RenderMonkey 练习 第四天 【OpenGL Texture Bump】

BumpTexture

1. 新建一个OpenGL 空effect;

2. 添加相关变量

右击Effect节点选择Add Variable->float->float / float3 添加镜面光强度、灯光位置和相机位置参数：

float fSpecularPower = 25.0;

float3 vec3LightPosition = {-100.0,100.0,100.0};

float3 vec3EyePosition = {0,0,100.0};

右击Effect节点选择AddTexture->Add 2DTexture 添加base和bump两张纹理图片：

Fieldstone.tga   ---->  base

FieldstoneBumpDOT3.tga  -----> bump

右击Effect节点选择Add Variable->Color 添加 环境光、散射光、镜面光颜色

fvAmbient  = {0.3，0.3, 0.3}；

fvDiffuse = {0.86,0.86,0.86}；

fvSpecular = {0.57,0.56,0.58}；

3. 修改Stream Mapping 中 添加NORMAL、TexCoord 、 BINORMAL、TANGENT

4. 在pass0中添加纹理对象 AddTextureObject 将base和bump图片添加进去，重新命名为baseMap和bumpMap

5. 修改vertex shader ：

uniform vec3 vec3LightPosition;
uniform vec3 vec3EyePosition;

varying vec2 texcoord;
varying vec3 viewDirection;
varying vec3 lightDirection;

attribute vec3 rm_BiNormal;
attribute vec3 rm_Tangent;

void main(void)
{
   gl_Position = ftransform();
   
   texcoord = gl_MultiTexCoord0.xy;
   vec4 fvObjectPosition = gl_ModelViewMatrix * gl_Vertex;
   
   vec3 fviewDirection = normalize(vec3EyePosition - fvObjectPosition.xyz);
   vec3 flightDirection = normalize(vec3LightPosition - fvObjectPosition.xyz);
   
   vec3 fvNormal = gl_NormalMatrix * gl_Normal;
   vec3 fvBiNormal = gl_NormalMatrix * rm_BiNormal;
   vec3 fvTangent = gl_NormalMatrix * rm_Tangent;
   
   viewDirection.x = dot(fvTangent, fviewDirection);
   viewDirection.y = dot(fvBiNormal, fviewDirection);
   viewDirection.z = dot(fvNormal, fviewDirection);
   
   lightDirection.x = dot(fvTangent, flightDirection);
   lightDirection.y = dot(fvBiNormal, flightDirection);
   lightDirection.z = dot(fvNormal, flightDirection);   
}

6.修改pixel shader：

uniform vec4 fvAmbient;
uniform vec4 fvSpecular;
uniform vec4 fvDiffuse;
uniform float fSpecularPower;

uniform sampler2D baseMap;
uniform sampler2D bumpMap;

varying vec2 Texcoord;
varying vec3 ViewDirection;
varying vec3 LightDirection;

void main( void )
{
   vec3  fvLightDirection = normalize( LightDirection );
   vec3  fvNormal         = normalize( ( texture2D( bumpMap, Texcoord ).xyz * 2.0 ) - 1.0 );
   float fNDotL           = dot( fvNormal, fvLightDirection );
   
   vec3  fvReflection     = normalize( ( ( 2.0 * fvNormal ) * fNDotL ) - fvLightDirection );
   vec3  fvViewDirection  = normalize( ViewDirection );
   float fRDotV           = max( 0.0, dot( fvReflection, fvViewDirection ) );
   
   vec4  fvBaseColor      = texture2D( baseMap, Texcoord );
   
   vec4  fvTotalAmbient   = fvAmbient * fvBaseColor;
   vec4  fvTotalDiffuse   = fvDiffuse * fNDotL * fvBaseColor;
   vec4  fvTotalSpecular  = fvSpecular * ( pow( fRDotV, fSpecularPower ) );
 
   gl_FragColor = ( fvTotalAmbient + fvTotalDiffuse + fvTotalSpecular );      
}

7. 效果图