OGLQuadRenderer.cpp

#include "OGLQuadRenderer.h"
#include "OGLProgram.h"
#include "OrthoCamera.h"
#include <glm/glm.hpp>
#include <glm/ext.hpp>
#include <vector>
#include "Quad.h"

OGLQuadRender::OGLQuadRender() 
{
        Program = new OGLProgram("resources/shaders/quadcolor.vert", "resources/shaders/quadcolor.frag");

        std::vector<float> Vertices = {
            0.5f, -0.5f, 0.0f, //bottom right
           -0.5f, -0.5f, 0.0f, //bottom left
           -0.5f,  0.5f, 0.0f, //top left

           -0.5f,  0.5f, 0.0f, //top left
            0.5f,  0.5f, 0.0f, //top right
            0.5f, -0.5f, 0.0f  //bottom right
    };

        //1. Create VAO
    glGenVertexArrays(1, &Vao);
    glBindVertexArray(Vao);

    //2. Create VBO to load data
    glGenBuffers(1, &Vbo);
    glBindBuffer(GL_ARRAY_BUFFER, Vbo);

    int DataSize = Vertices.size() * sizeof(float);
    glBufferData(GL_ARRAY_BUFFER, DataSize, Vertices.data(), GL_STATIC_DRAW);

    //3. Link to Vertex Shader
    GLuint Location_0 = 0;
    glVertexAttribPointer(Location_0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(Location_0);

    glClearColor(0, 0, 0, 0);
}

void OGLQuadRender::Draw(const std::vector<Quad*>& Quads, const OrthoCamera* Cam) 
{
    glViewport(0, 0, Cam->GetResoWidth(), Cam->GetResoHeight());
    glClear(GL_COLOR_BUFFER_BIT);

    glBindVertexArray(Vao);
    Program->Bind();
    auto VP = Cam->GetViewProjMat();

    static glm::mat4 uniMat = glm::mat4(1.0f);
    for (size_t i = 0; i < Quads.size(); i++)
    {
        auto* Each = Quads[i];

        glm::mat4 Translate = glm::translate(uniMat, Each->Position);
        glm::mat4 Rotate = glm::mat4_cast(glm::quat( glm::vec3(glm::radians(Each->Rotation.x), glm::radians(Each->Rotation.y), glm::radians(Each->Rotation.z)) ));
        glm::mat4 Scale = glm::scale(uniMat, Each->Scale);
        glm::mat4 Model = Translate * Rotate * Scale;

        glm::mat4 Mvp = VP * Model;

        Program->SetUniform("mvp", Mvp);
        Program->SetUniform("color", Each->Color);
        glDrawArrays(GL_TRIANGLES, 0, 6);
    }
}