post_processing.cpp

#include "post_proccesing.h"

float quadVertices[] =
{
       -1.0f,  1.0f,  0.0f, 1.0f,
       -1.0f, -1.0f,  0.0f, 0.0f,
        1.0f, -1.0f,  1.0f, 0.0f,

       -1.0f,  1.0f,  0.0f, 1.0f,
        1.0f, -1.0f,  1.0f, 0.0f,
        1.0f,  1.0f,  1.0f, 1.0f
};

PostProcessingQuad::PostProcessingQuad(unsigned int width, unsigned int height)
{
    SetupQuad();
    SetupFBO();
    SetupTCB(width, height);
    SetupRBO(width, height);
};

void PostProcessingQuad::UpdateResolution(int width, int height)
{
    SetupTCB(width, height);
    SetupRBO(width, height);
}

void PostProcessingQuad::Draw(ShaderProgram& shader)
{
    glUniform1i(glGetUniformLocation(shader.shaderProgram, "screentexture"), 0);
    glBindTexture(GL_TEXTURE_2D, tcb);
    glBindVertexArray(quadVAO);
    glDrawArrays(GL_TRIANGLES, 0, 6);
}

void PostProcessingQuad::SetupFBO()
{
    glGenFramebuffers(1, &framebuffer);
    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
}

void PostProcessingQuad::SetupTCB(const int SCR_WIDTH, const int SCR_HEIGHT)
{
    glGenTextures(1, &tcb);
    glBindTexture(GL_TEXTURE_2D, tcb);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, SCR_WIDTH, SCR_HEIGHT, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRROR_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRROR_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tcb, 0);
}

void PostProcessingQuad::SetupRBO(const int SCR_WIDTH, const int SCR_HEIGHT)
{
    glGenRenderbuffers(1, &rbo);
    glBindRenderbuffer(GL_RENDERBUFFER, rbo);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, SCR_WIDTH, SCR_HEIGHT);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rbo);
    if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
        std::cout << "ERROR::FRAMEBUFFER:: Framebuffer is not complete!" << std::endl;
    glBindFramebuffer(GL_FRAMEBUFFER, 0);

}

void PostProcessingQuad::SetupQuad()
{
    glGenVertexArrays(1, &quadVAO);
    glGenBuffers(1, &quadVBO);
    glBindVertexArray(quadVAO);
    glBindBuffer(GL_ARRAY_BUFFER, quadVBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), &quadVertices, GL_STATIC_DRAW);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)(2 * sizeof(float)));
}