firegun9

02-14-2007, 02:37 PM

Hi,

I follow the bump mapping example from the book "OpenGL Shading Language," but the result looks very different from what it does in the book.

Please see the comparison here:

http://joe.phsiao.googlepages.com/bump.jpg

The left one is what I got in Shader Designer, and it does not bump :( . The right one is the result in the book.

Here is the code:

varying vec3 LightDir;

varying vec3 EyeDir;

attribute vec3 Tangent;

void main()

{

vec3 LightPosition = vec3(0,0,0);

EyeDir = vec3(gl_ModelViewMatrix * gl_Vertex);

gl_Position = ftransform();

gl_TexCoord[0] = gl_MultiTexCoord0;

vec3 n = normalize(gl_NormalMatrix * gl_Normal);

vec3 t = normalize(gl_NormalMatrix * Tangent);

vec3 b = cross(n, t);

vec3 v;

v.x = dot(vec3(gl_LightSource[0].position), t);

v.y = dot(vec3(gl_LightSource[0].position), b);

v.z = dot(vec3(gl_LightSource[0].position), n);

LightDir = normalize(v);

v.x = dot(EyeDir, t);

v.y = dot(EyeDir, b);

v.z = dot(EyeDir, n);

EyeDir = normalize(v);

}

varying vec3 LightDir;

varying vec3 EyeDir;

void main()

{

vec3 litColor;

vec2 c = 16.0 * gl_TexCoord[0].st;

vec2 p = fract(c) - vec2(0.5);

float d, f;

d = p.x * p.x + p.y * p.y;

f = 1.0 / sqrt(d+1.0);

if(d >= 0.15)

{

p = vec2(0.0); f = 1.0;

}

vec3 normDelta = vec3(p.x, p.y, 1.0)*f;

litColor = vec3(.7, .6, .18) * max(dot(normDelta, LightDir), 0.0);

vec3 reflectDir = reflect(LightDir, normDelta);

float spec = max(dot(EyeDir, reflectDir), 0.0);

spec = pow(spec, 6.0);

spec *= .5;

litColor = min(litColor + spec, vec3(1.0));

gl_FragColor = vec4(litColor, 1.0);

}I just replaced all the uniform variables in the example to make it executable in the program Shader Designer. What is the problem?

I follow the bump mapping example from the book "OpenGL Shading Language," but the result looks very different from what it does in the book.

Please see the comparison here:

http://joe.phsiao.googlepages.com/bump.jpg

The left one is what I got in Shader Designer, and it does not bump :( . The right one is the result in the book.

Here is the code:

varying vec3 LightDir;

varying vec3 EyeDir;

attribute vec3 Tangent;

void main()

{

vec3 LightPosition = vec3(0,0,0);

EyeDir = vec3(gl_ModelViewMatrix * gl_Vertex);

gl_Position = ftransform();

gl_TexCoord[0] = gl_MultiTexCoord0;

vec3 n = normalize(gl_NormalMatrix * gl_Normal);

vec3 t = normalize(gl_NormalMatrix * Tangent);

vec3 b = cross(n, t);

vec3 v;

v.x = dot(vec3(gl_LightSource[0].position), t);

v.y = dot(vec3(gl_LightSource[0].position), b);

v.z = dot(vec3(gl_LightSource[0].position), n);

LightDir = normalize(v);

v.x = dot(EyeDir, t);

v.y = dot(EyeDir, b);

v.z = dot(EyeDir, n);

EyeDir = normalize(v);

}

varying vec3 LightDir;

varying vec3 EyeDir;

void main()

{

vec3 litColor;

vec2 c = 16.0 * gl_TexCoord[0].st;

vec2 p = fract(c) - vec2(0.5);

float d, f;

d = p.x * p.x + p.y * p.y;

f = 1.0 / sqrt(d+1.0);

if(d >= 0.15)

{

p = vec2(0.0); f = 1.0;

}

vec3 normDelta = vec3(p.x, p.y, 1.0)*f;

litColor = vec3(.7, .6, .18) * max(dot(normDelta, LightDir), 0.0);

vec3 reflectDir = reflect(LightDir, normDelta);

float spec = max(dot(EyeDir, reflectDir), 0.0);

spec = pow(spec, 6.0);

spec *= .5;

litColor = min(litColor + spec, vec3(1.0));

gl_FragColor = vec4(litColor, 1.0);

}I just replaced all the uniform variables in the example to make it executable in the program Shader Designer. What is the problem?