好吧，在睡了个好觉并应用了 RedOrav 关于正交投影的建议后，我做了更多的浏览并让它工作了！
RedOrav 给出的代码片段确实有效，但是在切换到正交投影后，我仍在绘制宽度为 0.15f 的正方形和三角形。几乎看不到，因为它小于 1 像素宽！
将背景/正方形/三角形代码更改为更合理的代码（30.0f）后，它们出现了！
更多地使用代码并让定位正常工作。对于那些想要查看项目工作副本的人，我已将代码提交给bitbucket 。
我需要 G.getYPos() 的原因是底部坐标 = 0，顶部是屏幕高度。在不倒置所有纹理的情况下，想不出更好的方法来反转它。
重要的初始化部分是：
全局助手
public class G {
public static float ratio;
public static int width, height;
/** The texture pointer */
public static int[] textures = new int[3];
final static int TEXTURE_DEFAULT = 0;
final static int TEXTURE_BG = 1;
final static int TEXTURE_ANDROID = 2;
final static int TEXTURE_TURTLE = 3;
/**
* Since (bottom = 0, top = height), we need to invert the values so they make sense logically.
*/
public static int getYPos(int top) {
return G.height - top;
}
}
渲染器类
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
this.loadGLTextures(gl);
gl.glClearColor(1.0f, 0.0f, 0.0f, 1.0f); //Red Background
}
@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
gl.glViewport(0, 0, width, height);
// Save these for global use.
G.width = width;
G.height = height;
G.ratio = (float) width / height;
// Set up orthogonal viewport and make adjustments for screen ratio
gl.glViewport(0, 0, width, height);
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
GLU.gluOrtho2D(gl, 0, width, 0, height); // The parameters are weird but bottom = 0 so we need an inverter function G.
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
// Start setting up the constructs we need
bg = new Background();
squares = new ArrayList<Square>();
squares.add(new Square(width / 2, G.getYPos(0))); // middle/top of the screen
squares.add(new Square(width / 2, G.height /2)); // center of the screen
triangles = new ArrayList<Triangle>();
triangles.add(new Triangle(0, G.getYPos(0))); // top left
triangles.add(new Triangle(width, G.getYPos(height))); // bottom right
triangles.add(new Triangle(width /2, height /2)); // middle
}
@Override
public void onDrawFrame(GL10 gl) {
// Clear the screen
gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
bg.draw(gl);
for (Square s : squares) {
s.draw(gl);
}
// Draw correctly scaled triangles
for (Triangle t : triangles) {
t.draw(gl);
}
try {
Thread.sleep(400);
}
catch (InterruptedException e) {
}
}
/**
* Loads the textures up.
*/
public void loadGLTextures(GL10 gl) {
int[] texture_map = new int[] { R.drawable.bg_game, R.drawable.ic_launcher };
Bitmap bitmap;
// generate one texture pointer, keep 0 as blank/default
gl.glGenTextures(texture_map.length, G.textures, 0);
for (int i = 0; i < texture_map.length; i++) {
// loading texture
bitmap = BitmapFactory.decodeResource(context.getResources(), texture_map[i]);
// ...and bind it to our array
gl.glBindTexture(GL10.GL_TEXTURE_2D, G.textures[i +1]);
// 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);
// 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();
}
}
背景类
p
ublic class Background {
private FloatBuffer vertexBuffer; // buffer holding the vertices
private float vertices[] = {
-1.0f, -1.0f, 0.0f, // V1 - bottom left
-1.0f, 1.0f, 0.0f, // V2 - top left
1.0f, -1.0f, 0.0f, // V3 - bottom right
1.0f, 1.0f, 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)
};
public Background() {
// Recalculate the vertices so they fit the screen
vertices[0] = 0; // v1 left
vertices[1] = G.height; // v1 bottom
vertices[3] = 0; // v2 left
vertices[4] = 0; // v2 top
vertices[6] = G.width; // v3 right
vertices[7] = G.height; // v3 bottom
vertices[9] = G.width; // v4 right
vertices[10] = 0; // v4 top
// 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);
}
public void draw(GL10 gl) {
gl.glEnable(GL10.GL_TEXTURE_2D); // Twig;
// Bind the previously generated texture
gl.glBindTexture(GL10.GL_TEXTURE_2D, G.textures[G.TEXTURE_BG]);
// Point to our buffers
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
// 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);
gl.glDisable(GL10.GL_TEXTURE_2D); // twig;
}
}
Square 类
与背景非常相似，除了它有一个位置并应用 alpha 透明度。
public class Square {
private FloatBuffer vertexBuffer; // buffer holding the vertices
private float vertices[] = {
-1.0f, -1.0f, 0.0f, // V1 - bottom left
-1.0f, 1.0f, 0.0f, // V2 - top left
1.0f, -1.0f, 0.0f, // V3 - bottom right
1.0f, 1.0f, 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)
};
public Square(float posX, float posY) {
float w = 30f;
float h = w;
vertices[0] = posX - w; // left
vertices[3] = posX - w;
vertices[6] = posX + w; // right
vertices[9] = posX + w;
vertices[1] = posY - h; // top
vertices[4] = posY + h;
vertices[7] = posY - h; // bottom
vertices[10] = posY + h;
// 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);
}
/** The draw method for the square with the GL context */
public void draw(GL10 gl) {
// Enable alpha transparency
gl.glEnable(GL10.GL_BLEND);
gl.glBlendFunc(GL10.GL_ONE, GL10.GL_ONE_MINUS_SRC_ALPHA);
// bind the previously generated texture
gl.glEnable(GL10.GL_TEXTURE_2D); // Twig;
gl.glBindTexture(GL10.GL_TEXTURE_2D, G.textures[G.TEXTURE_ANDROID]);
// Point to our buffers
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
// reset the colour for the square
gl.glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
// 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);
// Disable alpha transparency
gl.glDisable(GL10.GL_BLEND);
gl.glBlendFunc(GL10.GL_ONE, GL10.GL_ZERO);
gl.glDisable(GL10.GL_TEXTURE_2D); // twig;
}
}
三角班
public class Triangle {
private FloatBuffer vertexBuffer; // buffer holding the vertices
private float vertices[] = {
-0.5f, -0.5f, 0.0f, // V1 - first vertex (x,y,z)
0.5f, -0.5f, 0.0f, // V2 - second vertex
0.0f, 0.5f, 0.0f // V3 - third vertex
};
public Triangle(float posX, float posY) {
int w = 30;
int h = w;
vertices[0] = posX - (w/2); // left
vertices[3] = posX + (w/2); // right
vertices[6] = posX; // middle
vertices[1] = posY - (h/2); // bottom
vertices[4] = posY - (h/2); // bottom
vertices[7] = posY + (h/2); // top
// a float has 4 bytes so we allocate for each coordinate 4 bytes
ByteBuffer vertexByteBuffer = ByteBuffer.allocateDirect(vertices.length * 4);
vertexByteBuffer.order(ByteOrder.nativeOrder());
// allocates the memory from the byte buffer
vertexBuffer = vertexByteBuffer.asFloatBuffer();
// fill the vertexBuffer with the vertices
vertexBuffer.put(vertices);
// set the cursor position to the beginning of the buffer
vertexBuffer.position(0);
}
public void draw(GL10 gl) {
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
// set the colour for the triangle
gl.glColor4f(0.0f, 0.0f, 1.0f, 1.0f);
// Point to our vertex buffer
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
// Draw the vertices as triangle strip
gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, vertices.length / 3);
// Reset the colour
gl.glColor4f(1.0f, 1.0f, 1.0f, 0.0f);
//Disable the client state before leaving
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
}
}
希望这可以帮助其他在启动 OpenGL 时遇到类似问题的人。
