Jump to content
  • Advertisement
Sign in to follow this  
flyslasher

Unexpected problems with OpenGL lights

This topic is 2653 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

After spending much time on google, I finally got lights to somewhat work! It was the right code in the wrong places but anyways to the problem. The lights only seem to work when I am using my shader which is suppose to be a per-pixel lighting shader.
//Vertex Shader
varying vec3 lightDir,normal;

void main()
{
normal = normalize(gl_NormalMatrix * gl_Normal);

lightDir = normalize(vec3(gl_LightSource[0].position));
gl_TexCoord[0] = gl_MultiTexCoord0;

gl_Position = ftransform();
}


//Fragment Shader
varying vec3 lightDir,normal;
uniform sampler2D tex;

void main()
{
vec3 ct,cf;
vec4 texel;
float intensity,at,af;
intensity = max(dot(lightDir,normalize(normal)),0.0);

cf = intensity * (gl_FrontMaterial.diffuse).rgb +
gl_FrontMaterial.ambient.rgb;
af = gl_FrontMaterial.diffuse.a;
texel = texture2D(tex,gl_TexCoord[0].st);

ct = texel.rgb;
at = texel.a;
gl_FragColor = vec4(ct * cf, at * af);

}


And without the shaders enabled, my 3DS loaded appears as bright as it can be. The second problem is even if I have my shaders on, if I change the position of light0, they stop working, as in my object gets an ambient shade of light. It might be a problem with how I calculate normals which I borrowed from an example but I am not sure...
typedef struct{
float x,y,z;
}vertex_type;

vertex_type CalcNormal(vertex_type v1, vertex_type v2, vertex_type v3)
{
double v1x,v1y,v1z,v2x,v2y,v2z;
double nx,ny,nz;
double vLen;

vertex_type Result;

// Calculate vectors
v1x = v1.x - v2.x;
v1y = v1.y - v2.y;
v1z = v1.z - v2.z;

v2x = v2.x - v3.x;
v2y = v2.y - v3.y;
v2z = v2.z - v3.z;

// Get cross product of vectors
nx = (v1y * v2z) - (v1z * v2y);
ny = (v1z * v2x) - (v1x * v2z);
nz = (v1x * v2y) - (v1y * v2x);

// Normalise final vector
vLen = sqrt( (nx * nx) + (ny * ny) + (nz * nz) );

Result.x = (float)(nx / vLen);
Result.y = (float)(ny / vLen);
Result.z = (float)(nz / vLen);

return Result;
}

Share this post


Link to post
Share on other sites
Advertisement
Update: The lights stop working as soon as I change the z position even if it is set to 0 but x and y can be set without anything happening.

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!