i have the same code as on tutorial but for some reason the triangle is not showing up.
may be i missed some thing or i am doing some thing wrong?
i have two class.
GlRender.java
GLTriangle.java
i think the problem is in GLTriangle draw method.
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- public class GlRender implements Renderer {
- private GLTriangle glTriangleObj;
- private final float[] mModelMatrix = new float[16];
- private final float[] mProjectionMatrix = new float[16];
- private final float[] mViewMatrix = new float[16];
- private final float[] mRotationMatrix = new float[16];
- /************************/
- /*** create() method ***/
- /************************/
- @Override
- public void onSurfaceCreated(GL10 gl, EGLConfig config) {
- // Set the background color
- // 0 to 1
- // 1 = no transparent
- GLES20.glClearColor(0.8f, 0.2f, 0.2f, 1f);
- gl.glClearDepthf(1f);
- glTriangleObj = new GLTriangle();
- // glSquare = new Square(); //etc...
- // postion the eye behind the origin
- final float eyeX = 0.0f;
- final float eyeY = 0.0f;
- final float eyeZ = 1.5f;
- // we are looking toward the distance
- final float lookX = 0.0f;
- final float lookY = 0.0f;
- final float lookZ = -5.0f;
- // Set our up vector. This is where our head would be pointing were we
- // holding the camera.
- final float upX = 0.0f;
- final float upY = 1.0f;
- final float upZ = 0.0f;
- // Set the view matrix. This matrix can be said to represent the camera
- // position.
- // NOTE: In OpenGL 1, a ModelView matrix is used, which is a combination
- // of a model and
- // view matrix. In OpenGL 2, we can keep track of these matrices
- // separately if we choose.
- Matrix.setLookAtM(mViewMatrix, 0, eyeX, eyeY, eyeZ, lookX, lookY,
- lookZ, upX, upY, upZ);
- }
- /********************/
- /*** paint method ***/
- /********************/
- @Override
- public void onDrawFrame(GL10 gl) {
- // Redraw background color
- GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
- // do a complete rotation every 10 seconds
- // long time = SystemClock.uptimeMillis() % 10000L;
- // float angleInDegree = (360.0f / 10000.0f) * ((int) time);
- // draw the triangle face straight on
- // Matrix.setIdentityM(mModelMatrix, 0);
- // Matrix.rotateM(mModelMatrix, 0, angleInDegree, 0.0f, 0.0f, 1.0f);
- // Set the camera position (View matrix)
- Matrix.setLookAtM(mViewMatrix, 0, 0, -2, 0, 0f, 0f, 0f, 0f, 2.0f, 0.0f);
- // Calculate the projection and view transformation
- Matrix.multiplyMM(mModelMatrix, 0, mProjectionMatrix, 0, mViewMatrix, 0);
- glTriangleObj.draw(mModelMatrix);
- }
- /*****************************/
- /*** landscape to portrait ***/
- /*****************************/
- @Override
- public void onSurfaceChanged(GL10 gl, int width, int height) {
- if (height == 0)
- height = 1;
- // Set the OpenGL viewport to the same size as the surface.
- GLES20.glViewport(0, 0, width, height);
- // while the width will vary as per aspect ratio.
- 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 = 25.0f;
- Matrix.frustumM(mProjectionMatrix, 0, left, right, bottom, top, near,
- far);
- }
- }
GLTriangle.java
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- public class GLTriangle {
- // always same
- private final String vertexShaderCode = "attribute vec4 vPosition;"
- + "void main() {" + " gl_Position = vPosition;" + "}";
- private final String fragmentShaderCode = "precision mediump float;"
- + "uniform vec4 vColor;" + "void main() {"
- + " gl_FragColor = vColor;" + "}";
- // always start at zero when ploting a point as defult
- // trinagle Coordinates - vertex = 3(x y z)
- private float trinagleCoords[] = { 0f, 1f, // V 0 - top
- 1f, -1, // V 1 - right bottom
- -1f, 1f // V 2 - left bottom
- };
- private int COORDS_PER_VERTEX = 2; // number of points
- private FloatBuffer vertexBuffer;
- private short[] drawOrder = { 0, 1, 2 }; // order
- private ShortBuffer orderBuffer;
- float color[] = { 0.5f, 1f, 0f, 1f };
- private int vertexCount = trinagleCoords.length / COORDS_PER_VERTEX;
- private int vertexStride = COORDS_PER_VERTEX * 4; // bytes per vertex
- // used to pass in the transformation matrix
- private final int mProgram;
- // used to pass in model poition information
- private int mPositionHandle;
- // used to pass inmodel color information
- private int mColorHandle;
- private int mMVPMatrixHandle;
- public GLTriangle() {
- // vertices - has to be 4
- ByteBuffer byteBuffer = ByteBuffer
- .allocateDirect(trinagleCoords.length * 4);
- byteBuffer.order(ByteOrder.nativeOrder());
- vertexBuffer = byteBuffer.asFloatBuffer();
- vertexBuffer.put(trinagleCoords);
- vertexBuffer.position(0);
- // draw order - has to be 2
- ByteBuffer pointByteBuffer = ByteBuffer
- .allocateDirect(drawOrder.length * 2);
- pointByteBuffer.order(ByteOrder.nativeOrder());
- orderBuffer = pointByteBuffer.asShortBuffer();
- orderBuffer.put(drawOrder);
- orderBuffer.position(0);
- // shader - always same
- int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
- int fragmentShader = loadShader(GLES20.GL_FRAGMENT_SHADER,
- fragmentShaderCode);
- // create empty OpenGL ES Program
- mProgram = GLES20.glCreateProgram();
- // add the vertex shader to program
- GLES20.glAttachShader(mProgram, vertexShader);
- // add the fragment shader to program
- GLES20.glAttachShader(mProgram, fragmentShader);
- // creates OpenGL ES program executables
- GLES20.glLinkProgram(mProgram);
- }
- /************/
- /*** same ***/
- /************/
- public static int loadShader(int type, String shaderCode) {
- // create a vertex shader type (GLES20.GL_VERTEX_SHADER)
- // or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)
- int shader = GLES20.glCreateShader(type);
- // add the source code to the shader and compile it
- GLES20.glShaderSource(shader, shaderCode);
- GLES20.glCompileShader(shader);
- return shader;
- }
- public void draw(float[] mModelMatrix) {
- // 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);
- // Draw the triangle
- GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);
- // Disable vertex array
- GLES20.glDisableVertexAttribArray(mPositionHandle);
- // get handle to shape's transformation matrix
- mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
- // Apply the projection and view transformation
- GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mModelMatrix, 0);
- // Draw the triangle
- GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);
- }
- }