Sprite.cpp

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#include "Application.hpp"

SpriteRenderer::SpriteRenderer(Application* app)
    : m_app(app)
    , m_shader(app->getShaders().get("sprite"))
{   
    vec4 data[] = 
    {
        vec4(0,0,0,0),
        vec4(1,1,1,1),
        vec4(0,1,0,1),

        vec4(0,0,0,0),
        vec4(1,0,1,0),
        vec4(1,1,1,1)
    };

    glGenBuffers(1, &m_verticesBuffer);
    glBindBuffer(GL_ARRAY_BUFFER, m_verticesBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(data), data, GL_STREAM_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    glGenVertexArrays(1, &m_vao);
    glBindVertexArray(m_vao);

    glBindBuffer(GL_ARRAY_BUFFER, m_verticesBuffer);
    GLint positionIndex = Shader::position;
    glEnableVertexAttribArray(positionIndex);
    glVertexAttribPointer(positionIndex, 4, GL_FLOAT, GL_FALSE, 0, 0);

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

    m_shader->use();
    m_shader->uniform("tex", (int)0);
}
SpriteRenderer::~SpriteRenderer()
{
    glDeleteBuffers(1, &m_verticesBuffer);
    glDeleteVertexArrays(1, &m_vao);
}

void SpriteRenderer::begin2D()
{
    glDisable(GL_DEPTH_TEST);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glEnable( GL_BLEND );
}
void SpriteRenderer::end2D()
{
    glBindTexture(GL_TEXTURE_2D, 0);

    glEnable(GL_DEPTH_TEST);
    glDisable( GL_BLEND );
}
void SpriteRenderer::begin()
{
    m_shader->use();
    glBindVertexArray(m_vao);
}
void SpriteRenderer::end()
{
    glBindVertexArray(0);
}

void SpriteRenderer::draw(vec4 const & color, vec2 position, vec2 const & scale, vec2 const & uv_scale, HAlign hAlign, VAlign vAlign)
{       
    if (hAlign != HAlign::Left || vAlign != VAlign::Bottom)
    {
        switch(hAlign)
        {
            case(HAlign::Center):  position.x -= scale.x*0.5f; break;
            case(HAlign::Right):   position.x -= scale.x; break;
            default: break;
        }
        switch(vAlign)
        {
            case(VAlign::Middle): position.y -= scale.y*0.5f; break;
            case(VAlign::Top):    position.y -= scale.y; break;
            default: break;
        }
    }
    
    m_shader->uniform("color", color);
    m_shader->uniform("location", position);
    m_shader->uniform("scale", scale);
    m_shader->uniform("uv_scale", uv_scale);

    glDrawArrays(GL_TRIANGLES, 0, 6);   
}