public internet - Page 117

Rotate triangle so that its tip points in the direction of the point on the screen that we last touched

- by Sid

OpenGL ES - Android. Hello all, I am unable to rotate the triangle accordingly in such a way that its tip always points to my finger. What i did : Constructed a triangle in by GL.GL_TRIANGLES. Added touch events to it. I can rotate the triangle along my Z-axis successfully. Even made the vector class for it. What i need : Each time when I touch the screen, I want to rotate the triangle to face the touch point. Need some help. Here's what i implemented. I wonder that where i am going wrong? My code : public class Graphic2DTriangle { private FloatBuffer vertexBuffer; private ByteBuffer indexBuffer; private float[] vertices = { -1.0f,-1.0f, 0.0f, 2.0f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f }; private byte[] indices = { 0, 1, 2 }; public Graphic2DTriangle() { ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4); vbb.order(ByteOrder.nativeOrder()); // Use native byte order vertexBuffer = vbb.asFloatBuffer(); // Convert byte buffer to float vertexBuffer.put(vertices); // Copy data into buffer vertexBuffer.position(0); // Rewind // Setup index-array buffer. Indices in byte. indexBuffer = ByteBuffer.allocateDirect(indices.length); indexBuffer.put(indices); indexBuffer.position(0); } public void draw(GL10 gl) { gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer); gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_BYTE, indexBuffer); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); } } My SurfaceView class where i've done some Touch Events. public class BallThrowGLSurfaceView extends GLSurfaceView{ MySquareRender _renderObj; View _viewObj; float oldX,oldY,dX,dY; final float TOUCH_SCALE_FACTOR = 0.6f; Vector2 touchPos = new Vector2(); float angle=0; public BallThrowGLSurfaceView(Context context) { super(context); // TODO Auto-generated constructor stub _renderObj = new MySquareRender(context); this.setRenderer(_renderObj); this.setRenderMode(RENDERMODE_WHEN_DIRTY); } @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub touchPos.x = event.getX(); touchPos.y = event.getY(); Log.i("Co-ord", touchPos.x+"hh"+touchPos.y); switch(event.getAction()){ case MotionEvent.ACTION_MOVE : dX = touchPos.x - oldX; dY = touchPos.y - oldY; if(touchPos.y > getHeight()/2){ dX = dX*-1; } if(touchPos.x < getWidth()/2){ dY = dY*-1; } _renderObj.mAngle += (dX+dY) * TOUCH_SCALE_FACTOR; requestRender(); Log.i("AngleCo-ord", _renderObj.mAngle +"hh"); } oldX = touchPos.x; oldY = touchPos.y; Log.i("OldCo-ord", oldX+" hh "+oldY); return true; } } Last but not the least. My vector2 class. public class Vector2 { public static float TO_RADIANS = (1 / 180.0f) * (float) Math.PI; public static float TO_DEGREES = (1 / (float) Math.PI) * 180; public float x, y; public Vector2() { } public Vector2(float x, float y) { this.x = x; this.y = y; } public Vector2(Vector2 other) { this.x = other.x; this.y = other.y; } public Vector2 cpy() { return new Vector2(x, y); } public Vector2 set(float x, float y) { this.x = x; this.y = y; return this; } public Vector2 set(Vector2 other) { this.x = other.x; this.y = other.y; return this; } public Vector2 add(float x, float y) { this.x += x; this.y += y; return this; } public Vector2 add(Vector2 other) { this.x += other.x; this.y += other.y; return this; } public Vector2 sub(float x, float y) { this.x -= x; this.y -= y; return this; } public Vector2 sub(Vector2 other) { this.x -= other.x; this.y -= other.y; return this; } public Vector2 mul(float scalar) { this.x *= scalar; this.y *= scalar; return this; } public float len() { return FloatMath.sqrt(x * x + y * y); } public Vector2 nor() { float len = len(); if (len != 0) { this.x /= len; this.y /= len; } return this; } public float angle() { float angle = (float) Math.atan2(y, x) * TO_DEGREES; if (angle < 0) angle += 360; return angle; } public Vector2 rotate(float angle) { float rad = angle * TO_RADIANS; float cos = FloatMath.cos(rad); float sin = FloatMath.sin(rad); float newX = this.x * cos - this.y * sin; float newY = this.x * sin + this.y * cos; this.x = newX; this.y = newY; return this; } public float dist(Vector2 other) { float distX = this.x - other.x; float distY = this.y - other.y; return FloatMath.sqrt(distX * distX + distY * distY); } public float dist(float x, float y) { float distX = this.x - x; float distY = this.y - y; return FloatMath.sqrt(distX * distX + distY * distY); } public float distSquared(Vector2 other) { float distX = this.x - other.x; float distY = this.y - other.y; return distX * distX + distY * distY; } public float distSquared(float x, float y) { float distX = this.x - x; float distY = this.y - y; return distX * distX + distY * distY; } } PS : i am able to handle the touch events. I can rotate the triangle with the touch of my finger. But i want that ONE VERTEX of the triangle should point at my finger position respective of the position of my finger.

Search Results

Search found 48081 results on 1924 pages for 'public internet'.

Page 117/1924 | < Previous Page | 113 114 115 116 117 118 119 120 121 122 123 124 | Next Page >

- by Sid

- by Margus

- by SWD

- by ibrahim

- by Priyanka

- by Brian Frost

- by granadaCoder

- by Jeddizero

- by No one in particluar

- by Maxim Veksler

- by matt_tm

- by Memor-X

- by Roberto

- by Jeff Atwood

- by JavaRocky

- by daffers

- by amccormack

- by Jeff Atwood

- by jon3laze

- by posfan12

- by Craig Hinrichs

- by user23950

- by binarybunny

- by JMHein

- by dehmann

< Previous Page | 113 114 115 116 117 118 119 120 121 122 123 124 | Next Page >