// ----------------------------------------------------------------

// From Game Programming in C++ by Sanjay Madhav

// Copyright (C) 2017 Sanjay Madhav. All rights reserved.

//

// Released under the BSD License

// See LICENSE in root directory for full details.

// ----------------------------------------------------------------

#include "GBuffer.h"

#include <GL/glew.h>

#include "Texture.h"

GBuffer::GBuffer()

:mBufferID(0)

{

}

GBuffer::~GBuffer()

{

}

bool GBuffer::Create(int width, int height)

{

// Create the framebuffer object

glGenFramebuffers(1, &mBufferID);

glBindFramebuffer(GL_FRAMEBUFFER, mBufferID);

// Add a depth buffer to this target

GLuint depthBuffer;

glGenRenderbuffers(1, &depthBuffer);

glBindRenderbuffer(GL_RENDERBUFFER, depthBuffer);

glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT,

width, height);

glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,

GL_RENDERBUFFER, depthBuffer);

// Create textures for each output in the G-buffer

for (int i = 0; i < NUM_GBUFFER_TEXTURES; i++)

{

Texture* tex = new Texture();

// We want three 32-bit float components for each texture

tex->CreateForRendering(width, height, GL_RGB32F);

mTextures.emplace_back(tex);

// Attach this texture to a color output

glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i,

tex->GetTextureID(), 0);

}

// Create a vector of the color attachments

std::vector<GLenum> attachments;

for (int i = 0; i < NUM_GBUFFER_TEXTURES; i++)

{

attachments.emplace_back(GL_COLOR_ATTACHMENT0 + i);

}

// Set the list of buffers to draw to

glDrawBuffers(static_cast<GLsizei>(attachments.size()),

attachments.data());

// Make sure everything worked

if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)

{

Destroy();

return false;

}

return true;

}

void GBuffer::Destroy()

{

glDeleteFramebuffers(1, &mBufferID);

for (Texture* t : mTextures)

{

t->Unload();

delete t;

}

}

Texture* GBuffer::GetTexture(Type type)

{

if (mTextures.size() > 0)

{

return mTextures[type];

}

else

{

return nullptr;

}

}

void GBuffer::SetTexturesActive()

{

for (int i = 0; i < NUM_GBUFFER_TEXTURES; i++)

{

mTextures[i]->SetActive(i);

}

}