Mandelbrot not working!

OpenGL OpenGL: Basic Coding
1

Hi, this code gives me blackscreen, what is wrong? i want to use pallet to choose color from instead of an iter /100 or etc!

2

updated code:

#version 330 core

out vec4 pixelColor;
in vec2 coord;

uniform sampler1D tex;

void main()
{
    float   real  = coord.x;
    float   imag  = coord.y;

    float   Creal = real;  
    float   Cimag = imag;  

    int MaxIterations = 1000;

    float r2 = 0.0;

    float iter;

    for (iter = 0.0; iter < MaxIterations && r2 < 4.0; ++iter)
    {
        float tempreal = real;

        real = (tempreal * tempreal) - (imag * imag) + Creal;
        imag = 2.0 * tempreal * imag + Cimag;
        r2   = (real * real) + (imag * imag);
    }

    vec4 color;

    highp int iterint = int(iter);

    color =  texture1D(tex, (iter == MaxIterations ? 0.0 : iter) / 100.0);

    pixelColor = vec4(color.xyz, 1.0);
}

but i get blackscreen

main.cpp:

// GLEW
#define GLEW_STATIC
#include <GL/glew.h>

// GLFW
#include <GLFW/glfw3.h>

// GL includes
#include "Shader.h"

// GLM Mathemtics
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

// Other Libs
#include <SOIL/SOIL.h>

// Function prototypes
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);

// The MAIN function, from here we start our application and run our Program/Game loop
int main()
{
    // Init GLFW
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);

    GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", nullptr, nullptr); // Windowed
    glfwMakeContextCurrent(window);

    // Set the required callback functions
    glfwSetKeyCallback(window, key_callback);

    // Initialize GLEW to setup the OpenGL Function pointers
    glewExperimental = GL_TRUE;
    glewInit();

    // Define the viewport dimensions
    glViewport(0, 0, 800, 600);

    // Build and compile our shader program
    Shader shader("vertex.vs", "fragment.frag");

    // Set up our vertex data (and buffer(s)) and attribute pointers
    //GLfloat vertices[] = {
    //  // First triangle
    //  1.0f, 1.0f,	// Top Right
    //  1.0f, -1.0f,	// Bottom Right
    //  -1.0f, 1.0f, // Top Left 
    //  // Second triangle
    //  1.0f, -1.0f, // Bottom Right
    //  -1.0f, -1.0f, // Bottom Left
    //  -1.0f, 1.0f // Top Left
    //}; 
    GLfloat vertices[] = {
      1.0f, 1.0f,	// Top Right
      1.0f, -1.0f,	// Bottom Right
      -1.0f, -1.0f,  // Bottom Left
      -1.0f, 1.0f	// Top Left 
    };
    GLuint indices[] = {  // Note that we start from 0!
        0, 1, 3,	// First Triangle
        1, 2, 3		// Second Triangle
    };
    GLuint VBO, VAO, EBO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);
    glGenBuffers(1, &EBO);
    // Bind our Vertex Array Object first, then bind and set our buffers and pointers.
    glBindVertexArray(VAO);

    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, (GLvoid*)0);
    glEnableVertexAttribArray(0);

    glBindVertexArray(0); // Unbind VAO (it's always a good thing to unbind any buffer to prevent strange bugs), remember: do NOT unbind the EBO, keep it bound to this VAO

    // Uncommenting this call will result in wireframe polygons.
    //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

	GLuint texture;
	glGenTextures(1, &texture);  
	glBindTexture(GL_TEXTURE_1D, texture); 
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    int width, height;
	unsigned char* image = SOIL_load_image("pal.ppm", 
	  &width, &height, 0, SOIL_LOAD_RGB); 
	glTexImage1D(GL_TEXTURE_1D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
	glGenerateMipmap(GL_TEXTURE_1D);
	SOIL_free_image_data(image);
	glBindTexture(GL_TEXTURE_2D, 0);

    // Game loop
    while(!glfwWindowShouldClose(window))
    {
        // Check and call events
        glfwPollEvents();

        // Render
        // Clear the colorbuffer
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        // Draw our first triangle
        shader.Use();
        glBindTexture(GL_TEXTURE_1D, texture);
        glBindVertexArray(VAO);
        //glDrawArrays(GL_TRIANGLES, 0, 6);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        glBindVertexArray(0);

        // Swap the buffers
        glfwSwapBuffers(window);
    }

    glfwTerminate();
    return 0;
}

// Is called whenever a key is pressed/released via GLFW
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
    cout << key << endl;
    if(key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GL_TRUE);
}
3

bump :frowning: does anybody know whats wrong with this?:frowning: i only have problem with getting the 1d texture . other than that code works fine with iter / 100.0

4

glTexImage1D() doesn’t have a [var]height[/var] parameter. In fact, it only takes 8 parameters, but you’ve given 9. The compiler should have complained about that.

There’s not much point in generating a mipmap if you’re using GL_NEAREST.

5

omg thanks ! how can i be so stupid :smiley: + the bitmap was there from previous app :slight_smile: