#include "programs.h"
#include <glm/glm.hpp>

//---
// 2D Texture shader
//---

ProgramTexture::ProgramTexture(): Program()
{
    glBindVertexArray(this->vao);
    glEnableVertexAttribArray(0);
    glEnableVertexAttribArray(1);

    // TODO: Better way to access Azur's internal shaders
    extern char const *azur_glsl__vs_tex2d;
    extern char const *azur_glsl__fs_tex2d;

    this->prog = azur::gl::loadProgramSources(
        GL_VERTEX_SHADER,   azur_glsl__vs_tex2d,
        GL_FRAGMENT_SHADER, azur_glsl__fs_tex2d,
        0);
}

void ProgramTexture::set_vertex_attributes() const
{
    glVertexAttribPointer(glGetAttribLocation(this->prog, "a_vertex"),
       2, GL_FLOAT, GL_FALSE,
       sizeof(ProgramTexture_Attributes),
       (void *)offsetof(ProgramTexture_Attributes, vertex)
    );
    glVertexAttribPointer(glGetAttribLocation(this->prog, "a_texture_pos"),
       2, GL_FLOAT, GL_FALSE,
       sizeof(ProgramTexture_Attributes),
       (void *)offsetof(ProgramTexture_Attributes, uv)
    );
}

void ProgramTexture::add_texture(int x, int y, int width, int height)
{
    ProgramTexture_Attributes attr[4] = {
        { glm::vec2(x,       y),        glm::vec2(0.0, 0.0) },
        { glm::vec2(x+width, y),        glm::vec2(1.0, 0.0) },
        { glm::vec2(x,       y+height), glm::vec2(0.0, 1.0) },
        { glm::vec2(x+width, y+height), glm::vec2(1.0, 1.0) },
    };

    this->vertices.push_back(attr[0]);
    this->vertices.push_back(attr[1]);
    this->vertices.push_back(attr[2]);
    this->vertices.push_back(attr[1]);
    this->vertices.push_back(attr[2]);
    this->vertices.push_back(attr[3]);
}