hi,
as i notice that fttransform() method get the vertex position based on world position. is that right? so if i want to get camera direction (normalized) can i just call
vec3 camDirection = normalized(v);
or are there other way?
thanks in advance
camera direction on GLSL
Your question doesn't make any sense.
ftransform() is the equivalent of
outVertex = ProjectionMatrix * ModelViewMatrix * inVertex
What is "v" in your equation? What does it have to do with ftransform?
ftransform() is the equivalent of
outVertex = ProjectionMatrix * ModelViewMatrix * inVertex
What is "v" in your equation? What does it have to do with ftransform?
Author
ah ok i miss a line why copying it. the previous line i define v as:
vec3 v = ftransform();
and my OnReshape function, if its important, looks like this
can i just simply do normalize(v) to get the camera direction from vertex? i want to use this as specular calculation, and calculate this direction value to find the half vector.
EDIT:
ok here is what i wanna do: i want to get the camera position relative to the vertex position, using spherical coordinate system. here is the code that i put on the vertex shader:
now i have to switch the y and z value since my up is y and the formula around the net is for up=z. but im not getting the right value. did you notice anything wrong on my code?
thanks in advance
[Edited by - svnstrk on October 17, 2010 8:10:05 PM]
vec3 v = ftransform();
and my OnReshape function, if its important, looks like this
void onReshape(int w, int h) { glViewport (0, 0, (GLsizei) w, (GLsizei) h); glMatrixMode (GL_PROJECTION); glLoadIdentity (); gluPerspective(60.0, (GLdouble) width/(GLdouble) height, 1.0, 100.0); glGetDoublev(GL_PROJECTION_MATRIX, projectionMatrix); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glGetDoublev(GL_MODELVIEW_MATRIX, lookAtMatrix);}can i just simply do normalize(v) to get the camera direction from vertex? i want to use this as specular calculation, and calculate this direction value to find the half vector.
EDIT:
ok here is what i wanna do: i want to get the camera position relative to the vertex position, using spherical coordinate system. here is the code that i put on the vertex shader:
void main(){ vec3 spherical; gl_TexCoord[0] = gl_MultiTexCoord0; gl_Position = ftransform(); vec3 v = gl_Position.xyz; vec3 cameraPos; cameraPos.x = cameraPosX; cameraPos.y = cameraPosY; cameraPos.z = cameraPosZ; // ftransform get the position //vec3 cameraDir = normalize(cameraPos - v); vec3 ecPos = gl_ModelViewMatrix * gl_Vertex; //vec3 cameraDir = normalize(cameraPos - ecPos); vec3 cameraDir = normalize(-1.0 * v); spherical.x = sqrt((cameraDir.x*cameraDir.x) + (cameraDir.y*cameraDir.y) + (cameraDir.z*cameraDir.z)); spherical.y = acos(cameraDir.y/spherical.x); spherical.z = atan(cameraDir.z, cameraDir.x); sphIndexY = spherical.y * 180.0/(3.14159); sphIndexZ = spherical.z * 180.0/(3.14159); if (sphIndexY < 0) { sphIndexY = sphIndexY * -1.0; } if (sphIndexZ < 0) { sphIndexZ = sphIndexZ * -1.0; }}now i have to switch the y and z value since my up is y and the formula around the net is for up=z. but im not getting the right value. did you notice anything wrong on my code?
thanks in advance
[Edited by - svnstrk on October 17, 2010 8:10:05 PM]
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