如何解决光源设置不正确
我有这个代码,但灯光似乎无法正常工作,当我渲染物体时它很暗,然后当我旋转它时,光源似乎也旋转了。我无法弄清楚问题出在哪里。我尝试修改灯的模型,但仍然无法正常工作
这是程序:
while (!glfwWindowShouldClose(window))
{
/* Render here */
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glm::mat4 view = glm::mat4(1.0f);
glm::mat4 projection = glm::mat4(1.0f);
projection = glm::perspective(glm::radians(45.0f),(float)width / (float)heigh,0.1f,100.0f);
view = glm::translate(view,glm::vec3(0.0f,0.0f,transZ)); //this is for scroll mouse
view = glm::translate(view,-2.0f));
view = glm::translate(view,-5.0f));
glUseProgram(programT);
int lightColorLoc = glGetUniformLocation(programT,"lightColor");
glUniformMatrix4fv(lightColorLoc,1,GL_FALSE,glm::value_ptr(glm::vec3(1.0f,0.0f)));
int objectColorLoc = glGetUniformLocation(programT,"objectColor");
glUniformMatrix4fv(objectColorLoc,0.5f,0.31f)));
glm::vec3 lightPos(2.0f,4.0f,5.0f);
int lightPosLoc = glGetUniformLocation(programT,"lightPos");
glUniformMatrix4fv(lightPosLoc,glm::value_ptr(lightPos));
int projectionLocLight = glGetUniformLocation(programT,"projection");
glUniformMatrix4fv(projectionLocLight,glm::value_ptr(projection));
glm::mat4 modelLight = glm::mat4(1.0f);
int modelLocLight = glGetUniformLocation(programT,"model");
glUniformMatrix4fv(modelLocLight,glm::value_ptr(modelLight));
glm::mat4 viewLight = glm::mat4(1.0f);
int viewLocLight = glGetUniformLocation(programT,"view");
glUniformMatrix4fv(viewLocLight,glm::value_ptr(viewLight));
int viewLoc = glGetUniformLocation(programT,"view");
glUniformMatrix4fv(viewLoc,glm::value_ptr(view));
int projectionLoc = glGetUniformLocation(programT,"projection");
glUniformMatrix4fv(projectionLoc,glm::value_ptr(projection));
model = glm::rotate(model,glm::radians(rotX),glm::vec3(1.0f,0.0f));
model = glm::rotate(model,glm::radians(rotY),glm::vec3(.0f,1.0f,.0f));
model = glm::rotate(model,glm::radians(rotZ),1.0f));
int modelLoc = glGetUniformLocation(programT,"model");
glUniformMatrix4fv(modelLoc,glm::value_ptr(model));
glGenerateMipmap(GL_TEXTURE_2D);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D,textureArray[0]);
glUniform1i(glGetUniformLocation(programT,"ourTexture"),0);
glBindVertexArray(VAOArray[0]);
glDrawArrays(GL_TRIANGLES,myMeshes.at(0).Indices.size());
/* Swap front and back buffers */
glfwSwapBuffers(window);
/* Poll for and process events */
glfwPollEvents();
glfwSetKeyCallback(window,key_callback);
glfwSetScrollCallback(window,scroll_callback);
glfwSetFramebufferSizeCallback(window,framebuffer_size_callback);
}
以下是我的顶点着色器:
#version 330 core
layout (location = 0) in vec3 RealPos;
layout (location = 1) in vec3 vertex_color;
layout (location = 2) in vec2 vertex_textcoord;
layout (location = 3) in vec3 RealNor;
out vec3 vs_pos;
out vec3 vs_color;
out vec2 vs_text;
out vec3 normal;
out vec3 FragPos;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
vs_pos = RealPos;
vs_color = vertex_color;
vs_text=vertex_textcoord;
normal=RealNor;
FragPos = vec3(model * vec4(vs_pos,1.0));
gl_Position = projection * view * model * vec4(vs_pos,1.0);
}
以下是片段着色器:
#version 330 core
in vec2 vs_text;
in vec3 normal;
in vec3 FragPos;
uniform vec3 lightPos;
out vec4 gl_FragColor;
uniform vec3 objectColor;
uniform vec3 lightColor;
uniform sampler2D ourTexture;
void main()
{
vec3 norm = normalize(normal);
vec3 lightDir = normalize(lightPos - FragPos);
float ambientStrength = 0.1;
vec3 ambient = ambientStrength * lightColor;
float diff = max(dot(norm,lightDir),0.0);
vec3 diffuse = diff * lightColor;
vec3 result = (ambient + diffuse) * objectColor;
gl_FragColor = texture(ourTexture,vs_text) * vec4(result,1.0);
}
我该如何解决问题?
解决方法
片段着色器中的光计算是在世界空间中完成的。因此,您必须将具有法线矩阵的法线向量从对象空间转换到世界空间:
mat3 normalMatrix = transpose(inverse(mat3(model)));
normal = normalMatrix * RealNor;
FragPos = vec3(model * vec4(vs_pos,1.0));
见Why is the transposed inverse of the model view matrix used to transform the normal vectors? 和Why transforming normals with the transpose of the inverse of the modelview matrix?
想象一下桌子上有一个旋转器和一盏台灯。你的眼睛就是相机。 model
矩阵对旋转进行建模。这会导致旋转器的不同侧面在旋转时被照亮。但是,灯的位置不会相对于您的位置发生变化。
当你改变你的位置(眼睛的位置)时,灯的相对位置也会改变。这可以通过更改 view
矩阵来建模。
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