I am on my way to take my kids to the beach. I will look at it a bit closer next week. May be just give me the simple problem defintion and I will try to create the program for you and send the zip file.
But....I will try a quick answer Say you want a 20x20 graph. Specify your point vertices as (0,0) (1,1,)(5,5) all x,y and specify the z as 0 if needed. Then you need to set your camera using Matrix.setLookAtM(mVMatrix, 0, 0, 0, -15, 0f, 0f, 0f, 0f, 1.0f, 0.0f); This is saying set your camera on the 'z' axis at -15 and look at the origin (0,0,0) and make it look up (0,1,0) See the docs for full detail. This populate your client memory mVMatrix. then do //take your width and height of the window and do float ratio = (float) w / h; Matrix.frustumM(mProjMatrix, 0, -ratio * 30, ratio * 30, -30 //top, 30//bottom, 3, 7); Read up on frustum to give it enough height and width and some depth to fit your coords. You get the projection matrix. Now do Matrix.Multiply to do final MVP = projection * mVMarix; then send your position attributes to the shader and in the shader gl_position = final MVP * your_position_attribute; //like all matrix multiplications order is important On Sun, Sep 2, 2012 at 10:39 AM, Satya Komatineni < satya.komatin...@gmail.com> wrote: > Sorry this line > > Finally to get your gl_position = mvp * gl_position; and not the other way. > > > should read > > Finally to get your gl_position = mvp * positionAttributeVariable; and not > the other way. > > > On Sat, Sep 1, 2012 at 11:10 PM, Satya Komatineni < > satya.komatin...@gmail.com> wrote: > >> Guich, >> Given a number of ways how to do the same thing in OpenGL it will be >> quite hard to debug. >> >> On Sat, Sep 1, 2012 at 9:11 AM, guich <guiha...@gmail.com> wrote: >> >>> Hi, >>> >>> I've spent a full day trying to draw a series of points using GL_POINTS. >>> I know i could use a texture, but i want to learn how to draw points. The >>> resulting image (zoomed) is shown here: >>> >>> The code is written below. Any help on why are only 4 points appearing >>> is greatly appreciated. Although it is possible to create your model, view, >>> and projection matrices, it is better to use Matrix class and use the >>> methods available on that class to generate the required matrices. >>> >> >> To get the view matrix you can call >> Matrix.setLookAtM(viewMatrix....) >> >> To get the projection matrix >> Matrix.frustumM(projectionMatrix....) >> >> Then you can get your ModelViewProjection matrix by doing >> Matrix.multiplyMM(mvp, projmatrix, viewmatrix) >> >> Finally to get your gl_position = mvp * gl_position; and not the other >> way. >> >> I would start with a simple program that works and then gradually >> increase the complexity. A triangle or a square is a good place to start >> and then make it work using the examples in the tutorial on the android >> developer site. >> >> If there is a specific issue that you are not clear ask that specifically >> and you may be able to debug it that way >> >> http://satyakomatineni.com/android/training >> http://satyakomatineni.com >> http://androidbook.com >> http://twitter.com/SatyaKomatineni >> >> >>> >>> <https://lh5.googleusercontent.com/-lelPSZoY4dw/UEIH5mVQfII/AAAAAAAAAD4/o5q5GMFuL00/s1600/points.png> >>> >>> public class MainActivity extends Activity >>> { >>> class MyGLSurfaceView extends GLSurfaceView >>> { >>> public MyGLSurfaceView(Context context) >>> { >>> super(context); >>> >>> setEGLContextClientVersion(2); // Create an OpenGL ES 2.0 >>> context. >>> setEGLConfigChooser(8, 8, 8, 8, 0, 0); >>> getHolder().setFormat(PixelFormat.RGBA_8888); >>> setRenderer(new MyGLRenderer()); // Set the Renderer for >>> drawing on the GLSurfaceView >>> // setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY); // Render >>> the view only when there is a change in the drawing data (must be after >>> setRenderer!) >>> } >>> } >>> >>> public void onCreate(Bundle savedInstanceState) >>> { >>> super.onCreate(savedInstanceState); >>> setContentView(new MyGLSurfaceView(this)); >>> } >>> } >>> >>> class MyGLRenderer implements GLSurfaceView.Renderer >>> { >>> byte[][] bitmap = { >>> {1,1,1,1,1,1,1,1}, >>> {1,0,0,1,1,0,0,1}, >>> {1,0,0,1,1,0,0,1}, >>> {1,0,0,1,1,0,0,1}, >>> {1,0,0,1,1,0,0,1}, >>> {1,0,0,1,1,0,0,1}, >>> {1,0,0,1,1,0,0,1}, >>> {1,0,0,1,1,0,0,1}, >>> {1,1,1,1,1,1,1,1}}; >>> >>> static final int COORDS_PER_VERTEX = 3; >>> >>> // Set color with red, green, blue and alpha (opacity) values >>> float color[] = { 0,0,0, 1.0f }; >>> float coords[] = new float[4 * COORDS_PER_VERTEX]; >>> int w,h; >>> >>> public void onSurfaceCreated(GL10 unused, EGLConfig config) >>> { >>> } >>> >>> public void onDrawFrame(GL10 unused) >>> { >>> try >>> { >>> drawText(); >>> } catch (Exception e) {debug(e.getMessage());} >>> } >>> >>> private String vertexShaderCode(int w, int h) >>> { >>> return // http://www.songho.ca/opengl/gl_projectionmatrix.html >>> "attribute vec4 vPosition;" + >>> "mat4 projectionMatrix = mat4( 2.0/"+w+".0, 0.0, 0.0, -1.0,"+ >>> "0.0, -2.0/"+h+".0, 0.0, 1.0,"+ >>> "0.0, 0.0, -1.0, 0.0,"+ >>> "0.0, 0.0, 0.0, 1.0);"+ >>> "void main() {gl_Position = vPosition*projectionMatrix;}"; // >>> the matrix must be included as a modifier of gl_Position >>> } >>> >>> private final String fragmentShaderCode = >>> "precision mediump float;" + >>> "uniform vec4 vColor;" + >>> "void main() {gl_FragColor = vColor;}"; >>> >>> private int mProgram; >>> private int mPositionHandle; >>> private int mColorHandle; >>> >>> public void onSurfaceChanged(GL10 unused, int width, int height) >>> { >>> w = width; h = height; >>> // Adjust the viewport based on geometry changes, such as screen >>> rotation >>> GLES20.glViewport(0, 0, width, height); >>> >>> // prepare shaders and OpenGL program >>> int vertexShader = >>> MyGLRenderer.loadShader(GLES20.GL_VERTEX_SHADER,vertexShaderCode(width,height)); >>> 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 >>> GLES20.glUseProgram(mProgram); // Add program to OpenGL environment >>> >>> // get handle to fragment shader's vColor member >>> mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor"); >>> mPositionHandle = GLES20.glGetAttribLocation(mProgram, >>> "vPosition"); // get handle to vertex shader's vPosition member >>> GLES20.glEnableVertexAttribArray(mPositionHandle); // Enable a >>> handle to the vertices - since this is the only one used, keep it enabled >>> all the time >>> } >>> >>> float[] letter; int nletter; >>> private FloatBuffer letBuffer; >>> private void drawText() >>> { >>> setColor(0xFF00FFFF); >>> if (letter == null) >>> { >>> letter = new float[200]; >>> for (int i = 0; i < bitmap.length; i++) >>> { >>> byte[]b = bitmap[i]; >>> for (int j = 0; j < b.length; j++) >>> if (b[j] == 1) >>> { >>> letter[nletter++] = j; >>> letter[nletter++] = i; >>> nletter++; >>> } >>> } >>> ByteBuffer bb = ByteBuffer.allocateDirect(nletter * 4); // (# >>> of coordinate values * 4 bytes per float) >>> bb.order(ByteOrder.nativeOrder()); >>> letBuffer = bb.asFloatBuffer(); >>> letBuffer.put(letter,0,nletter); letBuffer.position(0); >>> } >>> >>> int nn = nletter/3; >>> GLES20.glVertexAttribPointer(mPositionHandle, >>> COORDS_PER_VERTEX, GLES20.GL_FLOAT, >>> false, COORDS_PER_VERTEX * nn, letBuffer); >>> GLES20.glDrawArrays(GLES20.GL_POINTS, 0,nn); >>> } >>> >>> public static int loadShader(int type, String shaderCode) >>> { >>> int shader = GLES20.glCreateShader(type); >>> GLES20.glShaderSource(shader, shaderCode); >>> GLES20.glCompileShader(shader); >>> return shader; >>> } >>> >>> public void setColor(int rgb) >>> { >>> color[0] = (float)((rgb >> 16 ) & 0xFF) / 255f; >>> color[1] = (float)((rgb >> 8 ) & 0xFF) / 255f; >>> color[2] = (float)((rgb ) & 0xFF) / 255f; >>> color[3] = (float)((rgb >>> 24) & 0xFF) / 255f; >>> GLES20.glUniform4fv(mColorHandle, 1, color, 0); // Set color for >>> drawing the line >>> } >>> } >>> >>> thanks, >>> >>> guich >>> >>> >>> >>> <https://lh5.googleusercontent.com/-lelPSZoY4dw/UEIH5mVQfII/AAAAAAAAAD4/o5q5GMFuL00/s1600/points.png> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Android Developers" group. >>> To post to this group, send email to android-developers@googlegroups.com >>> To unsubscribe from this group, send email to >>> android-developers+unsubscr...@googlegroups.com >>> For more options, visit this group at >>> http://groups.google.com/group/android-developers?hl=en >> >> >> >> >> >> > > > -- > http://satyakomatineni.com/android/training > http://satyakomatineni.com > http://androidbook.com > http://twitter.com/SatyaKomatineni > > -- http://satyakomatineni.com/android/training http://satyakomatineni.com http://androidbook.com http://twitter.com/SatyaKomatineni -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
