glSpriteRenderer.h

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#ifndef GLSPRITERENDERER_H
#define GLSPRITERENDERER_H
 
#include <jGL/OpenGL/Shader/glShader.h>
#include <jGL/OpenGL/gl.h>
#include <jGL/spriteRenderer.h>
 
namespace jGL::GL
{
    class glSpriteRenderer : public SpriteRenderer
    {
    public:
 
        glSpriteRenderer(size_t sizeHint)
        : SpriteRenderer(sizeHint)
        {
            xytheta = std::vector<float>(sizeHint*xythetaDim+padSprites*xythetaDim,0.0f);
            scale = std::vector<float>(sizeHint*scaleDim+padSprites*scaleDim,0.0f);
            textureRegion = std::vector<float>(sizeHint*textureRegionDim+padSprites*textureRegionDim,0.0f);
            textureOptions = std::vector<float>(sizeHint*textureOptionsDim+padSprites*textureOptionsDim,0.0f);
            initGL();
            shader = std::make_shared<glShader>(vertexShader, fragmentShader);
            shader->use();
        }
 
        ~glSpriteRenderer()
        {
            freeGL();
        }
 
    private:
 
        void draw
        (
            std::shared_ptr<Shader> shader,
            std::vector<std::pair<Info, Sprite>> & sprites
        );
 
        GLuint vao, a_position, a_xytheta, a_scale, a_textureRegion, a_textureOption;
 
        float quad[6*4] =
        {
            // positions  / texture coords
            0.5f,  0.5f, 1.0f, 1.0f,    // top right
            0.5f,  -0.5f, 1.0f, 0.0f,   // bottom right
            -0.5f,  -0.5f, 0.0f, 0.0f,  // bottom left
            -0.5f,  0.5f, 0.0f, 1.0f,   // top left
            -0.5f,  -0.5f, 0.0f, 0.0f,  // bottom left
            0.5f,  0.5f, 1.0f, 1.0f     // top right
        };
 
        std::vector<float> xytheta;
        size_t xythetaDim = 3;
        size_t xythetaAttribute = 1;
 
        std::vector<float> scale;
        size_t scaleDim = 2;
        size_t scaleAttribute = 2;
 
        std::vector<float> textureRegion;
        size_t textureRegionDim = 4;
        size_t textureRegionAttribute = 3;
 
        std::vector<float> textureOptions;  // texture unit, alpha
        size_t textureOptionsDim = 2;
        size_t textureOptionsAttribute = 4;
 
        size_t padSprites = 8;
 
        void initGL();
        void freeGL();
 
        const char * vertexShader =
            "#version " GLSL_VERSION "\n"
            "precision lowp float; precision lowp int;\n"
            "layout(location=0) in vec4 a_position;\n"
            "layout(location=1) in vec3 a_xytheta;\n"
            "layout(location=2) in vec2 a_scale;\n"
            "layout(location=3) in vec4 a_textureOffset;\n"
            "layout(location=4) in vec2 a_textureOptions;\n"
            "uniform mat4 proj;\n"
            "out vec2 texCoord;\n"
            "flat out float alpha;\n"
            "flat out int tex;\n"
            "void main(){"
                "vec2 pos = a_position.xy*a_scale;\n"
                "float ct = cos(a_xytheta.z); float st = sin(a_xytheta.z);\n"
                "mat2 rot = mat2(ct, -st, st, ct);\n"
                "pos = rot*pos + a_xytheta.xy;\n"
                "gl_Position = proj*vec4(pos,0.0,1.0);\n"
                "texCoord.x = (a_position.z * a_textureOffset.z)+a_textureOffset.x;\n"
                "texCoord.y = (a_position.w * a_textureOffset.w)+a_textureOffset.y;\n"
                "tex = int(a_textureOptions.x);\n"
                "alpha = a_textureOptions.y;\n"
            "}";
 
        const char * fragmentShader =
            "#version " GLSL_VERSION "\n"
            "precision lowp float; precision lowp int;\n"
            "uniform sampler2D sampler0;\n"
            "uniform sampler2D sampler1;\n"
            "uniform sampler2D sampler2;\n"
            "uniform sampler2D sampler3;\n"
            "in vec2 texCoord;\n"
            "flat in float alpha;\n"
            "flat in int tex;\n"
            "layout(location=0) out vec4 colour;\n"
            "void main(){\n"
                // is this mental?
                "if (tex == 0) {colour = texture(sampler0, texCoord);}\n"
                "else if (tex == 1) {colour = texture(sampler1, texCoord);}\n"
                "else if (tex == 2) {colour = texture(sampler2, texCoord);}\n"
                "else if (tex == 3) {colour = texture(sampler3, texCoord);}\n"
                "else {colour = vec4(0.0,0.0,0.0,alpha);}\n"
                "colour.a = colour.a*alpha;\n"
                ";\n"
            "}";
 
    };
}
 
#endif /* GLSPRITERENDERER_H */