C++ glsl-光线行进不在片段着色器中工作
我现在正在学习GLSL和ray marching。我试图将其转换为我的C++ glsl-光线行进不在片段着色器中工作,c++,opengl,glsl,glfw,C++,Opengl,Glsl,Glfw,我现在正在学习GLSL和ray marching。我试图将其转换为我的c++OpenGL项目,但失败了 以下是我的代码: Main.cpp: GLuint screenWidth = 1280, screenHeight = 720; int main () { GLFWwindow* window = NULL; const GLubyte* renderer; const GLubyte* version; if (!glfwInit ()) {
c++OpenGL
项目,但失败了
以下是我的代码:
Main.cpp:
GLuint screenWidth = 1280, screenHeight = 720;
int main ()
{
GLFWwindow* window = NULL;
const GLubyte* renderer;
const GLubyte* version;
if (!glfwInit ()) {
fprintf (stderr, "ERROR: could not start GLFW3\n");
return 1;
}
glfwWindowHint (GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint (GLFW_CONTEXT_VERSION_MINOR, 1);
glfwWindowHint (GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
glfwWindowHint (GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
window = glfwCreateWindow (screenWidth, screenHeight, "OpenGL", NULL, NULL);
if (!window) {
fprintf (stderr, "ERROR: could not open window with GLFW3\n");
glfwTerminate ();
return 1;
}
glfwMakeContextCurrent (window);
glewExperimental = GL_TRUE;
glewInit ();
glViewport(0, 0, screenWidth*2, screenHeight*2);
glEnable (GL_DEPTH_TEST);
glDepthFunc (GL_LESS);
Shader ourShader("vertex_shader.glsl", "fragment_shader.glsl");
GLint positionLocation = glGetAttribLocation(ourShader.Program, "a_position");
glUniform2f(glGetUniformLocation(ourShader.Program, "resolution"), (GLfloat)screenWidth, (GLfloat)screenHeight);
GLint mouseLocation = glGetUniformLocation(ourShader.Program, "mouse");
glUniform4f(mouseLocation, 0.0, 0.0, 0.0, 0.0);
GLfloat mx = glm::max(screenWidth, screenHeight);
GLfloat xdivmx = screenWidth/mx; //Coordinates range from [-1,1].
GLfloat ydivmx = screenHeight/mx;
GLint screenRatioLocation = glGetUniformLocation(ourShader.Program, "screenRatio");
glUniform2f(screenRatioLocation, xdivmx, ydivmx);
GLfloat timeLocation = glGetUniformLocation(ourShader.Program, "time");
glUniform1f(timeLocation, deltaTime);
GLfloat vertices[] = {
-1.0f, -1.0f,
1.0f, -1.0f,
-1.0f, 1.0f,
-1.0f, 1.0f,
1.0f, -1.0f,
1.0f, 1.0f // Top Left
};
GLuint VBO, VAO, EBO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glGenBuffers(1, &EBO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, (GLvoid*)0);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
while (!glfwWindowShouldClose(window))
{
glfwPollEvents();
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
ourShader.Use();
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 6);=
glBindVertexArray(0);
glfwSwapBuffers(window);
}
// Properly de-allocate all resources once they've outlived their purpose
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
glDeleteBuffers(1, &EBO);
// Terminate GLFW, clearing any resources allocated by GLFW.
glfwTerminate();
return 0;
}
顶点代码:
vertex_shader.glsl:
#version 410 core
layout (location = 0) in vec2 a_position;
out vec2 surfacePosition;
uniform vec2 screenRatio;
uniform vec2 resolution;
void main() {
surfacePosition = a_position * screenRatio;
gl_Position = vec4(a_position, 0, 1);
}
片段代码:
#version 410 core
in vec2 surfacePosition;
out vec4 color;
vec4 gl_FragCoord;
uniform float time;
uniform vec2 resolution;
uniform vec4 mouse;
const int MAX_MARCHING_STEPS = 255;
const float MIN_DIST = 0.0;
const float MAX_DIST = 100.0;
const float EPSILON = 0.0001;
#define PI 3.1415926535898 // That was from memory, so if things start flying off the screen...
float sphereSDF(vec3 samplePoint) {
return length(samplePoint) - 1.0;
}
float sceneSDF(vec3 samplePoint) {
return sphereSDF(samplePoint);
}
float shortestDistanceToSurface(vec3 eye, vec3 marchingDirection, float start, float end) {
float depth = start;
for (int i = 0; i < MAX_MARCHING_STEPS; i++) {
float dist = sceneSDF(eye + depth * marchingDirection);
if (dist < EPSILON) {
return depth;
}
depth += dist;
if (depth >= end) {
return end;
}
}
return end;
}
vec3 rayDirection(float fieldOfView, vec2 size, vec2 fragCoord) {
vec2 xy = fragCoord - size / 2.0;
float z = size.y / tan(radians(fieldOfView) / 2.0);
return normalize(vec3(xy, -z));
}
void main() {
vec3 dir = rayDirection(45.0, resolution.xy, surfacePosition.xy);
vec3 eye = vec3(0.0f, 0.0f, 5.0f);
float dist = shortestDistanceToSurface(eye, dir, MIN_DIST, MAX_DIST);
if (dist > MAX_DIST - EPSILON) {
// Didn't hit anything
color = vec4(0.0, 0.0, 0.0, 0.0);
return;
}
color = vec4(1.0, 0.0, 0.0, 1.0);
}
而且我还是有黑屏。当我转到片段着色器
并更改此行时:
vec3 dir = rayDirection(45.0, vec2(1280,720), surfacePosition.xy);//<-- explicitly my screen resolution, just to test.
vec3 dir=光线方向(45.0,vec2(1280720),surfacePosition.xy)//
始终记得检查编译、验证和链接状态。问题是您定义了gl\u FragCoord
,这与内置的gl\u FragCoord
冲突
假设您的着色器
类在默认情况下不调用glUseProgram()
。然后需要在调用任何glUniform*()
之前显式调用它。
请注意,任何glGetUniformLocation()
、glGetAttriblLocation()
、glGetActiveUniform()
和glGetActiveAttrib()
调用都没有这种需要(出于明显的原因)
您还启用了深度测试,但从未清除深度缓冲区。因此,要么禁用深度测试,要么清除深度缓冲区
最后,ShaderToy的fragCoord
相当于gl_fragCoord
。但是,您的表面位置
不是。所以只要使用gl_FragCoord
就可以了
因此,使用gl_FragCoord
而不是surfacePosition
您应该看到(如ShaderToy上的):
另外,glGenBuffers(1,&EBO)
是多余的,我不知道为什么要将视口设置为其大小的两倍。对glGetAttriblLocation()
的调用也是多余的,不仅仅是因为您没有使用它。但因为您正在使用布局限定符
请注意,您还有时间
和鼠标
,如果最终使用它们,同样需要指定它们
正如我前面提到的,因为您可以使用gl\u FragCoord
。这仍然意味着不需要surfacePosition
和screenRatio
我有:GLint resolutionLocation=glGetUniformLocation(ourShader.Program,“resolution”);glUniform2f(分辨率位置、屏幕宽度、屏幕高度)代码>,但它仍然不工作。顺便说一下,我正在使用OSX
和Xcode
,没有收到您的错误。甚至不是片段着色器的编译错误。这是链接错误,不是编译错误。另外,你在哪里定义屏幕宽度
和屏幕高度
?我想你是对的,分辨率
没有通过。我只是用glUniform2f(glGetUniformLocation(ourShader.Program,“resolution”)、1.0f(GLfloat)屏幕高度做了一个相当好的测试
,然后将fragment_着色器
更改为仅color=vec4(分辨率.x,0.0,0.0,1.0)代码>。我希望看到红色,但我还是会变黑。链接之间的某个地方有问题。是的,您确实需要在任何glUniform*()
之前调用glUseProgram()
。请注意,glGetUniformLocation()
,glGetAttriblLocation()
,glGetActiveUniform()
和glGetActiveAttrib()
没有这种需要(原因很明显)。
vec3 dir = rayDirection(45.0, vec2(1280,720), surfacePosition.xy);//<-- explicitly my screen resolution, just to test.
Link Failure: Fragment info
-------------
0(6) : error C5109: variable "gl_FragCoord" domain conflicts with semantics "WPOS"