OpenGL ES的，添加纹理圈子 [英] OpenGL ES, add texture to circle
本文介绍了OpenGL ES的，添加纹理圈子的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我画中的OpenGL ES一个圆圈，并添加纹理它是补充，而不是4倍，1（见下图）时。
在换句话说，是我的照片X4。我要的是作为中心在圈内一张图片核弹符号。
下面是我使用一个纹理绘制圆法（在Circle类）
公共无效drawTexture（GL10 GL）{
gl.glFrontFace（GL10.GL_CCW）; //前脸逆时针的方向
gl.glEnable（GL10.GL_CULL_FACE）; //启用剔除脸
gl.glCullFace（GL10.GL_BACK）; //卡尔背面（不显示） //启用顶点数组，并定义其缓冲区
gl.glEnableClientState（GL10.GL_VERTEX_ARRAY）;
gl.glEnableClientState（GL10.GL_TEXTURE_COORD_ARRAY）; //启用纹理坐标 - 阵列
gl.glVertexPointer（2，GL10.GL_FLOAT，0，vertexBuffer）;
gl.glTexCoordPointer（2，GL10.GL_FLOAT，0，texBuffer）; //定义纹理COORDS
//直接从顶点数组绘制原语 gl.glPushMatrix（）;
gl.glTranslatef（0.0，0.0，1.0F）;
gl.glDrawArrays（GL10.GL_TRIANGLE_FAN，0，numberOfVertices）;
gl.glPopMatrix（）; gl.glDisableClientState（GL10.GL_TEXTURE_COORD_ARRAY）;
gl.glDisableClientState（GL10.GL_VERTEX_ARRAY）;
gl.glDisable（GL10.GL_CULL_FACE）;}
目前的时刻，texBuffer是一样的vertexBuffer（也许问题？），因为它必须具有点相同数量的，我不知道它指向如果没有顶点
下面是我加载纹理以及在哪里设置我的顶点纹理的方式方法。
公共无效loadTexture（GL10 GL，上下文的背景下）{
gl.glGenTextures（1，textureIDs，0）; //生成纹理ID数组
gl.glBindTexture（GL10.GL_TEXTURE_2D，textureIDs [0]）; //绑定到纹理ID
//设置纹理过滤器
gl.glTexParameterf（GL10.GL_TEXTURE_2D，GL10.GL_TEXTURE_MIN_FILTER，GL10.GL_NEAREST）;
gl.glTexParameterf（GL10.GL_TEXTURE_2D，GL10.GL_TEXTURE_MAG_FILTER，GL10.GL_LINEAR）; //构造一个输入流纹理图像
InputStream中的IStream = context.getResources（）openRawResource（R.drawable.nuke）。
位图位图;
尝试{
//读取和德code输入为位图
位= BitmapFactory.de codeStream（istream的）;
} {最后
尝试{
istream.close（）;
}赶上（IOException异常五）{
}
} //从加载的位图纹理构建为当前绑定的纹理ID
GLUtils.texImage2D（GL10.GL_TEXTURE_2D，0，位图，0）;
bitmap.recycle（）;
}私人无效setUpTextureVertices（浮点半径）{
浮THETA =（浮点）（2 * Math.PI /（numberOfVertices-1））;
浮C =（浮点）Math.cos（THETA）;
浮S =（浮点）Math.sin（THETA）;
浮动X =半径;
浮Y = 0; 的for（int i = 0; I＆LT; numberOfVertices;我++）{
texVertices [I] [0] = X;
texVertices [I] [1] = Y;
浮动T = X;
X =（C * X - S * Y + 1）* 0.5F;
Y =（S * T + C * Y + 1）* 0.5F;
}
}私人无效setUpVertices（浮点半径）{
浮THETA =（浮点）（2 * Math.PI /（numberOfVertices-1））;
浮C =（浮点）Math.cos（THETA）;
浮S =（浮点）Math.sin（THETA）;
浮动X =半径;
浮Y = 0; 的for（int i = 0; I＆LT; numberOfVertices;我++）{
顶点[I] [0] = X;
顶点[I] [1] = Y;
浮动T = X;
X = C * X - S * Y;
Y = S * T + C * Y;
}
}
编辑：添加的构造函数Circle类
公开的社交圈（）{ setUpVertices（1.0F）;
//设置顶点数组缓冲区。顶点浮动。一个浮点有4个字节
的ByteBuffer VBB = ByteBuffer.allocateDirect（vertices.length * 4 * 2）;
vbb.order（ByteOrder.nativeOrder（））; //使用本地字节顺序
vertexBuffer = vbb.asFloatBuffer（）; //转换字节的缓冲区浮动 //循环遍历顶点并把它们放在vertexbuffer
的for（int i = 0; I＆LT; numberOfVertices;我++）{
为（中间体J = 0; J＆下; = 1; J ++）{
vertexBuffer.put（顶点[I] [J]）; //将数据复制到缓冲区
}
}
vertexBuffer.position（0）; //倒带 setUpTextureVertices（1.0F）; //设置纹理坐标 - 数组缓冲区，在浮动。一个浮动有4个字节
ByteBuffer的TBB = ByteBuffer.allocateDirect（vertices.length * 4 * 2）;
tbb.order（ByteOrder.nativeOrder（））;
texBuffer = tbb.asFloatBuffer（）;
//循环遍历顶点并把它们放在vertexbuffer
的for（int i = 0; I＆LT; numberOfVertices;我++）{
为（中间体J = 0; J＆下; = 1; J ++）{
texBuffer.put（texVertices [I] [J]）; //将数据复制到缓冲区
}
}
texBuffer.position（0）;
}
解决方案
您的问题是，你的UV去从-1到1。确保他们从0到1。
有一个窦的最低值是-1，而最高变为1
公式将是
X =（三* X - S * Y +1）* 0.5F;
Y =（S * T + C * Y +1）* 0.5F;
I'm drawing a circle in OpenGL ES and when adding a texture it is "added" 4 times instead of 1 (see the image below).
In other words, that is my picture x4. What I want is the nuke symbol centered as one picture in the circle.
Below is my method (in the Circle class) for drawing the circle using a texture
public void drawTexture(GL10 gl) {
gl.glFrontFace(GL10.GL_CCW); // Front face in counter-clockwise orientation
gl.glEnable(GL10.GL_CULL_FACE); // Enable cull face
gl.glCullFace(GL10.GL_BACK); // Cull the back face (don't display)
// Enable vertex-array and define its buffer
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); // Enable texture-coords-array
gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vertexBuffer);
gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, texBuffer); // Define texture-coords
// Draw the primitives from the vertex-array directly
gl.glPushMatrix();
gl.glTranslatef(0.0f, 0.0f, 1.0f);
gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, numberOfVertices);
gl.glPopMatrix();
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisable(GL10.GL_CULL_FACE);
}
At the moment, the texBuffer is the same as the vertexBuffer (maybe the problem?) since it has to have the same amount of points and I don't know which points if not the vertices.
Below is my method for loading the texture as well as the method where I set up my vertices for the texture.
public void loadTexture(GL10 gl, Context context) {
gl.glGenTextures(1, textureIDs, 0); // Generate texture-ID array
gl.glBindTexture(GL10.GL_TEXTURE_2D, textureIDs[0]); // Bind to texture ID
// Set up texture filters
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);
// Construct an input stream to texture image
InputStream istream = context.getResources().openRawResource(R.drawable.nuke);
Bitmap bitmap;
try {
// Read and decode input as bitmap
bitmap = BitmapFactory.decodeStream(istream);
} finally {
try {
istream.close();
} catch (IOException e) {
}
}
// Build Texture from loaded bitmap for the currently-bind texture ID
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
bitmap.recycle();
}
private void setUpTextureVertices(float radius) {
float theta = (float) (2 * Math.PI / (numberOfVertices-1));
float c = (float) Math.cos(theta);
float s = (float) Math.sin(theta);
float x = radius;
float y = 0;
for (int i = 0; i < numberOfVertices; i++) {
texVertices[i][0] = x;
texVertices[i][1] = y;
float t = x;
x = (c * x - s * y + 1) * 0.5f;
y = (s * t + c * y + 1) * 0.5f;
}
}
private void setUpVertices(float radius) {
float theta = (float) (2 * Math.PI / (numberOfVertices-1));
float c = (float) Math.cos(theta);
float s = (float) Math.sin(theta);
float x = radius;
float y = 0;
for (int i = 0; i < numberOfVertices; i++) {
vertices[i][0] = x;
vertices[i][1] = y;
float t = x;
x = c * x - s * y;
y = s * t + c * y;
}
}
EDIT: Added the constructor for the Circle class
public Circle() {
setUpVertices(1.0f);
// Setup vertex-array buffer. Vertices in float. A float has 4 bytes
ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4 * 2);
vbb.order(ByteOrder.nativeOrder()); // Use native byte order
vertexBuffer = vbb.asFloatBuffer(); // Convert byte buffer to float
// Loop through the vertices and put them in the vertexbuffer
for (int i = 0; i < numberOfVertices; i++) {
for (int j = 0; j <= 1; j++) {
vertexBuffer.put(vertices[i][j]); // Copy data into buffer
}
}
vertexBuffer.position(0); // Rewind
setUpTextureVertices(1.0f);
// Setup texture-coords-array buffer, in float. An float has 4 bytes
ByteBuffer tbb = ByteBuffer.allocateDirect(vertices.length * 4 * 2);
tbb.order(ByteOrder.nativeOrder());
texBuffer = tbb.asFloatBuffer();
// Loop through the vertices and put them in the vertexbuffer
for (int i = 0; i < numberOfVertices; i++) {
for (int j = 0; j <= 1; j++) {
texBuffer.put(texVertices[i][j]); // Copy data into buffer
}
}
texBuffer.position(0);
}
解决方案
Your problem is that your uv goes from -1 to 1 . Make sure they go from 0 to 1 .
The lowest value for a sinus is -1 , while the highest goes to 1.
formula would be
x = (c * x - s * y +1) *0.5f;
y = ( s * t + c * y +1)*0.5f;
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