I am relatively new to OpenGL, so this question might seem a bit trivial. I have this code in my Main.java, which is supposed to output a rectangle with the texture of the image on it:
float vertices[] = {
// positions // colors // texture coords
0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // top right
0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // bottom right
-0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, // bottom left
-0.5f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f // top left
};
int indices[] = {
0, 1, 3, // first triangle
1, 2, 3 // second triangle
};
int VBO = glGenBuffers(), VAO = glGenVertexArrays(), EBO = glGenBuffers();
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices, GL_STATIC_DRAW);
// position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, false, 8, 0);
glEnableVertexAttribArray(0);
// color attribute
glVertexAttribPointer(1, 3, GL_FLOAT, false, 8, 2);
glEnableVertexAttribArray(1);
// texture coord attribute
glVertexAttribPointer(2, 2, GL_FLOAT, false, 8, 5);
glEnableVertexAttribArray(2);
Texture texture = null;
try {
log.info("Loading texture");
texture = Texture.loadTexture("texture.png");
} catch (IOException e) {
log.severe("Texture loading failed due to IOException: " + e.getMessage());
e.printStackTrace();
}
while (!glfwWindowShouldClose(window))
{
glClear(GL_COLOR_BUFFER_BIT);
if(mainProgram != null) {
mainProgram.use();
}
glBindTexture(GL_TEXTURE_2D, texture.getId());
glBindVertexArray(VAO);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
//...
}
My shaders are the following: Vertex Shader:
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout(location = 2) in vec2 aTexCoord;
out vec3 vertexColor;
out vec2 texCoord;
void main()
{
gl_Position = vec4(aPos , 1.0);
vertexColor = aColor;
texCoord = aTexCoord;
}
Fragment Shader:
#version 330 core
out vec4 FragColor;
in vec3 ourColor;
in vec2 TexCoord;
// texture sampler
uniform sampler2D texture1;
void main()
{
FragColor = texture(texture1, TexCoord);
}
The Texture class referenced above is the following:
public class Texture {
public static Texture loadTexture(String fileName) throws IOException{
//load png file
PNGDecoder decoder = new PNGDecoder(new java.io.FileInputStream(new File("C:/Users/Using/Absolute/Paths/For/Demonstration/texture.png")));
//create a byte buffer big enough to store RGBA values
ByteBuffer buffer = BufferUtils.createByteBuffer(4 * decoder.getWidth() * decoder.getHeight());
//decode
decoder.decode(buffer, decoder.getWidth() * 4, PNGDecoder.Format.RGBA);
//flip the buffer so its ready to read
buffer.flip();
//create a texture
int id = glGenTextures();
//bind the texture
glBindTexture(GL_TEXTURE_2D, id);
//tell opengl how to unpack bytes
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
//set the texture parameters, can be GL_LINEAR or GL_NEAREST
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
//upload texture
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, decoder.getWidth(), decoder.getHeight(), 0, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
// Generate Mip Map
glGenerateMipmap(GL_TEXTURE_2D);
return new Texture(id);
}
private int id;
public Texture(int id){
this.id = id;
}
public int getId(){
return id;
}
}
Note that the path of the texture image is not the problem, as the code works without any Exceptions or Compiler errors. The PNGDecoder i used can be found here.
