Hi! i have some very strange behaviour with my shader.
the code i took here:
http://www.geeks3d.com/20091013/shader-library-phong-shader-with-multiple-
lights-glsl/
[CODE]
program = compileProgram(
['''
varying vec3 normal, eyeVec;
#define MAX_LIGHTS 8
varying vec3 lightDir[MAX_LIGHTS];
varying vec2 texture_coordinate;
uniform int numLights;
void main()
{
gl_Position = ftransform();
normal = gl_NormalMatrix * gl_Normal;
vec4 vVertex = gl_ModelViewMatrix * gl_Vertex;
eyeVec = -vVertex.xyz;
int i;
texture_coordinate = vec2(gl_MultiTexCoord0);
for (i=0; i<numLights; ++i)
lightDir[i] = vec3(gl_LightSource[i].position.xyz - vVertex.xyz);
}
''',],
['''
varying vec3 normal, eyeVec;
#define MAX_LIGHTS 8
varying vec3 lightDir[MAX_LIGHTS];
varying vec2 texture_coordinate;
uniform sampler2D my_color_texture;
uniform int numLights;
void main (void)
{
vec4 final_color = gl_FrontLightModelProduct.sceneColor;
vec4 texel = texture2D(my_color_texture, texture_coordinate);
vec3 N = normalize(normal);
int i;
for (i=0; i<numLights; ++i)
{
vec3 L = normalize(lightDir[i]);
float lambertTerm = dot(N,L);
if (lambertTerm > 0.0)
{
final_color +=
gl_LightSource[i].diffuse *
gl_FrontMaterial.diffuse *
lambertTerm;
vec3 E = normalize(eyeVec);
vec3 R = reflect(-L, N);
float specular = pow(max(dot(R, E), 0.0),
gl_FrontMaterial.shininess);
final_color +=
gl_LightSource[i].specular *
gl_FrontMaterial.specular *
specular;
}
}
gl_FragColor = final_color*texel;
}
''',])
#after this ->
if program:
glUseProgramObjectARB(program)
num_lights = glGetUniformLocationARB(program, "numLights")
glUniform1iARB(num_lights, 4)
[/CODE]
######################################################
it's ok at work but at home it crashes (win x64, geforce 7600 GT). Other shaders
work fine - i found that it crashes somewhere near for-loop
for (i=0; i<numLights; ++i)
lightDir[i] = vec3(gl_LightSource[i].position.xyz - vVertex.xyz);
The main question is can i somehow debug shader and print some log what's going
on?
and how it can be that everything is ok at one machine and invalidOperation at
other?..
thank you!
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