Purpose of the Sample:

Demonstrates how to bind and sample from multiple textures. The scene is rendered using MSAA and resolved prior to rendering to the backbuffer. This sample uses assimp to load models.

CGame.h

#ifndef __CGAME__
#define __CGAME__

#include <glad/glad.h>
#include "shader_s.h"

class Model;
class Mesh;

class CGame
{
public:
    CGame() {};

    void Initialize(unsigned int screenWidth, unsigned int screenHeight);
    void Shutdown();
    void Render();

    void OnResize(int screenWidth, int screenHeight);

private:
    void SetupGPUProgram();
    void SetupModel();

    Shader* m_pShaderPass0;

    Model* m_pManModel;
    GLuint m_ColorTextureId;
    GLuint m_IntermediateFBOId;
    GLuint m_TekkaTexture;
    GLuint m_RampTexture;
    Mesh* m_pFullscreenQuad;

    unsigned int m_Width;
    unsigned int m_Height;
};

#endif

#ifndef __CGAME__

#define __CGAME__

#include <glad/glad.h>

#include "shader_s.h"

class Model;

class Mesh;

class CGame

{

public:

CGame() {};

void Initialize(unsigned int screenWidth, unsigned int screenHeight);

void Shutdown();

void Render();

void OnResize(int screenWidth, int screenHeight);

private:

void SetupGPUProgram();

void SetupModel();

Shader* m_pShaderPass0;

Model* m_pManModel;

GLuint m_ColorTextureId;

GLuint m_IntermediateFBOId;

GLuint m_TekkaTexture;

GLuint m_RampTexture;

Mesh* m_pFullscreenQuad;

unsigned int m_Width;

unsigned int m_Height;

};

#endif

CGame.cpp

#include "CGame.h"

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image/stb_image.h"
#include "Model.h"
#include "Mesh.h"
#include "glm/mat4x4.hpp"
#include "glm/vec3.hpp"
#include "glm/glm.hpp"
#include "glm/gtc/matrix_transform.hpp"
#include "glm/gtc/type_ptr.hpp"
#include 

void CGame::Initialize(unsigned int screenWidth, unsigned int screenHeight)
{
    m_Width = screenWidth;
    m_Height = screenHeight;

    SetupGPUProgram();
    SetupModel();

    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LEQUAL);
    glEnable(GL_MULTISAMPLE);

    GLuint depthStencilId;

    glGenFramebuffers(1, &m_IntermediateFBOId);
    glBindFramebuffer(GL_FRAMEBUFFER, m_IntermediateFBOId);

    glGenTextures(1, &m_ColorTextureId);
    glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, m_ColorTextureId);
    glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, 4, GL_RGB8, m_Width, m_Height, GL_TRUE);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D_MULTISAMPLE, m_ColorTextureId, 0);

    glGenRenderbuffers(1, &depthStencilId);
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencilId);
    glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, screenWidth, screenHeight);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, depthStencilId);

    if (glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE)
    {
        // Great!
    }

    glBindFramebuffer(GL_FRAMEBUFFER, 0);
}

void CGame::Shutdown()
{
    
}

void CGame::OnResize(int width, int height)
{
    m_Width = width;
    m_Height = height;

    glViewport(0, 0, m_Width, m_Height);
    glScissor(0, 0, m_Width, m_Height);
}

void CGame::Render()
{
    static auto startTime = std::chrono::high_resolution_clock::now();

    auto currentTime = std::chrono::high_resolution_clock::now();
    float time = std::chrono::duration<float, std::chrono::seconds::period>(currentTime - startTime).count();

    glEnable(GL_MULTISAMPLE);
    glBindFramebuffer(GL_FRAMEBUFFER, m_IntermediateFBOId);

    glClearColor(0.2f, 0.2f, 0.2f, 1.0f);
    glClearDepth(1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Draw the Filled Man
    glm::mat4 model = glm::rotate(glm::mat4(1.0f), time * glm::radians(60.0f), glm::vec3(0.0f, 1.0f, 0.0f));
    glm::mat4 view;
    glm::vec3 eyePos = glm::vec3(0.0f, -1.0f, -2.5f);
    view = glm::translate(glm::mat4(1.0f), eyePos);
    glm::mat4 projection;
    projection = glm::perspective(glm::radians(60.0f), m_Width / static_cast(m_Height), 0.03f, 100.0f);
    glm::mat4 mvp = projection * view * model;

    // This must be done to assign the texture samplers to a texture unit.
    m_pShaderPass0->setInt("mainTexture", 0);
    m_pShaderPass0->setInt("rampTexture", 1);

    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, m_TekkaTexture);
    glActiveTexture(GL_TEXTURE1);
    glBindTexture(GL_TEXTURE_2D, m_RampTexture);

    m_pShaderPass0->use();
    m_pShaderPass0->setMatrix4x4("modelMatrix", glm::value_ptr(model));
    m_pShaderPass0->setMatrix4x4("viewMatrix", glm::value_ptr(view));
    m_pShaderPass0->setMatrix4x4("projectionMatrix", glm::value_ptr(projection));
    m_pShaderPass0->setMatrix4x4("mvpMatrix", glm::value_ptr(mvp));
    m_pShaderPass0->setVector3("eyePos", glm::value_ptr(eyePos));
    m_pShaderPass0->setFloat("time", time);
    m_pManModel->meshes[0].Draw(*m_pShaderPass0);

    // Bind the backbuffer
    glBindFramebuffer(GL_FRAMEBUFFER, 0);

    // Resolve the MSAA FBO
    glBindFramebuffer(GL_READ_FRAMEBUFFER, m_IntermediateFBOId);
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
    glBlitFramebuffer(0, 0, m_Width, m_Height, 0, 0, m_Width, m_Height, GL_COLOR_BUFFER_BIT, GL_NEAREST);
}

void CGame::SetupModel()
{
    m_pManModel = new Model();
    m_pManModel->Load("tekka.obj");

    int width, height, nrChannels;
    unsigned char *data = stbi_load("tekka.png", &width, &height, &nrChannels, 0);
    glGenTextures(1, &m_TekkaTexture);
    glBindTexture(GL_TEXTURE_2D, m_TekkaTexture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);

    unsigned char *data2 = stbi_load("ramp3.png", &width, &height, &nrChannels, 0);
    glGenTextures(1, &m_RampTexture);
    glBindTexture(GL_TEXTURE_2D, m_RampTexture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data2);
    glGenerateMipmap(GL_TEXTURE_2D);
}

void CGame::SetupGPUProgram()
{
    m_pShaderPass0 = new Shader("vertexPass0.glsl", "fragmentPass0.glsl");
}

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#include "CGame.h"

#define STB_IMAGE_IMPLEMENTATION

#include "stb_image/stb_image.h"

#include "Model.h"

#include "Mesh.h"

#include "glm/mat4x4.hpp"

#include "glm/vec3.hpp"

#include "glm/glm.hpp"

#include "glm/gtc/matrix_transform.hpp"

#include "glm/gtc/type_ptr.hpp"

#include

void CGame::Initialize(unsigned int screenWidth, unsigned int screenHeight)

{

m_Width = screenWidth;

m_Height = screenHeight;

SetupGPUProgram();

SetupModel();

glEnable(GL_DEPTH_TEST);

glDepthFunc(GL_LEQUAL);

glEnable(GL_MULTISAMPLE);

GLuint depthStencilId;

glGenFramebuffers(1, &m_IntermediateFBOId);

glBindFramebuffer(GL_FRAMEBUFFER, m_IntermediateFBOId);

glGenTextures(1, &m_ColorTextureId);

glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, m_ColorTextureId);

glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, 4, GL_RGB8, m_Width, m_Height, GL_TRUE);

glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D_MULTISAMPLE, m_ColorTextureId, 0);

glGenRenderbuffers(1, &depthStencilId);

glBindRenderbuffer(GL_RENDERBUFFER, depthStencilId);

glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, screenWidth, screenHeight);

glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, depthStencilId);

if (glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE)

{

// Great!

}

glBindFramebuffer(GL_FRAMEBUFFER, 0);

}

void CGame::Shutdown()

{

}

void CGame::OnResize(int width, int height)

{

m_Width = width;

m_Height = height;

glViewport(0, 0, m_Width, m_Height);

glScissor(0, 0, m_Width, m_Height);

}

void CGame::Render()

{

static auto startTime = std::chrono::high_resolution_clock::now();

auto currentTime = std::chrono::high_resolution_clock::now();

float time = std::chrono::duration<float, std::chrono::seconds::period>(currentTime - startTime).count();

glEnable(GL_MULTISAMPLE);

glBindFramebuffer(GL_FRAMEBUFFER, m_IntermediateFBOId);

glClearColor(0.2f, 0.2f, 0.2f, 1.0f);

glClearDepth(1.0f);

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

// Draw the Filled Man

glm::mat4 model = glm::rotate(glm::mat4(1.0f), time * glm::radians(60.0f), glm::vec3(0.0f, 1.0f, 0.0f));

glm::mat4 view;

glm::vec3 eyePos = glm::vec3(0.0f, -1.0f, -2.5f);

view = glm::translate(glm::mat4(1.0f), eyePos);

glm::mat4 projection;

projection = glm::perspective(glm::radians(60.0f), m_Width / static_cast(m_Height), 0.03f, 100.0f);

glm::mat4 mvp = projection * view * model;

// This must be done to assign the texture samplers to a texture unit.

m_pShaderPass0->setInt("mainTexture", 0);

m_pShaderPass0->setInt("rampTexture", 1);

glActiveTexture(GL_TEXTURE0);

glBindTexture(GL_TEXTURE_2D, m_TekkaTexture);

glActiveTexture(GL_TEXTURE1);

glBindTexture(GL_TEXTURE_2D, m_RampTexture);

m_pShaderPass0->use();

m_pShaderPass0->setMatrix4x4("modelMatrix", glm::value_ptr(model));

m_pShaderPass0->setMatrix4x4("viewMatrix", glm::value_ptr(view));

m_pShaderPass0->setMatrix4x4("projectionMatrix", glm::value_ptr(projection));

m_pShaderPass0->setMatrix4x4("mvpMatrix", glm::value_ptr(mvp));

m_pShaderPass0->setVector3("eyePos", glm::value_ptr(eyePos));

m_pShaderPass0->setFloat("time", time);

m_pManModel->meshes[0].Draw(*m_pShaderPass0);

// Bind the backbuffer

glBindFramebuffer(GL_FRAMEBUFFER, 0);

// Resolve the MSAA FBO

glBindFramebuffer(GL_READ_FRAMEBUFFER, m_IntermediateFBOId);

glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);

glBlitFramebuffer(0, 0, m_Width, m_Height, 0, 0, m_Width, m_Height, GL_COLOR_BUFFER_BIT, GL_NEAREST);

}

void CGame::SetupModel()

{

m_pManModel = new Model();

m_pManModel->Load("tekka.obj");

int width, height, nrChannels;

unsigned char *data = stbi_load("tekka.png", &width, &height, &nrChannels, 0);

glGenTextures(1, &m_TekkaTexture);

glBindTexture(GL_TEXTURE_2D, m_TekkaTexture);

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);

glGenerateMipmap(GL_TEXTURE_2D);

unsigned char *data2 = stbi_load("ramp3.png", &width, &height, &nrChannels, 0);

glGenTextures(1, &m_RampTexture);

glBindTexture(GL_TEXTURE_2D, m_RampTexture);

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data2);

glGenerateMipmap(GL_TEXTURE_2D);

}

void CGame::SetupGPUProgram()

{

m_pShaderPass0 = new Shader("vertexPass0.glsl", "fragmentPass0.glsl");

}

vertex.glsl

#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 uv;

uniform mat4 modelMatrix;
uniform mat4 viewMatrix;
uniform mat4 projectionMatrix;
uniform mat4 mvpMatrix;
uniform vec3 eyePos;
uniform float time;

out vec3 fsNormal;
out vec2 fsUV;

void main()
{
    vec4 pos = mvpMatrix * vec4(position.xyz, 1);
    fsNormal = vec3(modelMatrix * viewMatrix * vec4(normal, 0)).xyz;
    fsUV = uv;
    gl_Position = pos;
}

#version 330 core

layout (location = 0) in vec3 position;

layout (location = 1) in vec3 normal;

layout (location = 2) in vec2 uv;

uniform mat4 modelMatrix;

uniform mat4 viewMatrix;

uniform mat4 projectionMatrix;

uniform mat4 mvpMatrix;

uniform vec3 eyePos;

uniform float time;

out vec3 fsNormal;

out vec2 fsUV;

void main()

{

vec4 pos = mvpMatrix * vec4(position.xyz, 1);

fsNormal = vec3(modelMatrix * viewMatrix * vec4(normal, 0)).xyz;

fsUV = uv;

gl_Position = pos;

}

fragment.glsl

#version 330 core
out vec4 FragColor;

in vec3 fsNormal;
in vec2 fsUV;

uniform vec3 eyePos;
uniform sampler2D mainTexture;
uniform sampler2D rampTexture;

void main()
{
	vec3 lightDir = normalize(vec3(0, 0, 1));

	vec3 normal = normalize(fsNormal);

	float nDotl = clamp(dot(normal, lightDir), 0, 1);

	float ramp = texture(rampTexture, vec2(nDotl, 0.5)).r;

    vec3 albedo = texture(mainTexture, fsUV).rgb;
    vec3 diffuse = albedo * pow(ramp, 1.3);
    FragColor = vec4(diffuse, 1.0f);
}

#version 330 core

out vec4 FragColor;

in vec3 fsNormal;

in vec2 fsUV;

uniform vec3 eyePos;

uniform sampler2D mainTexture;

uniform sampler2D rampTexture;

void main()

{

vec3 lightDir = normalize(vec3(0, 0, 1));

vec3 normal = normalize(fsNormal);

float nDotl = clamp(dot(normal, lightDir), 0, 1);

float ramp = texture(rampTexture, vec2(nDotl, 0.5)).r;

vec3 albedo = texture(mainTexture, fsUV).rgb;

vec3 diffuse = albedo * pow(ramp, 1.3);

FragColor = vec4(diffuse, 1.0f);

}

xdPixel

OpenGL Multi-Texturing

Purpose of the Sample:

CGame.h

CGame.cpp

vertex.glsl

fragment.glsl

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