我正在学习GLSL,尝试实现一些光照和贴图技巧。我正在使用ShaderDesigner工具进行工作。在编写法线贴图后,我发现我的模型照明看起来不真实。以下是我的代码和一些图片。如果可能,请告诉我问题出在哪里。
顶点着色器(Vertex Shader)
#define MAX_LIGHTS 1
struct LightProps
{
vec3 direction[MAX_LIGHTS];
};
attribute vec3 tangent;
attribute vec3 bitangent;
varying LightProps lights;
void main()
{
vec3 N = normalize(gl_NormalMatrix*gl_Normal);
vec3 T = normalize(gl_NormalMatrix*tangent);
vec3 B = normalize(gl_NormalMatrix*bitangent);
mat3 TBNMatrix = mat3(T,B,N);
vec4 vertex = gl_ModelViewMatrix*gl_Vertex;
for(int i = 0; i < MAX_LIGHTS; i++)
{
vec4 lightPos = gl_LightSource[i].position;
lights.direction[i] = vec3(lightPos.w > 0 ? lightPos-vertex : lightPos);
lights.direction[i] *= TBNMatrix;
}
gl_TexCoord[0] = gl_MultiTexCoord0;
gl_Position = gl_ModelViewProjectionMatrix*gl_Vertex;
}
片元着色器
#define MAX_LIGHTS 1
struct LightProps
{
vec3 direction[MAX_LIGHTS];
};
uniform sampler2D textureUnit;
uniform sampler2D normalTextureUnit;
uniform vec4 TexColor;
varying LightProps lights;
void main()
{
vec3 N = normalize(texture2D(normalTextureUnit,gl_TexCoord[0].st).rgb*2.0-1.0);
vec4 color = vec4(0,0,0,0);
for(int i = 0; i < MAX_LIGHTS; i++)
{
vec3 L = lights.direction[i];
float dist = length(L);
L = normalize(L);
float NdotL = max(dot(N,L),0.0);
if(NdotL > 0)
{
float att = 1.0;
if(gl_LightSource[i].position.w > 0)
{
att = 1.0/ (gl_LightSource[i].constantAttenuation +
gl_LightSource[i].linearAttenuation * dist +
gl_LightSource[i].quadraticAttenuation * dist * dist);
}
vec4 ambient = gl_FrontLightProduct[i].ambient;
vec4 diffuse = clamp(att*NdotL*gl_FrontLightProduct[i].diffuse,0,1);
color += att*(ambient+diffuse);
}
}
vec4 textureColor = texture2D(textureUnit, vec2(gl_TexCoord[0]));
gl_FragColor = TexColor*textureColor + gl_FrontLightModelProduct.sceneColor + color;
}
我将TexColor设置为
(0.3,0.3,0.3,1.0)
并拍了照片:
截图
当我把相机和灯光转向左边时,有一点点的光照,但是当我转向右边时,平面完全被照亮。我认为这里有些问题,因为在没有法线贴图的情况下,平面从两侧看起来都是一样的。以下是法线纹理。提前感谢。
法线贴图: