Android GLES20.glDrawArrays(GLES20.GL\u LINE\u LOOP…)
这可能是一个非常新手的问题,但我找不到答案 使用谷歌的简单教程(http://developer.android.com/resources/tutorials/opengl/opengl-es20.html) 我试图画一个正方形(嗯,用常识?),但得到了有趣的结果。如果有人能告诉我出了什么问题,我将不胜感激Android GLES20.glDrawArrays(GLES20.GL\u LINE\u LOOP…),android,opengl-es,Android,Opengl Es,这可能是一个非常新手的问题,但我找不到答案 使用谷歌的简单教程(http://developer.android.com/resources/tutorials/opengl/opengl-es20.html) 我试图画一个正方形(嗯,用常识?),但得到了有趣的结果。如果有人能告诉我出了什么问题,我将不胜感激 private void initShapes(){ float triangleCoords[] = { // X, Y, Z -0
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);
}
其他一切都和教程一样
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");
}
谢谢大家! 正如我在上面的评论中所说: 似乎您可能希望将glvertexattributepointer调用的size参数从4更改为3,因为您没有使用4d向量(XYZW)
干杯首先,你的坐标不是正方形;它们形成了类似于《星际迷航》的符号。你还看到了什么有趣的结果?哎呀,忘了这一点,那只是在三角形上添加了第四个坐标。我得到的结果是这样的。我没有编译和测试它,但似乎您可能希望将GLVERTEXATTRIBPOINT调用的大小参数从4更改为3,因为您没有使用4d向量(XYZW)。谢谢您。这解决了问题。看起来我把尺码弄错了。