从0,0坐标绘制纹理的OpenGL的Android
我是新来opengGL和借口,如果问题是太天真了。我会通过一些tuturials对学习这门寻求帮助。我已经写在那里我借鉴了GLSurfaceView纹理的小程序。
I'm new to opengGL and excuse if the questions are too naive. I'm going through some tuturials for seeking help on learning this. I have a small program written where i'm drawing a texture on a GLSurfaceView.
我想提请按顺序一些纹理(位图图像)0,0坐标开始。此外,我需要的图像在屏幕上的一些差距。请帮忙。我需要改变的顶点缓冲区的定位。请建议。
I want to draw a number of textures(bitmap images) in a sequential order starting from 0,0 coordinates. Also I need some gap in images on the screen. Please help. Do I need to change the positioning of vertices buffer. please suggest.
下面是我的渲染code。
Here is my renderer Code.
public class GlRenderer implements Renderer{
private Square square; // square1
private Context context;
/** Constructor to set the handed over context */
public GlRenderer(Context context) {
this.context = context;
// initialise the square
this.square = new Square();
}
public void onDrawFrame(GL10 gl) {
// clear Screen and Depth Buffer
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
// Reset the Modelview Matrix
gl.glLoadIdentity();
// Drawing
gl.glTranslatef(0.0f, 0.0f, -5.0f); // move 5 units INTO the screen
square.draw(gl); // Draw the triangle
//gl.glTranslatef(0.0f, 0.0f, 0.0f); // move 5 units INTO the screen
//square2.draw(gl); // Draw the triangle
}
public void onSurfaceChanged(GL10 gl, int width, int height) {
if(height == 0) { //Prevent A Divide By Zero By
height = 1; //Making Height Equal One
}
gl.glViewport(0, 0, width, height); //Reset The Current Viewport
gl.glMatrixMode(GL10.GL_TEXTURE); //Select The Projection Matrix
gl.glLoadIdentity(); //Reset The Projection Matrix
//Calculate The Aspect Ratio Of The Window
GLU.gluPerspective(gl, 45.0f, (float)width / (float)height, 0.1f, 100.0f);
gl.glMatrixMode(GL10.GL_MODELVIEW); //Select The Modelview Matrix
gl.glLoadIdentity(); //Reset The Modelview Matrix
}
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
// Load the texture for the square
square.loadGLTexture(gl, this.context);
gl.glEnable(GL10.GL_TEXTURE_2D); //Enable Texture Mapping ( NEW )
gl.glShadeModel(GL10.GL_SMOOTH); //Enable Smooth Shading
gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f); //Black Background
gl.glClearDepthf(1.0f); //Depth Buffer Setup
gl.glEnable(GL10.GL_DEPTH_TEST); //Enables Depth Testing
gl.glDepthFunc(GL10.GL_LEQUAL); //The Type Of Depth Testing To Do
//Really Nice Perspective Calculations
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);
}
}
下面是正方形code
Here is the square code
public class Square {
private FloatBuffer vertexBuffer; // buffer holding the vertices
private float vertices[] = {
-1.0f, -.25f, 0.0f, // V1 - bottom left
-1.0f, .25f, 0.0f, // V2 - top left
1.0f, -.25f, 0.0f, // V3 - bottom right
1.0f, .25f, 0.0f // V4 - top right
};
private FloatBuffer textureBuffer; // buffer holding the texture coordinates
private float texture[] = {
// Mapping coordinates for the vertices
0.0f, 1.0f, // top left (V2)
0.0f, 0.0f, // bottom left (V1)
1.0f, 1.0f, // top right (V4)
1.0f, 0.0f // bottom right (V3)
};
/** The texture pointer */
private int[] textures = new int[1];
public Square() {
// a float has 4 bytes so we allocate for each coordinate 4 bytes
ByteBuffer byteBuffer = ByteBuffer.allocateDirect(vertices.length * 4);
byteBuffer.order(ByteOrder.nativeOrder());
// allocates the memory from the byte buffer
vertexBuffer = byteBuffer.asFloatBuffer();
// fill the vertexBuffer with the vertices
vertexBuffer.put(vertices);
// set the cursor position to the beginning of the buffer
vertexBuffer.position(0);
byteBuffer = ByteBuffer.allocateDirect(texture.length * 4);
byteBuffer.order(ByteOrder.nativeOrder());
textureBuffer = byteBuffer.asFloatBuffer();
textureBuffer.put(texture);
textureBuffer.position(0);
}
/**
* Load the texture for the square
* @param gl
* @param context
*/
public void loadGLTexture(GL10 gl, Context context) {
// loading texture
Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(),
R.drawable.progressbar_bg);
// generate one texture pointer
gl.glGenTextures(1, textures, 0);
// ...and bind it to our array
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
// create nearest filtered texture
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);
//Different possible texture parameters, e.g. GL10.GL_CLAMP_TO_EDGE
// gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT);
// gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT);
// Use Android GLUtils to specify a two-dimensional texture image from our bitmap
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
// Clean up
bitmap.recycle();
}
/** The draw method for the square with the GL context */
public void draw(GL10 gl) {
// bind the previously generated texture
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
// Point to our buffers
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
// Set the face rotation
gl.glFrontFace(GL10.GL_CW);
// Point to our vertex buffer
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);
// Draw the vertices as triangle strip
gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, vertices.length / 3);
//Disable the client state before leaving
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
}
}
我无法看到视图质感的实际大小。我跟gl.glTranslatef玩(0.0,0.0,-5.0f);操纵屏幕上的纹理的坐标。但还是没能得到实际的图像尺寸和坐标0,0开始纹理图像在所需位置loaction
I am not able to see the actual size of texture on the view. I was playing with gl.glTranslatef(0.0f, 0.0f, -5.0f); to manipulate the coordinates of texture on screen. But still not able to get the actual image size and position the texture image at desired loaction starting from 0,0 coordinates.
我用glTranslate解决问题()正常。现在我明白了翻译花费其当前位置表面的最后转换值。我曾与固定的X和Z坐标和y质感每次抽签后改变现在作出有关变更。我做了以下内容:
I solved the issue by using glTranslate() properly. Now I understand that translate takes the last translated value of the surface for its current position. I have made the changes for that now with fixed x and z coordinates and y changing after each draw of texture. I did the following:
float x = -1.0f;
float y = 1.5f;
float z = -5.0f;
// Drawing
gl.glTranslatef(x, y, z);
square1.draw(gl); // Draw the square
gl.glTranslatef(0.0f, -0.50f, 0.0f);
square2.draw(gl); // Draw the square
gl.glTranslatef(0.0f, -0.50f, 0.0f);
square2.draw(gl); // Draw the square
gl.glTranslatef(0.0f, -0.50f, 0.0f);
square2.draw(gl); // Draw the square