我从我的切线空间法线贴图着色器中得到了一些非常奇怪的结果 :). 在我展示的场景中，茶壶和棋盘墙使用我的普通Phong-Blinn着色器进行着色（显然，茶壶背面剔除使其具有轻微的虚幻感 :-)）。我尝试将法线贴图添加到球体上，结果是迷幻的：
光源来自右侧（仅作为黑色斑点可见）。我在球体上使用的法线贴图如下所示：
我正在使用AssImp处理输入模型，因此它会自动为每个顶点计算切线和副法线。
像素和顶点着色器如下所示。我不太确定出了什么问题，但如果切线基础矩阵出了问题，我也不会感到惊讶。我假设我必须将事物计算到眼睛空间中，然后将眼睛和光线向量转换为切线空间，并且这是正确的方法。请注意，光源位置已经以视图空间进入着色器。
光源来自右侧（仅作为黑色斑点可见）。我在球体上使用的法线贴图如下所示：
我正在使用AssImp处理输入模型，因此它会自动为每个顶点计算切线和副法线。像素和顶点着色器如下所示。我不太确定出了什么问题，但如果切线基础矩阵出了问题，我也不会感到惊讶。我假设我必须将事物计算到眼睛空间中，然后将眼睛和光线向量转换为切线空间，并且这是正确的方法。请注意，光源位置已经以视图空间进入着色器。
// Vertex Shader
#version 420
// Uniform Buffer Structures
// Camera.
layout (std140) uniform Camera
{
mat4 Camera_Projection;
mat4 Camera_View;
};
// Matrices per model.
layout (std140) uniform Model
{
mat4 Model_ViewModelSpace;
mat4 Model_ViewModelSpaceInverseTranspose;
};
// Spotlight.
layout (std140) uniform OmniLight
{
float Light_Intensity;
vec3 Light_Position; // Already in view space.
vec4 Light_Ambient_Colour;
vec4 Light_Diffuse_Colour;
vec4 Light_Specular_Colour;
};
// Streams (per vertex)
layout(location = 0) in vec3 attrib_Position;
layout(location = 1) in vec3 attrib_Normal;
layout(location = 2) in vec3 attrib_Tangent;
layout(location = 3) in vec3 attrib_BiNormal;
layout(location = 4) in vec2 attrib_Texture;
// Output streams (per vertex)
out vec3 attrib_Fragment_Normal;
out vec4 attrib_Fragment_Position;
out vec3 attrib_Fragment_Light;
out vec3 attrib_Fragment_Eye;
// Shared.
out vec2 varying_TextureCoord;
// Main
void main()
{
// Compute normal.
attrib_Fragment_Normal = (Model_ViewModelSpaceInverseTranspose * vec4(attrib_Normal, 0.0)).xyz;
// Compute position.
vec4 position = Model_ViewModelSpace * vec4(attrib_Position, 1.0);
// Generate matrix for tangent basis.
mat3 tangentBasis = mat3( attrib_Tangent,
attrib_BiNormal,
attrib_Normal);
// Light vector.
attrib_Fragment_Light = tangentBasis * normalize(Light_Position - position.xyz);
// Eye vector.
attrib_Fragment_Eye = tangentBasis * normalize(-position.xyz);
// Return position.
gl_Position = Camera_Projection * position;
}
...而像素着色器看起来像这样:
// Pixel Shader
#version 420
// Samplers
uniform sampler2D Map_Normal;
// Global Uniforms
// Material.
layout (std140) uniform Material
{
vec4 Material_Ambient_Colour;
vec4 Material_Diffuse_Colour;
vec4 Material_Specular_Colour;
vec4 Material_Emissive_Colour;
float Material_Shininess;
float Material_Strength;
};
// Spotlight.
layout (std140) uniform OmniLight
{
float Light_Intensity;
vec3 Light_Position;
vec4 Light_Ambient_Colour;
vec4 Light_Diffuse_Colour;
vec4 Light_Specular_Colour;
};
// Input streams (per vertex)
in vec3 attrib_Fragment_Normal;
in vec3 attrib_Fragment_Position;
in vec3 attrib_Fragment_Light;
in vec3 attrib_Fragment_Eye;
// Shared.
in vec2 varying_TextureCoord;
// Result
out vec4 Out_Colour;
// Main
void main(void)
{
// Compute normals.
vec3 N = normalize(texture(Map_Normal, varying_TextureCoord).xyz * 2.0 - 1.0);
vec3 L = normalize(attrib_Fragment_Light);
vec3 V = normalize(attrib_Fragment_Eye);
vec3 R = normalize(-reflect(L, N));
// Compute products.
float NdotL = max(0.0, dot(N, L));
float RdotV = max(0.0, dot(R, V));
// Compute final colours.
vec4 ambient = Light_Ambient_Colour * Material_Ambient_Colour;
vec4 diffuse = Light_Diffuse_Colour * Material_Diffuse_Colour * NdotL;
vec4 specular = Light_Specular_Colour * Material_Specular_Colour * (pow(RdotV, Material_Shininess) * Material_Strength);
// Final colour.
Out_Colour = ambient + diffuse + specular;
}
编辑：场景的3D工作室渲染（以展示球体上的UV是否正确）：
