GLSL random segfault

OpenGL OpenGL: Basic Coding
1

I was making a Julia set, and everything worked fine, but then I moved my vertices code into a vertex shader, and then suddenly I had a segfault at glLinkProgram(shaderProgram);

I have no idea why, as before when I checked the logs for each shader, they compiled fine with no errors, and the same code works completely fine in a different project

Code for compiling shaders/linking

    glGenBuffers(1,&vbo);
    glBindBuffer(GL_ARRAY_BUFFER,vbo);
    glBufferData(GL_ARRAY_BUFFER,sizeof(vertices),vertices,GL_STATIC_DRAW);
    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader,1,&pVertex,NULL);
    glCompileShader(vertexShader);
    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader,1,&pFragment,NULL);
    glCompileShader(fragmentShader);

    GLuint shaderProgram = glCreateProgram();

    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);
    glUseProgram(shaderProgram);

Code for Fragment Shader:

#version 130

uniform sampler1D tex;

uniform vec2 c;
uniform int iter;


void main()
{
	vec2 z;
	z.x = 3.0 * (gl_TexCoord[0].x - 0.5);
	z.y = 2.0 * (gl_TexCoord[0].y - 0.5);
	
	int i;
	for (i=0;i<iter;i++)
	{
		float x = (z.x * z.x - z.y * z.y) + c.x;
		float y = (z.y * z.x + z.x * z.y) + c.y;
		
		if ((x * x + y * y) > 4.0) break;
		z.x = x;
		z.y = y;
		
	}
	gl_FragColor = texture1D(tex, (i == iter ? 0.0 : float(i)) / 100.0);
}

Code for Vertex shader:

#version 130

attribute vec4 position;


void main()
{
	gl_Position = vec4(position.xyz, 1.0);
}
2

Alright, so now I’ve got the code working, but if I attempt to draw with glDrawArrays(…); it doesn’t display anything, but does not fail if i manually draw with glBegin(); and glEnd();

This is what I’m using to load the texture, and bind it

    glUniform1i(texUniform,0);
    glTexParameteri(GL_TEXTURE_1D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
    glTexParameteri(GL_TEXTURE_1D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
    glTexParameteri(GL_TEXTURE_1D,GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_1D,GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE);
    unsigned char *tex = SOIL_load_image("pal.png",&width,&height,0,SOIL_LOAD_RGBA);
    if (tex == 0)
    {
        std::cout << "Error loading texture";
    }
    glActiveTexture(GL_TEXTURE0 + 0);
    glTexImage1D(GL_TEXTURE_1D,0,GL_RGBA,600,0,GL_RGBA,GL_UNSIGNED_BYTE,tex);
3

did you check for any compilation / linking errors ??
did you check for any GL errors ??

https://www.opengl.org/wiki/Shader_Compilation#Example
https://www.opengl.org/wiki/OpenGL_Error

once you call glActiveTexture(…), you have to call (again) glBindTexture(…)

4

All error logs I have set up return “No Errors”

I’ll try what you said though

Edit: I’ve done what you said but to no avail, same thing


    glUniform1i(texUniform,0);
    glActiveTexture(GL_TEXTURE0 + 0);
    glBindTexture(GL_TEXTURE_1D,tex);
5

Issue’s resolved now; even using OpenGL 4.5 hints, GLEW says that glGenFramebuffers isn’t present, even though my hardware is physically capable of using FBOs, so I decided to just draw with legacy code instead :doh: