我正在尝试制作一个投影矩阵来缩放屏幕并制作一个协调系统。出于某种原因，我认为我的任何矩阵调用都不起作用......我正在使用的 3 个函数是
Matrix.orthoM(mProjMatrix, 0, 0, 1520, 0, 1000, -1, 10);
Matrix.setLookAtM(mVMatrix, 0, 0, 0, 1.0f, 0.0f, 0f, 0f, 0f, 1.0f, 0.0f);
Matrix.multiplyMM(mMVPMatrix, 0, mProjMatrix, 0, mVMatrix, 0);
他们是在互相抵消吗？有什么问题吗？（完整的渲染类代码在最后）
我这样做的主要目标是最终达到这样一种情况，即当我制作一个正方形时，我可以提供(200, 100,0) //x, y, z不仅在 -1 和 1 之间的坐标。
这是我的完整渲染类：
public class MyRenderer implements Renderer {
private static final String TAG = "MyRenderer";
Square square;
private final float[] mMVPMatrix = new float[16];
private final float[] mProjMatrix = new float[16];
private final float[] mVMatrix = new float[16];
private final float[] mRotationMatrix = new float[16];
private int camWidth,camHeight;
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
GLES20.glClearColor(0.0f, 0.0f, 1.0f, 0.5f);
camWidth=480;camHeight=320;
// initialize a square
square = new Square();
}
@Override
public void onDrawFrame(GL10 nope) {
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
//set camera position
GLES20.glViewport(0, 0, camWidth, camHeight);
Matrix.orthoM(mProjMatrix, 0, 0, 1520, 0, 1000, -10, 999999);
Matrix.setLookAtM(mVMatrix, 0, 0, 0, 1.0f, 0.0f, 0f, 0f, 0f, 1.0f, 0.0f);
Matrix.multiplyMM(mMVPMatrix, 0, mProjMatrix, 0, mVMatrix, 0);
square.draw(mMVPMatrix);
}
@Override
public void onSurfaceChanged(GL10 nope, int width, int height) {
GLES20.glViewport(0, 0, camWidth, camHeight);
Matrix.orthoM(mProjMatrix, 0, 0, 1520, 0, 1000, -10, 999999);
Matrix.setLookAtM(mVMatrix, 0, 0, 0, 1.0f, 0.0f, 0f, 0f, 0f, 1.0f, 0.0f);
}
public static 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;
}
}
我的 Square 课（不确定是否需要，但只是为了安全:)）-
public class Square {
private final String vertexShaderCode =
"attribute vec4 vPosition;" +
"void main() {" +
" gl_Position = vPosition;" +
"}";
private final String fragmentShaderCode = "precision mediump float;"
+ "uniform vec4 vColor;" + "void main() {"
+ " gl_FragColor = vColor;" + "}";
static final int COORDS_PER_VERTEX = 3;
static float triangleCoords[] = { // in counterclockwise order:
-0.5f, 0.5f, 0.0f, // top left
-0.5f, -0.5f, 0.0f, // bottom left
0.5f, -0.5f, 0.0f, // bottom right
0.5f, 0.5f, 0.0f
};
private short drawOrder[] = { 0, 1, 2, 0, 2, 3 };
private final int vertexCount = triangleCoords.length / COORDS_PER_VERTEX;
private final int vertexStride = COORDS_PER_VERTEX * 4; // bytes per vertex
// red-green-blue-alpha
float color[] = { 0.63f, 0.76f, 0.22f, 1.0f };
private final int mProgram;
private int mPositionHandle;
private int mColorHandle;
private int mMVPMatrixHandle;
private FloatBuffer vertexBuffer;
private ShortBuffer drawListBuffer;
public Square() {
ByteBuffer bb = ByteBuffer.allocateDirect(
// # of coords values * 4 bytes per float
triangleCoords.length * 4);
// use native byte order
bb.order(ByteOrder.nativeOrder());
// create a floating point buffer from the ByteBuffer
vertexBuffer = bb.asFloatBuffer();
// add coordination to FloatBuffer
vertexBuffer.put(triangleCoords);
// set the buffer to read first coordinate
vertexBuffer.position(0);
ByteBuffer dlb = ByteBuffer.allocateDirect(drawOrder.length * 2);
dlb.order(ByteOrder.nativeOrder());
drawListBuffer = dlb.asShortBuffer();
drawListBuffer.put(drawOrder);
drawListBuffer.position(0);
int vertexShader = ChizRenderer.loadShader(GLES20.GL_VERTEX_SHADER,
vertexShaderCode);
int fragmentShader = ChizRenderer.loadShader(GLES20.GL_FRAGMENT_SHADER,
fragmentShaderCode);
mProgram = GLES20.glCreateProgram();
GLES20.glAttachShader(mProgram, vertexShader);
GLES20.glAttachShader(mProgram, fragmentShader);
GLES20.glLinkProgram(mProgram);
}
public void draw(float[] mvpMatrix) {
// Add program to OpenGL ES environment
GLES20.glUseProgram(mProgram);
// get handle to vertex shader's vPosition member
mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
// Enable a handle to the triangle vertices
GLES20.glEnableVertexAttribArray(mPositionHandle);
// Prepare the triangle coordinate data
GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
GLES20.GL_FLOAT, false, vertexStride, vertexBuffer);
// get handle to fragment shader's vColor member
mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
// set color for drawing the triangle
GLES20.glUniform4fv(mColorHandle, 1, color, 0);
// get handle to shape's transformation matrix
mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
// apply the projection and view transformation
GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0);
// Draw the triangle
GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length,
GLES20.GL_UNSIGNED_SHORT, drawListBuffer);
// dispable vertex array
GLES20.glDisableVertexAttribArray(mPositionHandle);
}
}
最后，你可以有一些视觉效果：
这就是我的手机在有和没有前面提到的三个 metrix 功能的情况下的样子，似乎唯一对宽度和高度做出任何改变的东西是GLES20.glViewport(0, 0, camWidth, camHeight);
似乎metrix什么也没做。