Ok, first of all I totally agree that "TheNewBoston" tutorials are very... wrong at times. However that is what I was following to try to make a cube in OpenGL on android.
Anyways, I can't say that I have found great material on OpenGL to be honest. I have read through OpenGL Superbible... it was ok.
So here is the code that I have.
GLRenderer.java
package android.gem.opengltest;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
import android.opengl.GLU;
import android.opengl.GLSurfaceView.Renderer;
import android.os.SystemClock;
public class GLRenderer implements Renderer {
private GLCube cube;
public GLRenderer() {
cube = new GLCube();
}
#Override
public void onDrawFrame(GL10 gl) {
// TODO Auto-generated method stub
gl.glDisable(GL10.GL_DITHER);
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT | GL10.GL_STENCIL_BUFFER_BIT);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
GLU.gluLookAt(gl, 0, 0, -5, 0, 0, 0, 0, 2, 0);
long time = SystemClock.uptimeMillis() % 4000L;
float angle = .09f * ((int) time);
gl.glRotatef(angle, 1, 1.5f, 2);
cube.draw(gl);
}
#Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
// TODO Auto-generated method stub
float ratio = (float) width / height;
gl.glViewport(0, 0, width, height);
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
gl.glFrustumf(-ratio, ratio, -1, 1, 1, 25);
}
#Override
public void onSurfaceCreated(GL10 gl, EGLConfig eglConfig) {
// TODO Auto-generated method stub
// START OF PERFORMANCE //
gl.glDisable(GL10.GL_DITHER);
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);
// END OF PERFORMANCE //
gl.glClearColor(.8f, 0, .2f, 1f); // Red, Green, Blue, Alpha (0 - 1)
gl.glClearDepthf(1f);
}
}
GLCube.java
package android.gem.opengltest;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;
import javax.microedition.khronos.opengles.GL10;
public class GLCube {
private float verticies[] = {
1, 1, -1, // point 0 - topFrontRight
1, -1, -1, // point 1 - bottomFrontRight
-1, -1, -1, // point 2 - bottomFrontLeft
-1, 1, -1, // point 3 - frontTopLeft
1, 1, 1, // point 4 - topBackRight
1, -1, 1, // point 5 - bottomBackRight
-1, -1, 1, // point 6 - bottomBackLeft
-1, 1, 1 // point 7 - frontBackLeft
};
private float rgbaValues[] = {
1, 1, 0, 1,
.25f, 0, .85f, 1,
0, 1, 1, 1,
1, 1, 0, 1,
.25f, 0, .85f, 1,
0, 1, 1, 1,
.5f, .5f, .2f, 1,
.3f, .3f, .3f, 1
};
private FloatBuffer vertBuff, colorBuff;
private short[] pIndex = { // Indicies
3, 4, 0, 0, 4, 1, 3, 0, 1,
3, 7, 4, 7, 6, 4, 7, 3, 6,
3, 1, 2, 1, 6, 2, 6, 3, 2,
1, 4, 5, 5, 6, 1, 6, 5, 4
};
private ShortBuffer pBuffer;
public GLCube() {
ByteBuffer bBuff = ByteBuffer.allocateDirect(this.verticies.length * 4);
bBuff.order(ByteOrder.nativeOrder());
vertBuff = bBuff.asFloatBuffer();
vertBuff.put(this.verticies);
vertBuff.position(0);
ByteBuffer pbBuff = ByteBuffer.allocateDirect(this.pIndex.length * 2);
pbBuff.order(ByteOrder.nativeOrder());
pBuffer = pbBuff.asShortBuffer();
pBuffer.put(pIndex);
pBuffer.position(0);
ByteBuffer cBuff = ByteBuffer.allocateDirect(this.rgbaValues.length * 4);
cBuff.order(ByteOrder.nativeOrder());
colorBuff = cBuff.asFloatBuffer();
colorBuff.put(rgbaValues);
colorBuff.position(0);
}
public void draw(GL10 gl) {
gl.glFrontFace(GL10.GL_CW); // Clock Wise
gl.glEnable(GL10.GL_CULL_FACE); // Removes back end of cube
gl.glCullFace(GL10.GL_BACK);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, this.vertBuff);
gl.glColorPointer(4, GL10.GL_FLOAT, 0, this.colorBuff);
gl.glDrawElements(GL10.GL_TRIANGLES, this.pIndex.length, GL10.GL_UNSIGNED_SHORT, this.pBuffer);
gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisable(GL10.GL_CULL_FACE);
}
}
I get a cube that looks like this...
What am I doing wrong? What should I do to make it look like an actual cube?
Also, if it helps all my code is at the following address: https://github.com/gemurdock/OpenGlTest/tree/alpha.0.1.0
First of all, this is a (horribly deformed) cube, not a square. Unless you look at it face-on it is never going to look like a "good square" :)
Your polygon face culling appears to be culling the wrong side of your cube faces. It still looks like a cube, just an inside out cube.
This is likely because you have overridden OpenGL's default front face winding direction (GL_CCW).
Related
I'm using the processing.core.PApplet library in a simple Java Project.
I load multiple images in the setting function and I tried to draw them in the draw function but oddly the textures doesn't appear ?
There is the code I use to load them :
public void init() throws FileNotFoundException { // this get executed in the 'setting' function of my sketch
Registry.register(getImage("void"), "void");
}
public processing.core.PImage getImage(String name) throws FileNotFoundException {
String path = "src\\main\\resources\\blocks\\textures\\" + name + ".png";
File file = new File(path);
if(file.exists()) {
Logger.info("Texture " + file.getAbsolutePath() + " found.", "TextureMapping");
return sketch.loadImage(path);
} else {
throw new FileNotFoundException("File " + file.getAbsolutePath() + " not found." );
}
}
And the code I use to draw one of them :
// I create and draw a new cube in the 'draw' function of my sketch
// But it appears without any texture
public Cube(processing.core.PApplet sketch, BlockPos pos, #NotNull Block block) {
this.sketch = sketch;
this.block = block;
position = pos;
texture = Registry.getTextures().get("minecraft:void");
texture.loadPixels();
}
public void draw() {
sketch.pushMatrix();
sketch.translate(position.getX(), position.getY(), position.getZ());
sketch.box(10);
sketch.texture(texture); // Doin' nothing
sketch.popMatrix();
}
And the file are there, my Logger say that they are found, I get no error, and yet the texture has all the properties of an PImage ?
And second oddly thing :
Before the draw method, I do this in the draw function :
sketch.image(Registry.getTextures().get("minecraft:void"), 10, 10);
And there, the image loads perfectly ???
yes I'm doin' a Minecraft clone
I found !
The texture() is only working when runned between the preDraw() and postDraw() functions, but the box() function has these steps into it, so it cannot work, you have to create a cube using Vertex.
Processing offers us an example to make it there !
What I did to customize this example is a Box class that create vertex, a size can be set also, there it is :
public class Box {
private final PApplet sketch;
private final int scale;
public Box(PApplet sketch, int scale) {
this.sketch = sketch;
this.scale = scale;
}
public void generateVertex(PImage texture) {
sketch.scale(scale);
sketch.beginShape(sketch.QUADS);
sketch.texture(texture);
// +Z "front" face
sketch.vertex(-1, -1, 1, 0, 0);
sketch.vertex(1, -1, 1, 1, 0);
sketch.vertex(1, 1, 1, 1, 1);
sketch.vertex(-1, 1, 1, 0, 1);
// -Z "back" face
sketch.vertex(1, -1, -1, 0, 0);
sketch.vertex(-1, -1, -1, 1, 0);
sketch.vertex(-1, 1, -1, 1, 1);
sketch.vertex(1, 1, -1, 0, 1);
// +Y "bottom" face
sketch.vertex(-1, 1, 1, 0, 0);
sketch.vertex(1, 1, 1, 1, 0);
sketch.vertex(1, 1, -1, 1, 1);
sketch.vertex(-1, 1, -1, 0, 1);
// -Y "top" face
sketch.vertex(-1, -1, -1, 0, 0);
sketch.vertex(1, -1, -1, 1, 0);
sketch.vertex(1, -1, 1, 1, 1);
sketch.vertex(-1, -1, 1, 0, 1);
// +X "right" face
sketch.vertex(1, -1, 1, 0, 0);
sketch.vertex(1, -1, -1, 1, 0);
sketch.vertex(1, 1, -1, 1, 1);
sketch.vertex(1, 1, 1, 0, 1);
// -X "left" face
sketch.vertex(-1, -1, -1, 0, 0);
sketch.vertex(-1, -1, 1, 1, 0);
sketch.vertex(-1, 1, 1, 1, 1);
sketch.vertex(-1, 1, -1, 0, 1);
sketch.endShape();
}
public int getScale() {
return scale;
}
}
And this solve perfectly my problem, now I have a cube with textures !
I was trying to render a mesh (that i created programmatically) with textures. Everything works fine except that it doesn't render the texture. It's just a black triangle. Here is a simplified version of the code (which doesn't work either):
public ModelBatch batch;
public OrthographicCamera cam;
public Renderable renderable;
#Override
public void create () {
cam = new OrthographicCamera(5, 5);
batch = new ModelBatch();
Mesh mesh = new Mesh(true, 3, 3,
new VertexAttribute(VertexAttributes.Usage.Position, 2, "a_position"),
new VertexAttribute(VertexAttributes.Usage.TextureCoordinates, 2, "a_texCoord")
);
mesh.setVertices(new float[]{
0, 0, 0, 0,
1, 0, 1, 0,
1, 1, 1, 1
});
mesh.setIndices(new short[]{
0, 1, 2
});
renderable = new Renderable();
renderable.primitiveType = GL20.GL_TRIANGLES;
renderable.mesh = mesh;
renderable.meshPartOffset = 0;
renderable.meshPartSize = mesh.getNumIndices();
renderable.material = new Material(TextureAttribute.createDiffuse(new Texture("badlogic.jpg")));
}
#Override
public void render () {
Gdx.gl.glClearColor(1, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
batch.begin(cam);
batch.render(renderable);
batch.end();
}
I solved the problem.
I should have created the mesh this way:
Mesh mesh = new Mesh(true, 3, 3,
new VertexAttribute(VertexAttributes.Usage.Position, 2, "a_position"),
new VertexAttribute(VertexAttributes.Usage.TextureCoordinates, 2, "a_texCoord0")
);
The difference is that now the alias in the texture coordinates attribute is a_texCoord0 instead of a_texCoord.
I've got this class which I'm developing which I hope to eventually use to draw a terrain map. The code currently looks like this:
IntBuffer ib = BufferUtils.createIntBuffer(3);
int vHandle = ib.get(0);
int cHandle = ib.get(1);
int iHandle = ib.get(2);
FloatBuffer vBuffer = BufferUtils.createFloatBuffer(19);
FloatBuffer cBuffer = BufferUtils.createFloatBuffer(18);
ShortBuffer iBuffer = BufferUtils.createShortBuffer(6);
TerrainFlat(float x,float y,float z, float[] input /* here is where I want to put my draw distance stuff*/){
this.Map = input;
this.x=x;
this.y=y;
this.z=z;
}
#Override
public void initilize(){
float[] vertexData = {50, 20, 100, 50, -20, 100, 10, -20, 100, -10, -20, 100, -50, -20, 100, -50, 20, 100};
float[] colorData = {1, 0, 0, 0, 1, 0, 0, 0, 1, 0 , 0 , 1 , 0 , 1 , 0 , 1 , 0 , 0 };
short[] indexData = {0,1,2,3,4,5};
vBuffer.put(vertexData);
vBuffer.flip();
cBuffer.put(colorData);
cBuffer.flip();
iBuffer.put(indexData);
iBuffer.flip();
}
#Override
public void draw(){
glClear(GL_COLOR_BUFFER_BIT);
glGenBuffersARB(ib);
vHandle = ib.get(0);
cHandle = ib.get(1);
iHandle = ib.get(2);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, vHandle);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, vBuffer, GL_STATIC_DRAW_ARB);
glVertexPointer(3, GL_FLOAT, /* stride */3 << 2, 0L);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, cHandle);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, cBuffer, GL_STATIC_DRAW_ARB);
glColorPointer(3, GL_FLOAT, /* stride */3 << 2, 0L);
glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, iHandle);
glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB, iBuffer, GL_STATIC_DRAW_ARB);
glDrawElements(GL_TRIANGLES, /* elements */6, GL_UNSIGNED_SHORT, 0L);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 0);
}
#Override
public void destroy(){
ib.put(0, vHandle);
ib.put(1, cHandle);
ib.put(2, iHandle);
glDeleteBuffersARB(ib);
}
Now I'm wondering if I can bind my data in the initilize function, instead of the Draw function, in order to move the declarations:
FloatBuffer vBuffer = BufferUtils.createFloatBuffer(19);
FloatBuffer cBuffer = BufferUtils.createFloatBuffer(18);
ShortBuffer iBuffer = BufferUtils.createShortBuffer(6);
into the initilize function, or at the very least after the terrain functions so I can control their lengths via a draw distance function.
UPDATE:
I change my code based on the answer given (thank you btw) to this:
#Override
public void initilize(){
float[] vertexData = {50, 20, 100, 50, -20, 100, 10, -20, 100, -10, -20, 100, -50, -20, 100, -50, 20, 100};
float[] colorData = {1, 0, 0, 0, 1, 0, 0, 0, 1, 0 , 0 , 1 , 0 , 1 , 0 , 1 , 0 , 0 };
short[] indexData = {0,1,2,3,4,5};
vBuffer.put(vertexData);
vBuffer.flip();
cBuffer.put(colorData);
cBuffer.flip();
iBuffer.put(indexData);
iBuffer.flip();
glBindBufferARB(GL_ARRAY_BUFFER_ARB, vHandle);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, vBuffer, GL_STATIC_DRAW_ARB);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, cHandle);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, cBuffer, GL_STATIC_DRAW_ARB);
glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, iHandle);
glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB, iBuffer, GL_STATIC_DRAW_ARB);
}
#Override
public void setUp(float posX, float posY, float posZ){
}
#Override
public void draw(){
glClear(GL_COLOR_BUFFER_BIT);
glGenBuffersARB(ib);
vHandle = ib.get(0);
cHandle = ib.get(1);
iHandle = ib.get(2);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, vHandle);
glVertexPointer(3, GL_FLOAT, /* stride */3 << 2, 0L);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, cHandle);
glColorPointer(3, GL_FLOAT, /* stride */3 << 2, 0L);
glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, iHandle);
glDrawElements(GL_TRIANGLES, /* elements */6, GL_UNSIGNED_SHORT, 0L);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 0);
}
This executes but fails to draw anything, I do not have FACE_CULL enabled either.
You need to bind the buffers before drawing (except you are always drawing the same buffers) but you can move the glBufferData calls to your initialize function.
Something like this should work:
public void initilize() {
...
// set data for vHandle
glBindBufferARB(GL_ARRAY_BUFFER_ARB, vHandle);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, vBuffer, GL_STATIC_DRAW_ARB);
glVertexPointer(3, GL_FLOAT, /* stride */3 << 2, 0L);
// ... setup other handles
...
}
public void draw() {
...
glBindBufferARB(GL_ARRAY_BUFFER_ARB, vHandle);
// ... bind other buffers
glDrawElements(GL_TRIANGLES, /* elements */6, GL_UNSIGNED_SHORT, 0L);
...
}
When I just draw texture on SpriteBatch and set TextureWrap.Repeat everything is OK. But now I have 3D scene and I want have ground and texture must be repeated on model/mesh and this just don' t work.
public static StillModel createPlainMesh(float xs, float zs, Texture texture) {
final Mesh mesh = new Mesh(true, 4, 6, new VertexAttribute(
Usage.Position, 3, "a_position"), new VertexAttribute(
Usage.TextureCoordinates, 2, "a_texCoords"));
mesh.setVertices(new float[]
{ xs, 0f, zs, 0, 0,
xs, 0f, -zs, 0, 1,
-xs, 0f, zs, 1, 0,
-xs, 0f, -zs , 1,1
});
mesh.setIndices(new short[] { 0, 1, 2, 1, 2, 3 });
final StillModel model = new StillModel(new StillSubMesh(
"ground", mesh, GL10.GL_TRIANGLES, new Material()));
texture.setWrap(TextureWrap.Repeat, TextureWrap.Repeat);
model.setMaterial(new Material("material", new TextureAttribute(texture, 0, "s_tex")));
return model;
}
I have this code. I use setWrap(TextureWrap.Repeat, TextureWrap.Repeat), but textures are still streched. I don't know why, but it looks terrible.
I solved it. If you want repeat texture on model, You must modify this:
mesh.setVertices(new float[]
{ xs, 0f, zs, 0, 0,
xs, 0f, -zs, 0, 1,
-xs, 0f, zs, 1, 0,
-xs, 0f, -zs , 1,1
});
Modify Texture Coords - change to for example 20 if You want repeat it 20times
Example:
mesh.setVertices(new float[]
{ xs, 0f, zs, 0, 0,
xs, 0f, -zs, 0, 20,
-xs, 0f, zs, 20, 0,
-xs, 0f, -zs , 20,20
});
In an application, while trying to rotate an object using touch, I noticed drift in position of object after sometime (without any translation applied !!). The rotation is only about z-axis and works perfectly, but drift happens only after few rotations.
ds will be used for translation (using up-down button).
_uNozzleCentreMatrix and _ModelMatrixNozzle will use ds if I correct this.
private static final float[] _uNozzleCentre = new float[]{0.0f, 0.333605f, 0.0f, 1.0f};
protected static float[] _uNozzleCentreMatrix = new float[4];
public void onSurfaceChanged(GL10 gl, int width, int height) {
gl.glViewport(0, 0, width, height);
float ratio = (float) width / height;
Matrix.setLookAtM(GLES20Renderer._ViewMatrix, 0, 0, 0, 7f, 0, 0, 0, 0, 1, 0);
Matrix.frustumM(GLES20Renderer._ProjectionMatrix, 0, -ratio, ratio, -1, 1, 2, 8);
Matrix.setIdentityM(GLES20Renderer._ModelMatrixNozzle, 0);
}
private static void updateModel(int upDown, float xAngle, float yAngle, float zAngle) {
//ds = GLES20Renderer._upDown - GLES20Renderer._lastUpDown;
ds = 0; // ds changes with button up-down, but now it is made 0, so button up-down will not affect it
Matrix.multiplyMV(GLES20Renderer._uNozzleCentreMatrix, 0, GLES20Renderer._ModelMatrixNozzle, 0, GLES20Renderer._uNozzleCentre, 0);
if(Math.abs(ds) > 0) {
} else {
if(GLES20Renderer._zAngle >= 360) {
GLES20Renderer._zAngle = GLES20Renderer._zAngle - 360;
}
if(GLES20Renderer._zAngle <= -360) {
GLES20Renderer._zAngle = GLES20Renderer._zAngle + 360;
}
Matrix.translateM(GLES20Renderer._ModelMatrixNozzle, 0, GLES20Renderer._uNozzleCentreMatrix[0], GLES20Renderer._uNozzleCentreMatrix[1], 0);
Matrix.rotateM(GLES20Renderer._ModelMatrixNozzle, 0, GLES20Renderer._zAngle, 0, 0, 1);
Matrix.rotateM(GLES20Renderer._ModelMatrixNozzle, 0, -GLES20Renderer._lastZAngle, 0, 0, 1);
Matrix.translateM(GLES20Renderer._ModelMatrixNozzle, 0, -GLES20Renderer._uNozzleCentreMatrix[0], -GLES20Renderer._uNozzleCentreMatrix[1], 0);
}
Matrix.multiplyMM(GLES20Renderer._MVPMatrixNozzle, 0, GLES20Renderer._ViewMatrix, 0, GLES20Renderer._ModelMatrixNozzle, 0);
Matrix.multiplyMM(GLES20Renderer._MVPMatrixNozzle, 0, GLES20Renderer._ProjectionMatrix, 0, GLES20Renderer._MVPMatrixNozzle, 0);
GLES20Renderer._lastZAngle = zAngle;
}
Apk for download:
http://www.pixdip.com/opengles/rotation/rotation.apk
(Try swiping a longer horizontal area from extreme left to right to observe drift early. Please be patient! Drift can take 20 seconds to occur)
For those whom it did not happen, here is the automated apk:
http://www.pixdip.com/opengles/rotation/automatic.apk
and the edited part of code:
Matrix.translateM(GLES20Renderer._ModelMatrixNozzle, 0, GLES20Renderer._uNozzleCentreMatrix[0], GLES20Renderer._uNozzleCentreMatrix[1], 0);
Matrix.rotateM(GLES20Renderer._ModelMatrixNozzle, 0, GLES20Renderer._zAngle, 0, 0, 1);
//Matrix.rotateM(GLES20Renderer._ModelMatrixNozzle, 0, -GLES20Renderer._lastZAngle, 0, 0, 1);
Matrix.translateM(GLES20Renderer._ModelMatrixNozzle, 0, -GLES20Renderer._uNozzleCentreMatrix[0], -GLES20Renderer._uNozzleCentreMatrix[1], 0);
Sometimes floating point errors get accumulated because of matrix stack.
This can be removed by using separate matrices for some critical transformations:
private static float[] _TMatrix = new float[16];
private static float[] _ModelMatrix = new float[16];
Matrix.setIdentity(Renderer._ModelMatrix);
Matrix.setIdentity(Renderer._TMatrix);
Matrix.translate(Renderer._ModelMatrix, xmov,ymov,0);
Matrix.translate(Renderer._TMatrix, -xmov,-ymov,0);
Matrix.multiply(Renderer._ModelMatrix, Renderer._TMatrix, Renderer._ModelMatrix);
// will result in an identity model matrix, without any floating point errors