From 88fc14e2bfed72dbc6a653eeb96a41832eae06d1 Mon Sep 17 00:00:00 2001
From: Harry <harrysjh98@gmail.com>
Date: Tue, 21 Mar 2017 20:30:37 +0000
Subject: [PATCH] Added a simple render-to-texture ability via FrameBuffer

---
 res/runtime/resources.data |  4 +++-
 src/texture.cpp            | 49 ++++++++++++++++++++++++++++++++++----
 src/texture.hpp            | 12 +++++++++-
 3 files changed, 58 insertions(+), 7 deletions(-)

diff --git a/res/runtime/resources.data b/res/runtime/resources.data
index 2aea7edb82..3b65708a8a 100644
--- a/res/runtime/resources.data
+++ b/res/runtime/resources.data
@@ -79,4 +79,6 @@ speed: 2.5
 
 
 
-played: 117352
+
+
+played: 117375
diff --git a/src/texture.cpp b/src/texture.cpp
index 30e0317f75..08a0e1d052 100644
--- a/src/texture.cpp
+++ b/src/texture.cpp
@@ -1,5 +1,49 @@
 #include "texture.hpp"
 
+FrameBuffer::FrameBuffer(unsigned int width, unsigned int height): width(width), height(height), fbHandle(0)
+{
+	glGenFramebuffers(1, &this->fbHandle);
+	glBindFramebuffer(GL_FRAMEBUFFER, this->fbHandle);
+	
+	glGenTextures(1, &this->texHandle);
+	glBindTexture(GL_TEXTURE_2D, this->texHandle);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, this->width, this->height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
+	
+	//Filtering
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	
+	glGenRenderbuffers(1, &this->depthRenderBufferHandle);
+	glBindRenderbuffer(GL_RENDERBUFFER, this->depthRenderBufferHandle);
+	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, this->width, this->height);
+	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, this->depthRenderBufferHandle);
+	
+	//Configure framebuffer
+	glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, this->texHandle, 0);
+	GLenum drawBuffers[1] = {GL_COLOR_ATTACHMENT0};
+	glDrawBuffers(1, drawBuffers);
+	
+	if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
+	{
+		//problim
+	}
+}
+
+void FrameBuffer::setRenderTarget() const
+{
+	glBindFramebuffer(GL_FRAMEBUFFER, this->fbHandle);
+	glViewport(0, 0, this->width, this->height);
+}
+
+void FrameBuffer::bind(unsigned int id) const
+{
+	assert(id >= 0 && id <= 31);
+	// this sets which texture we want to bind (id can be from 0 to 31)
+	// GLTEXTURE0 is actually a number, so we can add the id instead of a massive switch statement
+	glActiveTexture(GL_TEXTURE0 + id);
+	glBindTexture(GL_TEXTURE_2D, this->texHandle);
+}
+
 unsigned char* Texture::loadTexture()
 {
 	return stbi_load((this->filename).c_str(), &(this->width), &(this->height), &(this->comps), 4);
@@ -66,11 +110,6 @@ void Texture::bind(GLuint shaderProgram, unsigned int id)
 	glUniform1i(this->textureID, id);
 }
 
-void Texture::setRenderTarget() const
-{
-	
-}
-
 std::string Texture::getFileName() const
 {
 	return this->filename;
diff --git a/src/texture.hpp b/src/texture.hpp
index cf67474f6d..230c06fc56 100644
--- a/src/texture.hpp
+++ b/src/texture.hpp
@@ -12,13 +12,23 @@
 #endif
 #include "glew.h"
 
+class FrameBuffer
+{
+public:
+	FrameBuffer(unsigned int width = 256, unsigned int height = 256);
+	void setRenderTarget() const;
+	void bind(unsigned int id) const;
+private:
+	unsigned int width, height;
+	GLuint fbHandle, texHandle, depthRenderBufferHandle;
+};
+
 class Texture
 {
 public:
 	Texture(std::string filename = "./res/textures/undefined.jpg");
 	~Texture();
 	void bind(GLuint shaderProgram, unsigned int id);
-	void setRenderTarget() const;
 	std::string getFileName() const;
 	static std::shared_ptr<Texture> getFromLink(std::string textureLink, std::vector<std::shared_ptr<Texture>> allTextures);
 protected: