I have a homework on Textures and I try to load a picture on my cube. Despite that, when I compile I only see my cube colored grey, but I dont understand why.
This is my Java code,from where the cube coordinates and the uv coordinates are passed to the shaders:
import static org.lwjgl.opengl.GL11.GL_FLOAT;
import static org.lwjgl.opengl.GL11.GL_TRIANGLES;
import static org.lwjgl.opengl.GL11.glDrawArrays;
import static org.lwjgl.opengl.GL15.GL_ARRAY_BUFFER;
import static org.lwjgl.opengl.GL15.GL_STATIC_DRAW;
import static org.lwjgl.opengl.GL15.glBindBuffer;
import static org.lwjgl.opengl.GL15.glBufferData;
import static org.lwjgl.opengl.GL15.glGenBuffers;
import static org.lwjgl.opengl.GL20.glEnableVertexAttribArray;
import static org.lwjgl.opengl.GL20.glVertexAttribPointer;
import static org.lwjgl.opengl.GL30.*;
import lenz.opengl.AbstractOpenGLBase;
import lenz.opengl.ShaderProgram;
import lenz.opengl.Texture;
public class Aufgabe3undFolgende extends AbstractOpenGLBase {
public Matrix4 matrix = new Matrix4();
public Matrix4 projMatrix = new Matrix4(0.8f,500f);
//Coordinates for cube, which is in the center of the screen
float[] cube = {
-1.0f,-1.0f,-1.0f, // triangle 1 : begin
-1.0f,-1.0f, 1.0f,
-1.0f, 1.0f, 1.0f, // triangle 1 : end
1.0f, 1.0f,-1.0f, // triangle 2 : begin
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f,-1.0f, // triangle 2 : end
1.0f,-1.0f, 1.0f,
-1.0f,-1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
-1.0f, 1.0f,-1.0f,
1.0f,-1.0f, 1.0f,
-1.0f,-1.0f, 1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
-1.0f,-1.0f, 1.0f,
1.0f,-1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f, 1.0f,
1.0f,-1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
1.0f, 1.0f,-1.0f,
-1.0f, 1.0f,-1.0f,
1.0f, 1.0f, 1.0f,
-1.0f, 1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
-1.0f, 1.0f, 1.0f,
1.0f,-1.0f, 1.0f
};
//UV Coordinates for texturing
float[] uvKoord = {
0.0f, 0.0f, // lower-left corner
1.0f, 0.0f, // lower-right corner
0.5f, 1.0f
};
private ShaderProgram shaderProgram;
public static void main(String[] args) {
new Aufgabe3undFolgende().start("CG Aufgabe 3", 700, 700);
}
@Override
protected void init() {
shaderProgram = new ShaderProgram("aufgabe3");
glUseProgram(shaderProgram.getId());
//vao bauen
int vaold = glGenVertexArrays();
glBindVertexArray(vaold);
makeVBOS(0,3,cube);
makeVBOS(1,2,uvKoord);
glEnable(GL_DEPTH_TEST); // z-Buffer activate
Texture texture = new Texture("pikatcu.png");
glBindTexture(GL_TEXTURE_2D, texture.getId());
}
//vbos bauen (jeder vbo ist ein Objekt) -- delete
public void makeVBOS(int index, int size, float[] name) {
int vbold = glGenBuffers();
glBindBuffer(GL_ARRAY_BUFFER, vbold);
glBufferData(GL_ARRAY_BUFFER, name, GL_STATIC_DRAW);
glVertexAttribPointer(index,size, GL_FLOAT, false, 0,0);
glEnableVertexAttribArray(index);
}
@Override
public void update() {
matrix = new Matrix4();
matrix.translate(0, 0, -3);
matrix.rotateZ(0.1f);
}
@Override
protected void render() {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
int loc
=glGetUniformLocation(shaderProgram.getId(),"viewMatrix");
glUniformMatrix4fv(loc,false,
matrix.getValuesAsArray());
int loc2
=glGetUniformLocation(shaderProgram.getId(),"projMatrix");
glUniformMatrix4fv(loc2,false,
projMatrix.getValuesAsArray());
glDrawArrays(GL_TRIANGLES, 0, 36); // 12*3 indices starting at
0 -> 12 triangles -> 6 squares
}
@Override
public void destroy() {
}
}
This is my vertex shader:
#version 330
layout(location=0) in vec3 vertex;
layout(location=1) in vec2 uvKoord;
uniform mat4 viewMatrix;
uniform mat4 projMatrix;
out vec3 vertexColor;
out vec2 uv;
void main(){
vertexColor = vec3(1.0, 0.0, 0.0);
uv=uvKoord;
gl_Position = projMatrix*viewMatrix*vec4(vertex, 1.0);
}
And this is my fragment shader:
#version 330
in vec3 vertexColor;
in vec2 uv;
out vec3 pixelColor;
uniform sampler2D smplr;
void main(){
vec4 texel = texture(smplr,uv);
pixelColor = texel.rgb;
}
Could someone help me understand what I am doing wrong? I would really apreciate an explanation and not just code as I would like to understand my mistake and not just copy the code. Thanks in advance.
PS: The class Texture was give from my lecturer. I did not upload this because I thought the post would get too long, but I can provide it if needed. The picture I am loading is this one https://mytoys.scene7.com/is/image/myToys/ext/7980544-01.jpg?$rtf_mt_prod-main_xl$ and I have changed its resolution to 256x256.
