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I am trying to change my OpenGL square's color only when it is touched. I looked around online at some good sources to see how I could find the coordinates to change its color, Converting pixel co-ordinates to normalized co-ordinates at draw time in OpenGL 3.0. However, I am still confused about how to get my square's or onTouchEvent inputs coordinates to be translated in OpenGL code(vertexShaderCode). I have tried to directly track my square coordinates in the onTouchEvent activity, but it wrongly tracks the position since I am working with two different coordinate systems(OpenGl, Android Studios).
//THIS IS NOT MY FULL CODE
public boolean onTouchEvent(MotionEvent e) {
// MotionEvent reports input details from the touch screen
// and other input controls. In this case, you are only
// interested in events where the touch position changed.
float x = e.getX();
float y = e.getY();
colorHolder = renderer.getmSquare().getColor();
switch (e.getAction()) {
case MotionEvent.ACTION_DOWN:
//THIS IS MY PROBLEM. I DON'T KNOW A GOOD WAY OF TRACKING THE SQUARE'S POSITION BESIDES
//ADDING VARIBLE TO IT'S MAIN CLASS THEN REFERENCING THEM HERE
if(renderer.mSquareY > (y / getHeight()) && renderer.mSquareX > (x / getWidth()))
renderer.getmSquare().color = tempColor;
case MotionEvent.ACTION_MOVE:
float dx = x - previousX;
float dy = y - previousY;
float tempHeight = y / getHeight();
float tempWidth = x / getWidth();
//THIS IS MY PROBLEM. I DON'T KNOW A GOOD WAY OF TRACKING THE SQUARE'S POSITION BESIDES ADDING VARIBLE TO IT'S MAIN CLASS THEN REFERENCING THEM HERE
if(renderer.mSquareY < (y / getHeight()) && renderer.mSquareX < (x / getWidth()))
renderer.getmSquare().color = tempColor;
renderer.mSquareX = (x / getWidth());
renderer.mSquareY = (y / getHeight());
...
I have three classes that handle creating the square, handles rendering, and the main activity in the corresponding order: Square.java, MyGLRenderer.java, MyGLSurfaceView.java.
public class Square {
private final String vertexShaderCode =
// This matrix member variable provides a hook to manipulate
// the coordinates of the objects that use this vertex shader
"uniform mat4 uMVPMatrix;" +
"attribute vec4 vPosition;" +
"void main() {" +
// The matrix must be included as a modifier of gl_Position.
// Note that the uMVPMatrix factor *must be first* in order
// for the matrix multiplication product to be correct.
" gl_Position = uMVPMatrix * vPosition;" +
"}";
private final String fragmentShaderCode =
"precision mediump float;" +
"uniform vec4 vColor;" +
"void main() {" +
" gl_FragColor = vColor;" +
"}";
private FloatBuffer vertexBuffer;
private ShortBuffer drawListBuffer;
private final int mProgram;
private int mPositionHandle;
private int mColorHandle;
private int mMVPMatrixHandle;
// number of coordinates per vertex in this array
static final int COORDS_PER_VERTEX = 3;
static float squareCoords[] = {
0.5f, 0.5f, 0.0f, // top left
0.5f, -0.5f, 0.0f, // bottom left
-0.5f, -0.5f, 0.0f, // bottom right
-0.5f, 0.5f, 0.0f }; // top right
private short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; // order to draw vertices
private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex
public float[] getColor() {
return color;
}
public void setColor(float[] color) {
this.color = color;
}
float color[] = { 0.2f, 0.709803922f, 0.898039216f, 1.0f };
public Square() {
// initialize vertex byte buffer for shape coordinates
ByteBuffer bb = ByteBuffer.allocateDirect(
// (# of coordinate values * 4 bytes per float)
squareCoords.length * 4);
bb.order(ByteOrder.nativeOrder());
vertexBuffer = bb.asFloatBuffer();
vertexBuffer.put(squareCoords);
vertexBuffer.position(0);
// initialize byte buffer for the draw list
ByteBuffer dlb = ByteBuffer.allocateDirect(
// (# of coordinate values * 2 bytes per short)
drawOrder.length * 2);
dlb.order(ByteOrder.nativeOrder());
drawListBuffer = dlb.asShortBuffer();
drawListBuffer.put(drawOrder);
drawListBuffer.position(0);
// prepare shaders and OpenGL program
int vertexShader = MyGLRenderer.loadShader(
GLES20.GL_VERTEX_SHADER,
vertexShaderCode);
int fragmentShader = MyGLRenderer.loadShader(
GLES20.GL_FRAGMENT_SHADER,
fragmentShaderCode);
mProgram = GLES20.glCreateProgram(); // create empty OpenGL Program
GLES20.glAttachShader(mProgram, vertexShader); // add the vertex shader to program
GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
GLES20.glLinkProgram(mProgram); // create OpenGL program executables
}
public void draw(float[] mvpMatrix) {
// Add program to OpenGL environment
GLES20.glUseProgram(mProgram);
// get handle to vertex shader's vPosition member
mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
// Enable a handle to the triangle vertices
GLES20.glEnableVertexAttribArray(mPositionHandle);
// Prepare the triangle coordinate data
GLES20.glVertexAttribPointer(
mPositionHandle, COORDS_PER_VERTEX,
GLES20.GL_FLOAT, false,
vertexStride, vertexBuffer);
// get handle to fragment shader's vColor member
mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
// Set color for drawing the triangle
GLES20.glUniform4fv(mColorHandle, 1, color, 0);
// get handle to shape's transformation matrix
mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
//MyGLRenderer.checkGlError("glGetUniformLocation");
// Apply the projection and view transformation
GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0);
//MyGLRenderer.checkGlError("glUniformMatrix4fv");
// Draw the square
GLES20.glDrawElements(
GLES20.GL_TRIANGLES, drawOrder.length,
GLES20.GL_UNSIGNED_SHORT, drawListBuffer);
// Disable vertex array
GLES20.glDisableVertexAttribArray(mPositionHandle);
}
}
public class MyGLRenderer implements GLSurfaceView.Renderer {
private Triangle mTriangle;
public Square getmSquare() {
return mSquare;
}
public void setmSquare(Square mSquare) {
this.mSquare = mSquare;
}
private Square mSquare;
private Circle mCircle;
// vPMatrix is an abbreviation for "Model View Projection Matrix"
private final float[] vPMatrix = new float[16];
private final float[] projectionMatrix = new float[16];
private final float[] viewMatrix = new float[16];
private float[] rotationMatrix = new float[16];
private float[] translationMatrix = new float[16];
private float[] scaleMatrix = new float[16];
public volatile float mAngle;
public float mSquareX = 1.5f;
public float mSquareY = 0.0f;
public float mRadius = 1.0f;
public float getAngle() {
return mAngle;
}
public void setAngle(float angle) {
mAngle = angle;
}
public void onSurfaceCreated(GL10 unused, EGLConfig eglconfig) {
// Set the background frame color
GLES20.glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
// initialize a triangle
mTriangle = new Triangle();
// initialize a square
mSquare = new Square();
// initialize a square
mCircle = new Circle();
}
#Override
public void onDrawFrame(GL10 unused) {
float[] scratch = new float[16];
float[] movementSquare = new float[16];
float[] scaleCircle = new float[16];
float tempscaleFactor = 1.0f * mRadius;
// Redraw background color
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
// Set the camera position (View matrix)
Matrix.setLookAtM(viewMatrix, 0, 0, 0, -3, 0f, 0f, 0f, 0f, 1.0f, 0.0f);
// Calculate the projection and view transformation
Matrix.multiplyMM(vPMatrix, 0, projectionMatrix, 0, viewMatrix, 0);
// Create a rotation transformation for the triangle
//long time = SystemClock.uptimeMillis() % 4000L;
//float angle = 0.090f * ((int) time);
Matrix.setRotateM(rotationMatrix, 0, mAngle, 0, 0, -1.0f);
Matrix.setIdentityM(translationMatrix,0);
Matrix.translateM(translationMatrix, 0, mSquareX, mSquareY,0);
//THIS PROBLEM HERE IS THAT MY CIRCLE TRANSLATE'S ON THE X-AXIS WHEN SCALING. MY GOAL IS TO TRY AND KEEP IT IN PLACE WHILE IT'S BEING SCALED. Y-AXIS HAS NOT ISSUES
Matrix.setIdentityM(scaleMatrix, 0);
Matrix.scaleM(scaleMatrix, 0, mRadius, mRadius, 0);
if(mRadius != 1f)
Matrix.translateM(scaleMatrix, 0, -(1 + (mRadius / 2)),0,0);
// Combine the rotation matrix with the projection and camera view
// Note that the vPMatrix factor *must be first* in order
// for the matrix multiplication product to be correct.
Matrix.multiplyMM(movementSquare, 0, vPMatrix, 0, translationMatrix, 0);
Matrix.multiplyMM(scratch, 0, vPMatrix, 0, rotationMatrix, 0);
Matrix.multiplyMM(scaleCircle, 0, vPMatrix, 0, scaleMatrix, 0);
// Draw shape
mTriangle.draw(scratch);
mSquare.draw(movementSquare);
mCircle.draw(scaleCircle);
}
#Override
public void onSurfaceChanged(GL10 unused, int width, int height) {
GLES20.glViewport(0, 0, width, height);
float ratio = (float) width / height;
// this projection matrix is applied to object coordinates
// in the onDrawFrame() method
Matrix.frustumM(projectionMatrix, 0, -ratio, ratio, -1, 1, 2, 7);
}
public static int loadShader(int type, String shaderCode){
// create a vertex shader type (GLES20.GL_VERTEX_SHADER)
// or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)
int shader = GLES20.glCreateShader(type);
// add the source code to the shader and compile it
GLES20.glShaderSource(shader, shaderCode);
GLES20.glCompileShader(shader);
return shader;
}
}
I am new to OpenGL and I am trying to find a way to give a drawn object such as a triangle an ID of some kind. This way I can call the Id and give it motion as well as ad touch events.
I am not sure if this is the correct way or if there is a much better way to do this. I have objects made but do not know how to call them and give them motion or onClick event. I have looked around however a lot of the ways seem to be outdated and do not work or the link is now dead.
I have a Renderer as such:
public class MyGLRenderer implements GLSurfaceView.Renderer {
private Triangle mTriangle;
// Called once to set up the view's opengl es environment
public void onSurfaceCreated(GL10 unused, EGLConfig config){
//Set the background frame color
GLES30.glClearColor(255.0f,255.0f,255.0f,0.0f);
mTriangle = new Triangle();
}
// Called for each redraw of the view
public void onDrawFrame(GL10 gl){
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
//Redraw background color
GLES30.glClear(GLES30.GL_COLOR_BUFFER_BIT);
mTriangle.draw();
}
// Called if the geometry of the view changes (example is when the screen orientation changes from landscape to portrait
public void onSurfaceChanged(GL10 unused, int width, int height){
// Called if the geometry of the viewport changes
GLES30.glViewport(0, 0, width, height);
}
public static int loadShader(int type, String shaderCode){
// create a vertex shader type (GLES30.GL_VERTEX_SHADER)
// or a fragment shader type (GLES30.GL_FRAGMENT_SHADER)
int shader = GLES30.glCreateShader(type);
// add the source code to the shader and compile it
GLES30.glShaderSource(shader, shaderCode);
GLES30.glCompileShader(shader);
return shader;
}
}
Surface View as Such:
public class MyGLSurfaceView extends GLSurfaceView {
private final MyGLRenderer mRenderer;
public MyGLSurfaceView(Context context, AttributeSet attrs){
super(context, attrs);
//Create an OpenGl 3.0 context
setEGLContextClientVersion(3);
mRenderer = new MyGLRenderer();
//Set the Renderer for drawing on the GLSurfaceView
setRenderer(mRenderer);
//Render the view only when there is a change in the drawing data
setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
}
}
And a Triangle Class as such:
public class Triangle {
private FloatBuffer vertexBuffer;
private final String vertexShaderCode =
"attribute vec4 vPosition;" +
"void main() {" +
" gl_Position = vPosition;" +
"}";
private final String fragmentShaderCode =
"precision mediump float;" +
"uniform vec4 vColor;" +
"void main() {" +
" gl_FragColor = vColor;" +
"}";
private final int mProgram;
// number of coordinates per vertex in this array
static final int COORDS_PER_VERTEX = 3;
static float triangleCoords[] = { // in counterclockwise order:
0.0f, 0.622008459f, 0.0f, // top
-0.5f, -0.311004243f, 0.0f, // bottom left
0.5f, -0.311004243f, 0.0f // bottom right
};
// Set color with red, green, blue and alpha (opacity) values
float color[] = { 0.63671875f, 0.76953125f, 0.22265625f, 1.0f };
public Triangle() {
// initialize vertex byte buffer for shape coordinates
ByteBuffer bb = ByteBuffer.allocateDirect(
// (number of coordinate values * 4 bytes per float)
triangleCoords.length * 4);
// use the device hardware's native byte order
bb.order(ByteOrder.nativeOrder());
// create a floating point buffer from the ByteBuffer
vertexBuffer = bb.asFloatBuffer();
// add the coordinates to the FloatBuffer
vertexBuffer.put(triangleCoords);
// set the buffer to read the first coordinate
vertexBuffer.position(0);
int vertexShader = MyGLRenderer.loadShader(GLES30.GL_VERTEX_SHADER,
vertexShaderCode);
int fragmentShader = MyGLRenderer.loadShader(GLES30.GL_FRAGMENT_SHADER,
fragmentShaderCode);
// create empty OpenGL ES Program
mProgram = GLES30.glCreateProgram();
// add the vertex shader to program
GLES30.glAttachShader(mProgram, vertexShader);
// add the fragment shader to program
GLES30.glAttachShader(mProgram, fragmentShader);
// creates OpenGL ES program executables
GLES30.glLinkProgram(mProgram);
}
private int mPositionHandle;
private int mColorHandle;
private final int vertexCount = triangleCoords.length / COORDS_PER_VERTEX;
private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex
public void draw() {
// Add program to OpenGL ES environment
GLES30.glUseProgram(mProgram);
// get handle to vertex shader's vPosition member
mPositionHandle = GLES30.glGetAttribLocation(mProgram, "vPosition");
// Enable a handle to the triangle vertices
GLES30.glEnableVertexAttribArray(mPositionHandle);
// Prepare the triangle coordinate data
GLES30.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
GLES30.GL_FLOAT, false,
vertexStride, vertexBuffer);
// get handle to fragment shader's vColor member
mColorHandle = GLES30.glGetUniformLocation(mProgram, "vColor");
// Set color for drawing the triangle
GLES30.glUniform4fv(mColorHandle, 1, color, 0);
// Draw the triangle
GLES30.glDrawArrays(GLES30.GL_TRIANGLES, 0, vertexCount);
// Disable vertex array
GLES30.glDisableVertexAttribArray(mPositionHandle);
}
I would like something to do the following:
drawnTriangleObject_ID.Add gravity to move down or up
drawnTriangleObject_ID.OnClick( // Do Something when this object is clicked )
In your triangle class, add positioning data
float x = 0.0f;
float y = 0.0f;
float z = 0.0f;
and when drawing the triangle, you have to apply the translation
Matrix.setIdentityM(modelmatrix, 0);
Matrix.translateM(modelmatrix, 0, x, y, z);
then multiply the model matrix by the view matrix
Matrix.multiplyMM(resultmodelview, 0, viewmatrix, 0, modelmatrix, 0);
then multiply the result with projection matrix
Matrix.multiplyMM(resultresultprojection, 0, ProjectionMatrix, 0, resultmodelview, 0);
and publish it
World.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, resultresultprojection, 0);
This all supposing you have the frustum and projection and view matrix built already (which if you see the triangle, could be already done)..
Good luck and have fun coding !
As for the "OnClick" it is a bit more tricky:
- Once the screen has been clicked, cast a ray from your XY plance (screen) to the 3D world. the ray (line) will have 2 coordinates, a start point and end point in form of X,Y,Z, or might have a start point and a vector(direction of the line)... On each frame you have to check if this ray is created, if it is, you need to use some Math to check if that line intersects your triangle (Don't forget to apply the rotation and translation of the triangle to it's vertices before checking intersection with the Ray). when the frame has been drawn don't forget to delete the ray
I'm trying to create a 360 video sphere (like the ones for cardboard) on Android. I have done this with a photo by rendering a sphere in OpenGL ES1.0 and than attaching a texture to it. Afterwards I can use the sensor values to rotate the sphere.
However, I can't figure out how to change the picture to a video. I've tried frame by frame rendering using texSubImage2D() but it's SUPER SLOW. My video is probably going to be about 4k density as I need a good quality even when only small portion of it is shown.
I've read some theoretical stuff about how this should be done (i.e. Frame Buffers, External Texture, Synchronization, etc.) but I couldn't find any example for these things, so some code would be EXTREMELY appreciated...
Here is how I render the Sphere, draw it and attach a texture to it (i.e. my Sphere class)...
import rapid.decoder.BitmapDecoder;
public class Sphere {
/** Buffer holding the vertices. */
private final List<FloatBuffer> mVertexBuffer = new ArrayList<FloatBuffer>();
/** The vertices for the sphere. */
private final List<float[]> mVertices = new ArrayList<float[]>();
/** Buffer holding the texture coordinates. */
private final List<FloatBuffer> mTextureBuffer = new ArrayList<FloatBuffer>();
/** Mapping texture coordinates for the vertices. */
private final List<float[]> mTexture = new ArrayList<float[]>();
/** The texture pointer. */
private final int[] mTextures = new int[1];
/** Total number of strips for the given depth. */
private final int mTotalNumStrips;
public Sphere(final int depth, final float radius) {
// Calculate basic values for the sphere.
this.mTotalNumStrips = Maths.power(2, depth - 1) * 5; //last 5 is related to properties of a icosahedron
final int numVerticesPerStrip = Maths.power(2, depth) * 3;
final double altitudeStepAngle = Maths.rad120 / Maths.power(2, depth);
final double azimuthStepAngle = Maths.rad360 / this.mTotalNumStrips;
double x, y, z, h, altitude, azimuth;
Log.e("mTotalNumStrips", ""+mTotalNumStrips);
Log.e("numVerticesPerStrip", ""+numVerticesPerStrip);
for (int stripNum = 0; stripNum < this.mTotalNumStrips; stripNum++) {
// Setup arrays to hold the points for this strip.
final float[] vertices = new float[numVerticesPerStrip * 3]; // x,y,z
final float[] texturePoints = new float[numVerticesPerStrip * 2]; // 2d texture
int vertexPos = 0;
int texturePos = 0;
// Calculate position of the first vertex in this strip.
altitude = Maths.rad90;
azimuth = stripNum * azimuthStepAngle;
// Draw the rest of this strip.
for (int vertexNum = 0; vertexNum < numVerticesPerStrip; vertexNum += 2) {
// First point - Vertex.
y = radius * Math.sin(altitude);
h = radius * Math.cos(altitude);
z = h * Math.sin(azimuth);
x = h * Math.cos(azimuth);
vertices[vertexPos++] = (float) x;
vertices[vertexPos++] = (float) y;
vertices[vertexPos++] = (float) z;
// First point - Texture.
texturePoints[texturePos++] = (float) (1 + azimuth / Maths.rad360);
texturePoints[texturePos++] = (float) (1 - (altitude + Maths.rad90) / Maths.rad180);
// Second point - Vertex.
altitude -= altitudeStepAngle;
azimuth -= azimuthStepAngle / 2.0;
y = radius * Math.sin(altitude);
h = radius * Math.cos(altitude);
z = h * Math.sin(azimuth);
x = h * Math.cos(azimuth);
vertices[vertexPos++] = (float) x;
vertices[vertexPos++] = (float) y;
vertices[vertexPos++] = (float) z;
// Second point - Texture.
texturePoints[texturePos++] = (float) (1 + azimuth / Maths.rad360);
texturePoints[texturePos++] = (float) (1 - (altitude + Maths.rad90) / Maths.rad180);
azimuth += azimuthStepAngle;
}
this.mVertices.add(vertices);
this.mTexture.add(texturePoints);
ByteBuffer byteBuffer = ByteBuffer.allocateDirect(numVerticesPerStrip * 3 * Float.SIZE);
byteBuffer.order(ByteOrder.nativeOrder());
FloatBuffer fb = byteBuffer.asFloatBuffer();
fb.put(this.mVertices.get(stripNum));
fb.position(0);
this.mVertexBuffer.add(fb);
// Setup texture.
byteBuffer = ByteBuffer.allocateDirect(numVerticesPerStrip * 2 * Float.SIZE);
byteBuffer.order(ByteOrder.nativeOrder());
fb = byteBuffer.asFloatBuffer();
fb.put(this.mTexture.get(stripNum));
fb.position(0);
this.mTextureBuffer.add(fb);
}
}
public void loadGLTexture(final GL10 gl, final Context context, final int texture) {
Bitmap bitmap = BitmapDecoder.from(context.getResources(), texture)
.scale(4048, 2024)
.decode();
// Generate one texture pointer, and bind it to the texture array.
gl.glGenTextures(1, this.mTextures, 0);
gl.glBindTexture(GL10.GL_TEXTURE_2D, this.mTextures[0]);
// Create nearest filtered texture.
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);
// Use Android GLUtils to specify a two-dimensional texture image from our bitmap.
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
// Tide up.
bitmap.recycle();
}
/**
* The draw method for the square with the GL context.
*
* #param gl Graphics handle.
*/
public void draw(final GL10 gl) {
// bind the previously generated texture.
gl.glBindTexture(GL10.GL_TEXTURE_2D, this.mTextures[0]);
// Point to our buffers.
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
// Set the face rotation, clockwise in this case.
gl.glFrontFace(GL10.GL_CW);
// Point to our vertex buffer.
for (int i = 0; i < this.mTotalNumStrips; i++) {
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, this.mVertexBuffer.get(i));
gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, this.mTextureBuffer.get(i));
// Draw the vertices as triangle strip.
gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, this.mVertices.get(i).length / 3);
}
// Disable the client state before leaving.
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
}
}
And this is my renderer...
#Override
public void onDrawFrame(final GL10 gl) {
zvector = new float[] {0,0,1,0};
resultvector = new float[] {0,0,1,0};
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glLoadIdentity();
float radiansX = (float) Math.toRadians(gyro_angle[1]);
float radiansY = (float) Math.toRadians(-gyro_angle[0]);
float radiansZ = (float) Math.toRadians(-gyro_angle[2]);
// Finds the Sin and Cosin for the half angle.
float sinX =(float) Math.sin(radiansX * 0.5);
float cosX =(float) Math.cos(radiansX * 0.5);
float sinY =(float) Math.sin(radiansY * 0.5);
float cosY =(float) Math.cos(radiansY * 0.5);
float sinZ =(float) Math.sin(radiansZ * 0.5);
float cosZ =(float) Math.cos(radiansZ * 0.5);
// Formula to construct a new Quaternion based on direction and angle.
quatX[0] = cosX;
quatX[1] = 1 * sinX;
quatX[2] = 0 * sinX;
quatX[3] = 0 * sinX;
quatY[0] = cosY;
quatY[1] = 0 * sinY;
quatY[2] = 1 * sinY;
quatY[3] = 0 * sinY;
quatZ[0] = cosZ;
quatZ[1] = 0 * sinZ;
quatZ[2] = 0 * sinZ;
quatZ[3] = 1 * sinZ;
quat1 = multiplyQuat(quatX, quatY);
quat2 = multiplyQuat(quat1, quatZ);
mMatrix = getMatrixfromQuat(quat1);
gl.glLoadMatrixf(mMatrix, 0);
this.mSphere.draw(gl);
}
#Override
public void onSurfaceChanged(final GL10 gl, final int width, final int height) {
final float aspectRatio = (float) width / (float) (height == 0 ? 1 : height);
gl.glViewport(0, 0, width, height);
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
GLU.gluPerspective(gl, 45.0f, aspectRatio, 0.1f, 100.0f);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
}
#Override
public void onSurfaceCreated(final GL10 gl, final EGLConfig config) {
this.mSphere.loadGLTexture(gl, this.mContext, R.drawable.pic360);
gl.glEnable(GL10.GL_TEXTURE_2D);
gl.glShadeModel(GL10.GL_SMOOTH);
gl.glClearColor(0.0f, 0.0f, 0.0f, 0.5f);
gl.glClearDepthf(1.0f);
gl.glEnable(GL10.GL_DEPTH_TEST);
gl.glDepthFunc(GL10.GL_LEQUAL);
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);
}
//CONSTRUCTER
public GlRenderer(final Context context) {
this.mContext = context;
this.mSphere = new Sphere(5, 2);
sensorManager = (SensorManager) this.mContext.getSystemService(this.mContext.SENSOR_SERVICE);
sensorGyroscope = sensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
sensorAccelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
sensorMagneticField = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
valuesAccelerometer = new float[3];
valuesMagneticField = new float[3];
matrixR = new float[9];
matrixI = new float[9];
matrixValues = new float[3];
sensorManager.registerListener(this, sensorGyroscope, SensorManager.SENSOR_DELAY_FASTEST);
sensorManager.registerListener(this, sensorAccelerometer, SensorManager.SENSOR_DELAY_FASTEST);
sensorManager.registerListener(this, sensorMagneticField, SensorManager.SENSOR_DELAY_FASTEST);
}
//HERE GOES SOME CURRENTLY IRRELEVANT STUFF ABOUT THE SENSORS AND QUATERNIONS
I had some this type of video texturing problem. First time I used ffmpeg for video decoding but the performance was so poor (just like you- Extracting frame by frame). For improving performance I used android default mediaplayer. You can use surface texture to create an opengl surface (sphere, cylinder, cube etc...) and then set the surface in the media player
Surface surface = new Surface(mSurface);//mSurface is your surface texture
mMediaPlayer.setSurface(surface);
mMediaPlayer.setScreenOnWhilePlaying(true);
This is just a technique. I did this for some commercial enclosed project, so I cant share the code. I hope I'll published a free code in github soon.
I'm developing an application for Android that uses OpenGL ES 2.0
Since it's my first time with OpenGL (I used to use WebGL), I made a custom and pretty simple API like THREE.js, which consists of a Object3D and Geometry objects.
Basicaly, what I did was: Store shapes inside the Geometry object, and create Mesh objects with the the geometry instance inside. Also, inside Mesh, I have: Vector3 object for: position, scale, rotation.
I created a circle to test, and here is what is happening
If I don't change ANY thing, the circle is perfect on the screen. If I change the vertices positions on the creation of the circle, the circle is still Ok also.
But, when I do some transformation (change the attribute position, scale or rotation) or Object3D (in this case, Mesh), the circle becomes "strech".
So, I think that there is some problem with the projectionMatrix, but the circle it's ok if I don't transform it.
Is there a problem with my matrix code? Should I send the Rotation, Translation and Scale matrix to the GPU?
Perhaps I'm complicating things, but since this is the first time I use OpenGL after reading lot's of information, it's acceptable...
Here is the Object3D code:
public class Object3D {
public Vector3 position = new Vector3();
public Vector3 rotation = new Vector3();
public Vector3 scale = new Vector3();
public Color color = new Color();
public float[] getMVMatrix(){
// Initialize matrix with Identity
float[] mvMatrix = new float[16];
Matrix.setIdentityM(mvMatrix, 0);
// apply scale
Matrix.scaleM(mvMatrix, 0, scale.x, scale.y, scale.z);
// set rotation
Matrix.setRotateM(mvMatrix, 0, rotation.x, 1f, 0, 0);
Matrix.setRotateM(mvMatrix, 0, rotation.y, 0, 1f, 0);
Matrix.setRotateM(mvMatrix, 0, rotation.z, 0, 0, 1f);
// apply translation
Matrix.translateM(mvMatrix, 0, position.x, position.y, position.z);
return mvMatrix;
}
}
This is the Geometry class, that simplifies the use of Triangles:
public class Geometry {
// Public, to allow modifications
public ArrayList<Vector3> vertices;
public ArrayList<Face3> faces;
// Type of Geometry
public int triangleType = GLES20.GL_TRIANGLES;
[...]
public FloatBuffer getVerticesBuffer(){
if(verticesBuffer == null || verticesBufferNeedsUpdate){
/*
* Cache faces
*/
int size = vertices.size();
// (size of Vector3 list) * (3 for each object) * (4 bytes per float)
ByteBuffer bb = ByteBuffer.allocateDirect( size * 3 * 4 );
// use the device hardware's native byte order
bb.order(ByteOrder.nativeOrder());
// Get the ByteBuffer as a floatBuffer
verticesBuffer = bb.asFloatBuffer();
for(int i = 0; i < size; i++)
verticesBuffer.put(vertices.get(i).toArray());
verticesBufferNeedsUpdate = false;
}
verticesBuffer.position(0);
return verticesBuffer;
}
public ShortBuffer getFacesBuffer(){
if(facesBuffer == null || facesBufferNeedsUpdate){
/*
* Cache faces
*/
int size = faces.size();
// Log.i(TAG, "FACES Size: "+size);
// (size of Vector3 list) * (3 for each object) * (2 bytes per short)
ByteBuffer bb = ByteBuffer.allocateDirect( size * 3 * 2 );
// use the device hardware's native byte order
bb.order(ByteOrder.nativeOrder());
// Get the ByteBuffer as a floatBuffer
facesBuffer = bb.asShortBuffer();
for(int i = 0; i < size; i++)
facesBuffer.put(faces.get(i).toArray());
facesBufferNeedsUpdate = false;
}
facesBuffer.position(0);
return facesBuffer;
}
}
Also, The Mesh class, responsable for resndering Geometry objects:
public class Mesh extends Object3D{
[...]
public void draw(float[] projectionMatrix, int shaderProgram){
float[] MVMatrix = getMVMatrix();
Matrix.multiplyMM(projectionMatrix, 0, projectionMatrix, 0, MVMatrix, 0);
// Check if geometry is set
if(geometry == null){
Log.i(TAG, "Geometry is null. skiping");
return;
}
// Add program to OpenGL environment
GLES20.glUseProgram(shaderProgram);
// Get, enable and Set the position attribute
positionHandle = GLES20.glGetAttribLocation(shaderProgram, "vPosition");
GLES20.glEnableVertexAttribArray(positionHandle);
// Prepare the triangles coordinate data
Buffer vertexBuffer = geometry.getVerticesBuffer();
GLES20.glVertexAttribPointer(positionHandle, COORDS_PER_VERTEX,
GLES20.GL_FLOAT, false,
COORDS_PER_VERTEX*4,
vertexBuffer);
// get handle to fragment shader's vColor member
int mColorHandle = GLES20.glGetUniformLocation(shaderProgram, "vColor");
// Set color for drawing the triangle
GLES20.glUniform4fv(mColorHandle, 1, color.toArray(), 0);
// get handle to shape's transformation matrix
int mMVPMatrixHandle = GLES20.glGetUniformLocation(shaderProgram, "uMVPMatrix");
ChwaziSurfaceView.checkGlError("glGetUniformLocation");
// Apply the projection and view transformation
GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, projectionMatrix, 0);
ChwaziSurfaceView.checkGlError("glUniformMatrix4fv");
// Draw the triangles
if(geometry.triangleType == GLES20.GL_TRIANGLES){
Buffer indexesBuffer = geometry.getFacesBuffer();
GLES20.glDrawElements(
GLES20.GL_TRIANGLES,
geometry.faces.size()*3,
GL10.GL_UNSIGNED_SHORT,
indexesBuffer);
}else{
GLES20.glDrawArrays(geometry.triangleType, 0, geometry.vertices.size());
ChwaziSurfaceView.checkGlError("glDrawArrays");
}
// Disable vertex array
GLES20.glDisableVertexAttribArray(positionHandle);
}
}
This is the sample code I made to test if it's working properly (just translation)
// Inside my Renderer...
#Override
public void onDrawFrame(GL10 unused) {
// Draw background color
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
GLES20.glCullFace(GLES20.GL_FRONT_AND_BACK);
// Set the camera position (View matrix)
Matrix.setLookAtM(mVMatrix, 0,
0, 0, -3,
0f, 0f, 0f,
0f, 1.0f, 0.0f);
// Calculate the projection and view transformation
Matrix.multiplyMM(mMVPMatrix, 0, mProjMatrix, 0, mVMatrix, 0);
// Create a rotation for the triangle
long time = SystemClock.uptimeMillis();// % 4000L;
myMesh.position.x = (time%4000)/4000f;
myMesh.draw(mMVPMatrix, shaderProgram.getProgram());
}
#Override
public void onSurfaceChanged(GL10 unused, int width, int height) {
GLES20.glViewport(0, 0, width, height);
float ratio = (float) width / height;
// this projection matrix is applied to object coordinates
Matrix.orthoM(mProjMatrix, 0, -1, 1, -1, 1, 0, 10);
}
EDIT
Shader code:
private final String vertexShaderCode =
// This matrix member variable provides a hook to manipulate
// the coordinates of the objects that use this vertex shader
"uniform mat4 uMVPMatrix;" +
"attribute vec4 vPosition;" +
"void main() {" +
// the matrix must be included as a modifier of gl_Position
" gl_Position = vPosition * uMVPMatrix;" +
"}";
private final String fragmentShaderCode =
"precision mediump float;" +
"uniform vec4 vColor;" +
"void main() {" +
" gl_FragColor = vColor;" +
"}";
Backstory:
I'm trying to draw as many squares the the screen as possible using a single draw call. I'm using a custom glsl vertex shader that is specialized for 2D drawing, and that is supposed to be pulling position data for the vertices of the squares from a samplerBuffer. Since I don't need to worry about rotating or scaling the squares all I should need to do is load the position data into a buffer, bind a texture to that buffer, and then use the sampler to get each vertex's position in the shader. In order to get an index into the texture I store each elements index as the z-component of the vertices.
Everything seems to work really well for a thousand or so squares, but after that I start to get weird blinking. It sort of seems like it's not drawing all of the squares every draw step, or possibly not using all of the positions so that many of the squares are overlapping.
The weird thing is, that if I use drawElements instead of drawElementsMulti, the blinking goes away (but of course then all the squares are drawn as one single object, which I don't want)
One question I have is if my position data is limited to the max texture size, or the max texture buffer size. And if I am limited to the much smaller max texture size, how do I get around it? There's got to be a reason all of that texture buffer space is there, but I obviously don't get how to properly use it.
I'm also thinking maybe glMultiDrawElements is doing something I'm not accounting for with the sampler somehow. Idk, I'm really lost at this point, and yet..it works perfectly for smaller numbers of squares, so I must be doing something right.
[EDIT] Code had changed to reflect suggestions below (and for readability), but the problem persists.
Ok, so here's some code. First the vertex shader:
uniform mat3 projection;
attribute vec3 vertex;
uniform samplerBuffer positionSampler;
attribute vec4 vertex_color;
varying vec4 color;
float positionFetch(int index)
{
// I've tried texelFetch here as well, same effect
float value = texelFetchBuffer(positionSampler, index).r;
return value;
}
void main(void)
{
color = vec4(1, 1, 1, 1);
// use the z-component of the vertex to look up the position of this instance in the texture
vec3 real_position = vec3(vertex.x + positionFetch(int(vertex.z)*2), vertex.y + positionFetch(int(vertex.z)*2+1), 1);
gl_Position = vec4(projection * real_position, 1);
}
And now my GLRenderer, sorry there is so much code, I just really want to make sure there's enough info here to get an answer. This has really been driving me nuts, and examples for java seem to be hard to come by (maybe this code will help someone else on their quest):
public class GLRenderer extends GLCanvas implements GLEventListener, WindowListener
{
private static final long serialVersionUID = -8513201172428486833L;
private static final int bytesPerFloat = Float.SIZE / Byte.SIZE;
private static final int bytesPerShort = Short.SIZE / Byte.SIZE;
public float viewWidth, viewHeight;
public float screenWidth, screenHeight;
private FPSAnimator animator;
private boolean didInit = false;
JFrame the_frame;
SquareGeometry geometry;
// Thought power of 2 might be required, doesn't seem to make a difference
private static final int NUM_THINGS = 2*2*2*2*2*2*2*2*2*2*2*2*2*2;
float[] position = new float[NUM_THINGS*2];
// Shader attributes
private int shaderProgram, projectionAttribute, vertexAttribute, positionAttribute;
public static void main(String[] args)
{
new GLRenderer();
}
public GLRenderer()
{
// setup OpenGL Version 2
super(new GLCapabilities(GLProfile.get(GLProfile.GL2)));
addGLEventListener(this);
setSize(1800, 1000);
the_frame = new JFrame("Hello World");
the_frame.getContentPane().add(this);
the_frame.setSize(the_frame.getContentPane().getPreferredSize());
the_frame.setVisible(true);
the_frame.addWindowListener(this);
animator = new FPSAnimator(this, 60);
animator.start();
}
// Called by the drivers when the gl context is first made available
public void init(GLAutoDrawable d)
{
final GL2 gl = d.getGL().getGL2();
IntBuffer asd = IntBuffer.allocate(1);
gl.glGetIntegerv(GL2.GL_MAX_TEXTURE_BUFFER_SIZE, asd);
System.out.println(asd.get(0));
asd = IntBuffer.allocate(1);
gl.glGetIntegerv(GL2.GL_MAX_TEXTURE_SIZE, asd);
System.out.println(asd.get(0));
shaderProgram = ShaderLoader.compileProgram(gl, "default");
gl.glLinkProgram(shaderProgram);
_getShaderAttributes(gl);
gl.glUseProgram(shaderProgram);
_checkGLCapabilities(gl);
_initGLSettings(gl);
// Calculate batch of vertex data from dirt geometry
geometry = new SquareGeometry(.1f);
geometry.buildGeometry(viewWidth, viewHeight);
geometry.finalizeGeometry(NUM_THINGS);
geometry.vertexBufferID = _generateBufferID(gl);
_loadVertexBuffer(gl, geometry);
geometry.indexBufferID = _generateBufferID(gl);
_loadIndexBuffer(gl, geometry);
geometry.positionBufferID = _generateBufferID(gl);
// initialize buffer object
int size = NUM_THINGS * 2 * bytesPerFloat;
System.out.println(size);
IntBuffer bla = IntBuffer.allocate(1);
gl.glGenTextures(1, bla);
geometry.positionTextureID = bla.get(0);
gl.glUniform1i(positionAttribute, 0);
gl.glActiveTexture(GL2.GL_TEXTURE0);
gl.glBindTexture(GL2.GL_TEXTURE_BUFFER, geometry.positionTextureID);
gl.glBindBuffer(GL2.GL_TEXTURE_BUFFER, geometry.positionBufferID);
gl.glBufferData(GL2.GL_TEXTURE_BUFFER, size, null, GL2.GL_DYNAMIC_DRAW);
gl.glTexBuffer(GL2.GL_TEXTURE_BUFFER, GL2.GL_R32F, geometry.positionBufferID);
}
private void _initGLSettings(GL2 gl)
{
gl.glClearColor(0f, 0f, 0f, 1f);
}
private void _loadIndexBuffer(GL2 gl, SquareGeometry geometry)
{
gl.glBindBuffer(GL2.GL_ELEMENT_ARRAY_BUFFER, geometry.indexBufferID);
gl.glBufferData(GL2.GL_ELEMENT_ARRAY_BUFFER, bytesPerShort*NUM_THINGS*geometry.getNumPoints(), geometry.indexBuffer, GL2.GL_STATIC_DRAW);
}
private void _loadVertexBuffer(GL2 gl, SquareGeometry geometry)
{
int numBytes = geometry.getNumPoints() * 3 * bytesPerFloat * NUM_THINGS;
gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, geometry.vertexBufferID);
gl.glBufferData(GL2.GL_ARRAY_BUFFER, numBytes, geometry.vertexBuffer, GL2.GL_STATIC_DRAW);
gl.glEnableVertexAttribArray(vertexAttribute);
gl.glVertexAttribPointer(vertexAttribute, 3, GL2.GL_FLOAT, false, 0, 0);
}
private int _generateBufferID(GL2 gl)
{
IntBuffer bufferIDBuffer = IntBuffer.allocate(1);
gl.glGenBuffers(1, bufferIDBuffer);
return bufferIDBuffer.get(0);
}
private void _checkGLCapabilities(GL2 gl)
{
// TODO: Respond to this information in a meaningful way.
boolean VBOsupported = gl.isFunctionAvailable("glGenBuffersARB") && gl.isFunctionAvailable("glBindBufferARB")
&& gl.isFunctionAvailable("glBufferDataARB") && gl.isFunctionAvailable("glDeleteBuffersARB");
System.out.println("VBO Supported: " + VBOsupported);
}
private void _getShaderAttributes(GL2 gl)
{
vertexAttribute = gl.glGetAttribLocation(shaderProgram, "vertex");
projectionAttribute = gl.glGetUniformLocation(shaderProgram, "projection");
positionAttribute = gl.glGetUniformLocation(shaderProgram, "positionSampler");
}
// Called by me on the first resize call, useful for things that can't be initialized until the screen size is known
public void viewInit(GL2 gl)
{
for(int i = 0; i < NUM_THINGS; i++)
{
position[i*2] = (float) (Math.random()*viewWidth);
position[i*2+1] = (float) (Math.random()*viewHeight);
}
gl.glUniformMatrix3fv(projectionAttribute, 1, false, Matrix.projection3f, 0);
// Load position data into a texture buffer
gl.glBindBuffer(GL2.GL_TEXTURE_BUFFER, geometry.positionBufferID);
ByteBuffer textureBuffer = gl.glMapBuffer(GL2.GL_TEXTURE_BUFFER, GL2.GL_WRITE_ONLY);
FloatBuffer textureFloatBuffer = textureBuffer.order(ByteOrder.nativeOrder()).asFloatBuffer();
for(int i = 0; i < position.length; i++)
{
textureFloatBuffer.put(position[i]);
}
gl.glUnmapBuffer(GL2.GL_TEXTURE_BUFFER);
gl.glBindBuffer(GL2.GL_TEXTURE_BUFFER, 0);
}
public void display(GLAutoDrawable d)
{
if (!didInit || geometry.vertexBufferID == 0)
{
return;
}
//long startDrawTime = System.currentTimeMillis();
final GL2 gl = d.getGL().getGL2();
gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT);
// If we were drawing any other buffers here we'd need to set this every time
// but instead we just leave them bound after initialization, saves a little render time
// No combination of these seems to fix the problem
//gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, geometry.vertexBufferID);
//gl.glVertexAttribPointer(vertexAttribute, 3, GL2.GL_FLOAT, false, 0, 0);
//gl.glBindBuffer(GL2.GL_ELEMENT_ARRAY_BUFFER, geometry.indexBufferID);
gl.glBindBuffer(GL2.GL_TEXTURE_BUFFER, geometry.positionBufferID);
//gl.glActiveTexture(GL2.GL_TEXTURE0);
//gl.glTexBuffer(GL2.GL_TEXTURE_BUFFER, GL2.GL_R32F, geometry.positionBufferID);
_render(gl, geometry);
// Also tried these
//gl.glFlush();
//gl.glFinish();
}
public void _render(GL2 gl, SquareGeometry geometry)
{
gl.glMultiDrawElements(geometry.drawMode, geometry.countBuffer, GL2.GL_UNSIGNED_SHORT, geometry.offsetBuffer, NUM_THINGS);
// This one works, but isn't what I want
//gl.glDrawElements(GL2.GL_LINE_LOOP, count, GL2.GL_UNSIGNED_SHORT, 0);
}
public void reshape(GLAutoDrawable d, int x, int y, int width, int height)
{
final GL2 gl = d.getGL().getGL2();
gl.glViewport(0, 0, width, height);
float ratio = (float) height / width;
screenWidth = width;
screenHeight = height;
viewWidth = 100;
viewHeight = viewWidth * ratio;
Matrix.ortho3f(0, viewWidth, 0, viewHeight);
if (!didInit)
{
viewInit(gl);
didInit = true;
}
else
{
// respond to view size changing
}
}
}
The final bit is the SquareGeometry class which holds all the bufferIDs and vertex data, but also is responsible for filling the vertex buffer correctly so that each vertex's z component can function as an index into the position texture:
public class SquareGeometry
{
public float[] vertices = null;
ShortBuffer indexBuffer;
IntBuffer countBuffer;
PointerBuffer offsetBuffer;
FloatBuffer vertexBuffer;
public int vertexBufferID = 0;
public int indexBufferID = 0;
public int positionBufferID = 0;
public int positionTextureID = 0;
public int drawMode;
protected float width = 0;
protected float height = 0;
public SquareGeometry(float size)
{
width = size;
height = size;
}
public void buildGeometry(float viewWidth, float viewHeight)
{
vertices = new float[4 * 2];
vertices[0] = -width/2;
vertices[1] = -height/2;
vertices[2] = -width/2;
vertices[3] = height/2;
vertices[4] = width/2;
vertices[5] = height/2;
vertices[6] = width/2;
vertices[7] = -height/2;
drawMode = GL2.GL_POLYGON;
}
public void finalizeGeometry(int numInstances)
{
if(vertices == null) return;
int num_vertices = this.getNumPoints();
int total_num_vertices = numInstances * num_vertices;
// initialize vertex Buffer (# of coordinate values * 4 bytes per float)
ByteBuffer vbb = ByteBuffer.allocateDirect(total_num_vertices * 3 * Float.SIZE);
vbb.order(ByteOrder.nativeOrder());
vertexBuffer = vbb.asFloatBuffer();
for(int i = 0; i < numInstances; i++)
{
for(int v = 0; v < num_vertices; v++)
{
int vertex_index = v * 2;
vertexBuffer.put(vertices[vertex_index]);
vertexBuffer.put(vertices[vertex_index+1]);
vertexBuffer.put(i);
}
}
vertexBuffer.rewind();
// Create the indices
vbb = ByteBuffer.allocateDirect(total_num_vertices * Short.SIZE);
vbb.order(ByteOrder.nativeOrder());
indexBuffer = vbb.asShortBuffer();
for(int i = 0; i < total_num_vertices; i++)
{
indexBuffer.put((short) (i));
}
indexBuffer.rewind();
// Create the counts
vbb = ByteBuffer.allocateDirect(numInstances * Integer.SIZE);
vbb.order(ByteOrder.nativeOrder());
countBuffer = vbb.asIntBuffer();
for(int i = 0; i < numInstances; i++)
{
countBuffer.put(num_vertices);
}
countBuffer.rewind();
// create the offsets
offsetBuffer = PointerBuffer.allocateDirect(numInstances);
for(int i = 0; i < numInstances; i++)
{
offsetBuffer.put(num_vertices*i*2);
}
offsetBuffer.rewind();
}
public int getNumPoints()
{
return vertices.length/2;
}
}
Ok first things first, you are not setting gl_Color in the shader maybe that can be the issue here and you only lucky with small numbers. It is a varying, but do you also have fragment shader that picks up the value?
At no point do you ensure that NUM_THINGS*2 < GL_MAX_TEXTURE_SIZE. I don't know how FloatBuffer.put reacts; being Java probably / hopefully an exception.
Also you bind the positionBufferID buffer, then unbind it but never rebind it.
You create positionTextureID but never put any data there. This also what you put into the sampler positionSampler and try to access.
Yea well lots of issues but my gut tells me the last one may be the real issue here.
Alright, I've got it solved, though I'm still really not clear on what the original problem was. I fixed it by simplifying the drawing to use drawArrays instead of drawElements or multiDrawElements. I'm really not sure why I thought I needed them, as I really don't in this case. I'm pretty sure I was messing up a few things with the indexes and offsets.
Furthermore, as far as the proper way to bind the texture buffer, neither the code I have above, nor example found at the link I posted in a comment are correct at all.
If anyone is interested in the correct way to use the texture buffer like this I just did a pretty extensive write-up on it here http://zebadiah.me/?p=44. Thanks all for the help.