Image.cpp

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/*
 * =====================================================================================
 *
 *       Filename:  Image.cpp
 *
 *    Description:
 *
 *        Created:  20/09/2014 16:22:12
 *
 *         Author:  Quentin Bazin, <gnidmoo@gmail.com>
 *
 * =====================================================================================
 */
#define GLM_FORCE_RADIANS
#include <glm/gtc/matrix_transform.hpp>

#include "gk/gl/GLCheck.hpp"
#include "gk/gl/Texture.hpp"
#include "gk/gl/Vertex.hpp"
#include "gk/graphics/Image.hpp"
#include "gk/resource/ResourceHandler.hpp"

namespace gk {

Image::Image(const std::string &textureName) {
    load(ResourceHandler::getInstance().get<Texture>(textureName));
}

Image::Image(const Texture &texture) {
    load(texture);
}

void Image::load(const Image &image) {
    m_texture = image.m_texture;

    m_width = image.m_width;
    m_height = image.m_height;

    m_clipRect = image.m_clipRect;
    m_posRect = image.m_posRect;

    m_color = image.m_color;

    updateVertexBuffer();
}

void Image::load(const std::string &textureName) {
    load(ResourceHandler::getInstance().get<Texture>(textureName));
}

void Image::load(const Texture &texture) {
    m_texture = &texture;

    m_width = m_texture->width();
    m_height = m_texture->height();

    setClipRect(0, 0, m_width, m_height);
    setPosRect(0, 0, m_width, m_height);
}

void Image::setClipRect(float x, float y, u16 width, u16 height) {
    m_clipRect = gk::FloatRect(x, y, width, height);

    m_posRect.width = width;
    m_posRect.height = height;

    updateVertexBuffer();
}

void Image::setPosRect(float x, float y, u16 width, u16 height) {
    m_posRect = gk::FloatRect(x, y, width, height);

    updateVertexBuffer();
}

void Image::updateVertexBuffer() const {
    Vertex vertices[4] = {
        {{m_posRect.x + m_posRect.width, m_posRect.y,                    0, -1}},
        {{m_posRect.x,                   m_posRect.y,                    0, -1}},
        {{m_posRect.x,                   m_posRect.y + m_posRect.height, 0, -1}},
        {{m_posRect.x + m_posRect.width, m_posRect.y + m_posRect.height, 0, -1}},
    };

    FloatRect texRect{
        m_clipRect.x / float(m_width),
        m_clipRect.y / float(m_height),
        m_clipRect.width / float(m_width),
        m_clipRect.height / float(m_height)
    };

    if (!m_isFlipped) {
        vertices[0].texCoord[0] = texRect.x + texRect.width;
        vertices[0].texCoord[1] = texRect.y;
        vertices[1].texCoord[0] = texRect.x;
        vertices[1].texCoord[1] = texRect.y;
        vertices[2].texCoord[0] = texRect.x;
        vertices[2].texCoord[1] = texRect.y + texRect.height;
        vertices[3].texCoord[0] = texRect.x + texRect.width;
        vertices[3].texCoord[1] = texRect.y + texRect.height;
    }
    else {
        vertices[0].texCoord[0] = texRect.x;
        vertices[0].texCoord[1] = texRect.y;
        vertices[1].texCoord[0] = texRect.x + texRect.width;
        vertices[1].texCoord[1] = texRect.y;
        vertices[2].texCoord[0] = texRect.x + texRect.width;
        vertices[2].texCoord[1] = texRect.y + texRect.height;
        vertices[3].texCoord[0] = texRect.x;
        vertices[3].texCoord[1] = texRect.y + texRect.height;
    }

    for (u8 i = 0 ; i < 4 ; ++i) {
        vertices[i].color[0] = m_color.r;
        vertices[i].color[1] = m_color.g;
        vertices[i].color[2] = m_color.b;
        vertices[i].color[3] = m_color.a;
    }

    VertexBuffer::bind(&m_vbo);
    m_vbo.setData(sizeof(vertices), vertices, GL_DYNAMIC_DRAW);
    VertexBuffer::bind(nullptr);
}

void Image::draw(RenderTarget &target, RenderStates states) const {
    states.transform *= getTransform();

    states.texture = m_texture;
    states.vertexAttributes = VertexAttribute::Only2d;

    glCheck(glDisable(GL_CULL_FACE));
    glCheck(glDisable(GL_DEPTH_TEST));

    static const GLubyte indices[] = {
        0, 1, 3,
        3, 1, 2
    };

    target.drawElements(m_vbo, GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, indices, states);
}

}