使用着色器渲染三角形时"vertex colored" OpenGL "black screen"
OpenGL "black screen" when rendering "vertex colored" triangle using shader
我对OpenGL很陌生,并且一直在遵循这个非常简单的教程,我应该在其中创建一个顶点色三角形(有问题的教程)。
虽然,我的结果只是黑屏。我已经尝试完全复制他的代码,但它仍然不起作用,这导致我相信本教程已经过时了。
我尝试删除着色器中的"#version 130",但这没有任何作用。我还调试了渲染函数,它确实被调用了。我不知道可能出了什么问题。
这是我的代码:
主.cpp
#ifdef _WIN32
#define _CRT_SECURE_NO_DEPRECATE
#endif
#include <GLglew.h>
#include <GLfreeglut.h>
#include <stdio.h>
#define BUFFER_OFFSET(i) ((char *)NULL + (i))
GLuint shaderProgramID;
GLuint vao = 0;
GLuint vbo;
GLuint positionID, colorID;
#pragma region SHADER_FUNCTIONS
static char* readFile(const char* filename) {
//Open the file
FILE* fp = fopen(filename, "r");
//Move to the end of file
fseek(fp, 0, SEEK_END);
long file_length = ftell(fp);
fseek(fp, 0, SEEK_SET);
char* contents = new char[file_length + 1];
//zero out memory
for (int i = 0; i < file_length + 1; i++) {
contents[i] = 0;
}
//Read file
fread(contents, 1, file_length, fp);
//Denote end
contents[file_length + 1] = ' ';
fclose(fp);
return contents;
}
GLuint makeVertexShader(const char* shaderSource) {
GLuint vertexShaderID = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShaderID, 1, (const GLchar**)&shaderSource, NULL);
glCompileShader(vertexShaderID);
return vertexShaderID;
}
GLuint makeFragmentShader(const char* shaderSource) {
GLuint fragmentShaderID = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShaderID, 1, (const GLchar**)&shaderSource, NULL);
glCompileShader(fragmentShaderID);
return fragmentShaderID;
}
GLuint makeShaderProgram(GLuint vertexShaderID, GLuint fragmentShaderID) {
GLuint shaderID = glCreateProgram();
glAttachShader(shaderID, vertexShaderID);
glAttachShader(shaderID, fragmentShaderID);
glLinkProgram(shaderID);
return shaderID;
}
#pragma endregion
void changeViewport(int w, int h) {
glViewport(0, 0, w, h);
}
void render() {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glDrawArrays(GL_TRIANGLES, 0, 3);
glutSwapBuffers();
printf("Debug");
}
int main(int argc, char** argv) {
//Init GLUT
glutInit(&argc, argv);
//Set up some memory buffers for our display
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);
//Set up window size
glutInitWindowSize(800, 600);
//Create window
glutCreateWindow("Project 1");
//Bind the two functions to respond when necessary
glutReshapeFunc(changeViewport);
glutDisplayFunc(render);
//Initialize OpenGL driver
GLenum err = glewInit();
if (GLEW_OK != err) {
fprintf(stderr, "GLEW error");
return 1;
}
//Vertices and colors of trangle
GLfloat vertices[] = {
-0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f,
0.0f,-0.5f, 0.0f
};
GLfloat colors[] = {
1.0f, 0.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f, 1.0f
};
#pragma region MAKE_SHADER
char* vertexShaderSourceCode = readFile("vertexShader.vs");
char* fragmentShaderSourceCode = readFile("fragmentShader.fs");
GLuint vertShaderID = makeVertexShader(vertexShaderSourceCode);
GLuint fragShaderID = makeFragmentShader(fragmentShaderSourceCode);
GLuint shaderProgramID = makeShaderProgram(vertShaderID, fragShaderID);
printf("vertShaderID is %dn", vertShaderID);
printf("fragmentShaderID is %dn", fragShaderID);
printf("shaderProgramID is %dn", shaderProgramID);
#pragma endregion
//Create the "remember-all"
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
//Create buffer
glBufferData(GL_ARRAY_BUFFER, 7 * 3 * sizeof(GLfloat), NULL, GL_STATIC_DRAW);
//Load the vertex points
glBufferSubData(GL_ARRAY_BUFFER, 0, 3 * 3 * sizeof(GLfloat), vertices);
//Load the colors
glBufferSubData(GL_ARRAY_BUFFER, 3 * 3 * sizeof(GLfloat), 3 * 4 * sizeof(GLfloat), colors);
//Find variables in shader
positionID = glGetAttribLocation(shaderProgramID, "s_vPosition");
colorID = glGetAttribLocation(shaderProgramID, "s_vColor");
glVertexAttribPointer(positionID, 3, GL_FLOAT, GL_FALSE, 0, 0);
glVertexAttribPointer(colorID, 4, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(3 * 3 * sizeof(GLfloat)));
glUseProgram(shaderProgramID);
glEnableVertexAttribArray(positionID);
glEnableVertexAttribArray(colorID);
//Start up a loop that runs in the background
glutMainLoop();
return 0;
}
fragmentShader.fs
#version 130
in vec4 color;
out vec4 fColor;
void main () {
fColor = color;
}
vertexShader.vs
#version 130
in vec4 s_vPosition;
in vec4 s_vColor;
out vec4 color;
void main () {
//gl_Position = s_mP*s_mV*s_mM*s_vPosition;
color = s_vColor;
gl_Position = s_vPosition;
}
呃,我很抱歉创建这个。睡觉并再次查看我的代码后,我意识到我所有的顶点都具有相同的"y 值"。
GLfloat vertices[] = {
-0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f,
0.0f, -0.5f, 0.0f
};
无论如何,它已经解决了。天哪,我觉得自己很傻。
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