Opengl 为什么几何体着色器未按预期从1点生成4点？
我试图了解着色器在OpenGL中是如何工作的。我希望实现以下目标：Opengl 为什么几何体着色器未按预期从1点生成4点？,opengl,glsl,shader,jogl,Opengl,Glsl,Shader,Jogl,我试图了解着色器在OpenGL中是如何工作的。我希望实现以下目标： INPUT: 1 VAO WITH 1 VBO WHICH CONTAINS 1 vec2(x,y) (i.e. just a point defined in vec2) ----> VERTEX SHADER: JUST TURNS THE vec2(x,y) INTO A vec4(x,y,0.0,1.0) ----> GEOMETRY SHADER: RECEIVES vec
INPUT:
1 VAO WITH 1 VBO WHICH CONTAINS 1 vec2(x,y) (i.e. just a point defined in vec2)
---->
VERTEX SHADER:
JUST TURNS THE vec2(x,y) INTO A vec4(x,y,0.0,1.0)
---->
GEOMETRY SHADER:
RECEIVES vec4(x,y,0.0,1.0) POINT AND TRANSLATES INTO 4 POINTS
vec4(x-0.2,y-0.2,0.0,1.0)
vec4(x-0.2,y+0.2,0.0,1.0)
vec4(x+0.2,y+0.2,0.0,1.0)
vec4(x+0.2,y-0.2,0.0,1.0)
---->
FRAGMENT SHADER:
DRAWS EACH ONE OF THE 4 PIXELS IN BLUE
@RABBI76表示x，y位置的vec2输入变量。顶点着色器旨在从已删除的向量2构造一个常规的vec4x，y，0.0，1.0。我已经编辑了该问题，以反映到目前为止所做的所有更改。不幸的是，在0.5,0.5处仍然有一个白点。是否可能根本没有执行着色器？如何/在何处检查错误？我希望看到对GL3.glGetError之类的东西的调用，或者java中的操作是否有所不同？因为这是我的第一个OpenGL程序，我不知道如何查看错误，但我将搜索如何查看错误，并尝试将其实现到代码中。-->max_texts=1@rabbi76表示x，y位置的vec2输入变量。顶点着色器旨在从已删除的向量2构造一个常规的vec4x，y，0.0，1.0。我已经编辑了该问题，以反映到目前为止所做的所有更改。不幸的是，在0.5,0.5处仍然有一个白点。是否可能根本没有执行着色器？如何/在何处检查错误？我希望看到对GL3.glGetError之类的东西的调用，或者java中的操作是否有所不同？因为这是我的第一个OpenGL程序，我不知道如何看到错误，但我将搜索如何做到这一点，并尝试在代码中实现。-->max_texts=1，这会导致几何体着色器从不写入逐顶点输出gl_位置，这会导致编译错误，因为所有以gl_开头的名称都保留用于实现，几何体着色器中的gl_位置变量是接口块的一部分，因此
这不算是正确地重新定义它。实现了所有更改请参见编辑的问题，但行为仍然相同，我将尝试获取着色器的编译输出，以查看其他相关问题是否存在其他错误，似乎顶点着色器没有编译，这解释了为什么其他两个着色器没有执行任何操作。它可以工作，但它还需要实现上述相关问题中readShader例程的修复。最后一个错误是提交代码时没有\n。除此之外，此答案还修复了所有OpenGL问题。这导致几何体着色器从不写入逐顶点输出gl_位置，这将导致编译错误，因为所有以gl_开头的名称都是为实现保留的，并且几何体着色器中的gl_位置变量是接口块的一部分，因此，这不算是正确地重新定义它。实现了所有更改请参见编辑的问题，但行为仍然相同，我将尝试获取着色器的编译输出，以查看其他相关问题是否存在其他错误，似乎顶点着色器没有编译，这解释了为什么其他两个着色器没有执行任何操作。它可以工作，但它还需要实现上述相关问题中readShader例程的修复。最后一个错误是提交代码时没有\n。除此之外，这个答案修复了所有OpenGL问题。
#version 330 core
layout (location = 0) in vec2 squareCenterPosition;
void main()
{
gl_Position = vec4(squareCenterPosition.x, squareCenterPosition.y, 0.0, 1.0);
}
#version 330 core
layout (points) in;
layout (points, max_vertices = 1) out;
void main() {
vec4 gl_Position;
gl_Position = gl_in[0].gl_Position + vec4(-0.2, -0.2, 0.0, 0.0);
EmitVertex();
EndPrimitive();
gl_Position = gl_in[0].gl_Position + vec4(-0.2, +0.2, 0.0, 0.0);
EmitVertex();
EndPrimitive();
gl_Position = gl_in[0].gl_Position + vec4(+0.2, +0.2, 0.0, 0.0);
EmitVertex();
EndPrimitive();
gl_Position = gl_in[0].gl_Position + vec4(+0.2, -0.2, 0.0, 0.0);
EmitVertex();
EndPrimitive();
}
#version 330 core
in vec4 vertexColor;
out vec4 color;
void main(void) {
color = vec4(1.0, 0.0, 0.0, 1.0);
}
package openglexample1;
import com.jogamp.common.nio.Buffers;
import com.jogamp.opengl.GL2;
import com.jogamp.opengl.GL3;
import com.jogamp.opengl.GLAutoDrawable;
import com.jogamp.opengl.GLCapabilities;
import com.jogamp.opengl.GLEventListener;
import com.jogamp.opengl.GLProfile;
import com.jogamp.opengl.awt.GLCanvas;
import com.jogamp.opengl.glu.GLU;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.FloatBuffer;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.Vector;
import java.util.stream.Stream;
import javax.swing.JFrame;
public class WindowC extends JFrame implements GLEventListener {
/**
* @return the glcanvas
*/
public GLCanvas getGlcanvas() {
return glcanvas;
}
//getting the capabilities object of GL2 profile
final private GLProfile profile;
final private GLCapabilities capabilities;
final private GLCanvas glcanvas;
// GL PROGAM
private int glProgram;
// VAO AND VBOs
private int vao[] = new int[1]; // VAO GROUPS VBOs, ONLY ONE USED
private int vbo[] = new int[2]; // 2 VBOs FOR 2 SQUARES
public WindowC() {
// OpenGL CAPABILITIES
profile = GLProfile.get(GLProfile.GL2);
capabilities = new GLCapabilities(profile);
// CANVAS
glcanvas = new GLCanvas(capabilities);
glcanvas.addGLEventListener(this);
glcanvas.setSize(400, 400);
// JFRAME
this.getContentPane().add(glcanvas);
this.setSize(this.getContentPane().getPreferredSize());
}
@Override
public void display(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2();
// USE PROGRAM
gl.glUseProgram(glProgram);
// USE VBOs
gl.glBindBuffer(gl.GL_ARRAY_BUFFER, vbo[0]);
gl.glVertexAttribPointer(0, 2, gl.GL_FLOAT, false, 0, 0); // associate 0th vertex attribute with active buffer
gl.glEnableVertexAttribArray(0); // enable the 0th vertex attribute
// DRAW POINT
gl.glDrawArrays(GL2.GL_POINTS, 0, 1);
}
@Override
public void init(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2();
// CREATE PROGRAM
glProgram = gl.glCreateProgram();
// CREATE VERTEX SHADER
int vertexShader = gl.glCreateShader(GL2.GL_VERTEX_SHADER);
int geometryShader = gl.glCreateShader(GL2.GL_GEOMETRY_SHADER_BIT);
int fragmentShader = gl.glCreateShader(GL2.GL_FRAGMENT_SHADER);
// LOAD SOURCE CODE
String[] vertexShaderSource = readShader("VertexShader1.glsl");
gl.glShaderSource(vertexShader, vertexShaderSource.length, vertexShaderSource, null, 0);
gl.glCompileShader(vertexShader);
String[] geometryShaderSource = readShader("GeometryShader1.glsl");
gl.glShaderSource(geometryShader, geometryShaderSource.length, geometryShaderSource, null, 0);
gl.glCompileShader(geometryShader);
String[] fragmentShaderSource = readShader("FragmentShader1.glsl");
gl.glShaderSource(fragmentShader, fragmentShaderSource.length, fragmentShaderSource, null, 0);
gl.glCompileShader(fragmentShader);
// ATTACH VERTEX SHADER TO PROGRAM, LINK AND DELETE SHADERS
gl.glAttachShader(glProgram, vertexShader);
gl.glAttachShader(glProgram, geometryShader);
gl.glAttachShader(glProgram, fragmentShader);
gl.glLinkProgram(glProgram);
gl.glDeleteShader(vertexShader);
gl.glDeleteShader(geometryShader);
gl.glDeleteShader(fragmentShader);
// CREATE VAO
gl.glGenVertexArrays(1, vao, 0);
gl.glBindVertexArray(vao[0]);
// COORDINATES SQUARES
float[] coordinatesSquare1 = new float[]{0.5f, 0.5f};
// CREATE VBOs
gl.glGenBuffers(1, vbo, 0);
// POPULATE VBO 1 FOR SQUARE 1
gl.glBindBuffer(gl.GL_ARRAY_BUFFER, vbo[0]);
FloatBuffer bufferSquare1 = Buffers.newDirectFloatBuffer(coordinatesSquare1);
gl.glBufferData(gl.GL_ARRAY_BUFFER, bufferSquare1.limit()*4, bufferSquare1, gl.GL_STATIC_DRAW);
}
@Override
public void dispose(GLAutoDrawable drawable) {
}
@Override
public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
System.out.println("reshape");
this.display(drawable);
}
private String[] readShader(String filename) {
Vector<String> lines = new Vector<String>();
try (Stream<String> stream = Files.lines(Paths.get(filename))) {
stream.forEach(x -> lines.add(x));
} catch (IOException e) {
e.printStackTrace();
}
// CONVERT VECTOR TO ARRAY
Object[] objArray = lines.toArray();
String[] array = Arrays.copyOf(objArray, objArray.length, String[].class);
return array;
}
}
package openglexample1;
import java.util.Date;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import javax.swing.WindowConstants;
public class OpenGLExample2 {
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
// THIRD WINDOW
WindowC basicFrame3 = new WindowC();
basicFrame3.setTitle("WindowC");
basicFrame3.setLocation(400,400);
basicFrame3.setVisible(true);
basicFrame3.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
}
}
package openglexample1;
import com.jogamp.common.nio.Buffers;
import com.jogamp.opengl.GL3;
import com.jogamp.opengl.GLAutoDrawable;
import com.jogamp.opengl.GLCapabilities;
import com.jogamp.opengl.GLEventListener;
import com.jogamp.opengl.GLProfile;
import com.jogamp.opengl.awt.GLCanvas;
import com.jogamp.opengl.glu.GLU;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.FloatBuffer;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.Vector;
import java.util.stream.Stream;
import javax.swing.JFrame;
public class WindowC extends JFrame implements GLEventListener {
/**
* @return the glcanvas
*/
public GLCanvas getGlcanvas() {
return glcanvas;
}
//getting the capabilities object of GL2 profile
final private GLProfile profile;
final private GLCapabilities capabilities;
final private GLCanvas glcanvas;
// GL PROGAM
private int glProgram;
// VAO AND VBOs
private int vao[] = new int[1]; // VAO GROUPS VBOs, ONLY ONE USED
private int vbo[] = new int[2]; // 2 VBOs FOR 2 SQUARES
public WindowC() {
// OpenGL CAPABILITIES
profile = GLProfile.get(GLProfile.GL3);
capabilities = new GLCapabilities(profile);
// CANVAS
glcanvas = new GLCanvas(capabilities);
glcanvas.addGLEventListener(this);
glcanvas.setSize(400, 400);
// JFRAME
this.getContentPane().add(glcanvas);
this.setSize(this.getContentPane().getPreferredSize());
}
@Override
public void display(GLAutoDrawable drawable) {
GL3 gl = drawable.getGL().getGL3();
// USE PROGRAM
gl.glUseProgram(glProgram);
// USE VBOs
gl.glBindBuffer(gl.GL_ARRAY_BUFFER, vbo[0]);
gl.glVertexAttribPointer(0, 2, gl.GL_FLOAT, false, 0, 0); // associate 0th vertex attribute with active buffer
gl.glEnableVertexAttribArray(0); // enable the 0th vertex attribute
// DRAW POINT
gl.glDrawArrays(GL3.GL_POINTS, 0, 1);
}
@Override
public void init(GLAutoDrawable drawable) {
GL3 gl = drawable.getGL().getGL3();
// CREATE PROGRAM
glProgram = gl.glCreateProgram();
// CREATE VERTEX SHADER
int vertexShader = gl.glCreateShader(GL3.GL_VERTEX_SHADER);
int geometryShader = gl.glCreateShader(GL3.GL_GEOMETRY_SHADER);
int fragmentShader = gl.glCreateShader(GL3.GL_FRAGMENT_SHADER);
// LOAD SOURCE CODE
String[] vertexShaderSource = readShader("VertexShader1.glsl");
gl.glShaderSource(vertexShader, vertexShaderSource.length, vertexShaderSource, null, 0);
gl.glCompileShader(vertexShader);
String[] geometryShaderSource = readShader("GeometryShader1.glsl");
gl.glShaderSource(geometryShader, geometryShaderSource.length, geometryShaderSource, null, 0);
gl.glCompileShader(geometryShader);
String[] fragmentShaderSource = readShader("FragmentShader1.glsl");
gl.glShaderSource(fragmentShader, fragmentShaderSource.length, fragmentShaderSource, null, 0);
gl.glCompileShader(fragmentShader);
// ATTACH VERTEX SHADER TO PROGRAM, LINK AND DELETE SHADERS
gl.glAttachShader(glProgram, vertexShader);
gl.glAttachShader(glProgram, geometryShader);
gl.glAttachShader(glProgram, fragmentShader);
gl.glLinkProgram(glProgram);
gl.glDeleteShader(vertexShader);
gl.glDeleteShader(geometryShader);
gl.glDeleteShader(fragmentShader);
// CREATE VAO
gl.glGenVertexArrays(1, vao, 0);
gl.glBindVertexArray(vao[0]);
// COORDINATES SQUARES
float[] coordinatesSquare1 = new float[]{0.5f, 0.5f};
// CREATE VBOs
gl.glGenBuffers(1, vbo, 0);
// POPULATE VBO 1 FOR SQUARE 1
gl.glBindBuffer(gl.GL_ARRAY_BUFFER, vbo[0]);
FloatBuffer bufferSquare1 = Buffers.newDirectFloatBuffer(coordinatesSquare1);
gl.glBufferData(gl.GL_ARRAY_BUFFER, bufferSquare1.limit()*4, bufferSquare1, gl.GL_STATIC_DRAW);
}
@Override
public void dispose(GLAutoDrawable drawable) {
}
@Override
public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
System.out.println("reshape");
this.display(drawable);
}
private String[] readShader(String filename) {
Vector<String> lines = new Vector<String>();
try (Stream<String> stream = Files.lines(Paths.get(filename))) {
stream.forEach(x -> lines.add(x));
} catch (IOException e) {
e.printStackTrace();
}
// CONVERT VECTOR TO ARRAY
Object[] objArray = lines.toArray();
String[] array = Arrays.copyOf(objArray, objArray.length, String[].class);
return array;
}
}
#version 330 core
layout (points) in;
layout (points, max_vertices = 4) out;
void main() {
gl_Position = gl_in[0].gl_Position + vec4(-0.2, -0.2, 0.0, 0.0);
EmitVertex();
EndPrimitive();
gl_Position = gl_in[0].gl_Position + vec4(-0.2, +0.2, 0.0, 0.0);
EmitVertex();
EndPrimitive();
gl_Position = gl_in[0].gl_Position + vec4(+0.2, +0.2, 0.0, 0.0);
EmitVertex();
EndPrimitive();
gl_Position = gl_in[0].gl_Position + vec4(+0.2, -0.2, 0.0, 0.0);
EmitVertex();
EndPrimitive();
}