Opengl照明照亮错误的表面
我正在使用OpenGL来显示简单的对象和它们上方的灯光。问题是我的对象的面孔没有正确的方式。这是我的结果
光应该在物体上方 我从波前文件中加载对象，如下所示：
if ( strcmp( lineHeader, "v" ) == 0 ){
glm::vec3 vertex;
fscanf(file, "%f %f %f\n", &vertex.x, &vertex.y, &vertex.z );
vertices.push_back(vertex);
}else if ( strcmp( lineHeader, "vt" ) == 0 ){
glm::vec2 uv;
fscanf(file, "%f %f\n", &uv.x, &uv.y );
uv.y = uv.y;
// Invert V coordinate since we will only use DDS texture, which are inverted. Remove if you want to use TGA or BMP loaders.
temp_uvs.push_back(uv);
}else if ( strcmp( lineHeader, "vn" ) == 0 ){
glm::vec3 normal;
fscanf(file, "%f %f %f\n", &normal.x, &normal.y, &normal.z );
temp_normals.push_back(normal);
}else if ( strcmp( lineHeader, "f" ) == 0 ){
std::string vertex1, vertex2, vertex3;
unsigned int vertexIndex[3], uvIndex[3], normalIndex[3];
int matches = fscanf(file, "%d/%d/%d %d/%d/%d %d/%d/%d\n", &vertexIndex[0], &uvIndex[0], &normalIndex[0], &vertexIndex[1], &uvIndex[1], &normalIndex[1], &vertexIndex[2], &uvIndex[2], &normalIndex[2] );
if (matches != 9){
printf("File can't be read by our simple parser :-( Try exporting with other options\n");
return false;
}
indices.push_back(vertexIndex[0]-1);
indices.push_back(vertexIndex[1]-1);
indices.push_back(vertexIndex[2]-1);
uvIndices .push_back(uvIndex[0]);
uvIndices .push_back(uvIndex[1]);
uvIndices .push_back(uvIndex[2]);
normalIndices.push_back(normalIndex[0]);
normalIndices.push_back(normalIndex[1]);
normalIndices.push_back(normalIndex[2]);
}else{
// Probably a comment, eat up the rest of the line
char stupidBuffer[1000];
fgets(stupidBuffer, 1000, file);
}
}
normals.reserve(indices.size());
uvs.reserve(indices.size());
for( unsigned int i=0; i<indices.size(); i++ ){
// Get the indices of its attributes
unsigned int uvIndex = uvIndices[i];
unsigned int normalIndex = normalIndices[i];
normals[indices[i]] = temp_normals[normalIndex-1];
uvs[indices[i]] = temp_uvs[uvIndex-1];
顶点着色器：
#version 150 core
in vec2 color;
in vec3 position;
in vec3 normal;
out vec2 UV;
out vec3 Position_worldspace;
out vec3 Normal_cameraspace;
out vec3 EyeDirection_cameraspace;
out vec3 LightDirection_cameraspace;
uniform mat4 MVP;
uniform mat4 V;
uniform mat4 M;
uniform vec3 LightPosition_worldspace;
void main() {
// Position of the vertex, in worldspace : M * position
Position_worldspace = (M * vec4(position.x , position.y , position.z ,1.0)).xyz;
// Vector that goes from the vertex to the camera, in camera space.
// In camera space, the camera is at the origin (0,0,0).
vec3 vertexPosition_cameraspace = ( V * M * vec4(position,1)).xyz;
EyeDirection_cameraspace = vec3(0,0,0) - vertexPosition_cameraspace;
// Vector that goes from the vertex to the light, in camera space. M is ommited because it's identity.
vec3 LightPosition_cameraspace = ( V * vec4(LightPosition_worldspace,1)).xyz;
LightDirection_cameraspace = LightPosition_cameraspace + EyeDirection_cameraspace;
// Normal of the the vertex, in camera space
Normal_cameraspace = ( V * M * vec4(normal,0)).xyz; // Only correct if ModelMatrix does not scale the model ! Use its inverse transpose if not.
// UV of the vertex. No special space for this one.
UV = color;
gl_Position = MVP*vec4(position.x , position.y , position.z , 1.0);
};
我的片段着色器是：
#version 150 core
// Interpolated values from the vertex shaders
in vec2 UV;
in vec3 Position_worldspace;
in vec3 Normal_cameraspace;
in vec3 EyeDirection_cameraspace;
in vec3 LightDirection_cameraspace;
out vec4 outColor
// Values that stay constant for the whole mesh.
uniform sampler2D myTextureSampler;
uniform vec3 LightPosition_worldspace;
void main(){
vec3 LightColor = vec3(1,1,1);
float LightPower = 20.0f;
// Material properties
vec3 MaterialDiffuseColor = texture2D( myTextureSampler, UV ).rgb;
vec3 MaterialAmbientColor = vec3(0.1,0.1,0.1) * MaterialDiffuseColor;
vec3 MaterialSpecularColor = vec3(0.3,0.3,0.3);
// Distance to the light
float distance = length( LightPosition_worldspace - Position_worldspace );
// Normal of the computed fragment, in camera space
vec3 n = normalize( Normal_cameraspace );
// Direction of the light (from the fragment to the light)
vec3 l = normalize( LightDirection_cameraspace );
// Cosine of the angle between the normal and the light direction,
// clamped above 0
// - light is at the vertical of the triangle -> 1
// - light is perpendicular to the triangle -> 0
// - light is behind the triangle -> 0
float cosTheta = clamp( dot( n,l ), 0,1 );
// Eye vector (towards the camera)
vec3 E = normalize(EyeDirection_cameraspace);
// Direction in which the triangle reflects the light
vec3 R = reflect(-l,n);
// Cosine of the angle between the Eye vector and the Reflect vector,
// clamped to 0
// - Looking into the reflection -> 1
// - Looking elsewhere -> < 1
float cosAlpha = clamp( dot( E,R ), 0,1 );
outColor.rgb =
// Ambient : simulates indirect lighting
MaterialAmbientColor +
// Diffuse : "color" of the object
MaterialDiffuseColor * LightColor * LightPower * cosTheta / (distance*distance) +
// Specular : reflective highlight, like a mirror
MaterialSpecularColor * LightColor * LightPower * pow(cosAlpha,5) / (distance*distance);
}
这里是装载的立方体：
# cube.obj
#
o cube
v 0.0 0.0 0.0
v 0.0 0.0 1.0
v 0.0 1.0 0.0
v 0.0 1.0 1.0
v 1.0 0.0 0.0
v 1.0 0.0 1.0
v 1.0 1.0 0.0
v 1.0 1.0 1.0
vn 0.0 0.0 1.0
vn 0.0 0.0 -1.0
vn 0.0 1.0 0.0
vn 0.0 -1.0 0.0
vn 1.0 0.0 0.0
vn -1.0 0.0 0.0
vt 0.25 0.0
vt 0.5 0.0
vt 0 0.25
vt 0.25 0.25
vt 0.5 0.25
vt 0.75 0.25
vt 0.0 0.5
vt 0.25 0.5
vt 0.5 0.5
vt 0.75 0.5
vt 0.25 0.75
vt 0.5 0.75
vt 0.25 1.0
vt 0.5 1.0
f 1/11/2 7/14/2 5/12/2
f 1/11/2 3/13/2 7/14/2
f 1/7/6 4/4/6 3/3/6
f 1/7/6 2/8/6 4/4/6
f 3/1/3 8/5/3 7/2/3
f 3/1/3 4/4/3 8/5/3
f 5/10/5 7/6/5 8/5/5
f 5/10/5 8/5/5 6/9/5
f 1/11/4 5/12/4 6/9/4
f 1/11/4 6/9/4 2/8/4
f 2/8/1 6/9/1 8/5/1
f 2/8/1 8/5/1 4/4/1
以及我如何加载我的VBO：
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
// Create a Vertex Buffer Object and copy the vertex data to it
glGenBuffers(1, &position_array_buffer);
glBindBuffer(GL_ARRAY_BUFFER, position_array_buffer);
glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(glm::vec3), &vertices[0], GL_STATIC_DRAW);
// Create an element array
glGenBuffers(1, &elements_array_buffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, elements_array_buffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size()*sizeof(GLuint), &indices[0], GL_STATIC_DRAW);
glGenBuffers(1, &normal_array_buffer);
glBindBuffer(GL_ARRAY_BUFFER, normal_array_buffer);
glBufferData(GL_ARRAY_BUFFER, normals.size() * sizeof(glm::vec3), &normals[0], GL_STATIC_DRAW);
if (textured) {
texture = new sf::Texture();
if(!texture->loadFromFile("textures/uv.jpeg"/*,sf::IntRect(0, 0, 128, 128)*/))
std::cout << "Error loading texture !!" << std::endl;
glGenBuffers(1, &color_array_buffer);
glBindBuffer(GL_ARRAY_BUFFER, color_array_buffer);
glBufferData(GL_ARRAY_BUFFER, uvs.size() * sizeof(glm::vec3), &uvs[0], GL_STATIC_DRAW);
}
以下是渲染场景的代码：
// Get a handle for our "myTextureSampler" uniform
GLuint TextureID = glGetUniformLocation(shaderProgram, "myTextureSampler");
if(!TextureID)
cout << "TextureID not found ..." << endl;
glActiveTexture(GL_TEXTURE0);
sf::Texture::bind(texture);
glUniform1i(TextureID, 0);
// 2nd attribute buffer : UVs
GLuint vertexUVID = glGetAttribLocation(shaderProgram, "color");
if(vertexUVID==-1)
cout << "vertexUVID not found ..." << endl;
glEnableVertexAttribArray(vertexUVID);
glBindBuffer(GL_ARRAY_BUFFER, color_array_buffer);
glVertexAttribPointer(vertexUVID, 2, GL_FLOAT, GL_FALSE, 0, 0);
// 3rd attribute buffer : normals
GLuint vertexNormal_modelspaceID = glGetAttribLocation(shaderProgram, "normal");
if(!vertexNormal_modelspaceID)
cout << "vertexNormal_modelspaceID not found ..." << endl;
glEnableVertexAttribArray(vertexNormal_modelspaceID);
glBindBuffer(GL_ARRAY_BUFFER, normal_array_buffer);
glVertexAttribPointer(vertexNormal_modelspaceID, 3, GL_FLOAT, GL_FALSE, 0, 0 );
// Specify the layout of the vertex data
GLint posAttrib;
posAttrib = glGetAttribLocation(shaderProgram, "position");
// glBindAttribLocation(shaderProgram,posAttrib,"position");
if(!posAttrib)
cout << "posAttrib not found ..." << endl;
glEnableVertexAttribArray(posAttrib);
glBindBuffer(GL_ARRAY_BUFFER, position_array_buffer);
glVertexAttribPointer(posAttrib, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, elements_array_buffer);
// Draw a rectangle from the indices_size/3 triangles using indices_size indices
glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, 0);
// glDrawArrays(GL_TRIANGLES,posAttrib,indices.size());
while ((error = glGetError()) != GL_NO_ERROR) {
cerr << "OpenGL error: " << error << endl;
}
我感觉我的法线没有正确加载，而且我想知道在我的元素数组中我是否必须输入关于法线和紫外线的信息，或者是否只是以经典的方式进行而没有索引。
编辑：更改了解析器，现在顶点加载正常但光线和纹理没有正确应用。
1 个答案:
答案 0 :(得分：2)
A）
normals.reserve(indices.size());
uvs.reserve(indices.size());
不要改变尺寸，只改变容量（试试自己：http://ideone.com/FbXtbm），例如此
glBufferData(GL_ARRAY_BUFFER, /*->*/normals.size() /*<-*/ * sizeof(glm::vec3),
&normals[0], GL_STATIC_DRAW);
接收零缓冲区大小作为参数。
B）片段着色器
中存在语法错误in vec3 LightDirection_cameraspace;
/*->*/ out vec4 outColor /*<-*/
// Values that stay constant for the whole mesh.
添加“;”在outColor之后。
C）您的glDrawElements电话未正确设置阵列。
在我吃完早餐咖啡后，我会添加一些示例代码。
编辑11:02
立方体有8个顶点，要正确绘制它们，每个立方体需要3个法线。 （为简单起见，我和uvs做了同样的事情）：
}
indices.push_back(vertexIndex[0]-1);
indices.push_back(vertexIndex[1]-1);
indices.push_back(vertexIndex[2]-1);
uvIndices .push_back(uvIndex[0]-1);
uvIndices .push_back(uvIndex[1]-1);
uvIndices .push_back(uvIndex[2]-1);
normalIndices.push_back(normalIndex[0]-1);
normalIndices.push_back(normalIndex[1]-1);
normalIndices.push_back(normalIndex[2]-1);
}else{
// Probably a comment, eat up the rest of the line
char stupidBuffer[1000];
fgets(stupidBuffer, 1000, file);
}
}
#if 1 // EITHER
vertices.resize(indices.size());
normals.resize(indices.size());
uvs.resize(indices.size());
for( unsigned int i=0; i<indices.size(); ++i){
vertices[i] = temp_vertices[indices[i]];
normals[i] = temp_normals[normalIndices[i]];
uvs[i] = temp_uvs[uvIndices[i]];
}
#else // OR
vertices.reserve(indices.size());
normals.reserve(indices.size());
uvs.reserve(indices.size());
for( unsigned int i=0; i<indices.size(); ++i){
vertices.push_back(temp_vertices[indices[i]]);
normals.push_back(temp_normals[normalIndices[i]]);
uvs.push_back(temp_uvs[uvIndices[i]]);
}
#endif
struct yield {
int i;
yield() : i(0) {}
int operator() (){ return i++;}
};
std::generate(indices.begin(), indices.end(), yield());
std::clog << "num vertices: " << vertices.size() << std::endl
<< "num normals: " << normals.size() << std::endl
<< "num uvs: " << uvs.size() << std::endl
<< "num indices: " << indices.size() << std::endl;
请注意我在循环中也改变了;我在那里递减所有指数。 人们不必展开所有三角形的所有索引，但这是最简单的方法。
D）我还重新考虑了你的着色器
#version 150 core
in vec2 color;
in vec3 position;
in vec3 normal;
out vec2 UV;
out vec3 Normal_cameraspace;
out vec3 EyeDirection_cameraspace;
out vec3 LightDirection_cameraspace;
uniform mat4 MVP;
uniform mat4 V;
uniform mat4 M;
uniform vec3 LightPosition_worldspace;
void main() {
// Position of the vertex, in worldspace : M * position
vec3 wPos = (M * vec4(position, 1.0)).xyz;
// Vector that goes from the vertex to the camera, in camera space.
// In camera space, the camera is at the origin (0,0,0).
vec3 vertexPosition_cameraspace = ( V * M * vec4(position,1)).xyz;
EyeDirection_cameraspace = -vertexPosition_cameraspace;
// Vector that goes from the vertex to the light, in camera space. M is ommited because it's identity.
vec3 LightPosition_cameraspace = ( V * vec4(LightPosition_worldspace,1)).xyz;
LightDirection_cameraspace = LightPosition_cameraspace - vertexPosition_cameraspace;
// Normal of the the vertex, in camera space
#if 0
// Only correct if ModelMatrix does not scale the model ! Use its inverse transpose if not.
Normal_cameraspace = (V * M * vec4(normal,0)).xyz;
#else
Normal_cameraspace = mat3(V) * inverse(transpose(mat3(M))) * normal;
#endif
Normal_cameraspace = normalize(Normal_cameraspace);
// UV of the vertex. No special space for this one.
UV = color;
gl_Position = MVP*vec4(position, 1.0);
} // void main()
#version 150 core
// Interpolated values from the vertex shaders
in vec2 UV;
in vec3 Normal_cameraspace;
in vec3 EyeDirection_cameraspace;
in vec3 LightDirection_cameraspace;
out vec4 outColor;
const float SHININESS = 5.0;
const float AMBIENCE = 0.1;
const float SPECULARITY = 0.3;
const vec3 LIGHT_COLOR = vec3(1.0, 1.0, 1.0);
const float LIGHT_INTENSITY = 300.0;
//uniform sampler2D myTextureSampler;
//uniform vec3 LightPosition_worldspace;
float lambert_fac(vec3 lightPos, vec3 normal) {
vec3 l_ = normalize(lightPos);
vec3 n_ = normalize(normal);
return max(dot(l_, n_),0.0);
}
float phong_fac(vec3 eyePos, vec3 lightPos, vec3 normal, float shiny) {
vec3 e_ = normalize(eyePos);
vec3 l_ = normalize(lightPos);
vec3 n_ = normalize(normal);
vec3 r_ = normalize(reflect(-l_, n_));
return pow(max(dot(r_, e_),0.0), shiny);
}
float attenuate(float d/*distance*/, float c/*constant*/,
float l/*linear*/, float q/*quadratic*/) {
return 1.0/(c + l * d + q * d * d);
}
struct Material {
vec3 ambient, diffuse, specular;
};
void main(){
Material mat;
/*texture2D( myTextureSampler, UV ).rgb;*/
vec3 baseColor =
vec3(UV.s, UV.t, clamp(UV.s + UV.t,0.,1.)); // just to save some attributes contributing to
// from the optimizer
mat.ambient = mat.diffuse = mat.specular = baseColor;
mat.ambient *= AMBIENCE; mat.specular *= SPECULARITY;
// attenuation
float att = attenuate(length(LightDirection_cameraspace), 0., 0., 1.);
// light
vec3 l_ = LIGHT_COLOR * LIGHT_INTENSITY * att;
// Diffuse Contribution
float dc = lambert_fac(LightDirection_cameraspace, Normal_cameraspace);
// Specular Contribution
float sc = phong_fac(EyeDirection_cameraspace,
LightDirection_cameraspace,
Normal_cameraspace,
SHININESS);
outColor = vec4(mat.ambient
+ mat.diffuse * dc * l_
+ mat.specular * sc * l_, 1.0);
} // void main()
而且这个
是它现在的样子
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