OpenGL-ES 1.0/2.0中的Ortho /投影

Question

以前我在OpenGL-ES 1.0上做过一个教程。作为参考，这可以在这里找到： SpaceInvaders（这是在德国虽然）

我现在的目标是移植到OpenGL ES 2.0的游戏。到目前为止，我能够加载网格和纹理并渲染它们。

现在我想有一个简单的矩形作为我的背景与纹理。这应该在Ortho-Perspective中呈现。然后，我切换到Projection-Perspective并绘制一个简单的框。当我现在拨打电话setLookAtM（...），我得到一个空白的场景。下面是代码：

public void onDrawFrame(GL10 gl) { 
    long currentFrameStart = System.nanoTime(); 
    deltaTime = (currentFrameStart - lastFrameStart)/1000000000.0f; 
    lastFrameStart = currentFrameStart; 

    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT); 
    GLES20.glUseProgram(programHandle); 
    checkGlError("glUseProgram"); 

    mMVPMatrixHandle = GLES20.glGetUniformLocation(programHandle, "uMVPMatrix"); 
    mMVMatrixHandle = GLES20.glGetUniformLocation(programHandle, "uMVMatrix"); 
    mLightPosHandle = GLES20.glGetUniformLocation(programHandle, "uLightPos"); 
    mTextureUniformHandle = GLES20.glGetUniformLocation(programHandle, "uTexture"); 

    mPositionHandle = GLES20.glGetAttribLocation(programHandle, "aPosition"); 
    mColorHandle = GLES20.glGetAttribLocation(programHandle, "aColor"); 
    mNormalHandle = GLES20.glGetAttribLocation(programHandle, "aNormal"); 
    mTextureCoordinateHandle = GLES20.glGetAttribLocation 
     (programHandle,"aTexCoordinate"); 

    Matrix.setIdentityM(mLightModelMatrix, 0); 
    Matrix.multiplyMV(mLightPosInWorldSpace, 0, mLightModelMatrix, 0,  
     mLightPosInModelSpace, 0); 
    Matrix.multiplyMV(mLightPosInEyeSpace, 0, mViewMatrix, 0, mLightPosInWorldSpace, 0); 

    Matrix.orthoM(mProjectionMatrix, 0, -width/2, width/2, -height/2, height/2, 
     0, 100); 
    drawBackground(); 

    GLES20.glEnable(GLES20.GL_CULL_FACE); 

    Matrix.setIdentityM(mProjectionMatrix, 0); 
    final float ratio = (float) width/height; 
    final float left = -ratio; 
    final float right = ratio; 
    final float bottom = -1.0f; 
    final float top = 1.0f; 
    final float near = 1.0f; 
    final float far = 100.0f; 
    Matrix.frustumM(mProjectionMatrix, 0, left, right, bottom, top, near, far); 

    Matrix.setLookAtM(mViewMatrix, 0, 0, 6, 2, 0, 0, -4, 0, 1, 0); 

    drawBlock(); 
} 

这里drawBackground方法：

private void drawBackground() { 
    GLES20.glActiveTexture(GLES20.GL_TEXTURE0); 
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, backgroundTextureHandle); 
    GLES20.glUniform1i(mTextureUniformHandle, 0); 

    Matrix.setIdentityM(mModelMatrix, 0); 
    Matrix.setIdentityM(mProjectionMatrix, 0); 

    mBackgroundPositions.position(0); 
    GLES20.glVertexAttribPointer(mPositionHandle, POSITION_DATA_SIZE, GLES20.GL_FLOAT, 
     false, 0, mBackgroundPositions); 
    GLES20.glEnableVertexAttribArray(mPositionHandle); 

    mBackgroundColors.position(0); 
    GLES20.glVertexAttribPointer(mColorHandle, COLOR_DATA_SIZE, GLES20.GL_FLOAT, false, 
     0, mBackgroundColors); 
    GLES20.glEnableVertexAttribArray(mColorHandle); 

    mBackgroundNormals.position(0); 
    GLES20.glVertexAttribPointer(mNormalHandle, NORMAL_DATA_SIZE, GLES20.GL_FLOAT, 
     false, 0, mBackgroundNormals); 
    GLES20.glEnableVertexAttribArray(mNormalHandle); 

    mBackgroundTextureCoordinates.position(0); 
    GLES20.glVertexAttribPointer(mTextureCoordinateHandle, TEXTURE_COORD_DATA_SIZE, 
     GLES20.GL_FLOAT, false, 0, mBackgroundTextureCoordinates); 
    GLES20.glEnableVertexAttribArray(mTextureCoordinateHandle); 

    // This multiplies the view matrix by the model matrix, and stores the result in the MVP matrix 
    // (which currently contains model * view). 
    Matrix.multiplyMM(mMVPMatrix, 0, mViewMatrix, 0, mModelMatrix, 0); 

    // Pass in the modelview matrix. 
    GLES20.glUniformMatrix4fv(mMVMatrixHandle, 1, false, mMVPMatrix, 0); 

    // This multiplies the modelview matrix by the projection matrix, and stores the result in the MVP matrix 
    // (which now contains model * view * projection). 
    Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mMVPMatrix, 0); 

    // Pass in the combined matrix. 
    GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mMVPMatrix, 0); 

    // Pass in the light position in eye space. 
    GLES20.glUniform3f(mLightPosHandle, mLightPosInEyeSpace[0], mLightPosInEyeSpace[1], 
     mLightPosInEyeSpace[2]); 

    ShortBuffer buf = 
     ByteBuffer.allocateDirect(12).order(ByteOrder.nativeOrder()).asShortBuffer(); 
    buf.put(new short[] {0, 1, 2, 0, 2, 3}); 
    buf.position(0); 

    // Draw the rectangle. 
    GLES20.glDrawElements(GLES20.GL_TRIANGLES, 6, GLES20.GL_UNSIGNED_SHORT, buf); 
    checkGlError("glDrawArrays"); 
} 

最后的drawBlock方法：

private void drawBlocks() { 
    GLES20.glUseProgram(colorProgramHandle); 
    checkGlError("glUseProgram"); 

    mMVPMatrixHandle = GLES20.glGetUniformLocation(colorProgramHandle, "uMVPMatrix"); 
    mMVMatrixHandle = GLES20.glGetUniformLocation(colorProgramHandle, "uMVMatrix"); 
    mLightPosHandle = GLES20.glGetUniformLocation(colorProgramHandle, "uLightPos"); 
    mTextureUniformHandle = GLES20.glGetUniformLocation(colorProgramHandle, "uTexture"); 

    mPositionHandle = GLES20.glGetAttribLocation(colorProgramHandle, "aPosition"); 
    mColorHandle = GLES20.glGetAttribLocation(colorProgramHandle, "aColor"); 
    mNormalHandle = GLES20.glGetAttribLocation(colorProgramHandle, "aNormal"); 
    mTextureCoordinateHandle = GLES20.glGetAttribLocation(colorProgramHandle, 
     "aTexCoordinate"); 

    Matrix.setIdentityM(mProjectionMatrix, 0); 
    Matrix.setIdentityM(mModelMatrix, 0); 

    blockMesh.vertexBuffer.position(0); 
    GLES20.glVertexAttribPointer(mPositionHandle, POSITION_DATA_SIZE, GLES20.GL_FLOAT, 
     false, 0, blockMesh.vertexBuffer); 
    GLES20.glEnableVertexAttribArray(mPositionHandle); 

    blockMesh.colorBuffer.position(0); 
    GLES20.glVertexAttribPointer(mColorHandle, COLOR_DATA_SIZE, GLES20.GL_FLOAT, false, 
     0, blockMesh.colorBuffer); 
    GLES20.glEnableVertexAttribArray(mColorHandle); 

    blockMesh.normalBuffer.position(0); 
    GLES20.glVertexAttribPointer(mNormalHandle, NORMAL_DATA_SIZE, GLES20.GL_FLOAT, 
     false, 0, blockMesh.normalBuffer); 
    GLES20.glEnableVertexAttribArray(mNormalHandle); 

    // This multiplies the view matrix by the model matrix, and stores the result in the 
    MVP matrix 
    // (which currently contains model * view). 
    Matrix.multiplyMM(mMVPMatrix, 0, mViewMatrix, 0, mModelMatrix, 0); 

    // Pass in the modelview matrix. 
    GLES20.glUniformMatrix4fv(mMVMatrixHandle, 1, false, mMVPMatrix, 0); 

    // This multiplies the modelview matrix by the projection matrix, and stores the 
    result in the MVP matrix 
    // (which now contains model * view * projection). 
    Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mMVPMatrix, 0); 

    // Pass in the combined matrix. 
    GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mMVPMatrix, 0); 

    // Pass in the light position in eye space. 
    GLES20.glUniform3f(mLightPosHandle, mLightPosInEyeSpace[0], mLightPosInEyeSpace[1], 
     mLightPosInEyeSpace[2]); 

    // Draw the cube. 
    GLES20.glDrawElements(GLES20.GL_TRIANGLES, 36, GLES20.GL_UNSIGNED_SHORT, 
     blockMesh.indexBuffer); 
    checkGlError("glDrawElements"); 
} 

我不知道什么，我缺少有关邻位和突起的透视。任何帮助表示赞赏。

Answer 1

您正在将投影矩阵作为drawBlocks的一部分进行擦除。如果您想使用已计算的透视投影绘制它，我认为您不想这样做。

... 
Matrix.setIdentityM(mProjectionMatrix, 0); <----- 
Matrix.setIdentityM(mModelMatrix, 0); 

blockMesh.vertexBuffer.position(0); 
...