shapes.cpp

#include "shapes.h"

Rectangle::Rectangle() : Rectangle(0.0f, 0.0f, black)
{
	offset = glm::vec2(0.0f);
	width = 0.0f;
	height = 0.0f;
	color = glm::vec3(0.0f);
	transparency = 0.0f;

	shader = Shader("vertexShader_shapes.vert", "fragmentShader_shapes.frag");
}

Rectangle::Rectangle(float x, float y, float width, float height,
	glm::vec3 color)
{
	offset = glm::vec2(x, y);
	this->width = width;
	this->height = height;
	this->color = color;
	transparency = 0.0f;

	shader = Shader("vertexShader_shapes.vert", "fragmentShader_shapes.frag");

	setup();
}

Rectangle::Rectangle(float x, float y, float width, float height,
	glm::vec3 color, float transparency)
{
	offset = glm::vec2(x, y);
	this->width = squareSize;
	this->height = squareSize;
	this->color = color;
	this->transparency = transparency;

	shader = Shader("vertexShader_shapes.vert", "fragmentShader_shapes.frag");

	setup();
}

Rectangle::Rectangle(float x, float y, glm::vec3 color)
{
	offset = glm::vec2(x, y);
	this->width = squareSize;
	this->height = squareSize;
	this->color = color;
	transparency = 0.0f;

	shader = Shader("vertexShader_shapes.vert", "fragmentShader_shapes.frag");

	setup();
}

Rectangle::Rectangle(float x, float y, glm::vec3 color, float transparency)
{
	offset = glm::vec2(x, y);
	this->width = squareSize;
	this->height = squareSize;
	this->color = color;
	this->transparency = transparency;

	shader = Shader("vertexShader_shapes.vert", "fragmentShader_shapes.frag");

	setup();
}

Rectangle::Rectangle(Position pos, glm::vec3 color, float transparency)
{
	offset = posToCoord(pos);
	this->width = squareSize;
	this->height = squareSize;
	this->color = color;
	this->transparency = transparency;

	shader = Shader("vertexShader_shapes.vert", "fragmentShader_shapes.frag");

	setup();
}

void Rectangle::setup()
{
	float x = offset.x;
	float y = offset.y;

	float vertices[8] = {
		// bottom left
		(2.0f / SCR_WIDTH) * x - 1.0f, (2.0f / 768.0f) * y - 1.0f,
		// top left
		(2.0f / SCR_HEIGHT) * x - 1.0f, (2.0f / 768.0f) * (y + height) - 1.0f,
		// bottom right
		(2.0f / SCR_WIDTH) * (x + width) - 1.0f, (2.0f / 768.0f) * y - 1.0f,
		// top right
		(2.0f / SCR_WIDTH) * (x + width) - 1.0f,
		(2.0f / SCR_HEIGHT) * (y + height) - 1.0f
	};

	unsigned int indices[6] = {
		0, 1, 2, // 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);

	// positions
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), (void*)0);

	glBindBuffer(GL_ARRAY_BUFFER, 0);
	glBindVertexArray(0);
}

void Rectangle::draw()
{
	shader.use();
	shader.set3f("color", color);
	shader.set1f("transparency", transparency);

	glBindVertexArray(VAO);
	glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
	glBindVertexArray(0);
}