Question

我一直试图让我的游戏引擎在android上工作，我被困在顶点缓冲区数组中。它使用FloatBuffer工作，但当我尝试使用VBO渲染时，我只有一个白色的屏幕。所以我想知道我的代码是否有问题。

这就是我创建VBO的方式：

private int[] vbo = new int[1];
private int[] ibo = new int[1];

private void setUpVBO()
{
    short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; // order to draw vertices
    float TextureCoords[] = 
    { 
    0.0f, 0.0f,   // bottom left
    0.0f, 1.0f,   // top left
    1.0f, 1.0f, // top right
    1.0f, 0.0f,   // bottom right
    };
    float squareCoords[] = { 
                -width / 2.f - 0.015f / 2.f,  height / 2.f + 0.015f / 2.f, 0.0f,   // top left
                -width / 2.f - 0.015f / 2.f, -height / 2.f - 0.015f / 2.f, 0.0f,   // bottom left
                 width / 2.f + 0.015f / 2.f, -height / 2.f - 0.015f / 2.f, 0.0f,   // bottom right
                 width / 2.f + 0.015f / 2.f,  height / 2.f + 0.015f / 2.f, 0.0f }; // top right
        ByteBuffer bb = ByteBuffer.allocateDirect(bb.order(ByteOrder.nativeOrder());
        bb.order(ByteOrder.nativeOrder());
        FloatBuffer vertexBuffer = bb.asFloatBuffer();
        vertexBuffer.put(squareCoords);
        vertexBuffer.position(0);

        // initialize vertex byte buffer for shape coordinates
        ByteBuffer tc = ByteBuffer.allocateDirect(TextureCoords.length * 4);
        tc.order(ByteOrder.nativeOrder());
        FloatBuffer TextureCoordinateBuffer = tc.asFloatBuffer();
        TextureCoordinateBuffer.put(TextureCoords);
        TextureCoordinateBuffer.position(0);


        // initialize byte buffer for the draw list
        ByteBuffer dlb = ByteBuffer.allocateDirect(drawOrder.length * 2);
        dlb.order(ByteOrder.nativeOrder());
        ShortBuffer drawListBuffer = dlb.asShortBuffer();
        drawListBuffer.put(drawOrder);
        drawListBuffer.position(0);


        GLES20.glGenBuffers(1, vbo, 0);
        GLES20.glGenBuffers(1, ibo, 0);

        if (vbo[0] > 0 && ibo[0] > 0) 
        {
            GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vbo[0]);
            GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, vertexBuffer.capacity() * 4,
                    vertexBuffer, GLES20.GL_STATIC_DRAW);

            GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vbo[0]);
            GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, TextureCoordinateBuffer.capacity() * 4,
                    TextureCoordinateBuffer, GLES20.GL_DYNAMIC_DRAW);


            GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, ibo[0]);
            GLES20.glBufferData(GLES20.GL_ELEMENT_ARRAY_BUFFER, drawListBuffer.capacity()
                    * 2, drawListBuffer, GLES20.GL_STATIC_DRAW);

            GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, 0);
            GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, 0);
    }
}

这是我呈现的方式：

public void render(float[] mMVPMatrix) 
{       
    if (vbo[0] > 0 && ibo[0] > 0) 
    {
        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vbo[0]);

        GLES20.glEnableVertexAttribArray(Values.mPositionHandle);
        GLES20.glVertexAttribPointer(Values.mPositionHandle, Values.COORDS_PER_VERTEX,
                GLES20.GL_FLOAT, false,
                Values.fullStride, 0);


        GLES20.glEnableVertexAttribArray(Values.mTextureCoordinateHandle);
        GLES20.glVertexAttribPointer(Values.mTextureCoordinateHandle, Values.COORDS_PER_VERTEX_TEXTURE, 
                GLES20.GL_FLOAT, false,
                Values.fullStride, 0);


        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureOfBody); 
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_REPEAT);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_REPEAT);
        GLES20.glUniform1i(Values.mTheActualTexture, 0);


    GLES20.glUniform4fv(Values.mColorHandle, 1, colorOfBody, 0);


        // Apply the projection and view transformation
        GLES20.glUniformMatrix4fv(Values.mMVPMatrixHandle, 1, false, mMVPMatrix, 0);

        // Draw the square
        GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, ibo[0]);
        GLES20.glDrawElements(GLES20.GL_TRIANGLE_STRIP, drawOrder.length, GLES20.GL_UNSIGNED_SHORT, 0);

        // Disable vertex array
        GLES20.glDisableVertexAttribArray(Values.mTextureCoordinateHandle);
        GLES20.glDisableVertexAttribArray(Values.mPositionHandle);


        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, 0);
        GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, 0);
    }
}

正确加载着色器。这是我的着色器：

顶点：

    uniform mat4 uMVPMatrix;
    attribute vec4 vPosition;
    attribute vec2 TexCoordinate;
    varying vec2 TexCoordinateGLFS;

    void main()
    {
        TexCoordinateGLFS = TexCoordinate;

        gl_Position = uMVPMatrix * newPosition ;
    }

片段：

    precision mediump float;
    uniform sampler2D theActualTexture;
    uniform vec4 vColor;
    varying vec2 TexCoordinateGLFS;

    void main() 
    {
        gl_FragColor = texture2D(theActualTexture, TexCoordinateGLFS) * vColor;
    }

一些变数：

public static final int COORDS_PER_VERTEX = 3;
public static final int COORDS_PER_VERTEX_TEXTURE = 2;

public static final int vertexStride = COORDS_PER_VERTEX * 4;
public static final int textureStride = COORDS_PER_VERTEX_TEXTURE * 4;
public static final int fullStride = (COORDS_PER_VERTEX + COORDS_PER_VERTEX_TEXTURE) * 4;

编辑：这是新的VBO结构：

    ByteBuffer bb = ByteBuffer.allocateDirect((squareCoords.length + TextureCoords.length) * 4);
        bb.order(ByteOrder.nativeOrder());
        vertexBuffer = bb.asFloatBuffer();
        vertexBuffer.put(squareCoords);
        vertexBuffer.put(TextureCoords);
        vertexBuffer.position(0);


GLES20.glGenBuffers(1, vbo, 0);
GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, vertexBuffer.capacity() * BYTES_PER_FLOAT,
                    vertexBuffer, GLES20.GL_DYNAMIC_DRAW);

我在这里画画：

        GLES20.glVertexAttribPointer(Values.mPositionHandle, Values.COORDS_PER_VERTEX,
                GLES20.GL_FLOAT, false,
                Values.vertexStride, 0);

        GLES20.glVertexAttribPointer(Values.mTextureCoordinateHandle, Values.COORDS_PER_VERTEX_TEXTURE, 
                GLES20.GL_FLOAT, false,
                Values.textureStride, squareCoords.length);

squareCoords.length == 12; （每个顶点（x，y，z）3个坐标 - > 4 * 3 = 12）

Answer 1

根据您发布的代码，您似乎会用纹理坐标覆盖您的位置坐标。通常，您需要与数组一样多的缓冲区，因此在您的情况下需要一个单独的缓冲区用于纹理坐标。更优雅的解决方案是将2个提到的数组合并为1个交错数组，将其推送到单个VBO并在设置顶点和纹理坐标指针时使用步幅。

这是完全禁止的：

GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vbo[0]);
GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, vertexBuffer.capacity() * 4, vertexBuffer, GLES20.GL_STATIC_DRAW);

GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vbo[0]);
GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, TextureCoordinateBuffer.capacity() * 4, TextureCoordinateBuffer, GLES20.GL_DYNAMIC_DRAW);

当您将相同的缓冲区绑定两次并将数据推送到GPU时，所以剩下的就是纹理坐标（实际上代码可能会在屏幕上的某处产生单个像素图像，具体取决于您的矩阵）

OpenGL ES 2.0 vbo白屏

1 个答案: