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我已经尝试按照此处找到的有关绘制形状和对其应用投影的课程进行学习，但投影似乎不起作用。据我所知，我已经复制粘贴了项目中的所有代码，以下是重要的代码部分：

在我的Renderer课堂上： 

@Override
public void onDrawFrame(GL10 unused) {
    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);

    // Set the camera position (View matrix)
    Matrix.setLookAtM(mVMatrix, 0, 0, 0, -3, 0f, 0f, 0f, 0f, 1.0f, 0.0f);

    // Calculate the projection and view transformation
    Matrix.multiplyMM(mMVPMatrix, 0, mProjMatrix, 0, mVMatrix, 0);

    // Draw shape
    mTriangle.draw(mMVPMatrix);
}

@Override
public void onSurfaceChanged(GL10 unused, int width, int height) {
    GLES20.glViewport(0, 0, width, height);

    float ratio = (float) width / height;
    Matrix.frustumM(mProjMatrix, 0, -ratio, ratio, -1, 1, 3, 7);
}

draw我Triangle班的方法：

public void draw(float[] mvpMatrix) {
    GLES20.glUseProgram(mProgram);

    mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition"); // get handle to vertex shader's vPosition member
    GLES20.glEnableVertexAttribArray(mPositionHandle); // Enable a handle to the triangle vertices

    GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStride, vertexBuffer); // Prepare the triangle coordinate data

    mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor"); // get handle to fragment shader's vColor member
    GLES20.glUniform4fv(mColorHandle, 1, color, 0); // Set color for drawing the triangle


    mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix"); // get handle to shape's transformation matrix
    GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0); // Apply the projection and view transformation

    GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount); // Draw the triangle

    GLES20.glDisableVertexAttribArray(mPositionHandle); // Disable vertex array
}

三角形仍在被拉伸。我究竟做错了什么？

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1 回答 1

1

您是否尝试在onSurfaceChanged中进行调试？这些行会发生什么？尤其：

    • 传递的值是width什么height？
    • 计算哪个值float ratio = (float) width / height;？
    • 通话后您是否看到mProjMatrixMatrix.frustumM(mProjMatrix, 0, -ratio, ratio, -1, 1, 3, 7);的值有任何变化？

  2. 你的private final String fragmentShaderCodeinclass Triangle看起来怎么样？因为行中的乘法顺序" gl_Position = uMVPMatrix * vPosition;" +很重要。

您提供的代码在这里看起来很好，很困难。

于 2013-06-25T10:23:34.973 回答