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//
// Created by saintruler on 04.05.19.
//
#ifndef OPENGLTEST_CANVAS_H
#define OPENGLTEST_CANVAS_H
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
struct Color
{
unsigned int r = 0, g = 0, b = 0;
};
class Canvas
{
public:
Canvas(int width, int height)
{
// vertices = {
// // positions // colors // texture coords
// 1.f, 1.f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // top right
// 1.f, -1.f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // bottom right
// -1.f, -1.f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, // bottom left
// -1.f, 1.f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f // top left
// };
//
// indices = {
// 0, 1, 3, // first triangle
// 1, 2, 3 // second triangle
// };
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glGenBuffers(1, &EBO);
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);
// position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
// color attribute
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
// texture coord attribute
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
glEnableVertexAttribArray(2);
this->width = width;
this->height = height;
canvas = (unsigned char*) malloc(width * height * 3);
glGenTextures(1, &texture);
}
void SetPixel(int x, int y, Color color)
{
canvas[y * width * 3 + x * 3 + 0] = color.r;
canvas[y * width * 3 + x * 3 + 1] = color.g;
canvas[y * width * 3 + x * 3 + 2] = color.b;
UpdateTexture();
}
void UpdateTexture()
{
// all upcoming GL_TEXTURE_2D operations now have effect on this texture object
glBindTexture(GL_TEXTURE_2D, texture);
// set texture wrapping to GL_REPEAT (default wrapping method)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// set texture filtering parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, width, 0, GL_RGB, GL_UNSIGNED_BYTE, canvas);
glGenerateMipmap(GL_TEXTURE_2D);
}
void DrawTexture()
{
glBindTexture(GL_TEXTURE_2D, texture);
// render container
// ourShader.use();
glBindVertexArray(VAO);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
}
unsigned int* GetTexture()
{
return &(this->texture);
}
private:
int width, height;
unsigned char* canvas;
unsigned int texture;
unsigned int VBO, VAO, EBO;
float* vertices;
unsigned int* indices;
};
#endif //OPENGLTEST_CANVAS_H
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