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POOpenGL ES 2.0 doesn't draw anything
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copied!<p>I have a problem with OpenGl ES 2.0. I've designed a very simple framework to help me load OBJ files and draw them on my Android phone, but I have 2 bugs that I haven't been able to fix:</p> <ol> <li><p>My app doesn't show anything until I change the orientation and the Activity gets scraped and reloaded. Until it reloads only GLES20.glClear() can be seen(I've set it to a grayish color).</p></li> <li><p>Sometimes when I load an OBJ and do the orientation trick, half of my faces are missing and I see gaps, but the problem might be with the OBJ files I've used.</p></li> </ol> <p><br></p> <pre><code>package com.ideas.opengl; import java.io.IOException; import javax.microedition.khronos.egl.EGLConfig; import javax.microedition.khronos.opengles.GL10; import android.opengl.GLES20; import android.opengl.GLSurfaceView.Renderer; import android.opengl.Matrix; public class DemoRenderer implements Renderer { public static int mProgramHandle; private int mMVPMatrixHandle; private float[] mModelMatrix = new float[16]; private float[] mViewMatrix = new float[16]; private float[] mProjectionMatrix = new float[16]; private float[] mMVPMatrix = new float[16]; public Object banana; private OpenGLDemoActivity activity; private int angle; public DemoRenderer(OpenGLDemoActivity activity) throws IOException { this.activity = activity; } @Override public void onSurfaceCreated(GL10 gl, EGLConfig config){ GLES20.glClearColor(0.65f, 0.65f, 0.65f, 0.65f); //GLES20.glEnable(GLES20.GL_CULL_FACE); GLES20.glEnable(GLES20.GL_DEPTH_TEST); GLES20.glEnable(GLES20.GL_TEXTURE_2D); Shader shader = null; try { shader = new Shader(activity, "simple"); } catch (IOException e) { e.printStackTrace(); } Vector position = new Vector(); Vector speed = new Vector(); Vector accel = new Vector(); Model model = null; try { model = new Model("banana", activity); } catch (IOException e) { e.printStackTrace(); } banana = new Object(position, speed, accel, model); mProgramHandle = shader.getProgramHandle(); final float eyeX = 0.0f; final float eyeY = 0.0f; final float eyeZ = 3.5f; final float lookX = 0.0f; final float lookY = 0.0f; final float lookZ = -5.0f; final float upX = 0.0f; final float upY = 1.0f; final float upZ = 0.0f; Matrix.setLookAtM(mViewMatrix, 0, eyeX, eyeY, eyeZ, lookX, lookY, lookZ, upX, upY, upZ); mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgramHandle, "u_MVPMatrix"); } @Override public void onSurfaceChanged(GL10 gl, int width, int height) { GLES20.glViewport(0, 0, width, height); final float ratio = (float) width / height; final float left = -ratio; final float right = ratio; final float bottom = -1.0f; final float top = 1.0f; final float near = 1.0f; final float far = 10.0f; Matrix.frustumM(mProjectionMatrix, 0, left, right, bottom, top, near, far); } @Override public void onDrawFrame(GL10 gl) { GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT); angle++; Matrix.setIdentityM(mModelMatrix, 0); Matrix.rotateM(mModelMatrix, 0, angle, 0.0f, 1.0f, 1.0f); Matrix.multiplyMM(mMVPMatrix, 0, mViewMatrix, 0, mModelMatrix, 0); Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mMVPMatrix, 0); GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mMVPMatrix, 0); banana.draw(); } } </code></pre> <p>`</p>

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