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