为什么Sprite不在OpenGL中渲染

Why is the sprite not rendering in OpenGL?

本文关键字:OpenGL Sprite 不在 为什么      更新时间:2023-10-16

我正在尝试在OpenGL中渲染2D(屏幕协调(精灵。但是,当我编译它时,它不会出现。我看到代码很好(甚至没有任何着色器编译错误,也没有任何其他错误(。我还设置了矩阵(我怀疑这引起了问题,这就是开始的困惑!(

(

这是源代码,顺便说一句(无需调试,使其简短(: -

main.cpp

// Including all required headers here...
#include <iostream>
#define GLEW_STATIC
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include "SOIL2/SOIL2.h"
#include <glm/glm.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/gtc/matrix_transform.hpp>
const GLchar * vertexShaderSource =
    "#version 330 coren"
    "layout(location = 0) in vec4 vertex;n"
    "out vec2 TexCoords;n"
    "uniform mat4 model;n"
    "uniform mat4 projection;n"
    "void main()n"
    "{n"
    "TexCoords = vertex.zw;n"
    "gl_Position = projection * model * vec4(vertex.xy, 0.0, 1.0);n"
    "}";
const GLchar * fragmentShaderSource =
    "#version 330 coren"
    "in vec2 TexCoords;n"
    "out vec4 color;n"
    "uniform sampler2D image;n"
    "uniform vec3 spriteColor;n"
    "void main()n"
    "{n"
    "color = vec4(spriteColor, 1.0) * texture(image, TexCoords);n"
    "}";
const GLint WIDTH = 800, HEIGHT = 600;
int main()
{
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GLFW_FALSE);
    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
    GLFWwindow *window = glfwCreateWindow(WIDTH, HEIGHT, "Rendering Sprites", nullptr, nullptr);
    int screenWidth, screenHeight;
    glfwGetFramebufferSize(window, &screenWidth, &screenHeight);
    glfwMakeContextCurrent(window);
    glewExperimental = GL_TRUE;
    glewInit();
    glViewport(0, 0, screenWidth, screenHeight);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);
    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);
    GLuint shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);
    GLuint quadVAO;
    GLuint VBO;
    GLfloat vertices[] =
    {
        0.0f, 1.0f, 0.0f, 1.0f,
        1.0f, 0.0f, 1.0f, 0.0f,
        0.0f, 0.0f, 0.0f, 0.0f,
        0.0f, 1.0f, 0.0f, 1.0f,
        1.0f, 1.0f, 1.0f, 1.0f,
        1.0f, 0.0f, 1.0f, 0.0f
    };
    glGenVertexArrays(1, &quadVAO);
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    glBindVertexArray(quadVAO);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (GLvoid*)0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);
    GLuint texture;
    int width, height;
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    unsigned char *image = SOIL_load_image("img.png", &width, &height, 0, SOIL_LOAD_RGBA);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
    SOIL_free_image_data(image);
    glBindTexture(GL_TEXTURE_2D, 0);
    while (!glfwWindowShouldClose(window))
    {
        glfwPollEvents();
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        glUseProgram(shaderProgram);
        glm::mat4 model;
        glm::mat4 projection = glm::ortho(0.0f, static_cast<GLfloat>(WIDTH), static_cast<GLfloat>(HEIGHT), 0.0f, -1.0f, 1.0f);
        glm::vec2 size = glm::vec2(10.0f, 10.0f);
        glm::vec2 position = glm::vec2(-10.0f, 10.0f);
        glm::vec3 color = glm::vec3(1.0f, 0.0f, 0.0f);
        GLfloat rotation = 0.0f;
        model = glm::translate(model, glm::vec3(position, 0.0f));
        model = glm::translate(model, glm::vec3(0.5f * size.x, 0.5f * size.y, 0.0f));
        model = glm::rotate(model, rotation, glm::vec3(0.0f, 0.0f, 1.0f));
        model = glm::translate(model, glm::vec3(-0.5f * size.x, -0.5f * size.y, 0.0f));
        model = glm::scale(model, glm::vec3(size, 1.0f));
        glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
        glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "model"), 1, GL_FALSE, glm::value_ptr(model));
        glUniform3f(glGetUniformLocation(shaderProgram, "spriteColor"), color.x, color.y, color.z);
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture);
        glBindVertexArray(quadVAO);
        glDrawArrays(GL_TRIANGLES, 0, 6);
        glBindVertexArray(0);
        glfwSwapBuffers(window);
    }
    glDeleteVertexArrays(1, &quadVAO);
    glDeleteBuffers(1, &VBO);
    glfwTerminate();
    return EXIT_SUCCESS;
}

您必须初始化模型矩阵变量glm::mat4 model

GLM API文档是指OpenGL阴影语言规范4.20。

5.4.2向量和矩阵构造函数

如果对向量构造函数有一个标量参数,则用于将构造向量的所有组件初始化为标量的值。如果矩阵构造函数有一个标量参数,则用于初始化矩阵对角线上的所有组件,其余的组件初始化为0.0。

这意味着可以通过单个参数1.0初始化身份矩阵:

glm::mat4 model(1.0f);

此外,您的精灵非常小,左侧不在视口(剪辑空间(:

这样更改您的代码:

glm::vec2 position = glm::vec2(10.0f, 10.0f); // 10.0f instead of -10.0f