How can I draw crisp per-pixel images with OpenGL ES on Android?
- by Qasim
I have made many Android applications and games in Java before, however I am very new to OpenGL ES. Using guides online, I have made simple things in OpenGL ES, including a simple triangle and a cube.
I would like to make a 2D game with OpenGL ES, but what I've been doing isn't working quite so well, as the images I draw aren't to scale, and no matter what guide I use, the image is always choppy and not the right size (I'm debugging on my Nexus S).
How can I draw crisp, HD images to the screen with GL ES?
Here is an example of what happens when I try to do it:
And the actual image:
Here is how my texture is created:
//get id
int id = -1;
gl.glGenTextures(1, texture, 0);
id = texture[0];
//get bitmap
Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.ball);
//parameters
gl.glBindTexture(GL10.GL_TEXTURE_2D, id);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,
GL10.GL_NEAREST);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER,
GL10.GL_LINEAR);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S,
GL10.GL_CLAMP_TO_EDGE);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T,
GL10.GL_CLAMP_TO_EDGE);
gl.glTexEnvf(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE,
GL10.GL_REPLACE);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
//crop image
mCropWorkspace[0] = 0;
mCropWorkspace[1] = height;
mCropWorkspace[2] = width;
mCropWorkspace[3] = -height;
((GL11) gl).glTexParameteriv(GL10.GL_TEXTURE_2D, GL11Ext.GL_TEXTURE_CROP_RECT_OES, mCropWorkspace, 0);
