Added framebuffer objects to allow postprocessing on a texture of the screen

This commit is contained in:
Nigel Barink 2022-10-16 18:26:50 +02:00
parent 3d4d81f260
commit d8e87b4787
9 changed files with 322 additions and 50 deletions

10
Framebuffers.fs Normal file
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@ -0,0 +1,10 @@
#version 460 core
out vec4 FragColor;
in vec2 TexCoords;
uniform sampler2D screenTexure;
void main(){
FragColor = texture(screenTexure, TexCoords);
}

12
Framebuffers.vs Normal file
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@ -0,0 +1,12 @@
#version 460 core
layout (location = 0) in vec2 aPos;
layout (location = 1) in vec2 aTexCoords;
out vec2 TexCoords;
void main()
{
gl_Position = vec4(aPos, 0.0f, 1.0f);
TexCoords = aTexCoords;
}

42
src/FrameBuffer.cpp Normal file
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@ -0,0 +1,42 @@
#include "FrameBuffer.hpp"
void FrameBuffer::Bind()
{
glBindFramebuffer(GL_FRAMEBUFFER, id);
}
void FrameBuffer::Unbind()
{
glBindFramebuffer(GL_FRAMEBUFFER, 0);
}
void FrameBuffer::Attach(const Texture& texture)
{
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture.id, 0);
}
void FrameBuffer::Attach(const RenderBuffer& renderbuffer)
{
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, renderbuffer.id);
}
bool FrameBuffer::IsComplete()
{
return glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE;
}
FrameBuffer::FrameBuffer()
{
glGenFramebuffers(1, &id );
}
FrameBuffer::~FrameBuffer()
{
glDeleteFramebuffers(1, &id);
}

22
src/FrameBuffer.hpp Normal file
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@ -0,0 +1,22 @@
#pragma once
#include <glad/glad.h>
#include "texture.h"
#include "RenderBuffer.hpp"
class FrameBuffer
{
public:
GLuint id;
void Bind();
void Unbind();
void Attach(const Texture& texture);
void Attach(const RenderBuffer& renderbuffer);
bool IsComplete();
FrameBuffer();
~FrameBuffer();
};

25
src/RenderBuffer.cpp Normal file
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@ -0,0 +1,25 @@
#include "RenderBuffer.hpp"
void RenderBuffer::UseDepthAndStencil (){
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, 800, 600); /// NOTE: should be part of creating but kept seperate for now!
}
void RenderBuffer::Bind()
{
glBindRenderbuffer(GL_RENDERBUFFER, id);
}
void RenderBuffer::Unbind()
{
glBindRenderbuffer(GL_RENDERBUFFER, 0);
}
RenderBuffer::RenderBuffer()
{
glGenRenderbuffers(1, &id);
}
RenderBuffer::~RenderBuffer()
{
glDeleteRenderbuffers(GL_RENDERBUFFER, &id);
}

17
src/RenderBuffer.hpp Normal file
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@ -0,0 +1,17 @@
#pragma once
#include <glad/glad.h>
class RenderBuffer
{
public:
unsigned int id;
void Bind();
void Unbind();
void UseDepthAndStencil();
RenderBuffer();
~RenderBuffer();
};

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@ -11,6 +11,10 @@
#include "shader.h" #include "shader.h"
#include "camera.h" #include "camera.h"
#include "model.h" #include "model.h"
#include "FrameBuffer.hpp"
#include "RenderBuffer.hpp"
// https://learnopengl.com/Advanced-OpenGL/Framebuffers
float deltaTime = 0.0f; // Time between current frame and last frame float deltaTime = 0.0f; // Time between current frame and last frame
float lastFrame = 0.0f; // Time of last frame float lastFrame = 0.0f; // Time of last frame
@ -19,8 +23,23 @@ Camera camera(glm::vec3(0.0f, 0.0f, 8.0f));
float lastX = 400, lastY = 300; float lastX = 400, lastY = 300;
bool firstMouse = true; bool firstMouse = true;
glm::mat4 model = glm::mat4(1.0f);
glm::mat4 view;
glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)800 / (float)600, 0.1f, 100.0f);
glm::vec3 lightpos(-0.2f, -1.0f, -0.3f); glm::vec3 lightpos(-0.2f, -1.0f, -0.3f);
std::vector<float> ScreenVertices = {
// vertex , uv
-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,
} ;
void framebuffer_size_callback(GLFWwindow* window, int width, int height) { void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
glViewport(0,0, width, height); glViewport(0,0, width, height);
} }
@ -40,7 +59,6 @@ void processInput( GLFWwindow* window){
camera.ProcessKeyboard(RIGHT,deltaTime); camera.ProcessKeyboard(RIGHT,deltaTime);
} }
void mouse_callback(GLFWwindow* window, double xpos, double ypos){ void mouse_callback(GLFWwindow* window, double xpos, double ypos){
if (firstMouse) // initially set to true if (firstMouse) // initially set to true
{ {
@ -62,8 +80,8 @@ void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
camera.ProcessMouseScroll(yoffset); camera.ProcessMouseScroll(yoffset);
} }
int main() { GLFWwindow* CreateWindowWithOpenGLContext()
printf("Hello OpenGL!\n"); {
glfwInit(); glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4); glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 6); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 6);
@ -74,13 +92,13 @@ int main() {
if( window == NULL){ if( window == NULL){
printf("Failed to create GLFW window!\n"); printf("Failed to create GLFW window!\n");
glfwTerminate(); glfwTerminate();
return -1; return nullptr;
} }
glfwMakeContextCurrent(window); glfwMakeContextCurrent(window);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)){ if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)){
printf("Failed to initialize GLAD!\n"); printf("Failed to initialize GLAD!\n");
return -1; return nullptr;
} }
glViewport(0,0, 800, 600); glViewport(0,0, 800, 600);
@ -89,40 +107,14 @@ int main() {
glfwSetCursorPosCallback(window, mouse_callback); glfwSetCursorPosCallback(window, mouse_callback);
glfwSetScrollCallback(window, scroll_callback); glfwSetScrollCallback(window, scroll_callback);
glEnable(GL_DEPTH_TEST); return window;
stbi_set_flip_vertically_on_load(true);
}
Shader shader ("shader.vs", "shader.fs"); void drawScene_pass(Shader& shader, Model& Object)
Shader outlineShader("shader.vs","outlineshader.fs");
Model backpack("Models/backpack.obj");
glEnable(GL_DEPTH_TEST);
glEnable(GL_STENCIL_TEST);
glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
///glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
while(!glfwWindowShouldClose(window))
{ {
float currentFrame = glfwGetTime(); glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
deltaTime = currentFrame - lastFrame; glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
lastFrame = currentFrame;
// std::cout << "Delta Time: " << deltaTime << std::endl;
processInput(window);
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
glm::mat4 model = glm::mat4(1.0f);
glm::mat4 view = camera.GetViewMatrix();
glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)800 / (float)600, 0.1f, 100.0f);
model = glm::mat4(1.0);
glStencilFunc(GL_ALWAYS, 1, 0xff); glStencilFunc(GL_ALWAYS, 1, 0xff);
glStencilMask(0xFF); glStencilMask(0xFF);
@ -131,37 +123,165 @@ while(!glfwWindowShouldClose(window))
shader.setMat4("view", view); shader.setMat4("view", view);
shader.setMat4("projection", projection); shader.setMat4("projection", projection);
Object.Draw(shader);
}
backpack.Draw(shader); void outline_pass( Shader& shader, Model& Object)
{
glStencilFunc(GL_NOTEQUAL, 1, 0xFF); glStencilFunc(GL_NOTEQUAL, 1, 0xFF);
glStencilMask(0x00); glStencilMask(0x00);
glDisable(GL_DEPTH_TEST); glDisable(GL_DEPTH_TEST);
outlineShader.use(); shader.use();
outlineShader.setMat4("model", model); shader.setMat4("model", model);
outlineShader.setMat4("view", view); shader.setMat4("view", view);
outlineShader.setMat4("projection", projection); shader.setMat4("projection", projection);
outlineShader.setVec3("outlineColor", glm::vec3(0.28, 0.10, 0.26)); shader.setVec3("outlineColor", glm::vec3(0.28, 0.10, 0.26));
model = glm::scale(model, glm::vec3(1.05f,1.05f, 1.05f)); model = glm::scale(model, glm::vec3(1.05f,1.05f, 1.05f));
// model = glm::translate(model, glm::vec3(1.0f, 0.0f, 0.0f)); shader.setMat4("model", model);
outlineShader.setMat4("model", model);
Object.Draw(shader);
}
void DrawToScreen( GLuint& VAO, GLuint& ScreenTexture, Shader& shader)
{
// draw to screen
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glDisable(GL_DEPTH_TEST);
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
backpack.Draw(outlineShader); shader.use();
shader.setInt("screenTexture",0);
glBindVertexArray(VAO);
glBindTexture(GL_TEXTURE_2D, ScreenTexture);
glDrawArrays(GL_TRIANGLES, 0, 6);
}
int main() {
printf("Hello OpenGL!\n");
// Setup OpenGL Context
GLFWwindow* window = CreateWindowWithOpenGLContext();
if(window == nullptr)
return -1;
glEnable(GL_DEPTH_TEST);
stbi_set_flip_vertically_on_load(true);
// Load scene resources
Shader shader ("shader.vs", "shader.fs");
Shader outlineShader("shader.vs","outlineshader.fs");
Shader framebufferShader("Framebuffers.vs", "Framebuffers.fs" );
Model backpack("Models/backpack.obj");
// Framebuffer outline effect
FrameBuffer outlineFrameBuffer = FrameBuffer();
outlineFrameBuffer.Bind();
// Create a texture attachment (colour attachment)
Texture* depthTexture = CreateTexture(800,600);
// attach texture to the frame buffer as a colour attachment
outlineFrameBuffer.Attach(*depthTexture);
// Add depth buffer attachment
RenderBuffer outlineRenderBuffer = RenderBuffer();
outlineRenderBuffer.Bind();
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, 800, 600);
outlineRenderBuffer.Unbind();
// attach depth buffer to our framebuffer
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, outlineRenderBuffer.id);
outlineFrameBuffer.Unbind();
// Post processing
FrameBuffer framebuffer = FrameBuffer();
framebuffer.Bind();
Texture* ColourBuffer = CreateTexture(800,600);
framebuffer.Attach(*ColourBuffer);
RenderBuffer renderbufferObject = RenderBuffer();
renderbufferObject.Bind();
renderbufferObject.UseDepthAndStencil();
renderbufferObject.Unbind();
framebuffer.Attach(renderbufferObject);
if(framebuffer.IsComplete() == false ){
std::cout << "ERROR::FRAMEBUFFER::Framebuffer is not complete! " << std::endl;
}
framebuffer.Unbind();
// Create ScreenVAO
GLuint ScreenVAO, VBO;
glGenVertexArrays(1, &ScreenVAO);
glBindVertexArray(ScreenVAO);
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, ScreenVertices.size() * sizeof(float), &ScreenVertices[0], 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)));
glBindVertexArray(0);
glEnable(GL_DEPTH_TEST);
glEnable(GL_STENCIL_TEST);
glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
while(!glfwWindowShouldClose(window))
{
float currentFrame = glfwGetTime();
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
processInput(window);
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
// Recalculate the Camera's view matrix
view = camera.GetViewMatrix();
// Reset the model matrix to an identity matrix
model = glm::mat4(1.0f);
framebuffer.Bind();
drawScene_pass(shader, backpack);
outline_pass(outlineShader, backpack);
// Reset stencil
glStencilMask(0xFF); glStencilMask(0xFF);
glStencilFunc(GL_ALWAYS, 1, 0xFF); glStencilFunc(GL_ALWAYS, 1, 0xFF);
glEnable(GL_DEPTH_TEST); glEnable(GL_DEPTH_TEST);
DrawToScreen(ScreenVAO, ColourBuffer->id, framebufferShader);
glfwSwapBuffers(window); glfwSwapBuffers(window);
glfwPollEvents(); glfwPollEvents();
} }
delete ColourBuffer;
delete depthTexture;
glfwTerminate(); glfwTerminate();
return 0; return 0;

20
src/texture.cpp Normal file
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@ -0,0 +1,20 @@
#include "texture.h"
Texture* CreateTexture(unsigned int width, unsigned int height)
{
Texture* result = new Texture();
glGenTextures(1, &result->id);
glBindTexture(GL_TEXTURE_2D, result->id);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glBindTexture(GL_TEXTURE_2D, 0);
return result;
}

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@ -1,8 +1,12 @@
#pragma once #pragma once
#include <string> #include <string>
#include <glad/glad.h>
struct Texture{ struct Texture{
unsigned int id; GLuint id;
std::string type; std::string type;
std::string path; std::string path;
}; };
Texture* CreateTexture(unsigned int width, unsigned int height);