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 -- You received this message because you are subscribed to the Google Groups "Android Developers" group. 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