JOGL/OpenGL VBO-如何渲染顶点? [英] JOGL/OpenGL VBO - How to render vertices?
问题描述
3我有以下SceneRenderer类，实现GLEventListener.我想我了解创建缓冲区，存储指向这些缓冲区的指针以及用数据填充这些缓冲区的过程(请参阅init方法).
3I have the following SceneRenderer class, implementing GLEventListener. I think I understand the process of creating buffers, storing pointers to those buffers and filling those buffers with data (see init method).
我遇到麻烦的是 display()方法.我已经尝试了几乎在互联网上找到的所有内容的所有组合，但仍然无法绘制任何内容.有人可以解释一下现在该怎么办，所有缓冲区都充满了等待渲染的数据吗?
Where I struggle is the display() method. I've tried almost every combination of EVERYTHING i found on the internet and I'm still not able to draw anything. Could someone explain me what to do now, with all the buffers filled with data waiting to be rendered ?
package cz.pscheidl.gui;
import javax.media.opengl.*;
import javax.media.opengl.glu.GLU;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;
public class SceneRenderer implements GLEventListener {
private IntBuffer buffers = IntBuffer.allocate(2);
private float[] square = {
-1.0f, -1.0f,
1.0f, -1.0f,
1.0f, 1.0f,
1.0f, 1.0f,
-1.0f, 1.0f,
-1.0f, -1.0f,
};
private float[] colorData = {
255, 0, 0,
255, 255, 0,
0, 255, 0,
0, 255, 0,
0, 0, 255,
255, 0, 0
};
FloatBuffer vertexFB = FloatBuffer.wrap(square);
FloatBuffer colorFB = FloatBuffer.wrap(colorData);
GLU glu = new GLU();
@Override
public void init(GLAutoDrawable glAutoDrawable) {
GL3 gl = glAutoDrawable.getGL().getGL3();
gl.glEnableClientState(GL2.GL_VERTEX_ARRAY);
gl.glEnable(GL2.GL_DEPTH_TEST);
gl.glClearDepthf(10.0f);
gl.glClearColor(0.8f, 0.6f, 0.8f, 1.0f);
gl.glDepthFunc(GL2.GL_LEQUAL);
gl.glGenBuffers(2, buffers);
gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, buffers.get(0));
gl.glBufferData(GL2.GL_ARRAY_BUFFER, 4 * 6 * 2, vertexFB, GL3.GL_STATIC_DRAW);
gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, buffers.get(1));
gl.glBufferData(GL2.GL_ARRAY_BUFFER, 4 * 6 * 3, colorFB, GL2.GL_STREAM_DRAW);
}
@Override
public void dispose(GLAutoDrawable glAutoDrawable) {
}
@Override
public void display(GLAutoDrawable glAutoDrawable) {
GL3 gl = glAutoDrawable.getGL().getGL3();
gl.glClear(GL3.GL_DEPTH_BUFFER_BIT | GL3.GL_COLOR_BUFFER_BIT);
gl.glBindBuffer(GL3.GL_ARRAY_BUFFER, buffers.get(0));
//After binding the buffer, now WHAT ?
}
@Override
public void reshape(GLAutoDrawable glAutoDrawable, int i, int i2, int i3, int i4) {
GL3 gl = glAutoDrawable.getGL().getGL3();
glu.gluPerspective(80.0f, 1920.0f / 1080.0f, 0.1f, 100f);
}
}
推荐答案
您缺少几件事:
1.着色器
着色器是在GPU上运行的程序.这是您告诉gpu如何处理数据的方式.这是您创建具有顶点和片段着色器的非常基本的程序的方式，该程序将显示您的网格.
1. Shaders
Shaders are programs that run on the gpu. This is how you tell the gpu what to do with your data. This is how you would create a very basic Program that has a Vertex and Fragment Shader, that would display your mesh.
使用您的类级var声明进行填充:
Put this up with your class level var declarations:
private int program;
这将在您的init()函数内部:
This would go inside your init() function:
// Create program.
program = gl.glCreateProgram();
// Create vertexShader.
int vertexShader = gl.glCreateShader(GL2ES2.GL_VERTEX_SHADER);
String[] vertexShaderSource = new String[1];
vertexShaderSource[0] = "#version 330\n" +
"layout(location=0) in vec2 position;\n" +
"layout(location=1) in vec3 color;\n" +
"out vec3 vColor;\n" +
"void main(void)\n" +
"{\n" +
"gl_Position = vec4(position, 0.0, 1.0);\n"
"vColor = vec4(color, 1.0);\n"
"}\n";
gl.glShaderSource(vertexShader, 1, vertexShaderSource, null);
gl.glCompileShader(vertexShader);
// Create and fragment shader.
int fragmentShader = gl.glCreateShader(GL2ES2.GL_FRAGMENT_SHADER);
String[] fragmentShaderSource = new String[1];
fragmentShaderSource[0] = "#version 330\n" +
"in vec4 vColor;\n" +
"out vec4 fColor;\n" +
"void main(void)\n" +
"{\n" +
"fColor = vColor;\n" +
"}\n";
gl.glShaderSource(fragmentShader, 1, fragmentShaderSource, null);
gl.glCompileShader(fragmentShader);
// Attach shaders to program.
gl.glAttachShader(program, vertexShader);
gl.glAttachShader(program, fragmentShader);
gl.glLinkProgram(program);
2.顶点数组
绘制时需要使用两个缓冲区.顶点阵列允许您存储多个缓冲区的状态，并将数据发送到着色器程序中的不同位置.
2. Vertex Array
You have two buffers that need to be used when you draw. A Vertex Array allows you to store the state of multiple buffers and to send the data to different locations in your shader program.
将其与您的类级var声明一起放置:
Put this with your class level var declarations:
IntBuffer vertexArray = IntBuffer.allocate(1);
在创建缓冲区之后，这也将进入您的init()函数中:
This would also go in your init() function, after you create the buffers:
// Create Vertex Array.
gl.glGenVertexArrays(1, vertexArray);
gl.glBindVertexArray(vertexArray.get(0));
// Specify how data should be sent to the Program.
// VertexAttribArray 0 corresponds with location 0 in the vertex shader.
gl.glEnableVertexAttribArray(0);
gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, buffers.get(0));
gl.glVertexAttribPointer(0, 2, GL.GL_FLOAT, false, 0, 0);
// VertexAttribArray 1 corresponds with location 1 in the vertex shader.
gl.glEnableVertexAttribArray(1);
gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, buffers.get(1));
gl.glVertexAttribPointer(1, 3, GL.GL_FLOAT, false, 0, 0);
您的display()函数现在应如下所示:
@Override
public void display(GLAutoDrawable glAutoDrawable) {
GL3 gl = glAutoDrawable.getGL().getGL3();
gl.glClear(GL3.GL_DEPTH_BUFFER_BIT | GL3.GL_COLOR_BUFFER_BIT);
gl.glUseProgram(program)
gl.glBindVertexArray(vertexArray.get(0));
gl.glDrawArrays(GL.GL_TRIANGLES, 0, 6)
}
其他注释:
-您的颜色值应该在0到1的范围内，而不是0到255.
-您应该研究销毁自己创建的OpenGL对象，以解决程序关闭时或不再需要它们的情况.
-我强烈建议您阅读以下教程: OpenGL书和学习现代3D图形编程.代码示例是C ++，但我发现它们非常有帮助.
Miscellaneous notes:
-Your color values should range from 0 to 1, not 0 to 255.
-You should research destroying the OpenGL objects you create, for when the program closes or you no longer need them.
-I highly recommend reading these tutorials: OpenGL Book and Learning Modern 3D Graphics Programming. The code examples are in C++ but I found them extremely helpful.
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