glDrawElements不会绘制任何东西

我对VBOs，VAO和Indices很新颖。我能渲染一个单一的立方体，现在我正在尝试渲染一大块立方体。我的目标是慢慢制作一个体素引擎。我的大块类有问题。由于某些原因，它不显示任何内容。任何人都可以快速查看，也许弄清楚什么是错误的，并指出了我？干杯glDrawElements不会绘制任何东西

class Chunk { 

private IntBuffer vaoID; 
private IntBuffer vboID; 
private IntBuffer indexID; 


public void createChunkVBO() { 

    FloatBuffer vertices = BufferUtils.createFloatBuffer(16 * 256 * 16 * 3 * 8); 
    FloatBuffer colors = BufferUtils.createFloatBuffer(16 * 256 * 16 * 4 * 8); 
    FloatBuffer indices = BufferUtils.createFloatBuffer(16 * 256 * 16 * 4 * 6); 

    vaoID = BufferUtils.createIntBuffer(1); // Create a buffer for the Vertex Array Object 
    vboID = BufferUtils.createIntBuffer(1); // Create a buffer for the Vertex Buffer Object 
    indexID = BufferUtils.createIntBuffer(1); // Create a buffer for the Vertex Indices 


    for (int x = 0; x < 16; x++) { 
     for (int y = 0; y < 256; y++) { 
      for (int z = 0; z < 16; z++) { 
       System.out.println(x + ", " + y + ", " + z); 
       vertices.put(x + World.BLOCK_SIZE); 
       vertices.put(y); 
       vertices.put(z + World.BLOCK_SIZE); 

       vertices.put(x); 
       vertices.put(y); 
       vertices.put(z + World.BLOCK_SIZE); 

       vertices.put(x); 
       vertices.put(y); 
       vertices.put(z); 

       vertices.put(x + World.BLOCK_SIZE); 
       vertices.put(y); 
       vertices.put(z); 

       vertices.put(x + World.BLOCK_SIZE); 
       vertices.put(y + World.BLOCK_SIZE); 
       vertices.put(z + World.BLOCK_SIZE); 

       vertices.put(x); 
       vertices.put(y + World.BLOCK_SIZE); 
       vertices.put(z + World.BLOCK_SIZE); 

       vertices.put(x); 
       vertices.put(y + World.BLOCK_SIZE); 
       vertices.put(z); 

       vertices.put(x + World.BLOCK_SIZE); 
       vertices.put(y + World.BLOCK_SIZE); 
       vertices.put(z); 


       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 


       indices.put(0 + x * y * z); 
       indices.put(1 + x * y * z); 
       indices.put(2 + x * y * z); 
       indices.put(3 + x * y * z); 


       indices.put(4 + x * y * z); 
       indices.put(5 + x * y * z); 
       indices.put(2 + x * y * z); 
       indices.put(3 + x * y * z); 


       indices.put(1 + x * y * z); 
       indices.put(3 + x * y * z); 
       indices.put(7 + x * y * z); 
       indices.put(5 + x * y * z); 


       indices.put(0 + x * y * z); 
       indices.put(3 + x * y * z); 
       indices.put(4 + x * y * z); 
       indices.put(7 + x * y * z); 


       indices.put(0 + x * y * z); 
       indices.put(1 + x * y * z); 
       indices.put(6 + x * y * z); 
       indices.put(7 + x * y * z); 


       indices.put(4 + x * y * z); 
       indices.put(5 + x * y * z); 
       indices.put(6 + x * y * z); 
       indices.put(7 + x * y * z); 

      } 
     } 
    } 


    glGenVertexArrays(vaoID); // Create an id for the VAO 
    glBindVertexArray(vaoID.get(0)); // Bind the VAO so it remembers all the Attributes (none right now) 

    glGenBuffers(vboID); // Create an id for the VBO 
    glBindBuffer(GL_ARRAY_BUFFER, vboID.get(0)); // Bind the VBO so we can put data into it 

    glBufferData(GL_ARRAY_BUFFER, 16 * 256 * 16 * 8 * 7 * Float.SIZE, GL_STATIC_DRAW); // We make an empty buffer with a specific size in bytes 
                     // 8 * 7 * sizeof(float) 
                     // 8 = number of vertices, 7 = xyzrgba 

    glBufferSubData(GL_ARRAY_BUFFER, 0, vertices); // Put the vertices at the beginning of the buffer 
    glBufferSubData(GL_ARRAY_BUFFER, 16 * 256 * 16 * 8 * 3 * Float.SIZE, colors); // Put the colors after the vertices 

    glGenBuffers(indexID); // Create an id for the Index Buffer 
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexID.get(0)); // Bind the Index Buffer so we can put data into it 
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices, GL_STATIC_DRAW); // Store the indices inside the currently bound Index Buffer 

} 

public void drawChunk() { 

    glEnableClientState(GL_VERTEX_ARRAY); // Enable the Vertex Array 
    glEnableClientState(GL_COLOR_ARRAY); // Enable the Color Array 

    glVertexPointer(3, GL_FLOAT, 0, 0); 
    glColorPointer(4, GL_FLOAT, 0, 16 * 256 * 16 * 8 * 3 * Float.SIZE); // Position of the colors in the currently bound buffer 

    glDrawElements(GL_QUADS, 24 * 16 * 256 * 16, GL_UNSIGNED_INT, 0); // Draws the elements from the Index Buffer 

} 


}

来源

2017-06-08 Grim Reaper

我不知道，我可以提供一个直接的解决方案，因为这个问题是不是很具体，但我可以提供，可以帮助您解决问题的一些普遍性的建议：

你的块类应该只有一个vaoID（整个块应该用一次绘制调用渲染）。它可以有多个与该vaoID关联的vboID。关键是，不需要使用IntBuffers来存储它们，并且如果明确指定每个vboID的话，它通常会使事情更加有组织。
使用BufferUtils创建FloatBuffer对象并将数据加载到这些对象中后，必须在所有对象上调用.flip（），以便OpenGL知道它们已准备好使用。（这很可能只是主问题）
作为您的程序其余部分的一般礼貌，您应该禁用在绘制方法中启用的任何属性，并解除绑定的任何VAOS。（我相信当绑定一个VAO绑定缓冲区对象时，该缓冲区仅在VAO绑定时绑定，我找不到要备份的文档，为了安全起见，我还要解除绑定缓冲区对象你与他们完成后）

下面是我认为应该给你的组块类的工作实现：

class Chunk { 

private int vaoID; 
private int vboID; 
private int indexID; 


public void createChunkVBO() { 

    FloatBuffer vertices = BufferUtils.createFloatBuffer(16 * 256 * 16 * 3 * 8); 
    FloatBuffer colors = BufferUtils.createFloatBuffer(16 * 256 * 16 * 4 * 8); 
    FloatBuffer indices = BufferUtils.createFloatBuffer(16 * 256 * 16 * 24); 

    // I am assuming that all of this is generated properly 
    for (int x = 0; x < 16; x++) { 
     for (int y = 0; y < 256; y++) { 
      for (int z = 0; z < 16; z++) { 
       System.out.println(x + ", " + y + ", " + z); 
       vertices.put(x + World.BLOCK_SIZE); 
       vertices.put(y); 
       vertices.put(z + World.BLOCK_SIZE); 

       vertices.put(x); 
       vertices.put(y); 
       vertices.put(z + World.BLOCK_SIZE); 

       vertices.put(x); 
       vertices.put(y); 
       vertices.put(z); 

       vertices.put(x + World.BLOCK_SIZE); 
       vertices.put(y); 
       vertices.put(z); 

       vertices.put(x + World.BLOCK_SIZE); 
       vertices.put(y + World.BLOCK_SIZE); 
       vertices.put(z + World.BLOCK_SIZE); 

       vertices.put(x); 
       vertices.put(y + World.BLOCK_SIZE); 
       vertices.put(z + World.BLOCK_SIZE); 

       vertices.put(x); 
       vertices.put(y + World.BLOCK_SIZE); 
       vertices.put(z); 

       vertices.put(x + World.BLOCK_SIZE); 
       vertices.put(y + World.BLOCK_SIZE); 
       vertices.put(z); 


       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 

       colors.put(1f); 
       colors.put(0f); 
       colors.put(0f); 
       colors.put(1f); 


       indices.put(0 + x * y * z); 
       indices.put(1 + x * y * z); 
       indices.put(2 + x * y * z); 
       indices.put(3 + x * y * z); 


       indices.put(4 + x * y * z); 
       indices.put(5 + x * y * z); 
       indices.put(2 + x * y * z); 
       indices.put(3 + x * y * z); 


       indices.put(1 + x * y * z); 
       indices.put(3 + x * y * z); 
       indices.put(7 + x * y * z); 
       indices.put(5 + x * y * z); 


       indices.put(0 + x * y * z); 
       indices.put(3 + x * y * z); 
       indices.put(4 + x * y * z); 
       indices.put(7 + x * y * z); 


       indices.put(0 + x * y * z); 
       indices.put(1 + x * y * z); 
       indices.put(6 + x * y * z); 
       indices.put(7 + x * y * z); 


       indices.put(4 + x * y * z); 
       indices.put(5 + x * y * z); 
       indices.put(6 + x * y * z); 
       indices.put(7 + x * y * z); 

      } 
     } 
    } 

    vertices.flip(); 
    colors.flip(); 
    indices.flip(); 


    glGenVertexArrays(vaoID); // Create an id for the VAO 
    glBindVertexArray(vaoID); // Bind the VAO so it remembers all the Attributes (none right now) 

    glGenBuffers(vboID); // Create an id for the VBO 
    glBindBuffer(GL_ARRAY_BUFFER, vboID); // Bind the VBO so we can put data into it 

    glBufferData(GL_ARRAY_BUFFER, 16 * 256 * 16 * 8 * 7 * Float.SIZE, GL_STATIC_DRAW); // We make an empty buffer with a specific size in bytes 
                    // 8 * 7 * sizeof(float) 
                    // 8 = number of vertices, 7 = xyzrgba 
    // I have not used subdata like this before so I will assume this is correct. 
    glBufferSubData(GL_ARRAY_BUFFER, 0, vertices); // Put the vertices at the beginning of the buffer 
    glBufferSubData(GL_ARRAY_BUFFER, 16 * 256 * 16 * 8 * 3 * Float.SIZE, colors); // Put the colors after the vertices 


    glGenBuffers(indexID); // Create an id for the Index Buffer 
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexID); // Bind the Index Buffer so we can put data into it 
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices, GL_STATIC_DRAW); // Store the indices inside the currently bound Index Buffer 

} 

public void drawChunk() { 

    glEnableClientState(GL_VERTEX_ARRAY); // Enable the Vertex Array 
    glEnableClientState(GL_COLOR_ARRAY); // Enable the Color Array 

    glVertexPointer(3, GL_FLOAT, 0, 0); 
    glColorPointer(4, GL_FLOAT, 0, 16 * 256 * 16 * 8 * 3 * Float.SIZE); // Position of the colors in the currently bound buffer 

    glDrawElements(GL_QUADS, 8 * 16 * 256 * 24, GL_UNSIGNED_INT, 0); // Draws the elements from the Index Buffer 
} 
}

请随时免费的，如果您有任何疑问，请联系我关于我所说的任何事情。

声明：我不是OpenGL或LWJGL的专家。请带上我的答案，因为这些答案几乎完全来自我的教育/个人经验。

来源

2017-06-09 20:58:30

谢谢你的精彩答案！我确实已经忘记翻转FloatBuffers。翻转他们部分地解决了这个问题。当我使用glDrawArrays时，我可以正确渲染四边形。但是，每个立方体只有2个四边形，因为我想使用索引。由于某种原因，glDrawElements似乎不起作用。我的猜测是，我搞砸了为每个立方体添加索引。感谢您提供所有重要提示！你有没有可能看看我如何存储索引，因为你对OpenGL的总体经验比我更有经验。我真的很感激！ –

我已阅读您的评论，并会很快进行测试。我在家里的桌面上需要安装Eclipse和JDK，我甚至可以进行简单的测试，大声笑......当我看完它时，我会回复你并编辑我的答案。 –

我必须道歉，我没有时间在工作和学校之间及时回答这个问题。我已经更正了index初始化的行和glDrawElements行的索引缓冲区大小。这可以解决你的问题。如果不是的话，我会建议先从一个小例子开始，然后继续工作到一个块。例如，以一个立方体开始，然后是一排立方体，然后是一个立方体网格，然后是一大块立方体。 –

glDrawElements不会绘制任何东西

回答

相关问题