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FIrst step in Physically based rendering

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This commit is contained in:
Nigel Barink 2023-05-20 21:20:02 +02:00
parent 4cba6ad37e
commit 7627df0fa0
6 changed files with 313 additions and 6 deletions
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106
Shaders/pbr.fs Normal file
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@ -0,0 +1,106 @@
#version 460 core
out vec4 FragColor;
in vec2 TexCoords;
in vec3 WorldPos;
in vec3 Normal;
uniform vec3 camPos;
uniform vec3 albedo;
uniform float metallic;
uniform float roughness;
uniform float ao;
uniform vec3 lightPositions[4];
uniform vec3 lightColors[4];
const float PI = 3.14159265359;
// ratio Refraction vs Reflection (F function)
vec3 fresnelSchlick (float cosTheta, vec3 F0)
{
return F0 + (1.0 - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
}
// Calculate Normal distribution (D function)
float DistributionGGX(vec3 N , vec3 H, float roughness){
float a = roughness*roughness;
float a2 = a*a;
float NdotH = max(dot(N, H), 0.0);
float NdotH2 = NdotH * NdotH;
float num = a2;
float denom = (NdotH2 * ( a2 - 1.0) + 1.0);
denom = PI * denom * denom;
return num / denom;
}
// G function
float GeometrySchlickGGX(float NdotV, float roughness){
float r = (roughness + 1.0);
float k = (r*r) / 8.0;
float num = NdotV;
float denom = NdotV * (1.0 - k) + k;
return num / denom;
}
float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
{
float NdotV = max(dot(N, V), 0.0);
float NdotL = max(dot(N,L), 0.0);
float ggx2 = GeometrySchlickGGX(NdotV, roughness);
float ggx1 = GeometrySchlickGGX(NdotL, roughness);
return ggx1 * ggx2;
}
void main(){
vec3 N = normalize(Normal);
vec3 V = normalize(camPos - WorldPos);
vec3 F0 = vec3(0.04);
F0 = mix(F0, albedo, metallic);
// Calculate the light contributions of each light source
vec3 Lo = vec3(0.0);
for( int i = 0; i < 4; ++i)
{
vec3 L = normalize(lightPositions[i] - WorldPos);
vec3 H = normalize(V + L);
float distance = length(lightPositions[i] - WorldPos);
float attenuation = 1.0/ (distance*distance);
vec3 radiance = lightColors[i] * attenuation;
float NDF = DistributionGGX(N,H, roughness);
float G = GeometrySmith(N,V,L, roughness);
vec3 F = fresnelSchlick(max(dot(H,V), 0.0), F0);
vec3 kS = F;
vec3 kD = vec3(1.0) - kS;
kD *= 1.0 - metallic;
vec3 numerator = NDF * G * F;
float denominator = 4.0 * max(dot(N,V), 0.0) * max(dot(N, L), 0.0) + 0.0001;
vec3 specular = numerator /denominator;
float NdotL = max(dot(N,L), 0.0);
Lo += (kD * albedo / PI + specular) * radiance * NdotL;
}
// Calculate the ambient term and add it
vec3 ambient = vec3(0.03) * albedo * ao;
vec3 color = ambient + Lo;
// Gamma correct the result
color = color / (color + vec3(1.0));
color = pow(color, vec3(1.0/2.2));
FragColor = vec4(color, 1.0);
}

22
Shaders/pbr.vs Normal file
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@ -0,0 +1,22 @@
#version 460 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aNormal;
layout (location = 2) in vec2 aTexCoords;
out vec2 TexCoords;
out vec3 WorldPos;
out vec3 Normal;
uniform mat4 projection;
uniform mat4 view;
uniform mat4 model;
uniform mat3 normalMatrix;
void main()
{
TexCoords = aTexCoords;
WorldPos = vec3(model * vec4(aPos, 1.0));
Normal = normalMatrix * aNormal;
gl_Position = projection * view * vec4(WorldPos, 1.0);
}

5
src/Primitives/shader.cpp
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@ -111,6 +111,11 @@ void Shader::setMat4(const std::string &name, glm::mat4 value)const{
glUniformMatrix4fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &value[0][0] );
}
void Shader::setMat3(const std::string& name, glm::mat3 value) const
{
glUniformMatrix3fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &value[0][0]);
}
void Shader::setVec3(const std::string &name, glm::vec3 value)const{
glUniform3fv(glGetUniformLocation(ID, name.c_str()), 1, &value.x);
}

1
src/Primitives/shader.h
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@ -22,6 +22,7 @@ class Shader
void setInt(const std::string &name, int value)const;
void setFloat(const std::string &name, float value)const;
void setMat4(const std::string &name, glm::mat4 value)const;
void setMat3(const std::string& name, glm::mat3 value)const;
void setVec3(const std::string &name, glm::vec3 value) const ;
};

180
src/Renderer/Renderer.cpp
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@ -14,11 +14,29 @@ static enum class RenderPass {
NONE = 0,
SKYBOX,
DEFAULT,
PBR
};
const int num_passes = static_cast<int>(RenderPass::DEFAULT) ;
Texture* colourAttachment;
glm::vec3 lightPositions[] = {
glm::vec3(-10.0f, 10.0f, 10.0f),
glm::vec3(10.0f, 10.0f, 10.0f),
glm::vec3(-10.0f, -10.0f, 10.0f),
glm::vec3(10.0f, -10.0f, 10.0f)
};
glm::vec3 lightColors[] = {
glm::vec3(300.0f, 300.0f, 300.0f),
glm::vec3(300.0f, 300.0f, 300.0f),
glm::vec3(300.0f, 300.0f, 300.0f),
glm::vec3(300.0f, 300.0f, 300.0f)
};
int nrRows = 7;
int nrColumns = 7;
float spacing = 2.5;
void Renderer::Setup()
{
@ -49,6 +67,8 @@ void Renderer::Setup()
shaders[static_cast<int>(RenderPass::SKYBOX)].Load("../Shaders/skybox.vs", "../Shaders/Cubemap.fs");
shaders[static_cast<int>(RenderPass::DEFAULT)] = Shader();
shaders[static_cast<int>(RenderPass::DEFAULT)].Load("../Shaders/shader.vs", "../Shaders/shader.fs");
shaders[static_cast<int>(RenderPass::PBR)] = Shader();
shaders[static_cast<int>(RenderPass::PBR)].Load("../Shaders/pbr.vs", "../Shaders/pbr.fs");
}
@ -94,10 +114,107 @@ void Renderer::resize(int width, int height ) {
}
unsigned int sphereVAO = 0;
unsigned int indexCount;
void renderSphere() {
if (sphereVAO == 0) {
glGenVertexArrays(1, &sphereVAO);
unsigned int vbo, ebo;
glGenBuffers(1, &vbo);
glGenBuffers(1, &ebo);
std::vector<glm::vec3> positions;
std::vector<glm::vec2> uv;
std::vector<glm::vec3> normals;
std::vector<unsigned int> indices;
const unsigned int X_SEGMENTS = 64;
const unsigned int Y_SEGMENTS = 64;
const float PI = 3.14159265359f;
for (unsigned int x = 0; x <= X_SEGMENTS; ++x) {
for (unsigned int y = 0; y <= Y_SEGMENTS; ++y) {
float xSegment = (float)x / (float)X_SEGMENTS;
float ySegment = (float)y / (float)Y_SEGMENTS;
float xPos = std::cos(xSegment * 2.0f * PI) * std::sin(ySegment * PI);
float yPos = std::cos(ySegment * PI);
float zPos = std::sin(xSegment * 2.0f * PI) * std::sin(ySegment * PI);
positions.push_back(glm::vec3(xPos, yPos, zPos));
uv.push_back(glm::vec2(xSegment, ySegment));
normals.push_back(glm::vec3(xPos, yPos, zPos));
}
}
bool oddRow = false;
for (unsigned int y = 0; y < Y_SEGMENTS; ++y)
{
if (!oddRow) // even rows: y == 0, y == 2; and so on
{
for (unsigned int x = 0; x <= X_SEGMENTS; ++x)
{
indices.push_back(y * (X_SEGMENTS + 1) + x);
indices.push_back((y + 1) * (X_SEGMENTS + 1) + x);
}
}
else
{
for (int x = X_SEGMENTS; x >= 0; --x)
{
indices.push_back((y + 1) * (X_SEGMENTS + 1) + x);
indices.push_back(y * (X_SEGMENTS + 1) + x);
}
}
oddRow = !oddRow;
}
indexCount = static_cast<unsigned int>(indices.size());
std::vector<float> data;
for (unsigned int i = 0; i < positions.size(); ++i)
{
data.push_back(positions[i].x);
data.push_back(positions[i].y);
data.push_back(positions[i].z);
if (normals.size() > 0)
{
data.push_back(normals[i].x);
data.push_back(normals[i].y);
data.push_back(normals[i].z);
}
if (uv.size() > 0)
{
data.push_back(uv[i].x);
data.push_back(uv[i].y);
}
}
glBindVertexArray(sphereVAO);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, data.size() * sizeof(float), &data[0], GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(unsigned int), &indices[0], GL_STATIC_DRAW);
unsigned int stride = (3 + 2 + 3) * sizeof(float);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, stride, (void*)0);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, stride, (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(2);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, stride, (void*)(6 * sizeof(float)));
}
glBindVertexArray(sphereVAO);
glDrawElements(GL_TRIANGLE_STRIP, indexCount, GL_UNSIGNED_INT, 0);
}
void Renderer::Render(Scene& scene)
{
static RenderPass currentPass = RenderPass::SKYBOX;
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
@ -105,7 +222,7 @@ void Renderer::Render(Scene& scene)
auto view = scene.MainCamera.GetViewMatrix();
auto model = glm::mat4(1.0f);
std::cout << "SKYBOX PASS!" << std::endl;
// Skybox
glDepthMask(GL_FALSE);
Shader shader = shaders.at(static_cast<int>(RenderPass::SKYBOX));
@ -124,7 +241,7 @@ void Renderer::Render(Scene& scene)
glDepthMask(GL_TRUE);
std::cout << "DEFAULT PASS!" << std::endl;
// Phong lighting
shader = shaders.at(static_cast<int>(RenderPass::DEFAULT));
shader.use();
@ -135,7 +252,7 @@ void Renderer::Render(Scene& scene)
scene.skybox.Bind();
glActiveTexture(GL_TEXTURE0);
model = glm::translate(model, glm::vec3(20.0f, 0.0f, 0.0f));
shader.setMat4("model", model);
shader.setMat4("view", view);
shader.setMat4("projection", projection);
@ -143,6 +260,59 @@ void Renderer::Render(Scene& scene)
entity.Draw(shader);
}
scene.skybox.Unbind();
// PBR
shader = shaders.at(static_cast<int>(RenderPass::PBR));
shader.use();
shader.setVec3("albedo", glm::vec3(0.5f, 0.0f, 0.0f));
shader.setFloat("ao", 1.0f);
shader.setMat4("projection", projection);
view = scene.MainCamera.GetViewMatrix();
shader.setMat4("view", view);
shader.setVec3("camPos", scene.MainCamera.Position);
model = glm::mat4(1.0f);
for (int row = 0; row < nrRows; ++row) {
shader.setFloat("metallic", (float)row / (float)nrRows);
for (int col = 0; col < nrColumns; ++col) {
shader.setFloat("roughness", glm::clamp((float)col / (float)nrColumns, 0.05f, 1.0f));
model = glm::mat4(1.0f);
model = glm::translate(model, glm::vec3(
(col - (nrColumns / 2)) * spacing,
(row - (nrRows / 2)) * spacing,
0.0f
));
shader.setMat4("model", model);
shader.setMat3("normalMatrix", glm::transpose(glm::inverse(glm::mat3(model))));
renderSphere();
}
}
// Render light source
for (unsigned int i = 0; i < sizeof(lightPositions) / sizeof(lightPositions[0]); ++i) {
glm::vec3 newPos = lightPositions[i] + glm::vec3(sin(glfwGetTime() * 5.0) * 5.0, 0.0, 0.0);
newPos = lightPositions[i];
shader.setVec3("lightPositions[" + std::to_string(i)+"]", newPos);
shader.setVec3("lightColors[" + std::to_string(i) + "]", lightColors[i]);
model = glm::mat4(1.0f);
model = glm::translate(model, newPos);
model = glm::scale(model, glm::vec3(0.5f));
shader.setMat4("model", model);
shader.setMat3("normalMatrix", glm::transpose(glm::inverse(glm::mat3(model))));
renderSphere();
}
/*
Shader OutlineShader;

5
src/main.cpp
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@ -53,6 +53,8 @@ public:
scene.MainCamera = Camera(glm::vec3(0.0f, 0.0f, 8.0f));
std::vector<std::string> faces = {
"../Textures/skybox/right.jpg",
"../Textures/skybox/left.jpg",
@ -67,7 +69,8 @@ public:
renderer.resize(WIDTH, HEIGHT);
renderer.Setup();
//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
while(!window.shouldClose())