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[SOLVED] Loading tiles from texture atlas problem

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[SOLVED] Loading tiles from texture atlas problem
« on: June 20, 2013, 18:07:23 »
Hello!

I'm new to these forums and I have run into a problem. I can load the sprites from the atlas completely fine, but the problem occurs when I try to bind the BufferedImage texture, which is not supported. So, I load the atlas, get the subimages but I can't bind them as textures. Is there a way to convert a BufferedImage to a working texture without 500 packages of premade code? Well, if you have any good solutions for this problem it'll certainly be appreciated.

Thank you.
« Last Edit: June 21, 2013, 08:25:47 by Raindeer »

Re: Loading tiles from texture atlas problem
« Reply #1 on: June 20, 2013, 20:59:34 »
I think you misunderstand how to use a texture atlas in OpenGL. You create an OpenGL texture using the whole atlas. Then you just adjust the texture coordinates used to select the parts of the atlas making up the sprite.

If you need a simple, easy-to-use texture loader, I would suggest the one in Slick Utils: http://slick.ninjacave.com/slick-util/
Programmers will, one day, rule the world... and the world won't notice until its too late.Just testing the marquee option ;D

Re: Loading tiles from texture atlas problem
« Reply #2 on: June 20, 2013, 22:09:40 »
I think you misunderstand how to use a texture atlas in OpenGL. You create an OpenGL texture using the whole atlas. Then you just adjust the texture coordinates used to select the parts of the atlas making up the sprite.

If you need a simple, easy-to-use texture loader, I would suggest the one in Slick Utils: http://slick.ninjacave.com/slick-util/

I actually did that as a placeholder, but things didn't work out quite well. The sprites interfere with each other, the edges' colors mix together and it looks really bad. And I am using slick utils. The sprites are 16x16 and are set to GL_NEAREST, pixelated textures, like in Minecraft. Dunno if the sprite resolution has anything to do with it.

Re: Loading tiles from texture atlas problem
« Reply #3 on: June 21, 2013, 08:10:46 »
This is the code for drawing a cuboid.

Code: [Select]
import org.lwjgl.opengl.GL11;

public class PolyVoxel extends Poly {

float x1, y1, z1, x2, y2, z2, centerX, centerY, centerZ;
float width, height, length;
float yTop, yBottom;
private float tx1, ty1, tx2, ty2;
private int textureX, textureY;

public PolyVoxel(float startX, float startY, float startZ, float endX, float endY, float endZ, int spriteX, int spriteY) {
x1 = startX;
y1 = startY;
z1 = startZ;
x2 = endX;
y2 = endY;
z2 = endZ;

width = x2 - x1;
height = y2 - y1;
length = z2 - z1;

centerX = x1 + (width/2);
centerY = y1 + (height/2);
centerZ = z1 + (length/2);

textureX = spriteX;
textureY = spriteY;

tx1 = (float) spriteX / 32f;
ty1 = (float) spriteY / 32f;

tx2 = tx1 + (1f / 32f);
ty2 = ty1 + (1f / 32f);

System.out.println(String.format("%s, %s, %s, %s", tx1, ty1, tx2, ty2));
}

public void render() {
GL11.glBegin(GL11.GL_QUADS);
{
//top
GL11.glTexCoord2f(tx1, ty1); GL11.glVertex3f(x1, y1, z1);
GL11.glTexCoord2f(tx2, ty1); GL11.glVertex3f(x1+width, y1, z1);
GL11.glTexCoord2f(tx2, ty2); GL11.glVertex3f(x1+width, y1, z1+length);
GL11.glTexCoord2f(tx1, ty2); GL11.glVertex3f(x1, y1, z1+length);

//bottom
GL11.glTexCoord2f(tx1, ty1); GL11.glVertex3f(x1, y1+height, z1);
GL11.glTexCoord2f(tx2, ty1); GL11.glVertex3f(x1+width, y1+height, z1);
GL11.glTexCoord2f(tx2, ty2); GL11.glVertex3f(x1+width, y1+height, z1+length);
GL11.glTexCoord2f(tx1, ty2); GL11.glVertex3f(x1, y1+height, z1+length);

//front
GL11.glTexCoord2f(tx1, ty1); GL11.glVertex3f(x1, y1, z1);
GL11.glTexCoord2f(tx2, ty1); GL11.glVertex3f(x1+width, y1, z1);
GL11.glTexCoord2f(tx2, ty2); GL11.glVertex3f(x1+width, y1+height, z1);
GL11.glTexCoord2f(tx1, ty2); GL11.glVertex3f(x1, y1+height, z1);

//back
GL11.glTexCoord2f(tx1, ty1); GL11.glVertex3f(x1, y1, z1+length);
GL11.glTexCoord2f(tx2, ty1); GL11.glVertex3f(x1+width, y1, z1+length);
GL11.glTexCoord2f(tx2, ty2); GL11.glVertex3f(x1+width, y1+height, z1+length);
GL11.glTexCoord2f(tx1, ty2); GL11.glVertex3f(x1, y1+height, z1+length);

//left
GL11.glTexCoord2f(tx1, ty1); GL11.glVertex3f(x1, y1, z1);
GL11.glTexCoord2f(tx2, ty1); GL11.glVertex3f(x1, y1, z1+length);
GL11.glTexCoord2f(tx2, ty2); GL11.glVertex3f(x1, y1+height, z1+length);
GL11.glTexCoord2f(tx1, ty2); GL11.glVertex3f(x1, y1+height, z1);

//right
GL11.glTexCoord2f(tx1, ty1); GL11.glVertex3f(x1+width, y1, z1);
GL11.glTexCoord2f(tx2, ty1); GL11.glVertex3f(x1+width, y1, z1+length);
GL11.glTexCoord2f(tx2, ty2); GL11.glVertex3f(x1+width, y1+height, z1+length);
GL11.glTexCoord2f(tx1, ty2); GL11.glVertex3f(x1+width, y1+height, z1);
}
GL11.glEnd();
}

public int getTextureX() {
return textureX;
}

public int getTextureY() {
return textureY;
}

public void setTexture(int texX, int texY) {
textureX = texX;
textureY = texY;

tx1 = (float) texX / 32f;
ty1 = (float) texY / 32f;

tx2 = tx1 + (1f / 32f);
ty2 = ty1 + (1f / 32f);
}

}

So the edges of the textures interfere, mixing the colors up. Here's the spritesheet:



And makes it turn out like this:


Re: [SOLVED] Loading tiles from texture atlas problem
« Reply #4 on: June 21, 2013, 08:26:20 »
The problem was somewhere else... The jpg format made the spritesheet quite low quality.. dangit.