the file). If you click a square I apply the red portion (upper right part of the file). Now I want to make the square disappear entirely when clicked. I suppose I can use a transparent texture but I was hoping I wouldn't have to so as to avoid loading / reloading two different texture files.
Here is the code I use to update the texture vbo:
//I don't bother offsetting my changes. I simply update the 'UVs'
//array and then copy the entire thing to the floatbuffer.
public void updateTexture(int offset)
{
//populate the texture buffer
//fbtex is a floatbuffer (16x16x8 in size). UVs is an array, same size.
fbtex.put( UVs );
fbtex.rewind();
glBindBuffer(GL_ARRAY_BUFFER, vboHandles.get(TEXTURE_IDX)); //the texture data
glBufferSubData(GL_ARRAY_BUFFER, offset, fbtex);
fbtex.clear(); //don't need this anymore
}
The VBO will contain up to 256 instances of my co-ords for Green:
public float[] UV_0 = { 0.02f,0.02f,
0.02f,0.24f,
0.24f,0.24f,
0.24f,0.02f};
or less if includes a few of my co-ords for Red:
public float[] UV_1 = { 0.24f,0.02f,
0.48f,0.02f,
0.48f,0.24f,
0.24f,0.24f};
Is there anything I can do to the VBO data to draw a section invisible? So the objects in the background can be seen for example?
You can just not render parts of the VBO. Normally you draw the entire data with something like
glDrawArrays(GL_TRIANGLES, 0, numElements);
glDrawArrays takes a first and count parameter which you can use to render only a part of the VBO. So if you wanted to not render some data, you would render all data before and then after this data in two draw calls.
If you create an RGBA format texture rather than RGB, just make one part within the texture transparent. (Alpha/opacity zero.) Then you just need to update the texture coord VBO with coords for the transparent square just like any other.
Or if the colors are flat with no gradients or patterning, just a single RGB value for each grid square, why use a texture at all? Change your "UV" buffer into an "RGBA" buffer and just set the color at each vertex to red/green/transparent.
I am currently working on a game in which i need pixel perfect collision with objects. The only obstacle i had gotten to however, is with actually getting a mask of the object. I thought about rendering a sprite of an object (which is properly scaled and transformed) to FrameBuffer, which then i'd convert to a pixmap, but i had no luck doing it (tried many methods, including this)
So, my question is: Is there a way of rendering a single sprite to a pixmap in LibGDX?
Sounds like putting the horse behind the cart. A Sprite is a region of a Texture, which in turn is an image loaded from file aka Pixmap. If you just want to load the image from file then you can do: new Pixmap(Gdx.files.internal("yourfile.png"));. You can also scale and transform your coordinates without rendering to a FBO first.
That said; getting the Pixmap of a FrameBuffer is as "simple" as taking a screenshot while the FBO is bound, because it is exactly that.
fbo.begin();
Gdx.gl.glClear(...);
... //render to the FBO
Pixmap pixmap = ScreenUtils.getFrameBufferPixmap(0, 0, fbo.getWidth(), fbo.getHeight());
fbo.end();
Note that this will look like it is up-side-down.
But you are probably only interested in the pixel data, so you might as well skip the Pixmap step in that case and use the ScreenUtils.getFrameBufferPixels method.
However, that said; using the pixel data for collision detection is most likely not the best solution for whatever it is you are trying to achieve. Instead I'd advise to look into other options, for example have a look at this tool which can be used to convert your images into a collision shape.
I am currently experiencing issues when drawing and scaling sprites.
I am loading my assets from a texture-atlas, which I packed no problem with the LibGDX texture packer gui tool. My texture atlas image currently looks like this.
These images are supposed to be buttons, but as you can see, the image is very small, so when the sprites are loaded, they load a sprite of say, 34x16 pixels. When I render these buttons, on a canvas of 1920x1080, they are much too small. I use sprite.scale(int scale) to scale the sprites, but when I scale them, they appear blurry. What I would like to happen, is when they are scaled, each pixel is scaled proportionally, keeping the pixelated effect on the button, rather than a blurry resized image from a really small texture. I currently render the sprites using sprite.render(SpriteBatch batch). Is this the proper way of rendering a sprite, after they are loaded using atlas.createSprite(String name)? I am new to using sprites, and loading textures from a texture-atlas, so i am wondering if this is the correct way of doing things.
Also, when I initialize my game, I load numerous different Sprite objects from a TextureAtlas. Each sprite holds a texture that will represent a game object, however it is my understanding that you render a sprite using sprite.render(SpriteBatch batch), so therefore I could only use a sprite, loaded from the TextureAtlas for one game object, because I would also have to set the scale, and position of the sprite, as it represents the game object. I am used to loading a Texture, then rendering this texture using batch.render(), at a given position, but I don't see how this is possible if I am using a sprite. Even if I use batch.render(Sprite, x, y), I am unable to scale the sprite properly, because as I mentioned before, I would like to scale the sprite while maintaining a pixelated effect, and even so, using the Sprite.scale() method, this would scale the Sprite object as a whole, making it impossible to use the Sprite's texture multiple times for numerous game objects.
Any suggestions would be greatly appreciated.
The code I am currently using to render/load the sprites is as follows:
Loading from TextureAtlas:
public static TextureAtlas atlas = new TextureAtlas(Gdx.files.internal("data/texture/pack/output/pack.pack"));
public static Sprite sprite = atlas.createSprite("buttonUp");
sprite.setScale(10);
Rendering Sprite: GdxGame.WIDTH/HEIGHT are 1920x1080. Though the Desktop window is scaled down from that size. Thus, everything is rendered as if the screen were 1920x1080.
batch = new SpriteBatch();
camera = new OrthographicCamera(GdxGame.WIDTH, GdxGame.HEIGHT);
camera.position.set(GdxGame.WIDTH/2, GdxGame.HEIGHT/2, 0);
camera.setToOrtho(false, GdxGame.WIDTH, GdxGame.HEIGHT);
public void render(float delta){
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
batch.setProjectionMatrix(camera.combined);
batch.begin();
camera.update();
sprite.draw(batch);
batch.end();
}
After further investigation, I have discovered that I can use Sprite.set(Sprite sprite) to make Sprite x a copy of Sprite y, and therefore render each sprite multiple times. However, this does not solve the issue of scaling the sprite. I must emphasize further that when rendering a scaled sprite, the scaling is not done by pixel, meaning that it is blurry. But, when rendering a TextureRegion, like: batch.draw(TextureRegion, x, y, width, height) if the width and height are greater than that of the original texture, it will scale each pixel, rather than blur the whole thing to try and make it look better. The following is an image of the blurriness I am talking about:
Notice how this sprite is scaled to be blurry, even though the original image is small, and pixelated.
What TextureFilter settings are you using in your code or in the texturepacker? Try the "Nearest" filter. If you have set it to "Linear" or alike, it will always take 4 texture pixels (texels) and interpolate them to get the color of the pixel to be drawn.
That might help against the blur, but I am not sure if it will produce exactly that 8-bit look you are aiming for...
I currently use LWJGL Textures to draw images on the screen. I would like to read Textures* from a sprite sheet. I am using slick's TextureLoader class to load the textures.
I draw an LWJGL Shape and bind a Texture onto it.
e.g:
Me drawing an image:
Texture texture = ResourceManager.loadTexture("Images/Tests/test.png");
GL11.glBegin(GL11.GL_QUADS);
{
GL11.glTexCoord2f(0, 0);
GL11.glVertex2f(0, 0);
GL11.glTexCoord2f(0, texture.getHeight());
GL11.glVertex2f(0, height);
GL11.glTexCoord2f(texture.getWidth(), texture.getHeight());
GL11.glVertex2f(width,height);
GL11.glTexCoord2f(texture.getWidth(), 0);
GL11.glVertex2f(width,0);
}
GL11.glEnd();
I think there is a way by when calling glTexCoord2f, I could give it a sprite offset and load the sprite sheet in the texture instead,
for example one call would be like this:
GL11.glTexCoord2f(0+spriteXOffset, texture.getHeight()-spriteYOffset);
But I would really like to know if there is a simpler way, maybe extracting Textures from a single texture for example like they do in here:
Reading images from a sprite sheet Java
Just instead of BufferedImage, Texture object.
Thank you for the help!
Texture coordinates for GL_TEXTURE_2D, used internally by the Slick texture loader, require normalized texture coordinates. That is, the coordinates range from 0.0 to 1.0. So (0,0) is the top-left corner of the texture, and (1,1) is the bottom-right corner. Assuming that you have your sprite coordinates in pixel coordinates at hand, you then have to divide the x coordinate by the texture width and the y coordinate by the texture height, resulting in normalized texture coordinates. You would then supply these coordinates to OpenGL using glTexCoord.
glTexCoord2f(spriteX / textureWidth, spriteY / textureHeight);
glVertex2f(coordinateX, coordinateY);
glTexCoord2f(spriteX+spriteWidth / textureWidth, spriteY / textureHeight);
glVertex2f(coordinateX2, coordinateY);
// Et cetera
There is, however, also an easier way of doing this. Take a look at this video (I created it), to see how you can use the pixel coordinates for textures instead of normalized ones.
I've have a little Problem with Textures and OpenGL. I made a small .obj Loader (with Texture Loading) but everything is drawn blue. Example:
I load a Texture. I bind the texture with GL11.glBindTexture(GL11.GL_TEXTURE_2D,textureId).
If I do:
glColor3f(1f,1f,1f);
glBegin(GL_QUADS);
glVertex3f(50f,0,-50);
glVertex3f(-50f,0,-50f);
glVertex3f(-50f,0,50f);
glVertex3f(50f,0,50f);
glEnd();
GL11.glBindTexture(GL11.GL_TEXTURE_2D, textureId);
it draws a white quad ... but if I do:
GL11.glBindTexture(GL11.GL_TEXTURE_2D, textureId);
glColor3f(1f,1f,1f);
glBegin(GL_QUADS);
glVertex3f(50f,0,-50);
glVertex3f(-50f,0,-50f);
glVertex3f(-50f,0,50f);
glVertex3f(50f,0,50f);
glEnd();
it draws a blue quad and everything else is blue too.
Maybe somebody knows a solution?
There is no texture because you didn't specify texture coordinates using glTexCoord2f.
The colors are wrong probably due to incorrect parameters to glTexImage.
Everything else is blue because, you are using the same texture for everything. Bind different texture or use the default texture 0.
This is the problem because you are not using the glTexCoord2f with each vertex. Please try this with each vertex because it can solve it as presently your color is not binding to all the areas.