android - 在 Z 轴上旋转纹理时 Opengles 图像倾斜

Question

您好，我正在开发一个基于 OpenGLES 的安卓应用程序，我需要在 z 轴上实时旋转纹理。但是当我向模型矩阵添加旋转时，图像发生了倾斜。

下图第一张是原图，第二张是z轴旋转后的歪斜图

这是我的着色器:

private final String mVertexShader = "" +
        "attribute vec4 position;\n" +
        "attribute vec2 textureCoordinate;\n" +
        "varying vec2 textureCoordinateVarying;\n" +
        "uniform mat4 modelMat;\n" +
        "uniform mat4 viewMat;\n" +
        "uniform mat4 projectionMat;\n" +
        "" +
        "void main() {\n" +
        "    gl_Position = projectionMat * viewMat * modelMat*position ;\n" +
        "    textureCoordinateVarying = textureCoordinate;\n" +
        "}";
private final String mFragmentShader = "precision highp float;\n" +
        "uniform sampler2D textureBackground;\n" +
        "uniform sampler2D textureNumbers;" +
        "varying highp vec2 textureCoordinateVarying;\n" +
        "void main() {\n" +
        "    vec4 background = texture2D(textureBackground, textureCoordinateVarying);" +
        "    vec4 foreground = texture2D(textureNumbers, textureCoordinateVarying);" +
        "    gl_FragColor = mix(background, foreground, 0.2);\n" +
        "}\n";

关于投影、 View 和模型矩阵，这是它们的初始化函数:

    Matrix.setIdentityM(model, 0);
    Matrix.setIdentityM(rotation, 0);
    Matrix.setIdentityM(view, 0);
    Matrix.setIdentityM(projection, 0);

    Matrix.translateM(view, 0,0,0,-3.0f);
    Matrix.perspectiveM(projection,0,45,(float)mBackground.getHeight()/(float)mBackground.getWidth(), 0.1f, 100f);

在onDraw函数中，我会更新模型矩阵的值；

public void onDrawFrame(GL10 gl) {
    //some function

    //update model matrix, and rotation is just a 4*4 identity matrix, and the degree is the z-axis rotation degree.
    Matrix.setRotateM(rotation, 0, degree, 0, 0, 1);
    Matrix.multiplyMM(model, 0, rotation, 0, model, 0);
    Matrix.setIdentityM(rotation,0);

    //draw my texture
}

我现在非常绝望，我们将不胜感激任何帮助。

Answer 1

看来这道题得自己杀了，其实我只是犯了一个愚蠢的错误，投影矩阵的比例应该是surface view的宽度除以同一个surface view的高度，这不应该是纹理图像宽度/高度的比率。