3
這可能是一個非常新手的問題,但我找不到答案。Android GLES20.glDrawArrays(GLES20.GL_LINE_LOOP ...)
使用從谷歌簡單的教程(http://developer.android.com/resources/tutorials/opengl/opengl-es20.html)
我是想畫一個正方形(ERRM,使用常識?),但獲得有趣的結果。如果有人能告訴我什麼是錯的,我將很感激。
private void initShapes(){
float triangleCoords[] = {
// X, Y, Z
-0.5f, -0.25f, 0,
0.5f, -0.25f, 0,
0.0f, 0.559016994f, 0,
0.0f, 0f, 0
};
// initialize vertex Buffer for triangle
ByteBuffer vbb = ByteBuffer.allocateDirect(
// (# of coordinate values * 4 bytes per float)
triangleCoords.length * 4);
vbb.order(ByteOrder.nativeOrder());// use the device hardware's native byte order
triangleVB = vbb.asFloatBuffer(); // create a floating point buffer from the ByteBuffer
triangleVB.put(triangleCoords); // add the coordinates to the FloatBuffer
triangleVB.position(0); // set the buffer to read the first coordinate
}
public void onDrawFrame(GL10 unused) {
// Redraw background color
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
// Add program to OpenGL environment
GLES20.glUseProgram(mProgram);
GLES20.glVertexAttribPointer(maPositionHandle, 4, GLES20.GL_FLOAT, false, 12, triangleVB);
GLES20.glEnableVertexAttribArray(maPositionHandle);
GLES20.glDrawArrays(GLES20.GL_LINE_LOOP, 0, 4);
}
其他與教程相同的內容。
private final String vertexShaderCode =
"attribute vec4 vPosition; \n" +
"void main(){ \n" +
" gl_Position = vPosition; \n" +
"} \n";
private final String fragmentShaderCode =
"precision mediump float; \n" +
"void main(){ \n" +
" gl_FragColor = vec4 (0.63671875, 0.76953125, 0.22265625, 1.0); \n" +
"} \n";
private int mProgram;
private int maPositionHandle;
private 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 onSurfaceCreated(GL10 unused, EGLConfig config) {
initShapes();
// Set the background frame color
GLES20.glClearColor(0f, 0f, 0f, 1.0f);
int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
int fragmentShader = 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); // creates OpenGL program executables
// get handle to the vertex shader's vPosition member
maPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
}
謝謝!
對於初學者來說,您的座標不會形成正方形;它們形成類似於星際迷航的符號。你看到了什麼其他有趣的結果? – Marc 2012-04-16 17:24:11
糟糕,忘記了這一點,那只是將一個第四座標添加到三角形。我得到的結果是 – 2012-04-16 18:07:02
http://farm8.staticflickr.com/7213/7084661585_071374e9d0_b.jpg就像這樣。 – 2012-04-16 18:13:49