我试图在这个tutorial中使用java中的opengl绘制纹理，一切都运行良好，直到我试图绘制纹理。它只绘制了一个彩色的盒子，但没有纹理。
这是我的代码：
package main;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.FloatBuffer;
import java.util.Scanner;
import org.lwjgl.BufferUtils;
import org.lwjgl.LWJGLException;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import org.newdawn.slick.opengl.Texture;
import org.newdawn.slick.opengl.TextureLoader;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL15.*;
import static org.lwjgl.opengl.GL20.*;
import static org.lwjgl.opengl.GL30.*;
//OpenGL version: 4.4.0
public class OpenGLTester {
final static int SIZE_OF_FLOAT = 4;
final int screenWidth = 1000;
final int screenHeight = 800;
int program;
final float[] vertices = {
// Position Color Texcoords
-0.5f, 0.5f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, // Top-left
0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // Top-right
0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, // Bottom-right
-0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f // Bottom-left
};
final byte[] elements = {
0, 1, 2,
2, 3, 0
};
private int vao;
private int vbo;
private int vertexShader;
private int fragmentShader;
private int ebo;
private FloatBuffer verticiesBuffer;
private ByteBuffer indicesBuffer;
private Texture texture;
public OpenGLTester() {
createDisplay();
initOpenGL();
while(!Display.isCloseRequested()) {
// Clear the screen to black
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
texture.bind();
glDrawElements(GL_TRIANGLES, indicesBuffer);
Display.update();
Display.sync(60);
}
glDeleteProgram(program);
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
glDeleteBuffers(vbo);
glDeleteBuffers(ebo);
glDeleteVertexArrays(vao);
texture.release();
}
private void createDisplay() {
//make display (this also automatically sets up the open glcontext
try {
Display.setDisplayMode(new DisplayMode(screenWidth, screenHeight));
Display.create();
} catch (LWJGLException e) {
e.printStackTrace();
}
}
private void initOpenGL() {
//do vao shit that is shit
vao = glGenVertexArrays();
glBindVertexArray(vao);
//give it the vertices, indices, and texture
vbo = glGenBuffers();
glBindBuffer(GL_ARRAY_BUFFER, vbo);
verticiesBuffer = BufferUtils.createFloatBuffer(vertices.length);
verticiesBuffer.put(vertices);
verticiesBuffer.flip();
glBufferData(GL_ARRAY_BUFFER, verticiesBuffer, GL_STATIC_DRAW);
indicesBuffer = BufferUtils.createByteBuffer(elements.length);
indicesBuffer.put(elements);
indicesBuffer.flip();
int tex = glGenTextures();
glBindTexture(GL_TEXTURE_2D, tex);
try {
texture = TextureLoader.getTexture("PNG", new FileInputStream("texture.png"));
ByteBuffer textureByteBuffer = BufferUtils.createByteBuffer(texture.getTextureData().length);
textureByteBuffer.put(texture.getTextureData());
textureByteBuffer.flip();
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, (int)texture.getWidth(), (int)texture.getHeight(), 0, GL_RGB, GL_BYTE, textureByteBuffer);
} catch (IOException e) {
System.out.println("texture didnt load correctly.");
}
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
//read in and compile the vertex shader
vertexShader = glCreateShader(GL_VERTEX_SHADER);
String vertexShaderSource = readInFile("VertexShader.txt");
glShaderSource(vertexShader, vertexShaderSource);
glCompileShader(vertexShader);
System.out.println(glGetShaderInfoLog(vertexShader, 512)); //print errors from vertex shader
//read in and compile the fragment shader
fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
String fragmentShaderSource = readInFile("FragmentShader.txt");
glShaderSource(fragmentShader, fragmentShaderSource);
glCompileShader(fragmentShader);
System.out.println(glGetShaderInfoLog(fragmentShader, 512)); //print errors from fragment shader
//combine the vertex and fragment shader into a program
program = glCreateProgram();
glAttachShader(program, vertexShader);
glAttachShader(program, fragmentShader);
glBindFragDataLocation(program, 0, "outColor");
glLinkProgram(program);
glUseProgram(program);
//tell opengl how to read in the vertex data
int positionAttribute = glGetAttribLocation(program, "position");
glVertexAttribPointer(positionAttribute, 2, GL_FLOAT, false, 7 * SIZE_OF_FLOAT, 0);
glEnableVertexAttribArray(positionAttribute);
int colorAttribute = glGetAttribLocation(program, "color");
glVertexAttribPointer(colorAttribute, 3, GL_FLOAT, false, 7 * SIZE_OF_FLOAT, 2 * SIZE_OF_FLOAT);
glEnableVertexAttribArray(colorAttribute);
int texAttrib = glGetAttribLocation(program, "texcoord");
glVertexAttribPointer(texAttrib, 2, GL_FLOAT, false, 7 * SIZE_OF_FLOAT, 5 * SIZE_OF_FLOAT);
glEnableVertexAttribArray(texAttrib);
ebo = glGenBuffers();
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, ebo, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}
private String readInFile(String name) {
File f = new File(name);
String out = "";
try {
Scanner s = new Scanner(f);
while(s.hasNextLine()) {
out += s.nextLine() + "\n";
}
s.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return out;
}
public static void main(String[] args) {
new OpenGLTester();
}
}
这是我的顶点着色器：
#version 150
in vec2 position;
in vec3 color;
in vec2 texcoord;
out vec3 Color;
out vec2 Texcoord;
void main() {
Color = color;
gl_Position = vec4(position, 0.0, 1.0);
Texcoord = texcoord;
}
和我的片段着色器
#version 150
in vec3 Color;
in vec2 Texcoord;
out vec4 outColor;
uniform sampler2D tex;
void main()
{
outColor = texture(tex, Texcoord) * vec4(Color, 1.0);
}
答案 0 :(得分：1)
uniform不是魔法。您必须抓住他们的位置（glGetUniformLocation()）并实际上传一些内容（glUniform()），以便包含有用信息。
与纹理单元索引类似，例如：
...
int texAttrib = glGetAttribLocation(program, "texcoord");
glVertexAttribPointer(texAttrib, 2, GL_FLOAT, false, 7 * SIZE_OF_FLOAT, 5 * SIZE_OF_FLOAT);
glEnableVertexAttribArray(texAttrib);
int texUnit = 0;
int texUniform = glGetUniformLocation( program, "tex" );
glUniform1i( texUniform, texUnit );
glActiveTexture( GL_TEXTURE0 + texUnit );
glBindTexture( GL_TEXTURE_2D, tex );
...