-OPENGL7-

Posted 2020-11-27 gearslogy

CP24: GeometryShader

 

 

教程中的一开始初始化的点是在NDC设备，我的同样一样，在shader中，教程中vert 不包含projection * view *model,我的依然存在。

如果在Geometry绘制的线段依然要满足透视关系，所以也得把projection * view * model带入

在这里修改了LoaderShader.h

#ifndef LOADSHADER_H
#define LOADSHADER_H


#include <GL/glew.h>

#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <vector>
#include "ALG_TextureDelegate.h"

namespace AlgebraMaster
{

using namespace std;
// Shaders

const char* vertexShaderSource = "#version 450 core
"
                                 "layout (location = 0) in vec4 v_position;
"
                                 "layout ( location = 1 ) in vec3 v_normal;
"
                                 "layout ( location = 2 ) in vec2 v_texCoord;
"
                                 "out vec2 myTexCoord;
"
                                 "uniform mat4 model;
"
                                 "uniform mat4 view;
"
                                 "uniform mat4 projection;
"
                                 "void main()
"
                                 "{
"
                                 "gl_Position = projection *   view * model * v_position;
"
                                 "myTexCoord = v_texCoord;
"
                                 "}";



const char* fragmentShaderSource = "#version 450 core
"
                                   "out vec4 fColor;
"
                                   "void main()
"
                                   "{
"
                                   "fColor = vec4(1.0f, 1.0f, 1.0f , 1.0f);
"
                                   "}
";

// this have texture
const char* fragmentShaderSource2 = "#version 450 core
"
                                    "out vec4 fColor;
"
                                    "in vec2 myTexCoord;
"
                                    "struct Material
"
                                    "{
"
                                    "float Kd;        // diffuse mult
"
                                    "float kS;        // specular mult
"
                                    "float shininess; // phong pow(,shine)
"
                                    "sampler2D diffuse_map;
"
                                    "sampler2D specular_map;
"
                                    "sampler2D emission_map;
"
                                    "};
"
                                    "uniform Material material;
"
                                    "void main()
"
                                    "{
"
                                    "vec4 df_tex=texture(material.diffuse_map, myTexCoord);
;"
                                    "fColor = vec4(df_tex.r,df_tex.g,df_tex.b,1.0f) ;
"
                                    "}
";

struct LoadShader
{
    enum ShaderIOType{FILE,INLINE_DEFAULT_PROJECTION,INLINE_TEXTURE_PROJECTION};
    void compileShaderProgram(bool needGeometryShader = false){
        // create shader program and check it
        GLint success;
        GLchar infoLog[512];
        shaderProgram = glCreateProgram();
        glAttachShader(shaderProgram,vertexShader);
        glAttachShader(shaderProgram,fragmentShader);
        // if we need attach geometry shader
        if (needGeometryShader){
            glAttachShader(shaderProgram,geometryShader);
        }
        glLinkProgram(shaderProgram );
        glGetProgramiv( shaderProgram, GL_LINK_STATUS, &success );  // Get Link Status
        if (!success)
        {
            glGetProgramInfoLog( shaderProgram, 512, NULL, infoLog );
            std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED
" << infoLog << std::endl;
        }
        // Delete the allShaders as they‘re linked into our program now and no longer necessery
        glDeleteShader( vertexShader );
        glDeleteShader( fragmentShader );
    }
    void compileVertexShader(const string& code){
        vertexShader = glCreateShader( GL_VERTEX_SHADER );

        const char * src = code.c_str();
        glShaderSource( vertexShader, 1, &(src), NULL );

        glCompileShader( vertexShader );
        GLint success;
        GLchar infoLog[512];

        glGetShaderiv( vertexShader, GL_COMPILE_STATUS, &success );
        if ( !success )
        {
            glGetShaderInfoLog( vertexShader, 512, NULL, infoLog );
            std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED
" << infoLog << std::endl;
        }
    }
    void compileGeometryShader(const string& code){
        const char *src = code.c_str();
        GLint success;
        GLchar infoLog[512];
        geometryShader = glCreateShader( GL_GEOMETRY_SHADER );
        glShaderSource( geometryShader, 1, &src, NULL );
        glCompileShader( geometryShader );
        glGetShaderiv( geometryShader, GL_COMPILE_STATUS, &success ); // Get Compile status
        if ( !success )
        {
            glGetShaderInfoLog( geometryShader, 512, NULL, infoLog );
            std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED
" << infoLog << std::endl;
        }
    }
    void compileFragmentShader(const string& code){
        const char * src = code.c_str();
        GLint success;
        GLchar infoLog[512];
        fragmentShader = glCreateShader( GL_FRAGMENT_SHADER );
        glShaderSource( fragmentShader, 1, &src, NULL );
        glCompileShader( fragmentShader );
        glGetShaderiv( fragmentShader, GL_COMPILE_STATUS, &success ); // Get Compile status
        if ( !success )
        {
            glGetShaderInfoLog( fragmentShader, 512, NULL, infoLog );
            std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED
" << infoLog << std::endl;
        }
    }

    void fromSrc(const string &vertCode, const string &fragCode){
        compileVertexShader(vertCode);
        compileFragmentShader(fragCode);
        compileShaderProgram();
    }
    void fromSrc(const string &vertCode, const string &fragCode, const string&geometryCode){
        compileVertexShader(vertCode);
        compileFragmentShader(fragCode);
        compileGeometryShader(geometryCode);
        compileShaderProgram(true);
    }


    LoadShader(){

    }
    ~LoadShader(){

    }

    // ------------ this method do not compile the geometry shader -----------------------
    void asSimpleTextureShader(){
        shaderName = "simpleTex";
        shaderIOType = INLINE_TEXTURE_PROJECTION;
        compileVertexShader(vertexShaderSource);
        compileFragmentShader(fragmentShaderSource2);
        compileShaderProgram();
    }
    void asSimpleShader()
    {
        shaderName = "simpleCol";
        shaderIOType = INLINE_DEFAULT_PROJECTION;
        compileVertexShader(vertexShaderSource);
        compileFragmentShader(fragmentShaderSource);
        compileShaderProgram();
    }
    // ------------ this method do not compile the geometry shader -----------------------


    void setShaderName(const string &name){
        shaderName = name;
    }


    // ------------ read text file -----------------------
    string _readFile(const char *path){
        ifstream stream;
        stringstream ss;
        stream.exceptions(ifstream::badbit);
        try
        {
            stream.open(path);    // open file
            ss << stream.rdbuf(); // get strings from file
        } catch (ifstream::failure e)
        {
            cout << "ERROR::OPEN FILE:" << path << endl;
        }
        // close file handle
        stream.close();

        // get str() from stringstream
        string shaderCode = ss.str();
        return shaderCode;
    }

    // ------------ load a vertex shader from a path ----------------------------------
    void _loadVertexShader(const char *path){
        // read shader code
        auto handle = _readFile(path);
        compileVertexShader(handle);
    }

    // ------------ load a fragment shader from a path ----------------------------------
    void _loadFragmentShader(const char *path){
        // read shader code
        auto handle = _readFile(path);
        compileFragmentShader(handle);
    }

    // ------------ load a geometry shader from a path ----------------------------------
    void _loadGeometryShader(const char *path){
        auto handle = _readFile(path);
        compileGeometryShader(handle);
    }

    // ------------ only load two shader : vert & frag ----------------------------------
    void load(const char* vertShaderPath, const char* fragShaderPath){
        shaderIOType = FILE;
        _loadVertexShader(vertShaderPath);
        _loadFragmentShader(fragShaderPath);
        // create shader program and check it
        compileShaderProgram();
    }
    // ------------ shader program have 3 shader: vert&frag&geometry ----------------------------------
    void load(const char* vertShaderPath, const char* fragShaderPath, const char* geometryShaderPath){
        shaderIOType = FILE;
        _loadVertexShader(vertShaderPath);
        _loadFragmentShader(fragShaderPath);
        _loadGeometryShader(geometryShaderPath);
        // create shader program and check it
        compileShaderProgram(true);
    }

    // ------------ active current shader program ----------------------------------
    void use(){
        glUseProgram(shaderProgram);
    }


    // ------------ set shader method ----------------------------------
    void setBool(const char *name, bool value) const
    {
        glUniform1i(glGetUniformLocation(shaderProgram, name), (int)value);
    }
    void setInt(const char *name, int value) const
    {
        glUniform1i(glGetUniformLocation(shaderProgram,name), value);
    }
    // ------------------------------------------------------------------------
    void setFloat(const char *name, float value) const
    {
        glUniform1f(glGetUniformLocation(shaderProgram, name), value);
    }
    // ------------------------------------------------------------------------
    void setVec2(const char *name, const glm::vec2 &value) const
    {
        glUniform2fv(glGetUniformLocation(shaderProgram,name), 1, &value[0]);
    }

    void setVec2(const char *name, float x, float y) const
    {
        glUniform2f(glGetUniformLocation(shaderProgram,name), x, y);
    }
    // ------------------------------------------------------------------------
    void setVec3(const char *name, const glm::vec3 &value) const
    {
        glUniform3fv(glGetUniformLocation(shaderProgram,name), 1, &value[0]);
    }
    void setVec3(const char *name, float x, float y, float z) const
    {
        glUniform3f(glGetUniformLocation(shaderProgram,name), x, y, z);
    }
    // ------------------------------------------------------------------------
    void setVec4(const char *name, const glm::vec4 &value) const
    {
        glUniform4fv(glGetUniformLocation(shaderProgram,name), 1, &value[0]);
    }
    void setVec4(const char *name, float x, float y, float z, float w)
    {
        glUniform4f(glGetUniformLocation(shaderProgram,name), x, y, z, w);
    }

    void setMat2(const char*name, const glm::mat2 &mat) const
    {
        glUniformMatrix2fv(glGetUniformLocation(shaderProgram, name), 1, GL_FALSE,glm::value_ptr(mat));
    }

    void setMat3(const char*name, const glm::mat3 &mat){
        GLuint location = glGetUniformLocation(shaderProgram, name);
        glUniformMatrix3fv(location,1, GL_FALSE, &mat[0][0]);
    }

    void setMat4(const char *name , const glm::mat4 &mat){
        GLuint location = glGetUniformLocation(shaderProgram, name);
        glUniformMatrix4fv(location,1, GL_FALSE, glm::value_ptr(mat));
    }

    GLuint shaderProgram;
    GLuint vertexShader;
    GLuint fragmentShader;
    GLuint geometryShader;
    ShaderIOType shaderIOType;
    string shaderName;
    vector <Texture*> textures;   // do not release this memory, scene will manipulate this mem

    glm::mat4 model;
    glm::mat4 view;
    glm::mat4 projection;

    // ------------ direct set shader projection,view,model ----------------------------------
    void setMatrix(const glm::mat4 &matModel , const glm::mat4 &matView , const glm::mat4 &matProjection){
        model = matModel;
        view = matView;
        projection = matProjection;

        setMat4("projection", projection);
        setMat4("view", view);
        setMat4("model", model);
    }
};

}


#endif // LOADSHADER_H

View Code

集合体shader->GeometryShader.geom:

#version 450 core
layout (points) in;
layout (line_strip, max_vertices = 2) out;


uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;

void main() {
    gl_Position = gl_in[0].gl_Position + projection*view*model*vec4(-.2, 0.0, 0.0, 0.0);
    EmitVertex();

    gl_Position = gl_in[0].gl_Position + projection*view*model*vec4( 0.2, 0.0, 0.0, 0.0);
    EmitVertex();

    EndPrimitive();
}

#version 450 core
// Final Color To export
out vec4 FragColor;

void main()
{

    FragColor =  vec4(1,0,1,1);
}

SurfaceShader.frag

#version 450 core
// INCOMING DATA
layout ( location = 0 ) in vec4 v_position; //  pos
//layout ( location = 1 ) in vec2 v_texCoord; //  st
//layout ( location = 2 ) in vec3 v_normal; //  st

// define out data
out vec2 f_TexCoord;
// normal at world matrix, we direct from C++ calcalation
out vec3 f_Normal;  // to world matrix : mat3( transpose(inverse(model)) ) * v_normal;
out vec3 f_Pos;


// INCOMING THE MATRIX FROM CLIENT to transform the gl point position
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;




void main(){
    // Transform the world matrix to view matrix

    //f_Normal = mat3(transpose(inverse(model))) * v_normal;  // f_Normal at world matrix
    //f_TexCoord = v_texCoord;          // out TexCoord
    //f_Pos = vec3(model *v_position);  // out fragment position

    gl_Position = projection *   view * model * v_position;

}

SurfaceShader.vert

#define GLEW_STATIC
// GLEW
#include <GL/glew.h>
#include <cstdlib>
#undef GLFW_DLL
// GLFW
#include <GLFW/glfw3.h>
#include <iostream>
#include "ALG_LoadShader.h"
#include "ALG_LoadTexture.h"
#include "ALG_GLFWCamera.h"
#include "ALG_FrameWindow.h"
#include "ALG_ModelDelegate.h"
#include "ALG_SceneDelegate.h"
#include "ALG_DrawGrid.h"
#include <cmath>
#include "ALG_OGLHelper.h"

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <map>
#include "ALG_DrawEnvBox.h"

using namespace AlgebraMaster;


const unsigned int SRC_WIDTH = 1400;
const unsigned int SRC_HEIGHT = 720;



static LoadShader SurfaceShader;

void init();
void display();


void processInput(GLFWwindow *window);
void framebuffer_size_callback(GLFWwindow* window, int width, int height); // framezize
void mouse_callback(GLFWwindow* window, double xpos, double ypos); // Maya Alt+LeftMouse
void scroll_callback(GLFWwindow *window, double xoffset, double yoffset);



static float lastX =  float(SRC_WIDTH) / 2.0f;
static float lastY =  float(SRC_HEIGHT) / 2.0f;
static bool firstMouse = true;
static bool firstMiddowMouse = true;
// timing
static float deltaTime = 0.0f;    // time between current frame and last frame
static float lastFrame = 0.0f;




// cube vao vbo
static unsigned int VAO,VBO;

// camera
static GLFWCamera *camera;
// light define
static glm::vec3 lightPos(0.0f, 4.0f,-2.0f);

static DrawGrid grid;
static DrawEnvBox envBox;

static LoadTexture cubeTex;
static LoadTexture groundTex;


static float testPoints[] = {
        -0.5f,  0.5f, // 左上
        0.5f,  0.5f, // 右上
        0.5f, -0.5f, // 右下
        -0.5f, -0.5f  // 左下
};

void init(){
    camera = new GLFWCamera;
    camera->pos.y = 1.0f;
    camera->pos.z = 4.0f;
    // GL depth zbuffer
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    SurfaceShader.load(
            "shaders/SurfaceShader.vert",
            "shaders/SurfaceShader.frag",
            "shaders/GeometryShader.geom");

    CreateGeometryBuffer(VAO,VBO);
    glBufferData(GL_ARRAY_BUFFER,sizeof(testPoints),&testPoints,GL_STATIC_DRAW);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), 0);


    grid.initialize();

}

// ----------- Render Loop ----------
void display(){


    // per-frame time logic
            // --------------------
    float currentFrame = glfwGetTime();
    deltaTime = currentFrame - lastFrame;
    lastFrame = currentFrame;

    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);




    // object .vert settings
    glm::mat4 projection = glm::perspective(glm::radians(camera->fov),float(SRC_WIDTH) / float(SRC_HEIGHT),0.1f,  1000.0f);
    glm::mat4 view = camera->GetViewMatrix();
    // object world transformation
    glm::mat4 model = glm::mat4(1.0f);
    grid.draw(projection,view);




    SurfaceShader.use();
    SurfaceShader.setMatrix(model,view,projection);

    glBindVertexArray(VAO);
    glDrawArrays(GL_POINTS,0,4);

}


int main()
{
    cout << sizeof(float) << endl;
    glfwInit();
    FrameWindow FrameWindow(SRC_WIDTH,SRC_HEIGHT);
    glfwSetFramebufferSizeCallback(FrameWindow.getWindow(), framebuffer_size_callback);
    glfwSetCursorPosCallback(FrameWindow.getWindow(),mouse_callback);
    glfwSetScrollCallback(FrameWindow.getWindow(), scroll_callback);
    init();
    // RENDER--------------
    //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    while(!glfwWindowShouldClose(FrameWindow.getWindow())){
        processInput(FrameWindow.getWindow());
        display();
        glfwSwapBuffers(FrameWindow.getWindow());
        glfwPollEvents();
    }
    delete camera;
    return 0;
}

void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    // make sure the viewport matches the new window dimensions; note that width and
    // height will be significantly larger than specified on retina displays.
    glViewport(0, 0, width, height);
}

void processInput(GLFWwindow *window)
{
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        glfwSetWindowShouldClose(window, true);
    if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
        camera->processKeyboardMove(deltaTime,GLFWCamera::FORWARD);
    if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
        camera->processKeyboardMove(deltaTime,GLFWCamera::BACKWARD);
    if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
        camera->processKeyboardMove(deltaTime,GLFWCamera::LEFT);
    if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
        camera->processKeyboardMove(deltaTime,GLFWCamera::RIGHT);
}

// ROTATE VIEW DIR
void mouse_callback(GLFWwindow* window, double xpos, double ypos){

    int middow_mouse_state = glfwGetMouseButton(window,GLFW_MOUSE_BUTTON_MIDDLE);
    int mouse_state = glfwGetMouseButton(window,GLFW_MOUSE_BUTTON_LEFT);
    int key_state = glfwGetKey(window,GLFW_KEY_LEFT_ALT);
    // set up the camera view
    if( mouse_state == GLFW_PRESS && key_state== GLFW_PRESS)
    {
        if (firstMouse){
            lastX = xpos;
            lastY = ypos;
            firstMouse = false;
        }
        float xoffset = xpos - lastX;
        float yoffset = lastY - ypos; // reversed since y-coordinates go from bottom to top
        lastX = xpos;
        lastY = ypos;
        camera->processMouseMove(xoffset,yoffset);
    }
    if (key_state == GLFW_RELEASE || mouse_state == GLFW_RELEASE){
        firstMouse = true;
    }


    // Move Camera Position
    if( middow_mouse_state == GLFW_PRESS) {

        if (firstMiddowMouse){
            lastX = xpos;
            lastY = ypos;
            firstMiddowMouse = false;
        }
        float xoffset = xpos - lastX;
        float yoffset = lastY - ypos; // reversed since y-coordinates go from bottom to top
        lastX = xpos;
        lastY = ypos;
        camera->pos.x += xoffset*0.01f;
        camera->pos.y += yoffset*0.01f;

    }
    if ( middow_mouse_state == GLFW_RELEASE){
        firstMiddowMouse = true;
    }

}

void scroll_callback(GLFWwindow *window, double xoffset, double yoffset){
    camera->processFov(yoffset);
}

main.cpp