【发布时间】：2022-01-20 19:06:31
【问题描述】：
我正在开发一个“Hello Triangle”程序，但我终其一生都无法弄清楚为什么片段着色器没有颜色。是什么导致所有片段输出为白色？我在 Visual Studio 2019 上，程序编译得很好，单步调试调试器不会产生任何结果。我假设错误是在 GLSL 或我的顶点属性管道中。 顶点着色器：
#version 450 core
layout (location = 0) in vec4 vPosition;
layout (location = 1) in vec4 color;
out vec4 fColor;
void main() {
fColor = color;
gl_Position = vPosition;
}
片段着色器：
#version 450 core
in vec4 fColor;
out vec4 fragColor;
void main() {
//fColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);
fragColor = fColor;
}
主要：
#include <Windows.h>
#include <stdio.h>
#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>
#include <cstdlib>
#include <string>
#include <GL/gl3w.h>
#include <GLFW/glfw3.h>
#include <glm/glm.hpp>
std::string readFile(const char* filePath) {
std::string content;
std::ifstream fileStream(filePath, std::ios::in);
if (!fileStream.is_open()) {
std::cerr << "Could not read file " << filePath << ". File does not exist." << std::endl;
return "";
}
std::string line = "";
while (!fileStream.eof()) {
std::getline(fileStream, line);
content.append(line + "\n");
}
fileStream.close();
return content;
}
void loadShaders(std::string filedir, GLenum type, GLuint &prog) {
GLenum errorVal;
std::string vertexSource = readFile("./vert.vert");
std::string fragmentSource = readFile("./frag.frag");
GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
const GLchar* source = (const GLchar*)vertexSource.c_str();
glShaderSource(vertexShader, 1, &source, 0);
glCompileShader(vertexShader);
GLint isCompiled = 0;
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &isCompiled);
if (isCompiled == GL_FALSE)
{
GLint maxLength = 0;
glGetShaderiv(vertexShader, GL_INFO_LOG_LENGTH, &maxLength);
// The maxLength includes the NULL character
std::vector<GLchar> infoLog(maxLength);
glGetShaderInfoLog(vertexShader, maxLength, &maxLength, &infoLog[0]);
// We don't need the shader anymore.
glDeleteShader(vertexShader);
// Use the infoLog as you see fit.
// In this simple program, we'll just leave
return;
}
GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
source = (const GLchar*)fragmentSource.c_str();
glShaderSource(fragmentShader, 1, &source, 0);
glCompileShader(fragmentShader);
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &isCompiled);
if (isCompiled == GL_FALSE)
{
GLint maxLength = 0;
glGetShaderiv(fragmentShader, GL_INFO_LOG_LENGTH, &maxLength);
// The maxLength includes the NULL character
std::vector<GLchar> infoLog(maxLength);
glGetShaderInfoLog(fragmentShader, maxLength, &maxLength, &infoLog[0]);
// We don't need the shader anymore.
glDeleteShader(fragmentShader);
// Either of them. Don't leak shaders.
glDeleteShader(vertexShader);
// Use the infoLog as you see fit.
// In this simple program, we'll just leave
return;
}
// Vertex and fragment shaders are successfully compiled.
// Now time to link them together into a program.
// Get a program object.
GLuint program = glCreateProgram();
glAttachShader(program, vertexShader);
glAttachShader(program, fragmentShader);
glLinkProgram(program);
GLint isLinked = 0;
glGetProgramiv(program, GL_LINK_STATUS, (int*)&isLinked);
if (isLinked == GL_FALSE)
{
GLint maxLength = 0;
glGetProgramiv(program, GL_INFO_LOG_LENGTH, &maxLength);
// The maxLength includes the NULL character
std::vector<GLchar> infoLog(maxLength);
glGetProgramInfoLog(program, maxLength, &maxLength, &infoLog[0]);
// We don't need the program anymore.
glDeleteProgram(program);
// Don't leak shaders either.
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
// Use the infoLog as you see fit.
// In this simple program, we'll just leave
return;
}
// Always detach shaders after a successful link.
glDetachShader(program, vertexShader);
glDetachShader(program, fragmentShader);
}
int main(int argc, char** argv) {
GLenum errorVal;
//glfw and gl3w initialization and window creation
glfwInit();
GLFWwindow* window = glfwCreateWindow(1920, 1080, "openGL bullshit", NULL, NULL);
glfwMakeContextCurrent(window);
gl3wInit();
//do shit here
GLuint VAOs[1];
GLuint bufferNames[1];
//vertices gets copied into the GPU, can be modified GPU-side using glMapData, glBufferSubData, or glNamedBufferStorage
GLfloat vertices[12][4] = {
{ -1.0f, 1.0f, 0.0f, 1.0f }, // Triangle 1
{ -1.0f, -1.0f, 0.0f, 1.0f },
{ 1.0f, -1.0f, 0.0f, 1.0f },
{ 1.0f, -1.0f, 0.0f, 1.0f }, //Traingle 2
{ 1.0f, 1.0f, 0.0f, 1.0f },
{ -1.0f, 1.0f, 0.0f, 1.0f },
{1.0f, 0.0f, 0.0f, 1.0f}, //colors
{1.0f, 0.0f, 0.0f, 1.0f},
{1.0f, 0.0f, 0.0f, 1.0f},
{1.0f, 0.0f, 0.0f, 1.0f},
{1.0f, 0.0f, 0.0f, 1.0f},
{1.0f, 0.0f, 0.0f, 1.0f}
};
glCreateVertexArrays(1, VAOs);
glCreateBuffers(1, bufferNames);
glNamedBufferStorage(bufferNames[0], sizeof(vertices), vertices, GL_DYNAMIC_STORAGE_BIT + GL_MAP_WRITE_BIT);
//glNamedBufferSubData(bufferNames[0], sizeof(GLfloat) * 12, sizeof(GLfloat)*24, colors);
//insert shader shit here
GLuint program = glCreateProgram();
loadShaders("./vert.vert", GL_VERTEX_SHADER, program); //ignore the inputs, they aren't used. This one command loads both vertex and fragment shaders
glUseProgram(program);
//binding and plumbing
glBindVertexArray(VAOs[0]);
glBindBuffer(GL_ARRAY_BUFFER, bufferNames[0]);
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4*sizeof(GLfloat), (void*)0);
glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (void*)(sizeof(GLfloat) * 24));
//glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0, (void*)(sizeof(GLfloat) * 2));
//main loop
GLfloat debugArr[6][2];
while (!glfwWindowShouldClose(window)) {
static const float black[] = { 0.0f, 0.0f, 0.0f, 0.0f };
vertices[0][0] += 0.0001f;
void *pointer = glMapNamedBuffer(bufferNames[0], GL_WRITE_ONLY);
memcpy(pointer, vertices, sizeof(vertices) / 12);
glUnmapNamedBuffer(bufferNames[0]);
glClearBufferfv(GL_COLOR, 0, black);
glDrawArrays(GL_TRIANGLES, 0, 6);
glfwSwapBuffers(window);
glfwPollEvents();
}
//shutdown if main loop stops
glfwDestroyWindow(window);
glfwTerminate();
}
【问题讨论】：
标签： c++ opengl glsl glfw glm-math