当我将切向量转移到顶点着色器后,反转它得到的结果如下:
“阴影”在错误的位置。
(只有当我通过Y轴旋转它时才有效,因此最后的图像似乎呈现了一个良好的视差映射立方体)
我确定这不是切向量或纹理坐标问题
因为:
我使用完全相同的切线计算函数和完全相同的立方体位置、法线和纹理坐标数据,与工作演示中一样。毕竟,我将包含位置/纹理坐标/法线/切向量数据的数组导出到.txt文件中,然后看到了我期望的内容(我期望的是与工作演示中相同的pos/tex/norm数据,包括我从工作演示中成功导出的计算切线)。
下一个参数是,我将我的着色器代码复制到工作演示中,它仍然有效。另一个是,我尝试了多种方法来渲染这个立方体。我尝试过使用glVertexAttribPointer的VBO,尝试过将切向量保存为其他纹理坐标的VBO(与演示中一样),尝试过使用glVertexAttrib4f的DisplayList。结果是……完全相同。
高度图正确加载,我尝试将其设置为漫反射贴图,看起来还不错。 glGetError()没有报错,着色器编译日志也是如此。
可能是相机或初始化状态的问题。
也许发布初始化代码会有所帮助。
void CDepthBase::OpenGLSet() {
glEnable( GL_TEXTURE_2D );
glShadeModel( GL_SMOOTH );
glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );
glClearDepth( 1.0f );
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glDepthFunc( GL_LEQUAL );
glEnable(GL_DEPTH_TEST);
glBlendFunc( GL_ONE, GL_ONE );
GLfloat ratio;
glViewport(0, 0, ResolutionWidth, ResolutionHeight);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0f, ResolutionWidth / (float)ResolutionHeight, 0.1f, 900.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
if (GLEW_OK != glewInit()) {
MBX("Failed to init GLEW.", "Error");
}
if (glewIsSupported("GL_ARB_vertex_buffer_object")) {
VBO_supported = true;
} else VBO_supported = false;
glHint( GL_FOG_HINT, GL_DONT_CARE );
glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST );
glShadeModel(GL_SMOOTH);
glAlphaFunc(GL_ALWAYS, 0);
}
顺便说一下,我正在使用带有扩展功能的GL Extension Wrangler。
着色器代码和日志(此导出文件包含直接传递给glShaderSource的代码):
Vertex shader was successfully compiled to run on hardware.
Fragment shader was successfully compiled to run on hardware.
Fragment shader(s) linked, vertex shader(s) linked.
------------------------------------------------------------------------------------------
varying vec3 lightDir;
varying vec3 viewDir;
attribute vec4 tangent;
void main()
{
gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
gl_TexCoord[0] = gl_MultiTexCoord0;
vec3 vertexPos = vec3(gl_ModelViewMatrix * gl_Vertex);
vec3 tn = tangent.xyz;
vec3 n = normalize(gl_NormalMatrix * gl_Normal);
vec3 t = normalize(gl_NormalMatrix * tangent.xyz);
vec3 b = cross(t, n) * -tangent.w;
mat3 tbnMatrix = mat3(t.x, b.x, n.x,
t.y, b.y, n.y,
t.z, b.z, n.z);
lightDir = (gl_LightSource[0].position.xyz - vertexPos) / 100.0;
lightDir = tbnMatrix * lightDir;
viewDir = -vertexPos;
viewDir = tbnMatrix * viewDir;
}
-----------------------------------------------------------------------------------------
varying vec3 lightDir;
varying vec3 viewDir;
uniform sampler2D diffuseMap;
uniform sampler2D normalMap;
uniform sampler2D heightMap;
uniform float scale;
uniform float bias;
void main()
{
vec3 v = normalize(viewDir);
vec2 TexCoord = gl_TexCoord[0].st;
{
float height = texture2D(heightMap, gl_TexCoord[0].st).r;
height = height * scale + bias;
TexCoord = gl_TexCoord[0].st + (height * v.xy);
}
vec3 l = lightDir;
float atten = max(0.0, 1.0 - dot(l, l));
l = normalize(l);
vec3 n = normalize(texture2D(normalMap, TexCoord).rgb * 2.0 - 1.0);
vec3 h = normalize(l + v);
float nDotL = max(0.0, dot(n, l));
float nDotH = max(0.0, dot(n, h));
float power = (nDotL == 0.0) ? 0.0 : pow(nDotH, gl_FrontMaterial.shininess);
vec4 ambient = gl_FrontLightProduct[0].ambient * atten;
vec4 diffuse = gl_FrontLightProduct[0].diffuse * nDotL * atten;
vec4 specular = gl_FrontLightProduct[0].specular * power * atten;
vec4 color = gl_FrontLightModelProduct.sceneColor + ambient + diffuse + specular;color *= texture2D(diffuseMap,TexCoord);
gl_FragColor = color ;
}
因为结果与常量值交换时相同,所以Uniforms正常工作。编译着色器:
void __Shader::import(){
if(imported) __Shader::~__Shader();
v = glCreateShader(GL_VERTEX_SHADER);
f = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(v, 1, (const GLchar **)&vsrc.cstr,NULL);
glShaderSource(f, 1, (const GLchar **)&fsrc.cstr,NULL);
glCompileShader(v);
glCompileShader(f);
p = glCreateProgram();
glAttachShader(p,v);
glAttachShader(p,f);
if(_flags & NORMAL_MAPPING)
glBindAttribLocation(p, ATTRIB_TANGENT, "tangent");
glLinkProgram(p);
if(_flags & DIFFUSE_MAPPING)
diffuseUni.loc = glGetUniformLocation(p, "diffuseMap");
if(_flags & NORMAL_MAPPING)
normalUni.loc = glGetUniformLocation(p, "normalMap");
if(_flags & PARALLAX_MAPPING)
heightUni.loc = glGetUniformLocation(p, "heightMap");
if(_flags & SPECULAR_MAPPING)
specularUni.loc = glGetUniformLocation(p, "specularMap");
imported = true;
}
在VBO中设置属性:
if(tangents.size() > 0){
buffered |= 3;
glGenBuffers(1, &VBO_tangent);
glBindBuffer(GL_ARRAY_BUFFER, VBO_tangent);
glBufferData(GL_ARRAY_BUFFER, tangents.size()*sizeof(tangent), tangents.get_ptr(), GL_STATIC_DRAW);
}
// and in draw:
if(buffered & 3) {
glBindBuffer(GL_ARRAY_BUFFER, VBO_tangent);
glVertexAttribPointer(__Shader::ATTRIB_TANGENT, 4, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(__Shader::ATTRIB_TANGENT);
}
and a small note
for(int i = 0; i < responders.size(); ++i)
if(strstr(responders[i].idea, "tangent problem"))
responders[i].please_dont_talk();
只需告诉我您对导致这些不良结果的其他想法即可。