SpriteBatch.h

#ifndef NTA_SPRITEBATCH_H_INCLUDED
#define NTA_SPRITEBATCH_H_INCLUDED
 
#include <vector>
 
#include "nta/Vertex.h"
#include "nta/utils.h"
 
#define NTA_DEFAULT_DEPTH 0.5
 
namespace nta {
    struct Glyph {
        Glyph(crvec4 posRect, crvec4 uvRect, GLuint texture, float d, crvec4 color) :
            textureID(texture), depth(d) {
            topLeft.setPosition(posRect.x, posRect.y);
            topLeft.setUV(uvRect.x, uvRect.y);
            topLeft.color = color;
            topLeft.hasTexture = texture != 0;
            topRight.setPosition(posRect.x + posRect[2], posRect.y);
            topRight.setUV(uvRect.x + uvRect[2], uvRect.y);
            topRight.color = color;
            topRight.hasTexture = texture != 0;
            botRight.setPosition(posRect.x + posRect[2], posRect.y - posRect[3]);
            botRight.setUV(uvRect.x + uvRect[2], uvRect.y + uvRect[3]);
            botRight.color = color;
            botRight.hasTexture = texture != 0;
            botLeft.setPosition(posRect.x, posRect.y - posRect[3]);
            botLeft.setUV(uvRect.x, uvRect.y + uvRect[3]);
            botLeft.color = color;
            botLeft.hasTexture = texture != 0;
        }
        Glyph(crvec4 posRect, crvec4 uvRect, GLuint tex, float d, crvec4 col, float angle) :
            textureID(tex), depth(d) {
            glm::vec2 extents(posRect[2]/2.f, posRect[3]/2.f), pos(posRect.x, posRect.y);
            glm::vec2 tl(-extents.x, extents.y),  tr(extents.x, extents.y),
                      bl(-extents.x, -extents.y), br(extents.x, -extents.y);
 
            topLeft.pos = utils::rotate(tl, angle) - tl + pos;
            topLeft.setUV(uvRect.x, uvRect.y);
            topLeft.color = col;
            topLeft.hasTexture = tex != 0;
            topRight.pos = utils::rotate(tr, angle) - tl + pos;
            topRight.setUV(uvRect.x + uvRect[2], uvRect.y);
            topRight.color = col;
            topRight.hasTexture = tex != 0;
            botRight.pos = utils::rotate(br, angle) - tl + pos;
            botRight.setUV(uvRect.x + uvRect[2], uvRect.y + uvRect[3]);
            botRight.color = col;
            botRight.hasTexture = tex != 0;
            botLeft.pos = utils::rotate(bl, angle) - tl + pos;
            botLeft.setUV(uvRect.x, uvRect.y + uvRect[3]);
            botLeft.color = col;
            botLeft.hasTexture = tex != 0;
        }
        GLuint textureID;
        float depth;
        Vertex2D topLeft;
        Vertex2D topRight;
        Vertex2D botRight;
        Vertex2D botLeft;
    };
    struct RenderBatch {
        RenderBatch(GLuint t, GLuint o, GLuint n, GLenum m = GL_TRIANGLES) :
            textureID(t), offset(o), numVertices(n), mode(m) {
        }
        GLuint textureID;
        GLuint offset;
        GLuint numVertices;
        GLenum mode;
    };
    class SpriteBatch {
    private:
        void createVertexArrayObject();
        void createRenderBatches();
        void sortGlyphs();
        static bool compareTexture(Glyph* lhs, Glyph* rhs);
        static bool compareDepth(Glyph* lhs, Glyph* rhs);
        std::vector<Glyph*> m_glyphPointers;
        std::vector<Glyph> m_glyphs;
        std::vector<RenderBatch> m_renderBatches;
        GLuint m_vao = 0;
        GLuint m_vbo = 0;
    public:
        SpriteBatch();
        ~SpriteBatch();
        void init();
        void begin();
        void end();
        void addGlyph(crvec4 posRect, GLuint texture = 0, 
                      crvec4 uvRect = glm::vec4(0,0,1,1), 
                      crvec4 color = glm::vec4(1),
                      float depth = NTA_DEFAULT_DEPTH);
        void addGlyph(crvec4 posRect, crvec4 uvRect, GLuint texture, 
                      float depth = NTA_DEFAULT_DEPTH, crvec4 color = glm::vec4(1));
        void addGlyph(crvec2 corner1, crvec2 corner2, crvec4 uvRect, GLuint texture, 
                      float depth = NTA_DEFAULT_DEPTH, crvec4 color = glm::vec4(1));
        void addGlyph(crvec4 posRect, crvec4 uvRect, GLuint texture, crvec4 color, 
                      float angle = 0.0f, float depth = NTA_DEFAULT_DEPTH);
        void addGlyph(crvec2 corner1, crvec2 corner2, crvec4 uvRect, GLuint texture, crvec4 color,
                      float angle = 0.0f, float depth = NTA_DEFAULT_DEPTH);
        void render() const;
    };
}
 
#endif // NTA_SPRITEBATCH_H_INCLUDED