LWJGL

Question

我最近决定重新审视我根据 LWJGL wiki 上的教程使用索引 VBO 编写的一些 LWJGL 渲染代码。在我的台式电脑上一切正常，但当我切换到我的学校笔记本电脑时，它拒绝渲染任何东西。

我有以下渲染代码：

GL20.glUseProgram(pId); System.out.println("NO Error? " + (GL11.glGetError() == GL11.GL_NO_ERROR));

    // Bind to the VAO that has all the information about the vertices and colors
    GL30.glBindVertexArray(vaoId);
    GL20.glEnableVertexAttribArray(0);
    GL20.glEnableVertexAttribArray(1);
    System.out.println("NO Error? " + (GL11.glGetError() == GL11.GL_NO_ERROR));

    // Bind to the index VBO that has all the information about the order of the vertices
    GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, vboiId);

    // Draw the vertices
    GL11.glDrawElements(GL11.GL_TRIANGLES, indicesCount, GL11.GL_UNSIGNED_INT, 0);

    System.out.println("NO Error? " + (GL11.glGetError() == GL11.GL_NO_ERROR));
    // Put everything back to default (deselect)
    GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, 0);
    GL20.glDisableVertexAttribArray(0);
    GL20.glDisableVertexAttribArray(1);
    GL30.glBindVertexArray(0);
    GL20.glUseProgram(0);
    System.out.println("NO Error? " + (GL11.glGetError() == GL11.GL_NO_ERROR));

这是我的 vertex/fragment 着色器

#version 130
uniform mat4 MVP;
in vec4 in_Position;
in vec4 in_Color;
out vec4 pass_Color;
void main(void) {
gl_Position = MVP * in_Position;
pass_Color = in_Color;
}
#version 130
in vec4 pass_Color;
out vec4 out_Color;
void main(void) {
out_Color = pass_Color;
}

这是我的 VBO 初始化函数

public void initialize(float[] vertices, float[] colors, int[] indices) {
    shaderSetup();
    //create the buffers to hold vertex color and index data
    FloatBuffer verticesBuffer = BufferUtils.createFloatBuffer(vertices.length);
    verticesBuffer.put(vertices);
    verticesBuffer.flip();
    System.out.println("NO Error? " + (GL11.glGetError() == GL11.GL_NO_ERROR));

    FloatBuffer colorsBuffer = BufferUtils.createFloatBuffer(colors.length);
    colorsBuffer.put(colors);
    colorsBuffer.flip();
    // OpenGL expects vertices in counter clockwise order by default
    indicesCount = indices.length;
    IntBuffer indicesBuffer = BufferUtils.createIntBuffer(indicesCount);
    indicesBuffer.put(indices);
    indicesBuffer.flip();
    System.out.println("NO Error? " + (GL11.glGetError() == GL11.GL_NO_ERROR));

    // Create a new Vertex Array Object in memory and select it (bind)
    vaoId = GL30.glGenVertexArrays();
    GL30.glBindVertexArray(vaoId);
    System.out.println("NO Error? " + (GL11.glGetError() == GL11.GL_NO_ERROR));

    // Create a new Vertex Buffer Object in memory and select it (bind) - VERTICES
    vboId = GL15.glGenBuffers();
    GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vboId);
    GL15.glBufferData(GL15.GL_ARRAY_BUFFER, verticesBuffer, GL15.GL_STATIC_DRAW);
    GL20.glVertexAttribPointer(0, 4, GL11.GL_FLOAT, false, 0, 0);
    GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);
    System.out.println("NO Error? " + (GL11.glGetError() == GL11.GL_NO_ERROR));

    // Create a new Vertex Buffer Object in memory and select it (bind) - COLORS
    vbocId = GL15.glGenBuffers();
    GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vbocId);
    GL15.glBufferData(GL15.GL_ARRAY_BUFFER, colorsBuffer, GL15.GL_STATIC_DRAW);
    GL20.glVertexAttribPointer(1, 4, GL11.GL_FLOAT, false, 0, 0);
    GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);
    System.out.println("NO Error? " + (GL11.glGetError() == GL11.GL_NO_ERROR));

    // Deselect (bind to 0) the VAO
    GL30.glBindVertexArray(0);
    // Create a new VBO for the indices and select it (bind) - INDICES
    System.out.println("NO Error? " + (GL11.glGetError() == GL11.GL_NO_ERROR));
    vboiId = GL15.glGenBuffers();
    GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, vboiId);
    GL15.glBufferData(GL15.GL_ELEMENT_ARRAY_BUFFER, indicesBuffer, GL15.GL_STATIC_DRAW);
    GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, 0);
    System.out.println("NO Error? " + (GL11.glGetError() == GL11.GL_NO_ERROR));
}

着色器设置代码：

int errorCheckValue = GL11.glGetError();
// Load the vertex shader
vsId = this.loadShader("Shaders/vertex.glsl", GL20.GL_VERTEX_SHADER);
// Load the fragment shader
fsId = this.loadShader("Shaders/fragment.glsl", GL20.GL_FRAGMENT_SHADER);
// Create a new shader program that links both shaders
pId = GL20.glCreateProgram();
GL20.glAttachShader(pId, vsId);
GL20.glAttachShader(pId, fsId);
GL20.glLinkProgram(pId);
// Position information will be attribute 0
GL20.glBindAttribLocation(pId, 0, "in_Position");
// Color information will be attribute 1
GL20.glBindAttribLocation(pId, 1, "in_Color");
GL20.glValidateProgram(pId);
errorCheckValue = GL11.glGetError();
if (errorCheckValue != GL11.GL_NO_ERROR) {
System.out.println("ERROR - Could not create the shaders");
    System.exit(-1);
}

我家里的台式机（按预期渲染所有内容）运行的是 nVidia GTX 460 显卡，而我学校的笔记本电脑（不渲染任何东西）有 AMD Firepro m4000 显卡。我最好的猜测是 VBO render/creation/shader 代码的某些部分与我的 m4000 卡不兼容，但我无法使用 glGetError() 找到任何错误。

Answer 1

您在着色器设置代码中的调用顺序将无法按预期工作：

GL20.glLinkProgram(pId);
GL20.glBindAttribLocation(pId, 0, "in_Position");
GL20.glBindAttribLocation(pId, 1, "in_Color");

glBindAttribLocation()需要在glLinkProgram()之前调用才能生效。来自 man page:

Attribute bindings do not go into effect until glLinkProgram is called. After a program object has been linked successfully, the index values for generic attributes remain fixed (and their values can be queried) until the next link command occurs.

因此调用顺序需要为：

GL20.glBindAttribLocation(pId, 0, "in_Position"); GL20.glBindAttribLocation(pId, 1, "in_Color"); GL20.glLinkProgram(pId);

虽然不是正确性问题，但您也没有非常有效地使用 VAO。属性 enable/disable 值和 GL_ELEMENT_ARRAY_BUFFER 绑定是 VAO 状态的一部分。因此，您可以在设置期间调用 glEnableVertexAttribArray() 和 GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, vboiId) 一次，同时绑定 VAO。然后在draw call中，只需要绑定VAO就可以设置所有的state。

LWJGL - VBO 在一个系统上渲染，但在另一个系统上渲染

LWJGL - VBO rendering on one system but not the other

opengl

vbo