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POOpenGL 2.0 ES Android Draw Rectangle
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copied!<p>I'm following Google's tutorial (<a href="http://developer.android.com/training/graphics/opengl/environment.html" rel="nofollow">http://developer.android.com/training/graphics/opengl/environment.html</a>) and i think that i everything correctly done. But i have problem, Triangle and Rectangle is invisible and LogCat doesn't show any error. This is my code for rectangle:</p> <pre><code>package com.example.gameengine; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.FloatBuffer; import java.nio.ShortBuffer; import android.opengl.GLES20; /** * A two-dimensional square for use as a drawn object in OpenGL ES 2.0. */ public class GLObject { 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 final FloatBuffer vertexBuffer; private final 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 final short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; // order to draw vertices private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex float color[] = { 0.2f, 0.709803922f, 0.898039216f, 1.0f }; /** * Sets up the drawing object data for use in an OpenGL ES context. */ public GLObject() { // 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 = GLRenderer.loadShader( GLES20.GL_VERTEX_SHADER, vertexShaderCode); int fragmentShader = GLRenderer.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 } /** * Encapsulates the OpenGL ES instructions for drawing this shape. * * @param mvpMatrix - The Model View Project matrix in which to draw * this shape. */ 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"); GLRenderer.checkGlError("glGetUniformLocation"); // Apply the projection and view transformation GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0); GLRenderer.checkGlError("glUniformMatrix4fv"); // Draw the square GLES20.glDrawElements( GLES20.GL_TRIANGLES, drawOrder.length, GLES20.GL_UNSIGNED_SHORT, drawListBuffer); // Disable vertex array GLES20.glDisableVertexAttribArray(mPositionHandle); } } </code></pre> <p>And this is how i draw rectangle:</p> <pre><code>GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT); // Set the camera position (View matrix) Matrix.setLookAtM(mViewMatrix, 0, 0, 0, -3, 0f, 0f, 0f, 0f, 1.0f, 0.0f); // Calculate the projection and view transformation Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mViewMatrix, 0); // Draw square mSquare.draw(mMVPMatrix); </code></pre> <p>GLSurface is correctly implmenent(i can change background color)</p>

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